Optimization Of DDGS Technology Of Solid State Fermented Corn And Its Effects On Growth Performance And Tissue Morphology Of Broilers

The purpose of this study was to study the reduction of mycotoxin content in corn distillers dried grains and soluble substances（corn DDGS）by solid state fermentation,so as to provide a theoretical basis for improving the quality of corn DDGS and increasing the use of corn DDGS in feed.Three kinds of probiotics were selected to optimize the solid-state fermentation conditions of DDGS by single factor and response surface tests.The degradation rate of mycotoxin content in corn DDGS was used as the index of comprehensive score.After determining the optimized fermentation conditions,the changes of mycotoxin content,nutrient composition and in vitro digestibility of corn before and after DDGS fermentation were analyzed.The application effect of fermented corn DDGS in yellow-feathered broilers was evaluated by animal experiment.1.Optimization of DDGS process conditions for solid state fermentation corn.The inoculation ratio of 3 bacteria was designed by orthogonal experiment,and the inoculation ratio of devos bacterium JA3,Bacillus subtilis ANSB01G and Bacillus subtilis ANSB060 was determined to be 1:1:2.The optimum conditions for DDGS of solid-state fermented corn were determined by single factor test and response surface test with inoculating amount,liquid-solid ratio,fermentation temperature and fermentation time as variables.The results showed that the optimal conditions for solid-state fermentation of DDGS of corn were as follows:inoculum volume of 1%,liquid-solid ratio of 1.25,fermentation temperature of 37℃,and fermentation time of 29.5 h.Under these conditions,the DDGS mycotoxin content was effectively reduced by solid state fermentation.2.Study on nutritive characteristics of DDGS of solid state fermented corn.The content of mycotoxin,nutrient composition and in vitro digestibility of DDGS of corn before and after fermentation were determined according to the optimized conditions.The results show that:Solid state fermentation could effectively degrade mycotoxins,and the contents of three common mycotoxins in fermented corn DDGS were significantly decreased（P<0.05）.The degradation rate of vomitoxin（DON）was 81.69%（P<0.05）,zalanenone（ZEN）was 55.18%（P<0.05）,and aflatoxin B₁（AFB₁）was 41.14%（P<0.05）.Solid state fermentation could significantly increase the content of nutrients,among which,crude protein（CP）and amino acid（AA）content in fermented corn DDGS was significantly increased（P<0.05）;Ash（Ash）content was significantly increased from 8.22%to 8.90%（P<0.05）,ether extract（EE）content was significantly increased from 10.48%to 11.05%（P<0.05）,and crude fiber（CF）content was significantly decreased from 9.66%to 6.05%（P<0.05）.The in vitro digestibility of dry matter（DM）,crude protein（CP）and CF of fermented corn DDGS were significantly increased（P<0.05）.The nutritional value and quality of corn DDGS were improved by solid state fermentation.3.Effects of fermented corn DDGS on growth performance and histopathology of broilers.A total of 420 one-day-old healthy yellow-feathered broilers were randomly divided into 7 treatments with 6 replicates per treatment and 10 broilers per replicate.The experiment lasted for 42 days and was divided into two feeding stages:1-21 days in the early stage and 22-42 days in the late stage.The control group was fed the basal diet.The other 6groups were supplemented with 5%corn DDGS（test group 1）,10%corn DDGS（test group2）,15%corn DDGS（test group 3）,5%fermented corn DDGS（test group 4）,10%fermented corn DDGS（test group 5）and 15%fermented corn DDGS（test group 6）,respectively.The results showed as follows:（1）The content of FCR in test groups 1,2 and 3 was significantly increased（P<0.05）,while the body weight（BW）,average daily feed intake（ADFI）and average daily gain（ADG）of broilers in test groups 5 and 6 were significantly increased,and the ratio of feed to meat（FCR）was significantly decreased（P<0.05）.Compared with test groups 1,2 and 3,test groups 4,5 and 6 significantly increased BW,ADFI and ADG,and significantly decreased FCR of broilers（P<0.05）.（2）Compared with the control group,the serum malondialdehyde（MDA）content in test groups 1,2 and 3 was significantly increased（P<0.05）,and the total antioxidant capacity（T-AOC）in test group 3 was significantly decreased（P<0.05）.Serum glutathione peroxidase（GSH-Px）activity in test groups 4,5and 6 was significantly increased（P<0.05）.Compared with test groups 1,2 and 3,the contents of T-AOC and GSH-Px in test groups 4,5 and 6 were significantly increased,while the content of MDA was significantly decreased（P<0.05）.（3）Pathological changes occurred in liver,heart and intestinal tissues of broilers in test groups 1,2 and 3,resulting in different degrees of damage.There was no difference between trial 4,Trial 5,and trial 6compared to the control group.The distribution of liver cells was orderly and the cell outline was clear.The myocardial tissue structure was normal,the myocardial fibers were tightly arranged and orderly,and there was no inflammatory cell infiltration in the tissue.The intestinal structure was normal,the intestinal villi was long,and the mucosal epithelial cells were closely arranged and orderly.（4）Compared with the control group,the villus height（VH）and crypt depth（CD）in test groups 2 and 3 were decreased,and the VH/CD value was significantly decreased（P<0.05）,and the VH and VH/CD values in test groups 5 and 6were significantly increased（P<0.05）.Compared with test groups 1,2 and 3,VH and VH/CD values in test groups 5 and 6 were significantly increased（P<0.05）.DDGS of fermented maize effectively improved the adverse effects caused by DDGS of maize and provided scientific basis for the application of DDGS of fermented maize.