Study On Optimization Of Enzymatic Hydrolysis Parameters Of Feather Meal And Its Feeding Value To Broilers

Based on the high temperature and high pressure hydrolysis of feathers,the enzymatic hydrolysis parameters of feather meal were studied by single factor and response surface trial methods,combined with the soluble protein content of the enzymatic hydrolysate and the relative molecular weight of peptides,the optimal enzymatic hydrolysis parameters of feather meal were further optimized.On this basis,the effects of 2%enzymatic hydrolyzed feather meal or 2%hydrolyzed feather meal instead of soybean meal on broiler growth performance,feed utilization,slaughter performance and meat quality were compared,and the mechanism was studied by analyzing the apparent metabolic rate of feed nutrients and serum related biochemical indicators.A total of 720 1-day-old male broilers were divided into 3 groups with 6 replicates each,40 broilers per replicate.Group 1 broilers were fed corn-soybean meal basic diets,group 2 were fed diets containing 2%hydrolyzed feather meal,and group 3 broilers were fed diets containing 2%enzymatic hydrolyzed feather meal.The trial was divided into Early stage(1-21 d),Middle stage(22-42 d),Finisher stage(43-63 d).Metabolic and slaughter experiments were carried out at 43 days and 64 days of ages,respectively.The results are as follows:1.The optimal enzymolysis parameters of feather meal per gram indicated that:keratinase(7×104 U/g)3.5 mg,alkaline protease(2×105 U/g)1.8 mg,pH 11.4,44.4℃,5.4 h.The soluble protein content of the enzymatic hydrolysate was up to 681.95μg/mL,and the content of low molecular weight peptide(less than 2000 Da)was more than 95%.The feather degradation rate was 75.40%,and the pepsin digestibility rate in vitro was 85.41%.2.The results of feeding trial showed that there was no significant difference in average daily gain and feed intake among all groups(P<0.05),but the feed gain ratio of the enzymatic hydrolyzed feather meal group was decreased by 3.24%(P<0.05)and 3.63%(P<0.05)compared with the control group and the hydrolyzed feather meal group.3.The results of slaughter performance indexes determination indicated that there was no significant difference in slaughter rate and evisceration rate among all groups(P>0.05).4.The results of meat quality indexes determination showed that there were no significant difference in the pH value and the drip loss among all groups(P>0.05).5.The results of metabolic trial manifested that the apparent metabolic rate of crude protein of enzymatic hydrolyzed feather meal group was increased by 12.92%(P<0.01)compared with the control group,but there was no significant difference compared with the hydrolyzed feather meal group(P>0.05).The apparent metabolic rate of amino acids of enzymatic hydrolyzed feather meal group was higher than control group(P<0.05),but there was no significant difference compared with the hydrolyzed feather meal group(P>0.05).6.The results of biochemical indexes determination in serum revealed that the concentration of uric acid of enzymatic hydrolyzed feather meal group was decreased by 8.98%(P<0.01)and 13.03%(P<0.01)compared with control group and enzymatic hydrolyzed feather meal group respectively,and there were no significant difference among all groups in total protein and albumin level(P>0.05).7.The results of free amino acid indexes determination in serum indicated that there was no significant difference among all groups(P>0.05).The above results indicate that replacing soybean meal with 2%enzymatic hydrolyzed feather meal can significantly increase the apparent metabolic rate of feed protein and amino acids,decrease the serum uric acid level,and achieve the effect of improving feed conversion rate,which is generally better than hydrolyzed feather meal.