Effects of dietary L‐tryptophan supplementation on growth performance, food intake, digestive enzyme activity and serotonin (5‐HT) levels in juvenile Chinese mitten crab (Eriocheir sinensis)

This study was designed to evaluate the effects of dietary L‐tryptophan (L‐trp) supplementation on growth performance, feeding and digestion, 5‐HT levels and the related receptor expression levels of Eriocheir sinensis. In this study, crabs were divided into four groups: the analysed tryptophan concentrations were 3.6 (Diet #A), 4.7 (Diet #B), 7.3 (Diet #C) and 10.5 (Diet #D) g/kg dry matter, respectively. In Trial 1, we found that there was no significant difference in the growth parameters (weight gain rate, carapace length increase rate, carapace width increase rate and hepatopancreas index) among the four dietary groups after 30 days, whereas the molting rate was significantly higher in the Diet #C group and the limb autotomy rate was significantly lower in the Diet #C group than in the Diet #A group (p