Effects of probiotics on growth and activities of digestive enzymes of Pennaus vannamei

The basal diet that was made of fish meal,soybean meal-solvent,plant-oil and starch,et al. was regarded as control group without probiotics added in. The trial groups were designed with 4 added levels of probiotics which were maxed with the basai diet. The added levels of probiotics were 0.5%,1.0%,3.0% and 5.0%. The whole ex-periment period was 58 d, and the first 29 d was the first stage,and the latter 29 d was the second stage. γSGR and ac-tivity of digestive enzy mes were examed at both stages by sampling at the end of each stage. The experimental results indicated that all the γSGR of trial groups were higher than that of control group in the first and second stage for Penaeus vannamei. In the first stage, the γSGR in the group of probiotics added level at 0.5% was higher than that in control group ( P 0.05) , but there was no significant differences in γSGR between control group and the other 3 trial groups with added level of probiotics at 1.0% ,3.0% and 5.0% (P 0.05 ) , and among all the trial groups either ( P 0.05); in the second stage, the γSGR in the group with added level of probiotics at 0.5 % was different from that in the group with added level of probiotics at 3.0% ( P 0.05 ) , and significant different from the control and the with group added level of probiotics at 5.0%(P0.01); but no significant difference bet ween the control group and the trial groups except the group with added level of probiotics at 0.5% ( P 0.05 ); survival rates of the trial groups were higher than those in control in both stages. The survival rates were higher in the first stage than in the second stage; the effects of probiotics on aetivities of digestive enzymes beheaved similar trend in both stages:com-pared with the control group, the aetivities of digestive enzymes affected by probiotics changed clearly in protease, didn' t change clearly in amylase,cellulase and lipase. The aetivities of several digestive enzymes didn' t show any difference in all trial groups. All these results demonstrated that the aetivities of digestive enzymes and survival rates of Penaeus vannamei were enhanced by probiotics preparation, which promoted nutrients of diets to be digested,de-composed and absorbed so to accelerate Penaeus vannamei to grow better.