Effects of partial fish meal substitution by fish peptide and protease on growth, intestinal digestive enzymes and intestinal microflora of Pacific white shrimp Litopenaeus vannamei
Abstract: In order to reveal that enzymatic peptide and protease replace 5% fish meal in the diet of Pacific white shrimp Litopenaeusvannamei, the effects of partial fish meal substitution by enzymatic peptide and protease on the growth, digestive indices and intestinal flora of Pacific white shrimp was investigated. Pacific white shrimp juveniles with initial body weight of (0.32±0.01)g were reared in an aquarium (40 cm×50 cm×60 cm)and fed basic diet (control group), and diet containing 5% fish meal replaced by 5% peptide (group EP) and by 0.3% protease (group PR) at water temperature of 28 ℃ for 56 d with three repetitions. The results showed that there were higher final body weight and weight gain rate in the shrimp in EP and PR groups than those in the control group, with significant differences in hepato-somatic ratio and dressing rate (P<0.05). The plasma glucose, total cholesterol and triglyceride levels were shown to be significantly higher in EP and PR groups than those in control group (P<0.05). The shrimp in EP and PR groups had higher activities of lipase, pepsin and protease than the shrimp in control group did (P<0.05). Shannon index in enzymatic peptide and protease groups was higher than that in control group, Simpson index in protease group was significantly lower than that in control group, and that in peptide group was significantly lower than that in protease group (P<0.05). At the phylum level, the number of Proteobacteria and Actinobacteria in group enzymatic peptide was higher than that in control group and protease group. At the class level, in enzymatic peptide and protease groups the Alphaproteobacteria of Proteus was lower than that in control group, and Gammaproteobacteria in enzymatic peptide and protease groups were higher than in control group and enzymatic peptide group, and Verrucomicrobiae was higher than in control group and protease group. At the genus level, it can be seen that the proportion of Rhodobacteraceae_unclassified in enzymatic peptide and protease groups was higher than that in the control group, with the large difference, and little difference among Flavobacterium_unclassified groups. The findings indicated that the addition of enzymatic peptide and protease in the diet improved the growth performance of Pacific white shrimp, with positive impact on digestive indices and intestinal structure, and that enzymatic peptide and protease were used as a new resource to reduce the addition of fish meal in shrimp formula feed.
2022, Vol. 37 
