A Study on Screening and Breeding of High-yield Lactic Acid Bacteria and the Nutritional Characteristics of Fermented Cottonseed Meal
|Course||Animal Nutrition and Feed Science|
|Keywords||Lactobacillus acidophilus solid fermentation fermentation cottonseed meal chicken serum metabolites|
Objective:Lactobacillus acidophilus was selected as starting strain in this study, screening out Lactobacillus acidophilus with properties of high-yield acid, through the optimization of fermentation condition parameters, bottom material composition, inoculation amount of the selected breeding strains with cottonseed meal and corn as solid fermentation substrate to explore the metabolic components and nutritional value of fermentation products of the breeding Lactobacillus acidophilus strains, and the effects on growth performance, blood physical and chemical indicators and immune indexes of broiler chicken, therefore providing theoretical support for the comprehensive assessment and rational utilization of fermentation cottonseed meal of Lactobacillus acidophilus.Method:This research is composed by four parts. Experiment1:Choose a good strain with higher acid produce and better growth through S1, W2and J2Lactobacillus acidophilus, and identify it as Lactobacillus acidophilus. Experiment2:In order to optimize biology forage fermentation parameters of Lactobacillus acidophilus,4factors5levels orthogonal and two factors with repeated observed value design method were combined through the lactic acid content of ferment substrate to determine fermentation condition parameters, bottom material composition and inoculation proportion. Experiment3: Lactobacillus acidophilus S5, W2and J2were selected according to the optimized conditions for ferment cottonseed meal, set four groups:CK、S5、W2、J2, respectively, to study the variation of organic acid, Vitamin B and free amino acid content. Experiment4:To study the effects of Lactobacillus acidophilus fermentation cottonseed meal on growth performance, blood physical and chemical indicators and immune indexes of broiler chicken,1001-day-old AA broiler chicken were selected to separate randomly into2groups in this experiment,5repeats each group, and10in each repeat. CK add6%no-fermentation cottonseed meal, the others add6%Lactobacillus acidophilus fermentation cottonseed meal.Results:Experiment1:Acid product amount of S5strain reached2.14g/L after fostering for36h, through physiology and biochemistry identification and16SDNA complete sequence analytical method to ascertain its species, and then confirm homologous gene by Gene Bank comparison, use DNAMAN software to draw phylogenetic tree, and identify it as Lactobacillus acidophilus. Experiment2:The optimized fermentation conditions parameters of Lactobacillus acidophilus biology forage are as follows:fermentation temperature is37℃, fermentation time cycle is48h, initial moisture of the substrate is30%and pH6; the optimized results of bottom material composition and inoculation amount are as follows:bottom material composition is90%cottonseed meal and10%corn, inoculation amount is50ml/kg. Experiment3:Compared to CK, S5group pentanoic acid content significantly improved49.32%, succinic acid and citric acid significantly decreased77.57%and1.93%, VB1,VB2and VB5content highly significantly increased28.53%,50.91%and89.47%(P<0.01), leucine and lysine highly significantly increased19.84%and33.63%(P<0.01) respectively; Ⅲ group pentanoic acid and citric acid significantly improved79.82%and10.77%(P<0.01), VB,, VB3and VB5content highly significantly reduced19.43%,91.35%and23.52%(P<0.01), leucine and phenylalanine significantly decreased16.64%and4.43%(P<0.01);Ⅳ group pentanoic acid and succinic acid content highly significantly increased127.19%and14.95%(P<0.01), VB1,VB2, VB3and VB5highly significantly decreased44.54%,23.50%,91.47%and23.52%(P<0.01) respectively. Experiment4:After adding Lactobacillus acidophilus fermentation cottonseed meal,(1) in0-42-day-old, compared to CK, average daily food consumption and average daily gain significantly increased10.20%and15.41%(P<0.05), forage weight proportion decreased4.63%(P>0.05);(2) in0-21-day-old, albumin and total protein significantly increased10.64%and5.68%(P<0.05), Ca and P improved7.31%and11.62%, but the difference is not significant (P>0.05), triglyceride significantly increased23.73%(P<0.05), total cholesterol significantly decreased6.72%(P<0.05);(3) in21-42-day-old, albumin improved2.86%, but the difference is not significant (P>0.05), total protein significantly increased8.14%(P<0.05), triglyceride significantly increased9.68%(P<0.05), total cholesterol decreased25.49%(P<0.01); serum immunoglobulins (IgG、IgA、IgM) content is significantly improved (P<0.05).Conclusions:Experiment1:Selected and breed a strain Lactobacillus acidophilus S5with better acid production. Experiment2:Ascertained the optimal biological fermentation forage parameters for acid production of fermentation metabolite, temperature is37℃, fermentation time cycle is48h, initial moisture of the substrate is30%and pH6; The optimized bottom material composition is90%cottonseed meal and10%corn, inoculation amount is50mL/kg. Experiment3:Organic acid, Vitamin B and free amino acid content of fermentation products differ because of strain type. After fermentation of cottonseed meal, organic acid, Vitamin B and free amino acid content of strain S5were significantly improved. Experiment4: Add Lactobacillus acidophilus fermentation cottonseed meal in daily forage of broiler chicken can improve its growth performance, blood physicochemical indexes and immune properties.