Dietary threonine requirement of juvenile largemouth bass, Micropterus salmoides

Abstract Threonine is an essential amino acid in fish nutrition, but no information is available on the dietary threonine requirement in largemouth bass, Micropterus salmoides. Thus, 360 fish (19.0 ± 0.1 g) were randomly divided into six experimental groups (20 fish per cage; three replicates), and offered diets supplemented with crystalline L-threonine at 0 g kg−1 (control), 2.5 g kg−1 (Thr-2.5), 5.0 g kg−1 (Thr-5.0), 7.5 g kg−1 (Thr-7.5), 10.0 g kg−1 (Thr-10.0) and 12.5 g kg−1 (Thr-12.5) for eight weeks to determine the optimum threonine requirement of largemouth bass. The results showed that dietary threonine significantly (P   0.05) by any dietary treatments, except the condition factor. Whole-body crude protein and lipid were lower (P