Study On Predigested Grape Seed Meal Based On Biological Fermentation And Its Application Effect On Yellow Feather-broiler

Objective:In this experiment,grape seed meal was predigested with probiotics and feed proteases to obtain the optimal technological parameters for predigestion,and bacteriase synergistic fermentation was prepared to predigest grape seed meal.On this basis,the predigested grape seed meal was further added to the diet of yellow feather broilers,and its application effect on yellow feather broilers was revealed through the evaluation of growth performance,slaughter performance,serum biochemistry and antioxidant function of yellow feather broilers,providing a theoretical basis and practical reference for the development and efficient utilization of grape seed meal,an exogenous feed in Xinjiang.Methods:Experiment 1: The technological parameters of grape seed meal predigestion based on in vitro enzymatic hydrolysis were studied.According to the characteristics of grape seed meal raw materials,five proteases including acid protease,neutral protease,alkaline protease,flavor protease and papain were selected for enzymatic digestion and pre-digestion,respectively,and the contents of acid-soluble protein,acid detergent fiber and volatile salt-based nitrogen were used as evaluation indicators to determine an optimal pre-digestion protease.On this basis,acid-soluble protein was used as an index to optimize the subsequent process parameters for the optimal addition of predigested protease.Experiment 2: Study on the pre-digestion process parameters of grape seed meal based on biological fermentation.Grape seed meal was used as the substrate,and Saccharomyces cerevisiae,Pseudomonas tropicalis,Lactobacillus acidophilus,Lactobacillus bulgaricus,and Bacillus subtilis were used for biofermentation predigestion,respectively,and an optimal bacterium was selected using acid-soluble protein,volatile salt-based nitrogen,and acid detergent fiber as evaluation indicators.On this basis,acid-soluble protein was used as an index to study the parameters of single factor experimental design for bacterial solution inoculum size,fermentation temperature,fermentation time and substrate water content,and three better levels were further selected,respectively,and four-factor three-level orthogonal design was used in order to determine the optimal biofermentation strains and their process parameters.Experiment 3: Study on fermentation of grape seed meal and its fermentation substrate nutrient components by bacteriase.On the basis of the above predigestion process,grape seed meal was fermented by bacteriase synergistically,and its in vivo and in vitro extravasation characteristics were analyzed.The analytical parameters include conventional nutritional components such as dry matter,crude protein,crude fat,and crude fiber and small molecule metabolic components,of which the analysis of small molecule components uses untargeted metabolomics methods.Experiment 4: The effects of fermented grape seed meal on growth performance,slaughter performance,serum biochemical and antioxidant parameters of yellow-feathered broilers.Two hundred and forty healthy14 male yellow feather broilers were randomly divided into 4 groups: 0%(group I),2%(group II),4%(group III)and 6%(group IV)fermented grape seed meal.The growth performance,slaughter performance,serum biochemical and antioxidant parameters of broilers were measured to study the application effect of fermented grape seed meal on broilers.Results:(1)Experiment 1: Acid protease was the best for enzymatic hydrolysis,in which the acid-soluble protein content was 0.77%,the specific parameters were substrate water content 40%,fermentation time 48 hours,fermentation temperature 37 ℃,and enzyme addition of 120U/g.(2)Experiment 2: The pre-digestion effect of grape seed meal fermented by Saccharomyces cerevisiae was better than that of other probiotics,and the specific parameters were substrate water content 45%,fermentation time 48 h,fermentation temperature 30 ℃,bacterial solution inoculum size 6%,and acid-soluble protein content0.55% under this condition.(3)Experiment 3: Through the screening of the combination of proteases and probiotics,it was determined that the combination of Saccharomyces cerevisiae and acid proteases synergistically hydrolyzed grape seed meal was superior to other combinations.Compared with the control group,the contents of acid-soluble protein and crude protein in the test group were increased,and the contents of neutral detergent fiber and acid detergent fiber were decreased.Based on the results of non-target metabolome analysis,synergistic fermentation of grape seed meal by bacterial enzymes caused changes in multiple metabolic pathways including ABC transporters,biosynthesis of amino acids,galactose metabolism and linoleic acid metabolism,and the main metabolic differences were classified in organic acid,polypeptide and carbohydrate metabolism.(4)Experiment 4: The average feed intake of broilers in the group treated with fermented grape seed meal was significantly higher than that in group I from 14 to 35day(P<0.05).At 56 day,the leg muscle rate of broilers treated with fermented grape seed meal was significantly higher than that of group I(P<0.05),the abdominal fat rate of broilers in group IV was significantly lower than that of group I(P<0.05),and the subcutaneous fat thickness of broilers in group III was significantly higher than that of group I and IV(P<0.05).Group III significantly decreased the total cholesterol concentration and urea nitrogen content in the serum of broilers and significantly increased the serum total protein concentration of broilers throughout the experimental period(14～56 day)(P<0.05).In the early stage of the experiment(14～35 day),the activity of superoxide dismutase in group IV was significantly higher than that in the other three groups(P<0.05);in the late stage of the experiment(36～56day),the malondialdehyde content in the treatment group supplemented with fermented grape seed meal was significantly higher than that in group I(P<0.05).Therefore,adding 4%～6% fermented grape seed meal to the diet of yellow-feathered broilers can improve the growth performance and antioxidant capacity of broilers.Conclusion: When grape seed meal was fermented by acid protease and Saccharomyces cerevisiae,compared with probiotic fermentation and protease enzymatic hydrolysis alone,the fermentation quality could be improved.The specific fermentation conditions were substrate water content 45%,fermentation time 48 h,fermentation temperature 30 ℃,bacterial solution inoculum size 6%,and enzyme addition120U/g.The fermentation of grape seed meal by bacteriase can increase the content of acid-soluble protein and crude protein,decrease the content of neutral detergent fiber and acid detergent fiber,and also cause the change of small molecules such as organic acids,peptides and sugars.Fermented grape seed meal added to broiler feed can significantly improve the growth performance of yellow-feathered broilers,improve their slaughter performance and antioxidant performance,the appropriate amount of supplementation is 4%～6%.