ORCID Profile
0000-0003-0694-4283
Current Organisation
University of Melbourne
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Fisheries Sciences | Animal Nutrition | Aquaculture | Aquaculture | Animal Nutrition | Food Chemistry and Molecular Gastronomy (excl. Wine)
Fish | Aquaculture | Food safety | Oils and fats (incl. margarines) | Aquaculture Fin Fish (excl. Tuna) |
Publisher: Cambridge University Press (CUP)
Date: 03-08-2015
DOI: 10.1017/S0007114515002457
Abstract: The effects of krill oil as an alternative source of n -3 long-chain PUFA have been investigated recently. There are conflicting results from the few available studies comparing fish oil and krill oil. The aim of this study was to compare the bioavailability and metabolic fate (absorption, β -oxidation and tissue deposition) of n -3 fatty acids originating from krill oil (phospholipid-rich) or fish oil (TAG-rich) in rats of both sexes using the whole-body fatty acid balance method. Sprague–Dawley rats (thirty-six male, thirty-six female) were randomly assigned to be fed either a krill oil diet (EPA+DHA+DPA=1·38 mg/g of diet) or a fish oil diet (EPA+DHA+DPA=1·61 mg/g of diet) to constant ration for 6 weeks. The faeces, whole body and in idual tissues were analysed for fatty acid content. Absorption of fatty acids was significantly greater in female rats and was only minimally affected by the oil type. It was estimated that most of EPA ( %) and more than half of DHA ( %) were β -oxidised in both diet groups. Most of the DPA was β -oxidised (57 and 67 % for female and male rats, respectively) in the fish oil group however, for the krill oil group, the majority of DPA was deposited (82–83 %). There was a significantly greater deposition of DPA and DHA in rats fed krill oil compared with those fed fish oil, not due to a difference in bioavailability (absorption) but rather due to a difference in metabolic fate (anabolism v. catabolism).
Publisher: Wiley
Date: 16-08-2007
DOI: 10.1007/S11745-007-3105-X
Abstract: Currently there are several contrasting methods utilized for estimating elongation and desaturation of fatty acids and their general metabolism. The majority of these methods involve an ex vivo approach, requiring expensive and sophisticated equipment, likely to result in considerable variation in enzyme activity between and within species. In the present paper we introduce a further development of the whole-body fatty acid balance method for the estimation of the elongation and desaturation of fatty acids. This method though receiving considerable attention because of its simplicity and reliability has yet to be presented in detail. Theoretically, the whole-body fatty acid balance method can potentially be applied to any organism and requires little more than a gas chromatography unit for fatty acid analysis and elementary calculations. As such in this paper we attempt to spell out in detail the theoretical basis and the methods of application drawing specific ex les. Using the present method it is possible to measure the fate of in idual fatty acids towards desaturation, elongation and oxidation and calculate the elongase, Delta-6 desaturase and Delta-5 desaturase activities.
Publisher: Springer Science and Business Media LLC
Date: 05-12-2012
DOI: 10.1007/S10695-012-9753-7
Abstract: Monounsaturated fatty acids (MUFA)-rich and n-6 polyunsaturated fatty acid (n-6 PUFA)-rich vegetable oils are increasingly used as fish oil replacers for aquafeed formulation. The present study investigated the fatty acid metabolism in juvenile European sea bass (Dicentrarchus labrax, 38.4 g) fed diets containing fish oil (FO, as the control treatment) or two different vegetable oils (the MUFA-rich canola/rapeseed oil, CO and the n-6 PUFA-rich cottonseed oil, CSO) tested in idually or as a 50/50 blend (CO/CSO). The whole-body fatty acid balance method was used to deduce the apparent in vivo fatty acid metabolism. No effect on growth performance and feed utilization was recorded. However, it should be noted that the fish meal content of the experimental diets was relatively high, and thus the requirement for n-3 long-chain polyunsaturated fatty acid (n-3 LC-PUFA) may have likely been fulfilled even if dietary fish oil was fully replaced by vegetable oils. Overall, relatively little apparent in vivo fatty acid bioconversion was recorded, whilst the apparent in vivo β-oxidation of dietary fatty acid was largely affected by the dietary lipid source, with higher rate of β-oxidation for those fatty acids which were provided in dietary surplus. The deposition of 20:5n-3 and 22:6n-3, as % of the dietary intake, was greatest for the fish fed on the CSO diet. It has been shown that European sea bass seems to be able to efficiently use n-6 PUFA for energy substrate, and this may help in minimizing the β-oxidation of the health benefiting n-3 LC-PUFA and thus increase their deposition into fish tissues.
Publisher: Public Library of Science (PLoS)
Date: 15-04-2015
Publisher: Hindawi Limited
Date: 04-04-2012
Publisher: Elsevier BV
Date: 12-2011
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 11-2010
Publisher: American Public Health Association
Date: 11-2013
Publisher: Springer Science and Business Media LLC
Date: 27-10-2008
Publisher: Public Library of Science (PLoS)
Date: 11-09-2013
Publisher: American Chemical Society (ACS)
Date: 11-12-2009
DOI: 10.1021/JF801962H
Abstract: The development of traceability methods to distinguish between farmed and wild-caught fish and seafood is becoming increasingly important. However, very little is known about how to distinguish fish originating from different farms. The present study addresses this issue by attempting to discriminate among intensively farmed freshwater Murray cod originating from different farms (indoor recirculating, outdoor floating cage, and flow through systems) in different geographical areas, using a combination of morphological, chemical, and isotopic analyses. The results show that stable isotopes are the most informative variables. In particular, delta(13)C and/or delta(15)N clearly linked fish to a specific commercial diet, while delta(18)O linked fish to a specific water source. Thus, the combination of these isotopes can distinguish among fish originating from different farms. On the contrary, fatty acid and tissue proximate compositions and morphological parameters, which are useful in distinguishing between farmed and wild fish, are less informative in discriminating among fish originating from different farms.
Publisher: Hindawi Limited
Date: 10-06-2013
DOI: 10.1111/ANU.12046
Publisher: Hindawi Limited
Date: 08-2013
DOI: 10.1111/ANU.12045
Publisher: American Chemical Society (ACS)
Date: 17-04-2009
DOI: 10.1021/JF900094W
Abstract: Dietary fatty acids are known to modulate fatty acid metabolism in fish. However, the innate capability of fish to bioconvert short chain fatty acids to health promoting long chain fatty acids (LCPUFA) is insufficient to compensate for a reduced dietary intake. While many studies have focused on the dietary regulation of the fatty acid bioconversion pathways, there is little known regarding the effects of the dietary levels of C(18) polyunsaturated fatty acids (PUFA) on fatty acid metabolism. Here, we show a greater degree of apparent enzyme activity (Δ-6 desaturase) in fish fed a diet with higher amounts of dietary C(18) PUFA. In particular, fish receiving high amounts of dietary C(18) PUFA had a greater amount of Δ-6 desaturase activity acting on 18:3n-3 than 18:2n-6. However, with the gradual reduction of dietary C(18) PUFA there was a shift in substrate preference of Δ-6 desaturase from 18:3n-3 to 18:2n-6. This information will provide valuable insight for the implementation of low fish oil diets, which permit the maintenance of n-3 LCPUFA levels in farmed Murray cod.
Publisher: Elsevier BV
Date: 02-2010
Publisher: Hindawi Limited
Date: 03-07-2003
Publisher: Elsevier BV
Date: 11-2020
Publisher: Wiley
Date: 14-08-2019
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 10-2014
Publisher: Informa UK Limited
Date: 03-2019
DOI: 10.1080/10408398.2018.1425978
Abstract: The health benefits of fish oil, and its omega-3 long chain polyunsaturated fatty acid content, have attracted much scientific attention in the last four decades. Fish oils that contain higher amounts of eicosapentaenoic acid (EPA 20:5n-3) than docosahexaenoic acid (DHA 22:6n-3), in a distinctive ratio of 18/12, are typically the most abundantly available and are commonly studied. Although the two fatty acids have traditionally been considered together, as though they were one entity, different physiological effects of EPA and DHA have recently been reported. New oils containing a higher quantity of DHA compared with EPA, such as fractionated and concentrated fish oil, tuna oil, calamari oil and microalgae oil, are increasingly becoming available on the market, and other oils, including those extracted from genetically modified oilseed crops, soon to come. This systematic review focuses on the effects of high DHA fish oils on various human health conditions, such as the heart and cardiovascular system, the brain and visual function, inflammation and immune function and growth/Body Mass Index. Although inconclusive results were reported in several instances, and inconsistent outcomes observed in others, current data provides substantiated evidence in support of DHA being a beneficial bioactive compound for heart, cardiovascular and brain function, with different, and at times complementary, effects compared with EPA. DHA has also been reported to be effective in slowing the rate of cognitive decline, while its possible effects on depression disorders are still unclear. Interestingly, gender- and age- specific ergent roles for DHA have also been reported. This review provides a comprehensive collection of evidence and a critical summary of the documented physiological effects of high DHA fish oils for human health.
Publisher: Wiley
Date: 10-02-2009
Publisher: Elsevier BV
Date: 03-2016
Publisher: Wiley
Date: 30-12-2015
DOI: 10.1007/S11745-014-3970-Z
Abstract: Whilst aquaculture feed is increasingly formulated with the inclusion of plant oils replacing fish oil, and increasing research effort has been invested in understanding the metabolic effects of reduced dietary n-3 long chain poly unsaturated fatty acids (n-3 LC-PUFA), relatively little information is available on the potential direct metabolic roles of dietary alpha-linolenic acid (ALA, 18:3n-3) and alpha-linolenic acid/linoleic acid (LNA, 18:2n-6) ratio in cultured marine finfish species. In this study, four plant oil based diets, with varying ALA/LNA ratio (0.0, 0.5, 1.0 and 1.5) were fed to juvenile large yellow croakers (Larimichthys crocea) and compared to a fish oil-based control diet (CD) to evaluate the resulting effects on growth, nonspecific immunity, anti-oxidant capacity and related gene expression. High dietary LNA negatively impacted fish growth performance, nonspecific immunity and antioxidant capacity, but growth and immunity were maintained to levels comparable to CD by increasing the ratio of dietary ALA/LNA. The over-expression of genes associated with inflammation (cyclooxygenase-2 and interleukin-1β) and fatty acid oxidation (carnitine palmitoyl transferase I and acyl CoA oxidase) in croakers fed high concentrations of LNA were reduced to levels comparable to those fed CD by increasing dietary ALA/LNA. This study showed that dietary ALA, by increasing the overall n-3/n-6 PUFA ratio, exerts direct anti-inflammatory and antioxidant effects, similar to those exerted by dietary n-3 LC-PUFA.
Publisher: Elsevier BV
Date: 10-2018
Publisher: Wiley
Date: 14-06-2016
DOI: 10.1007/S11745-016-4167-4
Abstract: A two part experiment was conducted to assess the response of barramundi (Lates calcarifer initial weight = 10.3 ± 0.03 g mean ± S.D.) fed one of five diets with varying eicosapentaenoic acid (diets 1, 5, 10, 15 and 20 g/kg) or one of four diets with varying arachidonic acid (1, 6, 12, 18 g/kg) against a fish oil control diet. After 6 weeks of feeding, the addition of EPA or ARA did not impact on growth performance or feed utilisation. Analysis of the whole body fatty acids showed that these reflected those of the diets. The ARA retention demonstrated an inversely related curvilinear response to either EPA or ARA. The calculated marginal utilisation efficiencies of EPA and ARA were high (62.1 and 91.9 % respectively) and a dietary ARA requirement was defined (0.012 g/kg(0.796)/day). The partial cDNA sequences of genes regulating eicosanoid biosynthesis were identified in barramundi tissues, namely cyclooxygenase 1 (Lc COX1a, Lc COX1b), cyclooxygenase 2 (Lc COX2) and lipoxygenase (Lc ALOX-5). Both Lc COX2 and Lc ALOX-5 expression in the liver tissue were elevated in response to increasing dietary ARA, meanwhile expression levels of Lc COX2 and the mitochondrial fatty acid oxidation gene carnitine palmitoyltransferase 1 (Lc CPT1a) were elevated in the kidney. A low level of EPA increased the expression of Lc COX1b in the liver. Consideration should be given to the EPA to ARA balance for juvenile barramundi in light of nutritionally inducible nature of the cyclooxygenase and lipoxygenase enzymes.
Publisher: Elsevier BV
Date: 04-2012
Publisher: Elsevier BV
Date: 11-2018
Publisher: Inter-Research Science Center
Date: 08-2018
DOI: 10.3354/AEI00274
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.PLEFA.2013.10.001
Abstract: Based on the results from a human study which showed significantly reduced incorporation of DPA compared with EPA into chylomicrons, this study was designed to test if dietary DPA was significantly less absorbed than EPA. Male Sprague Dawley rats were randomly assigned to three groups of six, and were fed a semi-synthetic high fat diet (23.5% fat) for 9 days. The test omega 3 fatty acids (EPA and DPA, 250mg/animal/day, free fatty acid form) or olive oil (250mg/animal/day) were added to the high fat diet on days 5, 6 and 7. Dietary EPA and DPA appeared in the faeces on days 6, 7 and 8, with the total amount of DPA excreted being 4.6-fold greater than that of EPA. The total amount of faecal fat did not differ significantly between the groups. At the conclusion of the study (day 9), it was found that liver DPA, EPA and total n-3 LC-PUFA levels were significantly increased by both DPA and EPA feeding compared with the olive oil fed control group. In the heart, DPA feeding increased the DPA content and both DPA and EPA feeding increased the total n-3 LC-PUFA levels. This study showed that DPA and EPA, both provided in free form, are metabolised differently, despite being chemically similar.
Publisher: Cambridge University Press (CUP)
Date: 22-06-2020
DOI: 10.1017/S0007114520002214
Abstract: Aquafeeds for carnivorous species face a nutritional–technological conundrum: containing sufficient starch to meet specific manufacturing requirements for binding, extrusion and expansion, but ideally containing as little starch as possible owing to their limited ability to utilise carbohydrates. The present study evaluated the effects of dietary starch with different amylose to amylopectin ratios and resistant starch contents on growth performance, hepatic glycogen accumulation and glucose metabolism of an important cultured carnivorous finfish, largemouth bass ( Micropterus salmoides ). A common starch source ( α -cassava starch (CS)) was tested as is or after being enzymatically de-branched at three different inclusion levels in diets for largemouth bass. Results showed that the increased dietary starch levels compromised performance and high dietary α -CS content led to obvious liver damage. However, the growth performances of fish fed the diets with de-branched starch (DS) were improved, and no manifest liver damages were observed even at the higher inclusion level. The increasing dietary starch contents significantly increased hepatic glycogen accumulation, but not when DS was used. High dietary starch content, without regard to starch sources, had no effect on the expression of glucose metabolism-related genes, except for down-regulation of insulin receptor expression. However, the use of dietary DS promoted the expression of genes involved in the insulin pathway and glycolysis. In conclusion, this study showed that the use of starch sources with a high amylose to amylopectin ratio and resistant starch in the feed for cultured carnivorous finfish could alleviate the hepatic glycogen deposition through regulating the insulin pathway and glycolysis.
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.CBPB.2006.01.013
Abstract: The whole-body fatty acid balance method was used to investigate the fatty acid metabolism in Murray cod (Maccullochella peelii peelii) fed diets containing canola (CO) or linseed oil (LO). Murray cod were able to elongate and desaturate both 18:2n-6 and 18:3n-3. In fish fed the CO diet, 54.4% of the 18:2n-6 consumed was accumulated, 38.5% oxidized and 6.4% elongated and desaturated to higher homologs. Fish fed the LO diet accumulated 52.9%, oxidized 37% and elongated and desaturated 8.6% of the consumed 18:3n-3. The overall roles of n-6 fatty acids appeared more important in Murray cod compared to other freshwater species. Murray cod also showed a preferential order of utilization of C18 fatty acid for energy production (18:3n-3 > 18:2n-6 > 18:1n-9). Moreover, it is demonstrated that an increase in dietary 18:3n-3 is directly responsible of increased desaturase activity and augmented saturated fatty acid accumulation in the fish body. The present study also suggests that, in the context of the possible maximization of the natural ability of fish to produce long chain polyunsaturated fatty acids, the whole-body approach can be considered well suited and informative and Murray cod is a suited candidate to fish oil replacement for its diets.
Publisher: MDPI AG
Date: 18-01-2020
DOI: 10.3390/NU12010248
Abstract: Docosahexaenoic acid (DHA) is an essential component for brain and visual acuity development during foetal and early postnatal life. A newly released directive under the European Commission stipulates DHA as a mandatory ingredient in infant formula. This poses challenges to manufacturers in preserving the stability and bioavailability of DHA at levels akin to human breast milk. The aims of this study were (a) to investigate the bioavailability of microencapsulated omega-3 DHA formulations in healthy toddlers compared with high DHA fish oil for a one-month period and (b) to assess the effect of DHA supplementation on children’s sleep and cry patterns. Sixty toddlers were randomly allocated to four groups: 1. unfortified formula, 2. unfortified formula plus high DHA tuna oil, 3. fortified formula with dairy-based microencapsulated high DHA tuna oil powder, and 4. fortified formula with allergenic-free microencapsulated high DHA tuna oil powder. Bioavailability was assessed from both blood and faecal fatty acid levels. The results showed an enhanced bioavailability with significantly greater concentrations of blood DHA levels in formulas with microencapsulated powders. There were no significant effects of treatment on sleep and cry patterns. Application and delivery of microencapsulated DHA tuna oil powder in toddlers’ formula provided better bioavailability of the active DHA.
Publisher: Elsevier BV
Date: 2011
Publisher: Hindawi Limited
Date: 04-02-2023
DOI: 10.1155/2023/1676340
Abstract: Australian abalone aquaculture is characterised by a prolonged culture period and slow and variable growth, and abalone is cultured in fluctuating water temperatures ranging between 10 and 25°C with distinct seasons. Temperature is a crucial environmental factor influencing abalone’s physiology and energetics, leading to a change in nutritional requirements. However, feeds are generally formulated to match the nutritional requirements at their optimal temperature. Hence, there is a need to optimise dietary protein levels to match temperature-specific requirements during extreme conditions (winter and summer). Given this, a growth trial evaluating five experimental feeds consisting of graded protein inclusion levels (320, 350, 380, 410, and 440 g·kg−1) was conducted on subadult hybrid abalone (Haliotis rubra × H. laevigata) at three different temperatures reflecting winter (12°C), summer (22°C), and the annual average water temperature (17°C) for 143 days. At lower water temperature (12°C), there was a marginal improvement in growth performance as dietary protein levels increased from 320 to 440 g·kg−1. However, at higher water temperatures (when the culture water temperature is above 17°C), there was a significant improvement in growth performance as dietary protein levels increased from 320 to 440 g·kg−1 as evidenced by an improved weight gain, specific growth rate, and feed conversion ratio. Furthermore, increasing dietary protein levels did not compromise the nutritional quality of the abalone tissue at all three tested temperatures. Therefore, during periods of higher water temperatures, feeding Australian hybrid abalone with a relatively high dietary protein level (410 g·kg−1) is expected to result in improved growth, shorter culture duration, and profit maximisation.
Publisher: MDPI AG
Date: 10-07-2015
DOI: 10.3390/NU7075241
Publisher: Wiley
Date: 11-11-2018
DOI: 10.1002/NAAQ.10067
Publisher: Informa UK Limited
Date: 2005
Publisher: Springer Science and Business Media LLC
Date: 2003
Publisher: Wiley
Date: 19-11-2007
Publisher: Hindawi Limited
Date: 30-11-2017
DOI: 10.1111/ANU.12389
Publisher: Cambridge University Press (CUP)
Date: 04-03-2010
DOI: 10.1017/S0007114510000541
Abstract: The present study was conducted to evaluate the effect of different dietary lipid sources, age and sex on the SFA and MUFA metabolism in broiler chickens using a whole body fatty acid balance method. Four dietary lipid sources (palm fat, Palm soyabean oil, Soya linseed oil, Lin and fish oil, Fish) were added at 3 % to a basal diet containing 5 % Palm. Diets were fed to female and male chickens from day 1 to either day 21 or day 42 of age. The accumulation (percentage of net intake and ex novo production) of SFA and MUFA was significantly lower in broilers fed on Palm than in broilers fed on the other diets (85·7 v. 97·4 %). Conversely, β-oxidation was significantly higher in Palm-fed birds than the average of the other dietary treatments (14·3 v. 2·6 %). On average, 33·1 % of total SFA and MUFA accumulated in the body were elongated, and 13·8 % were Δ-9 desaturated to longer chain or more unsaturated metabolites, with lower proportions being elongated and desaturated for the Palm and Fish diets than for the Soya and Lin diets. Total in vivo apparent elongase activity decreased exponentially in relation to the net intake of SFA and MUFA, while it increased with age. Total in vivo apparent Δ-9 desaturase activity was not significantly affected by dietary treatment or age. Total ex novo production and β-oxidation of SFA and MUFA showed a negative and positive curvilinear relationship with net intake of SFA and MUFA, respectively. Sex had no effect on SFA and MUFA metabolism.
Publisher: Elsevier BV
Date: 2015
Publisher: Frontiers Media SA
Date: 2014
Publisher: Cambridge University Press (CUP)
Date: 05-03-2019
DOI: 10.1017/S0007114519000473
Abstract: A more efficient utilisation of marine-derived sources of dietary n -3 long-chain PUFA ( n -3 LC PUFA) in cultured Atlantic salmon ( Salmo salar L.) could be achieved by nutritional strategies that maximise endogenous n -3 LC PUFA synthesis. The objective of the present study was to quantify the extent of n -3 LC PUFA biosynthesis and the resultant effect on fillet nutritional quality in large fish. Four diets were manufactured, providing altered levels of dietary n -3 substrate, namely, 18 : 3 n -3, and end products, namely, 20 : 5 n -3 and 22 : 6 n -3. After 283 d of feeding, fish grew in excess of 3000 g and no differences in growth performance or biometrical parameters were recorded. An analysis of fatty acid composition and in vivo metabolism revealed that endogenous production of n -3 LC PUFA in fish fed a diet containing no added fish oil resulted in fillet levels of n -3 LC PUFA comparable with fish fed a diet with added fish oil. However, this result was not consistent among all treatments. Another major finding of this study was the presence of abundant dietary n -3 substrate, with the addition of dietary n -3 end product (i.e. fish oil) served to increase final fillet levels of n -3 LC PUFA. Specifically, preferential β -oxidation of dietary C 18 n -3 PUFA resulted in conservation of n -3 LC PUFA from catabolism. Ultimately, this study highlights the potential for endogenous synthesis of n -3 LC PUFA to, partially, support a substantial reduction in the amount of dietary fish oil in diets for Atlantic salmon reared in seawater.
Publisher: Elsevier BV
Date: 2016
Publisher: Springer Science and Business Media LLC
Date: 29-11-2013
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 09-2007
Publisher: Elsevier BV
Date: 05-2011
Publisher: Elsevier BV
Date: 02-2020
Publisher: Cambridge University Press (CUP)
Date: 03-2010
DOI: 10.1017/S0007114510000395
Abstract: The PUFA metabolism in broiler chicken was studied through the whole body fatty acid balance method. Four dietary lipid sources (palm fat, Palm soyabean oil, Soya linseed oil, Lin fish oil, Fish) were added at 3 % to a basal diet containing 5 % palm fat. Diets were fed to female and male birds from day 1 to either day 21 or day 42 of age. Birds fed the Lin diet showed a significantly higher 18 : 2 n- 6 accumulation compared with the other diets (85·2 v. 73·6 % of net intake), whereas diet did not affect 18 : 3 n- 3 accumulation (mean 63 % of net intake). Bioconversion of 18 : 2 n- 6 significantly decreased in the order Palm Lin Soya Fish (4·7, 3·9, 3·4 and 1 % of net intake, respectively). The 18 : 3 n- 3 bioconversion on the Palm and Soya diets was similar and significantly higher than in broilers on the Lin diet (9·1 v. 5·8 % of net intake). The β-oxidation of 18 : 2 n- 6 was significantly lower on the Lin diet than on the other diets (10·8 v. 23·3 % of net intake), whereas β-oxidation of 18 : 3 n- 3 was significantly higher on the Fish diet than on the other diets (41·5 v. 27·3 % of net intake). Feeding fish oil suppressed apparent elongase and desaturase activity, whereas a higher dietary supply of 18 : 3 n- 3 and 18 : 2 n- 6 enhanced apparent elongation and desaturation activity on the PUFA involved in the n- 3 and n -6 pathway, respectively. Accumulation of 18 : 2 n- 6 and 18 : 3 n- 3 increased and β-oxidation decreased with age. Sex had a marginal effect on the PUFA metabolism.
Publisher: Elsevier BV
Date: 02-2017
Publisher: Wiley
Date: 30-12-2011
DOI: 10.1002/JEMT.21124
Abstract: In this study, we report ghrelin and leptin immunoreactive (ir) cells distribution in the gastrointestinal tract and blood ghrelin and leptin levels in rainbow trout (Oncorhynchus mykiss) and Murray cod (Maccullochella peelii peelii) fed diets with different fatty acid compositions. Juvenile rainbow trout and Murray cod were fed five iso-energetic experimental diets containing fish oil (FO) or one of the following vegetable oils (VO): olive oil (OO), sunflower oil (SO), linseed oil (LO), and palm oil (PO) as the added dietary lipid source. The presence and distribution of both ghrelin and leptin ir cells in the gastrointestinal tract were affected by the inclusion of VO. Ghrelin ir cells were found in the gastric glands of rainbow trout and in the mioenteric plexuses of the stomach of Murray cod fed FO. Ghrelin ir cells were localized in the mucosa of the intestine of rainbow trout and Murray cod fed VO. Leptin ir cells were more abundant in the epithelial lining of the mucosa folds and in the glands of the stomach of rainbow trout fed VO. Leptin immunoreactivity was detected in the gastric mioenteric plexus of Murray cod fed FO. No differences were found both in ghrelin and leptin levels in blood plasma or in the growth rates of rainbow trout and Murray cod fed the different experimental diets. These observations suggest that dietary fatty acids play a role in the peripheral feeding regulation.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Hindawi Limited
Date: 04-12-2021
DOI: 10.1111/ANU.13200
Publisher: Elsevier BV
Date: 03-2021
Publisher: Royal Swedish Academy of Sciences
Date: 02-2009
DOI: 10.1579/0044-7447-38.1.24
Abstract: Aquaculture is seen as an alternative to meeting the widening gap in global rising demand and decreasing supply for aquatic food products. Asia, the epicenter of the global aquaculture industry, accounts for over 90% of the global aquaculture production quantity and about 80% of the value. Asian aquaculture, as with global aquaculture, is dependent to a significant extent on alien species, as is the case for all the major food crops and husbanded terrestrial animals. However, voluntary and or accidental introduction of exotic aquatic species (alien species) is known to negatively impact local bio ersity. In this relatively young food production industry, mitigating the dependence on alien species, and thereby minimizing potential negative impacts on bio ersity, is an imperative for a sustainable future. In this context an attempt is made in this synthesis to understand such phenomena, especially with reference to Asian inland finfish, the mainstay of global aquaculture production. It is pointed out that there is potential for aquaculture, which is becoming an increasingly important food production process, not to follow the past path of terrestrial food crops and husbanded animals in regard to their negative influences on bio ersity.
Publisher: Hindawi Limited
Date: 04-2006
Publisher: Springer Science and Business Media LLC
Date: 2003
Publisher: Elsevier BV
Date: 03-2006
Publisher: Wiley
Date: 10-08-2014
DOI: 10.1007/S11745-014-3939-Y
Abstract: It is known that fatty acids (FA) regulate lipid metabolism by modulating the expression of numerous genes. In order to gain a better understanding of the effect of in idual FA on lipid metabolism related genes in rainbow trout (Oncorhynchus mykiss), an in vitro time-course study was implemented where twelve in idual FA (butyric 4:0 caprylic 8:0 palmitic (PAM) 16:0 stearic (STA) 18:0 palmitoleic16:1n-7 oleic 18:1n-9 11-cis-eicosenoic 20:1n-9 linoleic (LNA) 18:2n-6 α-linolenic (ALA) 18:3n-3 eicosapentenoic (EPA) 20:5n-3 docosahexaenoic (DHA) 22:6n-3 arachidonic (ARA) 20:4n-6) were incubated in rainbow trout liver slices. The effect of FA administration over time was evaluated on the expression of leptin, PPARα and CPT-1 (lipid oxidative related genes). Leptin mRNA expression was down regulated by saturated fatty acids (SFA) and LNA, and was up regulated by monounsaturated fatty acids (MUFA) and long chain PUFA, whilst STA and ALA had no effect. PPARα and CPT-1mRNA expression were up regulated by SFA, MUFA, ALA, ARA and DHA and down regulated by LNA and EPA. These results suggest that there are in idual and specific FA induced modifications of leptin, PPARα and CPT-1 gene expression in rainbow trout, and it is envisaged that such results may provide highly valuable information for future practical applications in fish nutrition.
Publisher: Hindawi Limited
Date: 10-2007
Publisher: Elsevier BV
Date: 03-2020
Publisher: American Chemical Society (ACS)
Date: 23-01-2007
DOI: 10.1021/JF062153X
Abstract: The aim of the present investigation was to quantify the fate of C18 and long chain polyunsaturated dietary fatty acids in the freshwater fish, Murray cod, using the in vivo, whole-body fatty acid balance method. Juvenile Murray cod were fed one of five iso-nitrogenous, iso-energetic, semipurified experimental diets in which the dietary fish oil (FO) was replaced (0, 25, 50, 75, and 100%) with a blended vegetable oil (VO), specifically formulated to match the major fatty acid classes [saturated fatty acids, monounsaturated fatty acids, n-3 polyunsaturated fatty acids (PUFA), and n-6 PUFA] of cod liver oil (FO). However, the PUFA fraction of the VO was dominated by C18 fatty acids, while C20/22 fatty acids were prevalent in the FO PUFA fraction. Generally, there was a clear reflection of the dietary fatty acid composition across each of the five treatments in the carcass, fillet, and liver. Lipid metabolism was affected by the modification of the dietary lipid source. The desaturation and elongation of C18 PUFAs increased with vegetable oil substitution, supported by the occurrence of longer and higher desaturated homologous fatty acids. However, increased elongase and desaturase activity is unlikely to fulfill the gap observed in fatty acid composition resulting from decreased highly unsaturated fatty acids intake.
Publisher: Cambridge University Press (CUP)
Date: 05-01-2009
DOI: 10.1017/S0007114508137874
Abstract: In consideration of economical and environmental concerns, fish oil (FO) substitution in aquaculture is the focus of many fish nutritionists. The most stringent drawback of FO replacement in aquafeeds is the consequential modification to the final fatty acid (FA) make-up of the fish fillet. However, it is envisaged that a solution may be achieved through a better understanding of fish FA metabolism. Therefore, the present study investigated the fate of in idual dietary FA in rainbow trout ( Oncorhynchus mykiss ) fed a FO-based diet (rich in 20 : 5 n -3) or a linseed oil-based diet (LO rich in 18 : 3 n -3). The study demonstrated that much of the 18 : 3 n -3 content from the LO diet was oxidised and, despite the significantly increased accretion of Δ-6 and Δ-5 desaturated FA, a 2- and 3-fold reduction in the fish body content of 20 : 5 n -3 and 22 : 6 n -3, respectively, compared with the FO-fed fish, was recorded. The accretion of longer-chain FA was unaffected by the dietary treatments, while there was a greater net disappearance of FA provided in dietary surplus. SFA and MUFA recorded a net accretion of FA produced ex novo . In the fish fed the FO diet, the majority of dietary 20 : 5 n -3 was accumulated (53·8 %), some was oxidised (14·7 %) and a large proportion (31·6 %) was elongated and desaturated up to 22 : 6 n -3. In the fish fed the LO diet, the majority of dietary 18 : 3 n -3 was accumulated (58·1 %), a large proportion was oxidised (29·5 %) and a limited amount (12·4 %) was bio-converted to longer and more unsaturated homologues.
Publisher: Elsevier BV
Date: 07-2011
Publisher: Springer Science and Business Media LLC
Date: 28-09-2013
DOI: 10.1007/S10695-013-9868-5
Abstract: Largely attributable to concerns surrounding sustainability, the utilisation of omega-3 long-chain polyunsaturated fatty acid-rich (n-3 LC-PUFA) fish oils in aquafeeds for farmed fish species is an increasingly concerning issue. Therefore, strategies to maximise the deposition efficiency of these key health beneficial fatty acids are being investigated. The present study examined the effects of four vegetable-based dietary lipid sources (linseed, olive, palm and sunflower oil) on the deposition efficiency of n-3 LC-PUFA and the circulating blood plasma concentrations of the appetite-regulating hormones, leptin and ghrelin, during the grow-out and finishing phases in rainbow trout culture. Minimal detrimental effects were noted in fish performance however, major modifications were apparent in tissue fatty acid compositions, which generally reflected that of the diet. These modifications diminished somewhat following the fish oil finishing phase, but longer-lasting effects remained evident. The fatty acid composition of the alternative oils was demonstrated to have a modulatory effect on the deposition efficiency of n-3 LC-PUFA and on the key endocrine hormones involved in appetite regulation, growth and feed intake during both the grow-out and finishing phases. In particular, n-6 PUFA (sunflower oil diet) appeared to 'spare' the catabolism of n-3 LC-PUFA and, as such, resulted in the highest retention of these fatty acids, ultimately highlighting new nutritional approaches to maximise the maintenance of the qualitative benefits of fish oils when they are used in feeds for aquaculture species.
Publisher: Elsevier BV
Date: 2019
Publisher: Wiley
Date: 11-03-2016
DOI: 10.1007/S11745-016-4136-Y
Abstract: Due to the scarcity of marine fish oil resources, the aquaculture industry is developing more efficient strategies for the utilization of dietary omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). A better understanding of how fish utilize EPA and DHA, typically provided by fish oil, is needed. However, EPA and DHA have different physiological functions, may be metabolized and incorporated into tissues differently, and may vary in terms of their importance in meeting the fatty acid requirements of fish. To address these questions, Atlantic salmon were fed experimental diets containing, as the sole added dietary lipid source, fish oil (positive control), tallow (negative control), or tallow supplemented with EPA, DHA, or both fatty acids to ~50 or 100% of their respective levels in the positive control diet. Following 14 weeks of feeding, the negative control diet yielded optimum growth performance. Though surprising, these results support the notion that Atlantic salmon requirements for n-3 LC-PUFA are quite low. EPA was largely β-oxidized and inefficiently deposited in tissues, and increasing dietary levels were associated with potential negative effects on growth. Conversely, DHA was completely spared from catabolism and very efficiently deposited into flesh. EPA bioconversion to DHA was largely influenced by substrate availability, with the presence of preformed DHA having little inhibitory effect. These results clearly indicate EPA and DHA are metabolized differently by Atlantic salmon, and suggest that the n-3 LC-PUFA dietary requirements of Atlantic salmon may be lower than reported and different, if originating primarily from EPA or DHA.
Publisher: Elsevier BV
Date: 02-2011
Publisher: Hindawi Limited
Date: 14-03-2003
Publisher: MDPI AG
Date: 10-07-2018
DOI: 10.3390/SU10072397
Publisher: Springer Science and Business Media LLC
Date: 10-07-2008
Publisher: Springer Science and Business Media LLC
Date: 03-08-2020
Publisher: Wiley
Date: 04-09-2011
DOI: 10.1007/S11745-011-3607-4
Abstract: Five experimental diets with constant total C(18) PUFA and varying 18:3n-3/18:2n-6 ratios were fed to rainbow trout over an entire production cycle. The whole-body fatty acid balance method demonstrated a clear trend of progressively reduced fatty acid bioconversion activity along the n-3 and n-6 pathways, up to the production of 20:5n-3 and 20:4n-6, respectively. This suggests that the pathway exhibits a "funnel like" progression of activity rather than the existence of a single rate limiting step. The production of 22:5n-3 and 22:6n-3 was more active than that of 20:5n-3. However, despite this trend in reduced apparent in vivo net enzyme activity, the efficiency of the various bioconversion steps (measured as % of bioconverted substrate) confirmed an opposing trend. A 3.2-fold higher Δ-6 desaturase affinity towards 18:3n-3 over 18:2n-6 and an 8-fold greater Δ-5 desaturase affinity towards 20:4n-3 over 20:3n-6 were recorded. The main results of the study were that (1) rainbow trout are quite efficient at bioconverting 18:3n-3 to 22:6n-3, and (2) the LC-PUFA biosynthetic pathway is substrate limited. Fillet n-3 LC-PUFA concentrations increased with the increasing dietary supply of 18:3n-3. Despite an almost identical dietary supply of n-3 LC-PUFA, originating from the fish meal fraction of the diets, the fillets of trout fed the diet richest in 18:3n-3 were 2-fold higher in n-3 LC-PUFA than fish fed low 18:3n-3 diets. Nevertheless, fillets of trout fed a fish oil control diet contained more than double the amount of n-3 LC-PUFA compared to fish fed the diets richest in 18:3n-3.
Publisher: Elsevier BV
Date: 02-2009
Publisher: Elsevier BV
Date: 04-2018
Publisher: American Chemical Society (ACS)
Date: 27-02-2012
DOI: 10.1021/JF204963W
Abstract: Fish oil replacement in aquaculture feeds results in major modifications to the fatty acid makeup of cultured fish. Therefore, in vivo fatty acid biosynthesis has been a topic of considerable research interest. Evidence suggests that pyridoxine (vitamin B(6)) plays a role in fatty acid metabolism, and in particular, the biosynthesis of LC-PUFA has been demonstrated in mammals. However, there is little information on the effects of dietary pyridoxine availability in fish fed diets lacking LC-PUFA. This study demonstrates a relationship between dietary pyridoxine supplementation and fatty acid metabolism in rainbow trout. In particular, the dietary pyridoxine level was shown to modulate and positively stimulate the activity of the fatty acid elongase and Δ-6 and Δ-5 desaturase enzymes, deduced by the whole-body fatty acid balance method. This activity was insufficient to compensate for a diet lacking in LC-PUFA but does highlight potential strategies to maximize this activity in cultured fish, especially when fish oil is replaced with vegetable oils.
Publisher: Hindawi Limited
Date: 06-04-2020
DOI: 10.1111/ARE.14622
Publisher: Springer Science and Business Media LLC
Date: 06-06-2019
Publisher: American Chemical Society (ACS)
Date: 11-09-2008
DOI: 10.1021/JF801286N
Abstract: The aim of this study was to determine the effects of starvation and water quality during the purging process on the biometric parameters, fatty acids, and flavor volatiles of Murray cod farmed in a recirculation system. Market size Murray cod, at the end of the grow-out stage, were ided into eight treatments. The treatments were either fed/starved (F or S) and kept in clean water (CW: CWF2, CWS2, CWF4, and CWS4) or fed/starved and kept in recycled water (RW: RWF2, RWS2, RWF4, and RWS4) for either 2 or 4 weeks. Fish were s led at 0, 2, and 4 week intervals. Food deprivation was responsible for a significant (P < 0.05) weight loss compared to that of fed treatments. The same was observed for the condition factor (K), hepatosomatic index (HSI), and dress-out percentage (DP). No significant changes were, however, observed in the visceral fat index (VFI). Saturated fatty acids (SFA) were highest in RWF4 and lowest in CWS4 (P < 0.05), while monounsaturated fatty acids (MUFA) were lowest in CWF4 (P < 0.05). Starvation did not affect the flavor volatile compounds, which were mainly affected by changes in water quality. Specifically, total aldehyde (% w/w) content was significantly (P < 0.05) affected by water quality, but the time of purging was not responsible for any noteworthy differences. This study was able to separate the effects of starvation and water quality, in the purging process, on the final eating quality of farmed market size Murray cod. It is concluded that because of the inevitable weight loss during starvation, Murray cod should be fed during the purging stage but kept in clean water and deprived of food only for the time necessary to empty the gastro-intestinal tract.
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.AQUATOX.2019.06.003
Abstract: Tamoxifen (TAM) is an antiestrogenic agent and can enter the aquatic environment in wastewater. It has been reported that TAM can induce hepatic steatosis in vertebrates, however, the effects of TAM exposure on lipid metabolism of hepatopancreas in crustaceans remains unclear. In this study, four TAM concentrations (0, 6.7, 13.4 and 20 μg g
Publisher: Elsevier BV
Date: 04-2008
Publisher: Public Library of Science (PLoS)
Date: 29-08-2014
Publisher: Elsevier BV
Date: 02-2014
Publisher: Springer Science and Business Media LLC
Date: 06-07-2010
Publisher: Hindawi Limited
Date: 03-09-2020
DOI: 10.1111/ANU.13146
Publisher: Elsevier BV
Date: 10-2011
Publisher: Cambridge University Press (CUP)
Date: 28-09-2015
DOI: 10.1017/S0007114515003529
Abstract: Barramundi ( Lates calcarifer ), a catadromous teleost of significant and growing commercial importance, are reported to have limited fatty acid bioconversion capability and therefore require preformed long-chain PUFA (LC-PUFA) as dietary essential fatty acid (EFA). In this study, the response of juvenile barramundi (47·0 g/fish initial weight) fed isolipidic and isoenergetic diets with 8·2 % added oil was tested. The experimental test diets were either devoid of fish oil (FO), and thus with no n -3 LC-PUFA (FO FREE diet), or with a low inclusion of FO (FO LOW diet). These were compared against a control diet containing only FO (FO CTRL diet) as the added lipid source, over an 8-week period. Interim s les and measurements were taken fortnightly during the trial in order to define the aetiology of the onset and progression of EFA deficiency. After 2 weeks, the fish fed the FO FREE and FO LOW diets had significantly lower live-weights, and after 8 weeks significant differences were detected for all performance parameters. The fish fed the FO FREE diet also had a significantly higher incidence of external abnormalities. The transcription of several genes involved in fatty acid metabolism was affected after 2 weeks of feeding, showing a rapid nutritional regulation. This experiment documents the aetiology of the onset and the progression of EFA deficiency in juvenile barramundi and demonstrates that such deficiencies can be detected within 2 weeks in juvenile fish.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 06-2011
Publisher: Central Fisheries Research Institute (SUMAE)
Date: 2012
Publisher: Oxford University Press (OUP)
Date: 24-03-2021
DOI: 10.1093/BJS/ZNAB101
Abstract: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351 best case 196, worst case 816) or non-cancer surgery (733 best case 407, worst case 1664). Both exceeded the NNV in the general population (1840 best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population.
Publisher: Elsevier BV
Date: 06-2011
Publisher: Central Fisheries Research Institute (SUMAE)
Date: 07-04-2021
DOI: 10.4194/1303-2712-V21_7_03
Abstract: This study assessed the potential of omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA) enrichment in red earthworm (Eisenia fetida, REW), via the addition of fish oil (FO, anchovy oil) to the culture-compost. FO addition to compost was tested at graded inclusion doses (0, 2.5, 5 and 10 g/100 g compost) and for different timeperiods, up to 96h. Dose, time, as well as dose and time interactions of FO compost enrichment had significant effects on all fatty acids of earthworm bodies. The enrichment with 10 g FO/100 g compost sharply increased DHA levels of the worms (14.01 mol%) within just 24 h, compared to the control group (0.92 mol%). Similar increases (ranging between 10.99 and 15.55 mol%) occurred only after 48 and 96 h in lower FO enrichment levels (2.5 and 5.0 g/100 g compost, respectively). Therefore, it was concluded that, to obtain maximum n-3 LC-PUFA enrichment efficiency in REW, an enrichment period of 24 h is ideal and recommended for the 10 g FO/ 100 g compost, whereas longer enrichment periods (48-96 h) are more suitable for lower levels of FO inclusions (2.5 or 5 g/100 g compost).
Publisher: Hindawi Limited
Date: 07-2009
Publisher: Hindawi Limited
Date: 10-2007
Publisher: Wiley
Date: 12-06-2015
DOI: 10.1002/JEMT.22528
Abstract: In this study, we report the distribution of orexin A (OXA), orexin B (OXB), and orexin receptor (OX2R) immunoreactive (ir) cells in the hypothalamus and gastrointestinal tract of Oncorhynchus mykiss fed diets with different dietary fatty acid compositions. Trout were fed five iso-energetic experimental diets containing fish oil, or one of four different vegetable oils (olive, sunflower, linseed, and palm oils) as the added dietary lipid source for 12 weeks. OXA, OXB, and OX2R immunoreactive neurons and nervous fibers were identified in the lateral and ventro-medial hypothalamus. OXA, OXB, and OX2R ir cells were found in the mucosa and glands of the stomach and in the mucosa of both the pyloric cecae and intestine. OX2R ir cells were localized in the mucosa layer of both the pyloric cecae and intestine. These immunohistochemical (IHC) results were confirmed via Western blotting. Antibodies against preproorexin (PPO) crossreacted with a band of ∼16 kDa in the hypothalamus, stomach, pyloric cecae, and intestine. Antibodies against OX2R crossreacted with a band of ∼38 kDa in the hypothalamus, pyloric cecae, and intestine. The presence and distribution of OXA, OXB, and OX2R ir cells in the hypothalamus and gastrointestinal tract did not appear to be affected by dietary oils. The presence of orexin system immunoreactive cells in the stomach, pyloric cecae, and intestine of rainbow trout, but not in the enteric nervous system, could suggest a possible role of these peptides as signaling of gastric emptying or endocrine modulation, implying a main local action played by orexins.
Publisher: Elsevier BV
Date: 2016
Publisher: Informa UK Limited
Date: 22-10-2020
Publisher: Public Library of Science (PLoS)
Date: 24-11-2015
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.CBPA.2016.06.028
Abstract: An experiment was conducted with barramundi (Asian seabass Lates calcarifer) to examine the allometric scaling effect of in idual fatty acids. Six treatment size classes of fish were deprived of food for 21days (Treatment A, 10.5±0.13g Treatment B, 19.2±0.11g Treatment C, 28.3±0.05g Treatment D, 122.4±0.10g Treatment E, 217.6±0.36g Treatment F, 443.7±1.48g mean±SD) with each treatment comprising of fifteen fish, in triplicate. The assessment of somatic losses of whole-body energy and lipid were consistent with previous studies, validating the methodology to be extended to in idual fatty acids. Live-weight (LW) exponent values were determined to be 0.817±0.010 for energy and 0.895±0.007 for lipid. There were significant differences among the fatty acids ranging from 0.687±0.005 for 20:5n-3 (eicosapentaenoic acid) and 0.954±0.008 for 18:1n-9 (oleic acid). The LW exponent values were applied to existing fatty acid intake and deposition data of barramundi fed with either 100% fish oil or 100% poultry oil. From this the maintenance requirement for each fatty acid was determined. The metabolic demands for maintenance and growth were then iteratively determined for fish over a range of size classes. Application of these exponent values to varying levels of fatty acid intake demonstrated that the biggest driver in the utilisation of fatty acids in this species is deposition demand and despite their reputed importance, the long-chain polyunsaturated fatty acids had nominal to no maintenance requirement.
Publisher: CRC Press
Date: 19-07-2011
Publisher: Elsevier BV
Date: 08-2012
Abstract: The implementation of alternative lipid sources for use in aquaculture is of considerable interest globally. However, the possible benefit of using stearidonic acid (SDA)-rich fish oil (FO) alternatives has led to scientific confusion. Two hundred and forty rainbow trout (Oncorhynchus mykiss) were fed 1 of 4 diets (3 replicate tanks/treatment) containing either FO, linseed oil (LO), echium oil, or mixed vegetable oil (72% LO, 23% sunflower oil, and 6% canola oil) as the dietary lipid source (16.5%) for 73 d to investigate the competition and long-chain PUFA (LC-PUFA) biosynthesis between the fatty acid substrates α-linolenic acid (ALA) and SDA. SDA was more efficiently bioconverted to LC-PUFA compared with ALA. However, when the dietary lipid sources were directly compared, the increased provision of C18 PUFA within the LO diet resulted in no significant differences in (n-3) LC-PUFA content compared with fish fed the other diets. This study therefore shows that, rather than the previously speculated substrate competition, the limiting process in the apparent in vivo (n-3) LC-PUFA biosynthesis appears to be substrate availability. Rainbow trout fed the SDA- and ALA-rich dietary lipid sources subsequently had similar significant reductions in (n-3) LC-PUFA compared with fish fed the FO diet, therefore providing no additional dietary benefit on (n-3) LC-PUFA concentrations.
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.FOODCHEM.2013.03.069
Abstract: Monola oil, a high oleic acid canola cultivar, and canola oil were evaluated as replacers of fish oil at three levels of inclusion (60%, 75% and 90%) in rainbow trout diets. After a 27-week grow-out cycle, the diet-induced effects on growth, fatty acid metabolism and final eating quality were assessed. Overall, no effects were noted for growth, feed utilisation or fish biometry, and the fatty acid composition of fish fillets mirrored that of the diets. Dietary treatments affected fillet lipid oxidation (free malondialdehyde), pigmentation and flavour volatile compounds, but only minor effects on sensorial attributes were detected. Ultimately, both oils were demonstrated to possess, to differing extents, suitable qualities to adequately replace fish oil from the perspective of fish performance and final product quality. However, further research is required to alleviate on-going issues associated with the loss of health promoting attributes (n-3 long chain polyunsaturated fatty acids) of final farmed products.
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.PLIPRES.2014.09.001
Abstract: This review considers the bioavailability of different forms of omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA), including ethyl esters (EEs), free fatty acids (FFAs), triacylglycerols (TAGs) and phospholipids (PLs). The retrieved studies include short-term and longer-term studies in humans, and a number of animal studies, which were highly heterogeneous in their design making it difficult to draw substantiated conclusions. The apparent bioavailability (as defined by the authors of these studies) seems to be lowest for the EE form and highest for the FFA form, whilst no conclusion can be made for TAG versus PL from human data. Animal studies suggest that there are substantial differences in the bioavailability of PL form of LC-PUFA compared with the TAG form. This apparent limited knowledge and understanding is fundamentally driven by methodological limitations of these studies. The major limitations with the studies to date include: (between studies) loose definition of the term "bioavailability", lack of standardisation of analytical methodology, and differences in which blood compartment was analysed (within a study) failure to provide equal amounts the n-3 LC-PUFA of the different forms being compared, failure to provide the dose of n-3 LC-PUFA on a body weight basis, failure to measure fatty acid excretion, failure to control the total fat intake, and failure to adequately power the studies from a statistical point of view. This review has laid out a set of suggestions and criteria for conducting future studies on the bioavailability of different chemical forms of n-3 LC-PUFA.
Publisher: Elsevier BV
Date: 2007
Publisher: American Chemical Society (ACS)
Date: 11-01-2011
DOI: 10.1021/JF104242Y
Abstract: Global shortages in fish oil are forcing the aquaculture feed industry to use alternative oil sources, the use of which negatively affects the final fatty acid makeup of cultured fish. Thus, the modulation of fatty acid metabolism in cultured fish is the core of an intensive global research effort. The present study aimed to evaluate the effects of various dietary α-linolenic acid (ALA, 18:3n-3)/linoleic acid (LA, 18:2n-6) ratios in cultured fish. A feeding trial was implemented on the freshwater finfish Murray cod, in which fish were fed either a fish oil-based control diet or one of five fish oil-deprived experimental diets formulated to contain an ALA/LA ratio ranging from 0.3 to 2.9, but with a constant total C₁₈ PUFA (ALA+LA) content. The whole-body fatty acid balance method was used to evaluate fish in vivo fatty acid metabolism. The results indicate that dietary ALA was more actively β-oxidized and bioconverted, whereas LA appears to be more efficiently deposited. LA was β-oxidized at a constant level (~36% of net intake) independent of dietary availability, whereas ALA was oxidized proportionally to dietary supply. The in vivo apparent Δ-6 desaturase activity on n-3 and n-6 PUFA exhibited an increasing and decreasing trend, respectively, in conjunction with the increasing dietary ALA/LA ratio, clearly indicating that this enzymatic activity is substrate dependent. However, the maximum Δ-6 desaturase activity acting on ALA peaked at the substrate level of 3.2186 (μmol g fish⁻¹ day⁻¹), suggesting that additional inclusion of ALA is not only wasteful but counterproductive in terms of n-3 LC-PUFA production. Despite a constant total supply of ALA+LA, the recorded total in vivo apparent Δ-6 desaturase activity on both substrates (ALA and LA) increased in synchrony with the ALA/LA ratio, peaking at 1.54, and a 3.2-fold greater Δ-6 desaturase affinity toward ALA over LA was recorded.
Publisher: Wiley
Date: 19-08-2008
Publisher: Informa UK Limited
Date: 09-2012
DOI: 10.1080/10408398.2010.509553
Abstract: Omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) are almost unanimously recognized for their health benefits, while only limited evidence of any health benefit is currently available specifically for the main precursor of these fatty acids, namely α-linolenic acid (ALA, 18:3n-3). However, both the n-3 LC-PUFA and the short-chain C₁₈ PUFA (i.e., ALA) are commonly referred to as "omega-3" fatty acids, and it is difficult for consumers to recognize this difference. A current gap of many food labelling legislations worldwide allow products containing only ALA and without n-3 LC-PUFA to be marketed as "omega-3 source" and this misleading information can negatively impact the ability of consumers to choose more healthy diets. Within the context of the documented nutritional and health promoting roles of omega-3 fatty acids, we briefly review the different metabolic fates of dietary ALA and n-3 LC-PUFA. We also review food sources rich in n-3 LC-PUFA, some characteristics of LC-PUFA and current industry and regulatory trends. A further objective is to present a case for regulatory bodies to clearly distinguish food products containing only ALA from foods containing n-3 LC-PUFA. Such information, when available, would then avoid misleading information and empower consumers to make a more informed choice in their food purchasing behavior.
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.ACA.2008.02.005
Abstract: The present study was conducted to characterize caviar obtained from farmed white sturgeons (Acipenser transmontanus) subjected to different dietary treatments. Twenty caviar s les from fish fed two experimental diets containing different dietary lipid sources have been analysed for chemical composition, fatty acids and flavour volatile compounds. Fatty acid make up of caviar was only minimally influenced by dietary fatty acid composition. Irrespective of dietary treatments, palmitic acid (16:0) and oleic acid (OA, 18:1 n-9) were the most abundant fatty acid followed by docosahexaenoic acid (DHA, 22:6 n-3) and eicopentaenoic (EPA, 20:5 n-3). Thirty-three volatile compounds were isolated using simultaneous distillation-extraction (SDE) and identified by GC-MS. The largest group of volatiles were represented by aldehydes with 20 compounds, representing the 60% of the total volatiles. n-Alkanals, 2-alkenals and 2,4-alkadienals are largely the main responsible for a wide range of flavours in caviar from farmed white surgeon.
Publisher: The Royal Society
Date: 09-2014
Abstract: The health benefits of diets containing rich sources of long-chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA) are well documented and include reductions in the risk of several diseases typical of Western societies. The dietary intake of n-3 LC-PUFA has also been linked to fertility, and there is abundant evidence that a range of ejaculate traits linked to fertility in humans, livestock and other animals depend on an adequate intake of n-3 LC-PUFA from dietary sources. However, relatively few studies have explored how n-3 LC-PUFA influence reproductive fitness, particularly in the context of sexual selection. Here, we show that experimental reduction in the level of n-3 LC-PUFA in the diet of guppies ( Poecilia reticulata ) depresses a male's share of paternity when sperm compete for fertilization, confirming that the currently observed trend for reduced n-3 LC-PUFA in western diets has important implications for in idual reproductive fitness.
Publisher: Springer Science and Business Media LLC
Date: 23-06-2013
DOI: 10.1007/S00394-012-0396-3
Abstract: Despite the detailed knowledge of the absorption and incorporation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) into plasma lipids and red blood cells (RBC) in humans, very little is known about docosapentaenoic acid (DPA, 22:5 n-3). The aim of this study was to investigate the uptake and incorporation of pure DPA and EPA into human plasma and RBC lipids. Ten female participants received 8 g of pure DPA or pure EPA in randomized crossover double-blinded manner over a 7-day period. The placebo treatment was olive oil. Blood s les were collected at days zero, four and seven, following which the plasma and RBC were separated and used for the analysis of fatty acids. Supplementation with DPA significantly increased the proportions of DPA in the plasma phospholipids (PL) (by twofold) and triacylglycerol (TAG) fractions (by 2.3-fold, day 4). DPA supplementation also significantly increased the proportions of EPA in TAG (by 3.1-fold, day 4) and cholesterol ester (CE) fractions (by 2.0-fold, day 7) and of DHA in TAG fraction (by 3.1-fold, day 4). DPA proportions in RBC PL did not change following supplementation. Supplementation with EPA significantly increased the proportion of EPA in the plasma CE and PL fractions, (both by 2.7-fold, day 4 and day 7) and in the RBC PL (by 1.9-fold, day 4 and day 7). EPA supplementation did not alter the proportions of DPA or DHA in any lipid fraction. These results showed that within day 4 of supplementation, DPA and EPA demonstrated different and specific incorporation patterns. The results of this short-term study suggest that DPA may act as a reservoir of the major long-chain n-3 fatty acids (LC n-3 PUFA) in humans.
Publisher: Hindawi Limited
Date: 12-2009
Publisher: Elsevier BV
Date: 11-2010
Publisher: Informa UK Limited
Date: 11-12-2010
Publisher: Wiley
Date: 29-03-2015
DOI: 10.1111/JFB.12661
Abstract: Using the polyandrous livebearing guppy Poecilia reticulata, this study revealed no main effects of carotenoids in the diet on ejaculate traits, but significant main effects of polyunsaturated fatty acids (PUFAs) on sperm viability and weak but significant interacting effects of both nutrients on sperm length. Collectively, these findings not only add evidence that PUFAs are critical determinants of sperm quality, but also provide tentative evidence that for some traits these effects may be moderated by carotenoid intake.
Location: Australia
Location: Australia
Location: Australia
Start Date: 2007
End Date: 06-2010
Amount: $265,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2019
End Date: 12-2024
Amount: $339,300.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2010
End Date: 03-2015
Amount: $340,566.00
Funder: Australian Research Council
View Funded Activity