Effects of Dietary Inclusion of Two Protein Hydrolysates on Growth Performance and Intestinal Histological Structure of Juvenile Turbot (Scophthalmus maximus L.)

Abstract:

This experiment used laboratory-made fish protein hydrolysates (PHf) and the commercial chicken protein hydrolysate (PHc) to replace 10% total fish meal protein and designed three isonitrogenous and isoenergetic diets: the control group (FM), PHf group (fish protein hydrolysate) and PHc group (chicken protein hydrolysate). Juvenile turbot (Scophthalmus maximus L.) (4.16±0.01 g) were fed with these three diets for 12 weeks to investigate the effects of different protein hydrolysates on the growth performance and intestinal structure of juvenile turbot. Results of this study showed that the specific growth rate, feed efficiency, protein efficiency ratio and protein retention in FM group and PHf group had no significant difference (P>0.05), but both the two groups were significantly higher than the PHc group (P<0.05); there was no significant difference in feeding rate in the three groups (P>0.05). PHf and PHc had higher crude protein than FM (P<0.05), while had no significant difference in crude lipid (P>0.05). PHf and PHc had higher essential amino acid content than FM (P<0.05). The plica height in foregut and midgut of PHf and PHc were higher than FM, and PHf had significant difference with FM (P<0.05), while the intestinal wall thickness of FM was higher than the other two groups, and significantly higher than PHf (P<0.05); there was no significant difference in foregut and midgut enterocytes height of the experimental groups (P>0.05). These results indicated that the growth response and feed utilization of PHf was superior to PHc, which suggesting that replaced fish meal by fish protein hydrolysates in high plant protein diets had some advantage over chicken protein hydrolysates.