Optimizing zinc supplementation levels of rainbow trout ( O ncorhynchus mykiss ) fed practical type fishmeal‐ and plant‐based diets

Rainbow trout (23.1 ± 0.4 g) were fed either a fishmeal- or plant-based diet supplemented with various levels of zinc (0, 15, 30, 60 or 120 mg kg−1) for 12 weeks. Trout fed the fishmeal diet had significantly higher weight gain than with the plant-based diet. Zinc supplementation in the fishmeal diet had no effect on growth performance, suggesting that additional dietary supplementation of zinc is not required. However, in trout fed the...