Effects of feeding strategies on growth，body composition, intestine digestive enzymes activities and intestine histology of Megalobrama pellegrini (Tchang, 1930) early juveniles raised in flow-through system

Abstract

To determine the effects of feeding rate and feeding frequency on growth performance, digestive enzymes activities, and intestine development of Megalobrama pellegrini in a replicated flow-through system, we conducted a 42day experiment. We designed three feeding rates (5%, 6.5%, and 8% body weight/day, BW/d) and two feeding frequencies (2 and 3 meals/day; m/d) in this experiment. Fish (0.57 ± 0.01 g) were distributed into 18 tanks with 70 individuals and fed with a commercial diet (33% crude protein, 4% total lipid). Results showed that the highest weight gain was found in the fish fed diet with 6.5% BW/day and 3 m/d, which was significantly higher in comparison with that of other feeding rate groups (5% BW/d and 6.5% BW/d) at both feeding frequency (2 and 3 m/d). Fish growth performance was significantly affected by the feeding rate but not by the feeding frequency. The significantly higher feed conversion ratio (FCR) was recorded at 8% BW/d with 3 m/d than other treatments. Furthermore, fish fed diet at 8% BW/d with 2 m/d had significantly high mortality during the middle of this trial. In contrast, we found that other fish groups' survival rates were higher (over 90%), and there were no significant differences among them. We saw a significantly lower whole-body crude protein, lipid, and intestinal digestive enzymes in fish fed at a ratio of 8% BW/d with 3 m/d compared with other treatments. Moreover, our findings revealed intestinal villi fusion and exfoliation in this group compared with other treatments. In conclusion, the Megalobrama pellegrini received a feeding rate of 6.5% BW/d, and a feeding frequency of 2 m/d may be the optimum feeding regime for raising Megalobrama pellegrini in a flow-through system.

Effects of short-time fasting and feeding frequencies within 24 hours on histology, cholecystokinin and trypsin enzyme activities of digestive organs in black bream, Megalobrama pellegrini (Tchang, 1930), juvenile

“…Another report (Li et al, 2013) described the effects of starvation and re-feeding on the growth and digestive enzyme activity of juvenile M. pellegrini. At the same time, Qu et al (Qu et al, 2021) conducted a series of analyses on the body weight and optimal feeding frequency of juvenile M. pellegrini in a stream culture mode. The overall growth performance of bream was inferior to that of other sh of the same genus (Li et al, 2007a).…”

Influence of Stocking Density on Growth Performance, Intestinal Antioxidant Status, and Immune‐Related Gene Expression of Endangered Megalobrama pellegrini Reared in a Flow‐Through System

“…A recent report indicated that M. pellegrini is omnivorous, with algae and mussels as the primary two food resources (Zhang et al 2020). Moreover, Qu et al (2020) determined that a feeding rate of 6.5% of body weight/d and a feeding frequency of 2 meals/d constituted the optimum feeding strategy for raising this species under laboratory conditions.…”