Influence of dietary fat and carbohydrate levels on growth and body composition of rainbow trout Oncorhynchus mykiss under self-feeding conditions |
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Authors: | Takeshi Yamamoto Koji Konishi Takao Shima Hirofumi Furuita Nobuhiro Suzuki Mitsuo Tabata |
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Affiliation: | Feed Section, Inland Station, National Research Institute of Aquaculture, Tamaki, Mie 519-0423;, Hakojima Branch, Gunma Prefectural Fisheries Experiment Station, Azuma, Gunma 377-0301 and; Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan |
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Abstract: | SUMMARY: An 8-week feeding experiment was conducted to examine the influence of fat and carbohydrate levels in a 40% protein level diet on growth and body composition of rainbow trout Oncorhynchus mykiss under self-feeding conditions. Five fish meal-based diets were prepared to include gelatinized potato starch at four levels (9, 18, 27, and 36%) and dextrin (34%). Dietary fat levels were isoenergetically reduced from 18 to 7% by the digestible carbohydrates. Each diet was fed to four replicate groups (28 g/fish, 20–23 fish/group) using self-feeders. Specific growth rate, percentage weight gain and percentage protein retention did not differ between the treatments. Feed efficiency and protein efficiency ratios were higher in the 18% starch (s18) and s27 diet groups, and decreased in higher fat or carbohydrate diet groups. Although gross energy intake (kJ/kg BW per day) decreased as the starch level increased, levels of digestible energy intake did not differ between the treatments. Fat levels in the carcass, viscera and liver decreased as dietary carbohydrate level increased. These results suggest that a 40% protein diet with either 15% fat and 18% starch or 11% fat and 27% starch is appropriate for juvenile rainbow trout under self-feeding conditions. |
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Keywords: | carbohydrate diet fat growth Oncorhynchus mykiss rainbow trout self-feeder |
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