ORCID Profile
0000-0002-4829-6926
Current Organisation
Deakin University - Warrnambool Campus
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Aquaculture | Fisheries Sciences | Animal Nutrition | Food Chemistry and Molecular Gastronomy (excl. Wine)
Publisher: Hindawi Limited
Date: 04-12-2021
DOI: 10.1111/ANU.13200
Publisher: Hindawi Limited
Date: 21-02-2021
DOI: 10.1111/ANU.13243
Publisher: Springer Science and Business Media LLC
Date: 11-09-2023
Publisher: Hindawi Limited
Date: 04-2006
Publisher: Elsevier BV
Date: 03-2006
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: Wiley
Date: 10-04-2018
DOI: 10.1111/GCB.14116
Abstract: Ocean warming (OW) and ocean acidification (OA) are threatening coral reef ecosystems, with a bleak future forecast for reef-building corals, which are already experiencing global declines in abundance. In contrast, many coral reef sponge species are able to tolerate climate change conditions projected for 2100. To increase our understanding of the mechanisms underpinning this tolerance, we explored the lipid and fatty acid (FA) composition of four sponge species with differing sensitivities to climate change, experimentally exposed to OW and OA levels predicted for 2100, under two CO
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: Hindawi Limited
Date: 04-04-2012
Publisher: Elsevier BV
Date: 12-2011
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: 23-01-2017
DOI: 10.1017/S0007114516004487
Abstract: Nutritional strategies are currently developed to produce farmed fish rich in n -3 long-chain PUFA (LC-PUFA) whilst replacing fish oil by plant-derived oils in aquafeeds. The optimisation of such strategies requires a thorough understanding of fish lipid metabolism and its nutritional modulation. The present study evaluated the fatty acid bioconversion capacity of rainbow trout ( Oncorhynchus mykiss ) fry previously depleted in n -3 PUFA through a 60-d pre-experimental feeding period with a sunflower oil-based diet (SO) followed by a 36-d experimental period during which fish were fed either a linseed oil-based diet (LO) (this treatment being called SO/LO) or a fish oil-based diet (FO) (this treatment being called SO/FO). These treatments were compared with fish continuously fed on SO, LO or FO for 96 d. At the end of the 36-d experimental period, SO/LO and SO/FO fish recovered % of the n -3 LC-PUFA reported for LO and FO fish, respectively. Fish fed on LO showed high apparent in vivo elongation and desaturation activities along the n -3 biosynthesis pathway. However, at the end of the experimental period, no impact of the fish n -3 PUFA depletion was observed on apparent in vivo elongation and desaturation activities of SO/LO fish as compared with LO fish. In contrast, the fish n -3 PUFA depletion negatively modulated the n -6 PUFA bioconversion capacity of fish in terms of reduced apparent in vivo elongation and desaturation activities. The effects were similar after 10 or 36 d of the experimental period, indicating the absence of short-term effects.
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: Public Library of Science (PLoS)
Date: 28-11-2018
Publisher: Elsevier BV
Date: 07-2011
Publisher: Elsevier BV
Date: 2019
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: Springer Science and Business Media LLC
Date: 12-02-2015
DOI: 10.1038/SREP08402
Abstract: Coral reefs face a crisis due to local and global anthropogenic stressors. A large proportion of the ~50% coral loss on the Great Barrier Reef has been attributed to outbreaks of the crown-of-thorns-seastar (COTS). A widely assumed cause of primary COTS outbreaks is increased larval survivorship due to higher food availability, linked with anthropogenic runoff . Our experiment using a range of algal food concentrations at three temperatures representing present day average and predicted future increases, demonstrated a strong influence of food concentration on development is modulated by temperature. A 2°C increase in temperature led to a 4.2–4.9 times (at Day 10) or 1.2–1.8 times (Day 17) increase in late development larvae. A model indicated that food was the main driver, but that temperature was an important modulator of development. For instance, at 5000 cells ml −1 food, a 2°C increase may shorten developmental time by 30% and may increase the probability of survival by 240%. The main contribution of temperature is to ‘push’ well-fed larvae faster to settlement. We conclude that warmer sea temperature is an important co-factor promoting COTS outbreaks.
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: 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: 02-2010
Publisher: MDPI AG
Date: 07-02-2017
DOI: 10.3390/D9010008
Publisher: Elsevier BV
Date: 2019
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: Springer Science and Business Media LLC
Date: 02-2019
Publisher: Elsevier BV
Date: 10-2014
Publisher: Springer Science and Business Media LLC
Date: 13-02-2016
Publisher: Hindawi Limited
Date: 18-05-2022
DOI: 10.1155/2022/3645868
Abstract: The effects of tuna viscera hydrolysate (TVH) on juvenile pompano Trachinotus blochii, growth performance, nutritional response, intestinal and liver health, and resistance to Streptococcus iniae were investigated in this study. Five isonitrogenous and isocaloric diets (protein 46.0%, lipid 10.0%) were formulated in which TVH was added to replace fishmeal protein at levels of 0 (control), 30, 60, 90, and 120 g kg-1, labelled as TVH0, TVH05, TVH10, TVH15, and TVH20, respectively. Triplicate groups of pompano were fed the respective diets for ten weeks. The results showed that fish fed diets containing TVH10 produced significantly higher final body weight and specific growth rate in comparison to the fishmeal control ( P 0.05 ). Dietary TVH did not produce any effect on feed utilisation, somatic indices, and proximate composition of juvenile pompano ( P 0.05 ). While most amino acids were unchanged by the dietary inclusion of TVH, phenylalanine and valine levels were significantly lower in the fish fed TVH20 diet compared to the control. Fish fed the TVH20 diet had significantly lowered total serum protein compared to the TVH10 treatment, whereas other biochemical parameters in the blood did not show any difference among treatments. The intestinal histology indicated a significant increase in goblet cell numbers in fish fed TVH10 diet. Fish fed diet supplemented with TVH showed the highest disease resistance against Streptococcus iniae after 14 days of challenge. Based on a quadratic regression between final body weight and dietary TVH levels, the optimum TVH was calculated to be 10% or 60.0 g kg-1 for maximum growth performance when fed to pompano.
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: Inter-Research Science Center
Date: 09-07-2023
DOI: 10.3354/AEI00305
Publisher: PeerJ
Date: 02-08-2017
DOI: 10.7717/PEERJ.3645
Abstract: Lipids are involved in a host of biochemical and physiological processes in corals. Therefore, changes in lipid composition reflect changes in the ecology, nutrition, and health of corals. As such, accurate lipid extraction, quantification, and identification is critical to obtain comprehensive insight into a coral’s condition. However, discrepancies exist in s le preparation methodology globally, and it is currently unknown whether these techniques generate analogous results. This study compared the two most common s le preparation techniques for lipid analysis in corals: (1) tissue isolation by air-spraying and (2) crushing the coral in toto . S les derived from each preparation technique were subsequently analysed to quantify lipids and their constituent classes and fatty acids in four common, scleractinian coral species representing three distinct morphotypes ( Acropora millepora , Montipora crassotuberculata , Porites cylindrica , and Pocillopora damicornis ). Results revealed substantial amounts of organic material, including lipids, retained in the skeletons of all species following air-spraying, causing a marked underestimation of total lipid concentration using this method. Moreover, lipid class and fatty acid compositions between the denuded skeleton and sprayed tissue were substantially different. In particular, the majority of the total triacylglycerol and total fatty acid concentrations were retained in the skeleton (55–69% and 56–64%, respectively). As such, the isolated, sprayed tissue cannot serve as a reliable proxy for lipid quantification or identification in the coral holobiont. The in toto crushing method is therefore recommended for coral s le preparation prior to lipid analysis to capture the lipid profile of the entire holobiont, permitting accurate diagnoses of coral condition.
Publisher: Elsevier BV
Date: 11-2019
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-05-2018
Abstract: Multiple invertebrates possess enzymes enabling de novo biosynthesis of essential omega-3 fatty acids.
Publisher: Hindawi Limited
Date: 03-09-2020
DOI: 10.1111/ANU.13146
Publisher: Elsevier BV
Date: 10-2011
Publisher: Oxford University Press (OUP)
Date: 02-11-2016
Abstract: At two natural volcanic seeps in Papua New Guinea, the partial pressure of carbon dioxide (pCO2) in the seawater is consistent with projections for 2100. Here, the cover of massive scleractinian corals Porites spp. is twice as high at elevated compared with ambient pCO2, while that of branching corals such as Acropora millepora is greater than twofold reduced. To assess the underlying mechanisms for such community shifts under long-term exposure to elevated pCO2, biochemical parameters related to tissue biomass, energy storage, pigmentation, cell protection, and cell damage were compared between Porites spp. and A. millepora from control (mean pHtotal = 8.1, pCO2 = 323 µatm) and CO2 seep sites (mean pHtotal = 7.8, pCO2 = 803 µatm) each at two reefs. In Porites spp., only one of the biochemical parameters investigated (the ratio of photoprotective to light-harvesting pigments) responded to pCO2, while tissue biomass, total lipids, total proteins, and some pigments differed between the two reefs, possibly reflecting differences in food availability. Furthermore, some fatty acids showed pCO2 –reef interactions. In A. millepora, most pigments investigated were reduced at elevated pCO2, while other parameters (e.g. tissue biomass, total proteins, total lipids, protein carbonyls, some fatty acids and pigments) differed between reefs or showed pCO2–reef interactions. Tissue biomass, total lipids, and cell-protective capacities were distinctly higher in Porites spp. than in A. millepora, indicating higher resistance to environmental stress in massive Porites. However, our data suggest that important biochemical measures remain relatively unaffected in these two coral species in response to elevated pCO2 up to 800 µatm, with most responses being smaller than differences between species and locations, and also when compared with responses to other environmental stressors such as ocean warming.
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.MOLBIOPARA.2017.08.007
Abstract: This study on the eggs of the tropical monogenean Neobenedenia girellae presents the first detailed quantitative biochemical information of a marine parasite species' eggs. Moisture and protein composed the majority of the contents of freshly laid eggs (79.12±0.82 and 11.51±0.49% respectively) followed by lipid (2.50±0.15%). Lipids were composed of approximately equal amounts of saturated, monounsaturated, and polyunsaturated fatty acids and the predominant lipid class was triacylglycerol (33.82±1.20%). This study represents a fundamental step towards a better understanding of the early life biology of this important species of parasite.
Publisher: Elsevier BV
Date: 04-2012
Publisher: Public Library of Science (PLoS)
Date: 28-11-2017
Publisher: Inter-Research Science Center
Date: 08-2018
DOI: 10.3354/AEI00274
Publisher: Elsevier
Date: 2013
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: Elsevier BV
Date: 2011
Publisher: Hindawi Limited
Date: 07-2009
Publisher: Hindawi Limited
Date: 10-2007
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: Cambridge University Press (CUP)
Date: 18-09-2020
DOI: 10.1017/S0007114520003669
Abstract: Choline plays a crucial role in lipid metabolism for fish, and its deficiency in aquafeed has been linked to compromised health and growth performance. A 56-d experiment was conducted to examine the effects of dietary choline on lipid composition, histology and plasma biochemistry of yellowtail kingfish ( Seriola lalandi YTK 156 g initial body weight). The dietary choline content ranged from 0·59 to 6·22 g/kg diet. 2-Amino-2-methyl-1-propanol (AMP) (3 g/kg) was added to diets, except for a control diet, to limit de novo choline synthesis. The results showed that the liver lipid content of YTK was similar among diets containing AMP and dominated by NEFA. In contrast, fish fed the control diet had significantly elevated liver TAG. Generally, the SFA, MUFA and PUFA content of liver lipid in fish fed diets containing AMP was not influenced by choline content. The SFA and MUFA content of liver lipid in fish fed the control diet was similar to other diets except for a decrease in PUFA. The linear relationship between lipid digestibility and plasma cholesterol was significant, otherwise most parameters were unaffected. When AMP is present, higher dietary choline reduced the severity of some hepatic lesions. The present study demonstrated that choline deficiency affects some plasma and liver histology parameters in juvenile YTK which might be useful fish health indicators. Importantly, the present study elucidated potential reasons for lower growth in choline-deficient YTK and increased the knowledge on choline metabolism in the fish.
Publisher: Wiley
Date: 04-07-2014
DOI: 10.1111/RAQ.12040
Publisher: Elsevier BV
Date: 04-2015
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: 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: 04-2017
Publisher: MDPI AG
Date: 07-07-2022
DOI: 10.3390/MD20070445
Abstract: Driven by consumer demand and government policies, synthetic additives in aquafeed require substitution with sustainable and natural alternatives. Seaweeds have been shown to be a sustainable marine source of novel bioactive phenolic compounds that can be used in food, animal and aqua feeds, or microencapsulation applications. For ex le, phlorotannins are a structurally unique polymeric phenolic group exclusively found in brown seaweed that act through multiple antioxidant mechanisms. Seaweed phenolics show high affinities for binding proteins via covalent and non-covalent bonds and can have specific bioactivities due to their structures and associated physicochemical properties. Their ability to act as protein cross-linkers means they can be used to enhance the rheological and mechanical properties of food-grade delivery systems, such as microencapsulation, which is a new area of investigation illustrating the versatility of seaweed phenolics. Here we review how seaweed phenolics can be used in a range of applications, with reference to their bioactivity and structural properties.
Publisher: Elsevier BV
Date: 06-2017
DOI: 10.1016/J.MARPOLBUL.2017.03.066
Abstract: This study explores how plasticity in biochemical attributes, used as indicators of health and condition, enables the coral Acropora tenuis to respond to differing water quality regimes in inshore regions of the Great Barrier Reef. Health attributes were monitored along a strong and weak water quality gradient, each with three reefs at increasing distances from a major river source. Attributes differed significantly only along the strong gradient corals grew fastest, had the least dense skeletons, highest symbiont densities and highest lipid concentrations closest to the river mouth, where water quality was poorest. High nutrient and particulate loads were only detrimental to skeletal density, which decreased as linear extension increased, highlighting a trade-off. Our study underscores the importance of assessing multiple health attributes in coral reef monitoring. For ex le, autotrophic indices are poor indicators of coral health and condition, but improve when combined with attributes like lipid content and biomass.
Publisher: Elsevier BV
Date: 12-2016
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: 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: 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: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 09-2007
Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 05-2011
Publisher: Elsevier BV
Date: 11-2010
Publisher: PeerJ
Date: 29-01-2018
DOI: 10.7717/PEERJ.4239
Abstract: Scleractinian corals are colonial organisms comprising multiple physiologically integrated polyps and branches. Colonialism in corals is highly beneficial, and allows a single colony to undergo several life processes at once through physiological integration and compartmentalised functioning. Elucidating differences in the biochemical composition of intra-colonial branch positions will provide valuable insight into the nutritional reserves underlying different regions in in idual coral colonies. This will also ascertain prudent harvesting strategies of wild donor-colonies to generate coral stock with high survival and vigour prospects for reef-rehabilitation efforts and captive husbandry. This study examined the effects of colony branch position on the nutritional profile of two different colony sizes of the common scleractinian, Acropora millepora . For smaller colonies, branches were s led at three locations: the colony centre (S-centre), 50% of the longitudinal radius length (LRL) (S-50), and the colony edge (S-edge). For larger colonies, four locations were s led: the colony centre (L-centre), 33.3% of the LRL (L-33), 66.6% of the LRL (L-66), and the edge (L-edge). Results demonstrate significant branch position effects, with the edge regions containing higher protein, likely due to increased tissue synthesis and calcification. Meanwhile, storage lipid and total fatty acid concentrations were lower at the edges, possibly reflecting catabolism of high-energy nutrients to support proliferating cells. Results also showed a significant effect of colony size in the two classes examined. While the major protein and structural lipid sink was exhibited at the edge for both sizes, the major sink for high-energy lipids and fatty acids appeared to be the L-66 position of the larger colonies and the S-centre and S-50 positions for the smaller colonies. These results confirm that the scleractinian coral colony is not nutritionally homogeneous, and while different regions of the coral colony are functionally specialised, so too are their nutritional profiles geared toward meeting specific energetic demands.
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
Start Date: 03-2019
End Date: 12-2024
Amount: $339,300.00
Funder: Australian Research Council
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