| Bacillus natto antimicrobial lipopeptide is a new type of antibacterial peptides of microorganisms found in recent years, with potential to be developed into a green feed additive, the purpose of this study is to evaluate its effect ongrowth promoting and non-specific immunity of Litopenaeus vannamei. Added 0 mg/kg, 50 mg/kg, 100 mg/kg, 150 mg/kg and 200 mg/kg antibacterial lipopeptide in basic diet respectively to feed L. vannamei of group A0, A1, A2, A3 and A4 which was 1.12 (±0.10) g in weight for 8 weeks, and AKP (alkaline phosphatase), T-SOD (superoxide dismutase), LZM(lysozyme), T -AOC (total antioxidant capacity) in serum and hepatopancreas and POD (peroxidase ) in serum andmorphological indexes of shrimp were measured. Results showed that after 8 weeks of feeding experiment, the growth rate of shrimp of experiment groups was faster than that of control group, in which the shrimp of group A2 was the fastest and its relative growth rate reached 58.13%. The morphological indexes of shrimp of experimental groups
were affected by antimicrobial lipopeptides significantly,and the overall appearance of the commodity form was improved. The content of crude protein and fat in muscle of experimental groups had significant difference compared with those of control group, but the difference of crude ash was not significant. The activity of LZM in serum of experimental groups was significantly higher than that in control group, and the group A2 was affected most significantly. The activity of POD in serum of group A1 was higher than that of other groups. The difference of AKP activity in the serum
of the experimental groups was not significant. T-AOC and T-SOD activity in serum of experimental groups had significant differences compared with control group, and the group A2 had the highest. The activity of T-AOC, LZM,AKP and T -SOD of hepatopancreas in group A4 was significantly higher than those in control group. The improvement of non-specific immune indexes of shrimp contributed to improving its survival rate to some extent, and the survival rate of group A2 was the highest. The result indicated that adding a certain amount of NT -6antimicrobial lipopeptides in the feed could significantly promote the growth of L. vannamei and improve its nonspecific immunity, and therefore the antimicrobial lipopeptides could be used as a substitute of antibiotic feed additives. |
