Effects Of Adding Compound Probiotics In Diet On Growth Performance, Intestinal Protease Activity And Feed Digestibility In Oreochromis

The experiment was conducted to investigate the effect of adding compound probiotics in diet on the growth performance,intestinal protease activity and feed digestibility in tilapia.In experiment1, mono-sex tilapias with average initial body weight of18.00g±2.5g were randomly divided into six treatments with three replicates per treament and forty tilapias per replicate. Diets containting compound probiotics0.0%(control group),0.3%,0.4%,0.5%,0.6%,0.7%were fed to tilapia in the net cage for102day to investigate the effect of adding diffenet level compound probiotics in diets on growth performance and intestinal protease activity of tilapia.The results showed that compared with control group,adding with0.5%,0.6%compound probiotics AWG,WGR,SRG were significantly increased(P<0.05),FCR of adding groups were significantly decreased (P<0.05);compared with control group, adding compound probiotics0.3%～0.6%intestinal protease activity were significantly increased,the significantly at0.01probability(P<0.01),adding0.7%compound probiotics intestinal protease activity were significantly decreased (P<0.05).The conclusion were that suitable adding compound probiotics in diets could significantly increase growth rate of tilapia and significantly decrease the feed coefficient,save the cost of feed and increase economic profit of culture.The result of regression analysis showed that the compound probiotics suitable adding level in diets was0.40%～0.66%for tilapia.In experiment2, mono-sex tilapias with average body weight of16.97g±0.88g were randomly divided into six treatments with two replicates per treatment and twenty tilapias per replicate.Diets containing compound probiotics0.0%(control group),0.3%,0.4%,0.5%,0.6%,0.7%were fed to tilapia, Cr2O3was exogenous indicator,fish feces was collected. The content of Cr2O3and protein of both feces and diet were examed to investigate effect of adding diffenet level compound probiotics in diets on digestibility.The result showed that compared with control group,adding0.3%,0.4%,0.5%,0.6%compound probiotics total digestibility were significantly increased15.29%,14.92%,18.68%,24.41%respectively, and protein digstibility were significantly increased13.05%,12.73%,14.06%,16.22%respectively,the significantly at0.01probability (P <0.01); adding0.7%compound probiotics compared with adding0.3%,0.4%,0.5%,0.6%compound probiotics total digestibility were significantly decreased12.04%,11.67%,15.43%,21.16%respectively,and protein digestibility were significantly decreased12.46%,12.14%,13.47%,15.63%respectively, the significantly at0.01probability(P<0.01).The conclusion were that suitable adding compound probiotics could significantly increase digestibility and over adding it would decrease digestibility. The result of regression analysis showed that the compound probiotics suitable adding level in diets was0.40%for tilapia.The integrative results showed that the compound probiotics suitable adding level in diet was0.40%～0.66%for tilapia.