Study On Enzymatic Hydrolysis Of Aquatic Feedstuffs By Proteinase And Its Application

Protease is a general term of an enzyme can catalyze the hydrolysis of the peptide bond,widely exists in plants and microorganisms.With the development of aquaculture,protein resource problems are increasingly prominent.Protease as a highly efficient,environmentally friendly and safe feed additives can not only improve the nutritional value of plant protein raw materials such as soybean meal,rapeseed meal,cottonseed meal,etc,as well as improve feed raw materials,improve animal growth performance,enhanced immunity and reduce environmental pollution of N and P,and so on.This topic closely based on actual production,with rapeseed meal and soybean meal as its main raw material,using protease for their solutions,then studied the enzymatic hydrolysis of protease under different conditions and investigated the enzymatic hydrolysis of protease and other enzymes.Then,the synergistic effect of digestive enzyme and protease was studied.Finally,the results of this study were verified by animal experiments.The results were as follows:In the study of enzymatic hydrolysis of plant protein,rapeseed meal and soybean meal were used as the raw materials,and crude protein content and small peptide content were used as the index.When using single enzyme,the effects of different enzyme dosage,enzymolysis time,enzymolysis temperature and material to liquid ratio on enzymatic hydrolysis were studied by single factor method.Results showed that the conditions of enzymatic hydrolysis of rapeseed meal suitable for enzyme concentration 3.5%,extraction time 4h,enzymatic hydrolysis temperature of 35 ?,material to liquid ratio 1:8;suitable for enzymatic hydrolysis of soybean meal as the enzyme concentration 2.5%,extraction time 4h,enzymatic hydrolysis temperature of 35 ?,material to liquid ratio 1:8.In the experiment of the determination of acid soluble protein and small peptide,results show that the date of the filtering methods just below the date of the centrifugal method,and the difference between the results of centrifugal speed 5500 r/min and 11000 r/min is not obvious(P>0.05).So centrifugal method is recommended to take supernatant,speed can be set to 5500 r/min.When using complex enzyme,the synergistic digestion of cellulase,lipase and protease was studied by stepwise and synchronized enzymatic hydrolysis.Results showed that,there was no significant difference in the content of small peptides between synchronized enzymatic hydrolysis and single protease hydrolysis(P>0.05),and the content of small peptides of stepwise enzymatic hydrolysis was significantly higher than that of single protease hydrolysis(P<0.01).In the simulated fish intestinal digestion test,using fish meal,rapeseed meal and soybean meal as raw material to study the synergistic digestion of protease and intestinal fluid in grass carp and tilapia.The results showed that adding 0.25% protease in grass carp and Tilapia intestinal fluid could significantly increase the content of small peptide(P <0.01).In the evaluation experiment of the animal feeding effect of the protease,the protease was added in the basal diet formulation of the experimental group,to study the effect of adding proteinase on the quality and growth performance of grass carp.The results showed that adding proper amount of protease in feed,grass carp weight gain rate is improved and the feed coefficient decreased significantly(P<0.05).Relative fatness,organ-body ratios,ratio of liver weight and body weight and ratio of rat to body weight have decreased,suggesting that enzyme helps improve the digestibility of the protein,and also had a positive effect on the morphological indexes of fish,but the difference was not obvious.