Study On The Technology Of Enzymatic Hydrolysis Of Plant Feed Ingredients In Vitro And Feeding Effects

This paper studies on the optimum conditions for phytase enzymatic hydrolysis of plant feed ingredients in vitro, and the influence of growth performance and body composition in genetically improved farmed tilapia (GIFT). Pretreat the substrate which is mixed of soybean meal, cottonseed meal and rapeseed meal (15:9:7) by phytase in vitro, analyze the effects of different factors on the efficiency of phytase by single factor test, and on this basis,use Lg(34) orthogonal test to determine the optimal parameters of hydrolysis by phytase of plant raw materials in vitro and investigate the effects on the growth performance,body composition and apparent digestibility of feeds of GIFT using the phytase-pretreat feed.The paper is divided into two parts:Expt.1Study on the Process Parameters of Hydrolysis by Phytase of Plant Raw Materials in vitroThis experiment used the substrate which is mixed of soybean meal, cottonseed meal and rapeseed meal according to the GIFT feed formulation ratio of15:9:7,consider the enzymatic efficiency as an indicator,apply orthogonal test based on single-factor test to determine the optimal parameters of hydrolysis by phytase of plant raw materials in vitro,the result as follows:addition of enzyme2000U per kilogram of substrate,the reaction temperature35℃,addition of water50%, enzymatic reaction time3h.Under these conditions enzymatic efficiency comes to42.19%.Expt.2Study on the Feeding Effects of GIFT using the Phytase-pretreat Feed to Replace Inorganic PhosphorusIn this experiment,feed the GIFT about15.0g for60days,in the blank control group use the basal diet (mix of untreated soybean meal,cottonseed meal and rapeseed meal), in the control group add phytase1280U per kilogram feed in basal diet, and in the experimental group respectively add0%,0.6%andl.2%of mono calcium phosphat(MCP) in the diet,investigate the influences of GIFT’S growth performance and body composition in these groups.The main results are as follows:(1)Weight gain rates of GIFT in the three experimental group were all higher than the control group;1.2%and0.6%MCP-replace groups were significantly higher than the control group (P<0.05).(2)Crude protein contents in three experimental groups were significantly higher than the control group and the blank control group (P <0.05);1.2%and0.6%MCP-replace experimental groups were no significant different from the rest experimental group (P>0.05).(3)The contents of calcium and phosphorus in fish in three experimental groups were higher than the control group and the blank control group;1.2%MCP-replace experimental group was significantly higher than the control groups;but there was no significantly difference among the three experimental groups (P>0.05).(4)Phosphorus storage rate in1.2%MCP-replace experimental group was significantly higher than other groups (P<0.05); the blank control group was significantly lower than other groups (P<0.05); there was no significantly difference among0%,0.6%MCP-replace experimental group and the control group (P>0.05).(5)Apparent digestibilities for crude protein in0%>0.6%MCP-replace experimental group and the control group were significantly higher than the blank control group (P<0.05); apparent digestibilities for calcium and phosphorus in all experimental groups and the control group were significantly higher than the blank control group (P<0.05).In conclusion, under this trial conditions, phytase in the feed can significantly improve the growth performance of tilapia Yoshitomi significantly improve GIFT’s body calcium,phosphorus and phosphorus accumulation rate, and also improved on fish crude protein and crude ash. Compared with the phytase to feed,phytase pretreatment feed in vitro have more significant role to improve the GIFT’s growth performance and fish of crude protein, crude ash, calcium, phosphorus content and phosphorus storage product rate.