Optimization of Dietary Manganese for Rainbow Trout,Oncorhynchus mykiss,Fed a Plant‐based Diet |
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Authors: | Thomas L Welker Ken Overturf Jason Abernathy Frederic T Barrows Gibson Gaylord |
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Institution: | 1. USDA‐ARS, Hagerman Fish Culture Experiment Station, 3059F National Fish Hatchery Road, Hagerman, Idaho 83332, USA;2. USDA‐ARS, Fish Technology Center, 4050 Bridger Canyon Road, Bozeman, Montana 59715, USA;3. USFWS, Fish Technology Center, 4050 Bridger Canyon Road, Bozeman, Montana 59715, USA |
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Abstract: | Juvenile rainbow trout were fed a plant‐based diet supplemented with inorganic Mn added at 0, 0.5, 1, 2, 4, 8, 16, or 32 mg/kg diet for 12 wk. Whole‐body Mn concentrations increased with increasing dietary levels. Rainbow trout fed 2–8 mg Mn/kg diet exhibited weight gain that was significantly higher than fish fed 0, 0.5, 1, 16, and 32 mg Mn/kg diet. Feed conversion ratio (FCR) showed a similar trend, where FCR values decreased with increasing dietary Mn until concentrations reached 8 mg Mn/kg, after which they increased. A rational nonlinear model (R2 = 0.84) fit to weight‐gain data showed that the optimal predicted supplementation level for Mn was 4.8 mg/kg diet. The optimal predicted supplementation level for Mn was similar for FCR (5 mg Mn/kg diet). The predicted 5 mg/kg diet of supplemental Mn required for the plant‐based diet formulation examined in this study is lower than the National Research Council–recommended supplementation level of 12 mg/kg. However, due to potential differences in bioavailability or retention of Mn among plant‐protein sources, the level of dietary supplementation for optimal growth could be slightly higher or lower depending on the dietary formulation. |
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Keywords: | alternative protein dietary requirement micromineral |
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