Influence of A3a-peptidoglycan on growth, immune capability and anti-infectivity of Litopenaeus vannamei

Six experiment groups, including groups for continuously feeding, interval feeding and immersing were arranged to evaluate the effect of PG on the growth, immunological capability of Litopenaeus vannamei. 30d, 60d and 90d later, body weight and body length of shrimp, immunological capability of shrimp and the capability of resistance to WSSV were all determined. The results showed: compared with the control, 30d later, body length of shrimp of all groups with a exception of the group for interval feeding, body weight of shrimp of groups for immersing and feeding with the diet containing 0.05% and 0.1% PG increased significantly (P<0.05), shrimp of groups fed with the diet containing 0.05 % and 0.1% PG showed much higher PO activity (P<0.05) ; 60d later, both body length and body weight of shrimp of groups fed with the diet containing 0.05% and 0.1% PG increased most significantly (P<0.01), shrimps of group for immersing and feeding with the diet containing 0.1% PG showed much higher phagocytic activity, PO activity in plasma supernatant of shrimp of group for immersing and feeding with the diet containing 0.05% and 0.1% PG, all were much higher (P<0.05) ; 90d later, body length and body weight of shrimps of group for immersing increased more than the control did (P<0.05), shrimp of group for interval feeding showed higher PO activity in plasma supernatant (P<0.05). All infection experiments proved that PG could enhance the resistance of shrimp to WSSV.