Effects of supplemental amino acids and bile acid in a completely replaced fish meal by enzymatically hydrolysed soybean meal diet on growth performance, liver health and fillet quality of rainbow trout ( Oncorhynchus mykiss )

Abstract

In order to evaluate the supplemental effects of amino acids and bile acid to completely replace fish meal by enzymatically hydrolysed soybean meal diet for rainbow trout (Oncorhynchus mykiss), a 56‐day feeding trial was conducted with five diets, including 40% fish meal (FM) as a positive control diet, 45% enzymatically hydrolysed soybean meal without the fish meal (ESM) as a negative control diet, the addition of methionine (Met) and lysine (Lys) (0.76%) to the ESM diet (E+A), the addition of 0.02% bile acid to ESM diet (E+B) and the addition of Met and Lys (0.76%) and 0.02% bile acid to ESM diet (E+AB). The results showed that the ESM group reduced the growth performance but significantly alleviated the liver health problem, decreased lipid and saturated fatty acids (SFA) contents and increased protein content in fish muscle. The E+A group significantly improved growth performance, pepsin activity and fillet protein content, while the E+B group inhibited growth and protease activity but increased amylase activity, elevated SFA, monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) contents and improved lipid utilization. The E+AB group had superiority in enhancing liver health compared with E+A and E+B groups. This study suggested that supplemental amino acids and bile acid alone or in combination can be used according to practical feeding demand.

Effect of dietary bile acids supplementation on growth performance, feed utilization, intestinal digestive enzyme activity and fatty acid transporters gene expression in juvenile leopard coral grouper (Plectropomus leopardus)

“…A study by Yin et al (2021) found that there were no significant differences in the WG of largemouth bass fed a high-fat diet with 0.03%, 0.06%, and 0.09% dietary bile acids. Similarly, dietary supplementation of lower levels of bile acids did not significantly affect the growth performance of black seabream (Sparus microcephalus) (0.02%) (Jin et al, 2019) and rainbow trout (Oncorhynchus mykiss) (Hang et al, 2022). Most of the studies including current study reported that fish fed with higher levels of dietary bile acids did not exhibit growth retardation.…”

Seeking the best alternatives:Asystematic review and meta‐analysis on replacing fishmeal with plant protein sources in carnivorous fish species

“…The possible mechanism that drive these adverse effects could be explained in many aspects. Some studies suggested that the fibre and anti‐nutritional factors contained in plant protein sources are responsible, 37–39 whereas others blamed imbalanced amino acid profiles 40,41 and the lack of cholesterol 42 . However, since the condition of every experiment was distinct from each other and the supply ratios of plant protein varied among research, the results could be divergent.…”