ORCID Profile
0000-0002-1226-8798
Current Organisations
University of Tasmania
,
CSIRO Hobart
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Publisher: Elsevier BV
Date: 03-2022
DOI: 10.1016/J.FSI.2022.02.035
Abstract: Amoebic gill disease, caused by the protozoan ectoparasite Neoparamoeba perurans, remains a significant threat to commercial Atlantic salmon aquaculture operations worldwide, despite partial control afforded by selective breeding and therapeutic intervention. Anecdotal reports from commercial producers suggest that historically, smaller Atlantic salmon smolts are more susceptible to AGD than larger smolts. Here, large (>350 g) and small (<200 g) commercially sourced, AGD-naïve Atlantic salmon cohorts were experimentally exposed to 50 N. perurans trophozoites L
Publisher: Wiley
Date: 08-03-2021
DOI: 10.1111/JFD.13363
Abstract: Amoebic gill disease (AGD) is a significant issue in Atlantic salmon mariculture. Research on the development of treatments or vaccines uses experimental challenges where salmon is exposed to amoebae concentrations ranging from 500 to 5,000/L. However, the water concentrations of N. perurans on affected salmon farms are much lower. The lowest concentration of N. perurans previously reported to cause AGD was 10/L. Here, we report that concentrations as low as 0.1/L of N. perurans can cause AGD. We propose that concentrations of N. perurans that reflect those measured on salmon farms should be used for future experimental challenges.
Publisher: Springer Science and Business Media LLC
Date: 07-04-2022
DOI: 10.1038/S41598-022-09806-5
Abstract: Neoparamoeba perurans , the aetiological agent of amoebic gill disease, remains a persistent threat to Atlantic salmon mariculture operations worldwide. Innovation in methods of AGD control is required yet constrained by a limited understanding of the mechanisms of amoebic gill disease pathogenesis. In the current study, a comparative transcriptome analysis of two N. perurans isolates of contrasting virulence phenotypes is presented using gill-associated, virulent (wild type) isolates, and in vitro cultured, avirulent (clonal) isolates. Differential gene expression analysis identified a total of 21,198 differentially expressed genes between the wild type and clonal isolates, with 5674 of these genes upregulated in wild type N. perurans . Gene set enrichment analysis predicted gene sets enriched in the wild type isolates including, although not limited to, cortical actin cytoskeleton, pseudopodia, phagocytosis, macropinocytic cup, and fatty acid beta-oxidation. Combined, the results from these analyses suggest that upregulated gene expression associated with lipid metabolism, oxidative stress response, protease activity, and cytoskeleton reorganisation is linked to pathogenicity in wild type N. perurans . These findings provide a foundation for future AGD research and the development of novel therapeutic and prophylactic AGD control measures for commercial aquaculture.
Publisher: Wiley
Date: 14-02-2023
DOI: 10.1111/JWAS.12943
Abstract: This study evaluated the effect of two commercial probiotics, zymetin, and super PS, on the culture environment, production, and economics of Macrobrachium rosenbergii aquaculture . The experiment was conducted using three treatments, including T 1 , probiotics applied in all culture phases T 2 , during grow‐out and a control ( C ). Prawns were fed commercial pelleted diets. Earthen ponds were used at a stocking density of two juveniles/m 2 . Water concentrations of non‐ionized ammonia and nitrite‐nitrogen were significantly lower ( p 0.05) in T 1 than in T 2 and C . Probiotic application significantly ( p 0.05) reduced phosphate content and balanced soil pH. Growth performance, condition factor, survival, protein utilization, and production were significantly higher in T 1 followed by T 2 compared to C by the end of grow‐out. Application of zymetin and super PS in all culture phases significantly ( p 0.05) reduced the feed conversion ratio in T 1 compared to T 2 and C . Positive allometric growth was observed in T 1 , whereas growth was isometric in C and T 2 . Probiotic treatment during all culture phases achieved the highest net returns to land, family labor, and management. Application of probiotics during the entire culture cycle could be the best practice for improving production and economics in M. rosenbergii aquaculture.
Location: Australia
No related grants have been discovered for Aaron Smith.