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Stone D.A.J.,University of Idaho | Oliveira A.C.M.,University of Alaska Fairbanks | Ross C.F.,Washington State University | Plante S.,Coastal Zones Research Institute | And 3 more authors.
Aquaculture Nutrition

Rainbow trout (186g) were fed three test diets where the lipid source (150gkg-1) was either menhaden oil (MO), pollock oil (PO) or canola oil (CO) for eight weeks to an average weight of 370g. The CO group was then divided into two groups, one continuing on the CO diet and the other switched to the PO diet (CO-PO). After nine additional weeks of feeding, the average fish weight approximately doubled (719-749g). No significant differences were found in average final weight or fillet yield among dietary treatment groups. Fatty acid profiles of fillets from trout fed MO, PO or CO-supplemented diets reflected the fatty acid profiles of the added oils, whereas the fatty acid profile of fillet from trout in the CO-PO group exhibited values similar to those of fish fed PO. The ratio of ω3:ω6 FA was nearly 2.5 times higher in fillets from the CO-PO group compared to the CO group. Sensory analysis showed that panelists preferred CO-fed fillets over those fed MO, PO, or CO-PO. Phase-feeding CO and PO reduced fish oil use and resulted in fillets with double the content of Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) over CO-fed fish, similar to levels in MO-fed fish. © 2010 Blackwell Publishing Ltd. Source

Stone D.A.J.,University of Idaho | Oliveira A.C.M.,University of Alaska Fairbanks | Plante S.,Coastal Zones Research Institute | Smiley S.,University of Alaska Fairbanks | And 2 more authors.
Aquaculture Nutrition

Rainbow trout, average weight 185-187g, were fed feeds containing menhaden oil, canola oil or fish oils (pollock, pink salmon or rockfish) produced from Alaskan seafood processing waste as the added oil for 8weeks, at which time the fish weighed 391-411g (average 404g, pooled SE=5.7). The fish were previously fed from 75g average weight fed commercial feed containing poultry oil as the added oil. No significant differences were measured in final weight or feed conversion ratio among dietary treatment groups. Significant differences were found in fillet ω-3 fatty acid (FA) levels from fish receiving fish oil-supplemented feeds compared to those from fish receiving feeds containing canola oil. Fillet contents of eicosapentaenoic acid (EPA; 20:5ω3) and decosahexaenoic acid (DHA; 22:6ω3) were highest in the pollock oil treatment group, although all fish oils increased highly unsaturated ω-3 FA contents (mg100g-1) of fillets. Fish oil used through the production cycle was reduced by 25% by supplementing feeds with poultry oil during the middle phase of production (75-175g) compared to using feeds containing fish oil throughout the production cycle. Fish oils recovered from Alaskan seafood processing waste were suitable alternatives to conventional fish oil as ingredients in rainbow trout production feeds. © 2010 Blackwell Publishing Ltd. Source

Dumas A.,Coastal Zones Research Institute | Lopez S.,University of Leon | Kebreab E.,University of California at Davis | Gendron M.,Environnement Illimite Inc. | And 2 more authors.
CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources

Simple growth models have proven helpful to study and predict growth trajectories of fish with different life histories and from various environments, and have found numerous applications in ecology, fisheries and aquaculture worldwide. The most applied simple models (e.g. von Bertalanffy) convey little information about life history traits, are facing criticism, and their goodness of fit is assessed using a limited number of statistical outputs. This review challenges the von Bertalanffy and certain statistical outputs using real-life data, and proposes more explanatory alternatives. The length-at-age relationship from three different wild populations of four fish species (lake herring, lake whitefish, northern pike and walleye) is described using the monomolecular, Schumacher, Gompertz, logistic, von Bertalanffy and Richards equations. Comparison between models was based on least squares and likelihood theories involving several statistical outputs currently encountered in model comparison and selection studies. The analysis demonstrates that the monomolecular, Schumacher and Richards equations often stood as alternatives to the von Bertalanffy and highlighted residual sum of squares, standard error (SE) of parameter estimates and, to a lesser extent, Akaike weight as statistical outputs facilitating discrimination between candidate models. Based on visual appraisal, different equations fitted similar trajectories across the 12 growth profiles. However, the assumptions and statistical performance served to select the most appropriate models and discern life history traits of the species under study. Results indicate that comparison and selection of models should consider not only the statistical performance of equations but also the purpose of the study along with the biological/physical interpretation of parameters. © CAB International 2012. Source

Overturf K.,U.S. Department of Agriculture | Barrows F.T.,U.S. Department of Agriculture | Hardy R.W.,University of Idaho | Brezas A.,University of Idaho | Dumas A.,Coastal Zones Research Institute

Increasing feed efficiency and muscle growth in aquaculture are of high priority and require understanding how dietary components are interactively processed and trigger molecular, tissue and whole-body responses. A 67-day trial was conducted to describe the effects of three feeds with varying dietary protein (P) to lipid (L) ratios (43P:20L, 50P:15L, 62P:6L) on growth trajectory, body composition, nutrient deposition, muscle histology, gene expression and protein degradation pathways of juvenile rainbow trout (initial weight 11.2 g). The growth trajectories of trout fed the 43P:20L and 50P:15L diets were identical and higher than trout fed the 62P:6L diet. The overall TGC was 0.261 for trout fed the 43P:20L and 50P:15L diets. Feed intake was associated with dietary protein level, not energy. Body composition differed among treatments early (at day 14) in the experiment and continued throughout. Body lipid and body protein contents varied significantly (< 0.05) from 7.36 (62P:6L) to 12.91% (43P:20L) and 14.95 (43P:20L) to 16.24% (50P:15L) at day 67, respectively). Simple mathematical models were developed to predict body lipid content and feed intake of growing trout. Analysis of gene expression data using RT-PCR correlated with other measured parameters, provided significant information to evaluate metabolic processing of the different diets. The relative expression level of Pax7 in fish fed the 43P:20L diet was higher than in fish fed the other diets and the statistical difference was nearly significant (= 0.058). The relative content of small muscle fibers (0-25 μm) increased significantly (< 0.05) with time in trout fed the 43P:20L diet, whereas the opposite was observed in fish fed the other treatments. An increased proportion of small muscle fibers was associated with the highest relative expression of PAX7 over time and increased lysosomal activity in fish fed the 43P:20L dietary treatment. This is the first study in vivo using fish to show that increases in hyperplasia is linked to autophagy activity. The overall rate of protein deposition was significantly (< 0.05) higher in trout fed the 50P:15L (16.58 ± 0.57 mg (°C-d)-1) compared to the 62P:6L (13.26 ± 0.66 mg (°C-d)-1), but there was no significant difference with trout fed the 43P:20L diet (15.05 ± 0.69 mg (°C-d)-1). This study demonstrates that macronutrients are potent regulators of muscle development and growth, and provides new opportunities in nutrigenomics to program performance and flesh quality of organisms. Statement of relevance: Nutrigenomics can foster sustainable aquaculture. © 2016 Elsevier B.V. Source

Mansour N.,Kafr El Sheikh University | Mansour N.,University of Salzburg | Lahnsteiner F.,University of Salzburg | McNiven M.A.,University of Prince Edward Island | And 2 more authors.

This study investigated the relationship between fertility and fatty acid (FA) profiles of egg chorions, total egg, and sperm cells of Arctic char, Salvelinus alpinus (L.) broodstock housed in tanks and fed a commercial diet. Fertility of semen from individual males was assessed using pooled eggs, and vice versa. Fertility of the gametes of broodstock fish was classified according to the percentages of eyed stage embryos into: (a) for males, high, ≤ 68%, medium: 49-67% and low: ≤ 48%; (b) for females, high: ≤ 55%; medium: 28-54% and low: ≤ 27%.Spermatozoa from the high fertility group contained less short-chain saturated FAs, more n-3 and n-6 FAs with a higher n-3 to n-6 ratio compared to the sperm from the low fertility group. Egg chorions from the high fertility group also had less short-chain saturated FAs compared to the low fertility group. For spermatozoa significant correlations were found between C15:0, total saturated FAs, C22:5n-3, C22:6n-3, total n-3 FAs, and the ratios of n-3 to n-6 and their fertility, but no correlations were found between fatty acid profiles of egg chorions and of total eggs and egg fertility. In conclusion, sperm fertility of Arctic char is influenced to a much higher extent by their fatty acid composition than that of the eggs. © 2011 Elsevier B.V. Source

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