Effects Of Fermented Flammulina Velutipes Residue On Growth Performance,Meat Quality,Rumen Fermentation And Microbiota Of Hu Sheep In Fattening Period

This project aimes at the problem that the yield of Flammulina velutipes residue is large and can not be used reasonably.Flammulina velutipes residue was treated by solid-state fermentation with probiotics to transform it into high-quality feed for ruminants.Firstly,the compatibility of Flammulina velutipes residue and its fermentation parameters were optimized.Then,the effects of Flammulina velutipes residue on growth performance,meat quality and rumen microbial community composition of Hu sheep were studied.The results of this project provide data for the feed utilization of agricultural wastes such as Flammulina velutipes residue.1.Optimization of compound strains compatibility and fermentation parameters of Flammulina velutipes residueFirstly,the compound strain compatibility of fermented Flammulina velutipes residue was optimized.According to the ratio of Lactobacillus plantarum L₁:Saccharomyces cerevisiae Y₂:Bacillus subtilis B₆,four groups（L₁:Y₂:B₆=1:1:1,2:2:1,2:1:2,and 1:2:2）were performed in the present study,and each group has 4 repetitions.Flammulina velutipes residue,bran and corn flour were mixed in a ratio of 6:3:1 as fermentation substrates,and then 10%compound microbe solution was mixed with the fermentation substrate.After fermented at 37℃for 7 days,the p H,lactic acid,viable cell count,ammonium nitrogen,reducing sugar,acetic acid,propionic acid,butyric acid,neutral detergent fiber,acid detergent fiber of fermentation substrate were measured.The results showed that viable microbe count in the group 3 and 4 was significantly higher than that the group 1 and 2（P<0.05）,and the content of NH₃-N of the group 3 was significantly lower than that the group 1,2 and 4（P<0.05）.The content of propionic acid in the group 1 and 2was significantly higher than that in the group 3 and 4.We found that the group 3 had the highest comprehensive score（0.901）by the TOPSIS analysis.Therefore,the optimized compatibility of microbial culture for fermenting Flammulina velutipes residue was L₁:Y₂:B₆=2:1:2.Then,the fermentation parameters were optimized by controlling the fermentation temperature（33°C,35°C,37°C）,moisture content（50%,60%,70%）,incubation time（5 days,7 days,9 days）and the rate of microbial inoculation（5%,10%,15%）.A L9（3⁴）orthogonal experiment design was used and 9 trial groups were set up.The results showed that the first group had the highest score（0.846）by TOPSIS analysis.In addition,we found that the crude protein content was significantly increased after fermentation（P<0.05）.In summary,the optimized fermentation parameters was rate of microbial inoculation,5%;fermentation temperature,33℃;moisture content,50%;and incubation time,5 days.2.Effects of fermented Flammulina velutipes residue on growth performance,meat quality and economic benefits of Hu sheep during the fattening periodIn this experiment,14 male Hu sheep in during the fattening period were randomly divided into two groups according to the principle of similar body weight and age,The control group（CON,n=7）was fed with the basal diet,and the trial group（FMR,n=7）was fed a diet with 17.5%fermented Flammulina velutipes residue replaced of wheat bran（14.7%）and corn（2.3%）in the basal diet.This experiment lasted 7 weeks.The feed intake was recorded every day and weighing was carried out weekly.Blood samples were collected from jugular vein before morning feeding on the 47th day.All sheep were slaughtered on the 49th day.The longissimus dorsi muscle samples were collected.The results showed that there were no significant differences for the feed/gain ratio and average daily gain between the control and trial group（P>0.05）.The activity of alkaline phosphatase（ALP）,alanine aminotransferase（ALT）,aspartate aminotransferase（AST）and L-lactate dehydrogenase in the serum were not significantly affected by treatment（P>0.05）.The total protein,albumin and globulin in the serum were not significantly affected by treatment（P>0.05）.Triglyceride and cholesterol glucose in the serum were not significantly affected by treatment（P>0.05）.The muscle p H_{45 min} in the trial group was significantly higher than that in the control group（P<0.05）,while the shear force was significantly lower than that in the control group（P<0.05）.During the experiment,the average feed cost per kilogram gain of Hu sheep in the trial group was reduced by 0.94yuan compared with that in the control group.In summary,the addition of 17.5%fermented Flammulina velutiformis residue in the basal diet to replace a part of concentrate did not affected the growth performance,the blood biochemical measurements,while.improved the muscle tenderness,reduced feed cost and improved the income.3.Effects of fermented Flammulina velutipes residue on rumen fermentation parameters and microbial community structure in rumen of Hu sheepThe rumen liquid and content samples of Hu sheep were collected after sheep were slaughtered.The rumen p H,volatile fatty acid content and bacterial community structure were analyzed.The results showed that compared with the control group,the p H value of rumen fluid in the trial group was not significantly different（P=0.790）,but the concentration of acetic acid,propionic acid,and total volatile fatty acids was significantly increased（P<0.05）,while butyric acid,valeric acid,and ethylene-propylene ratio had no significant difference（P>0.05）.The results of high-throughput sequencing for rumen bacteria showed that compared with the control group,the OTU number（P=0.025）and Shannon index（P=0.006）of the trial group were significantly increased,the Simpson index was significantly reduced（P=0.025）,and the Chao1 index had a tendency to increase（P=0.055）.PCo A analysis showed that there were no significant difference in the bacterial community structure between the two groups（ANOSIMR,R=0.075,P=0.101）.There was no significant difference in the relative abundance between the two groups at the phylum level（P>0.05）.At the genus level,171 genera were formed,of which 33 genera had relative abundance greater than 1%,and 25 dominant genera were further analyzed in the following.Compared with the control group,the relative abundance of Unclassified Veillonellaceae in the trial group was significantly increased（P=0.018）,Blautia was significantly reduced（P=0.035）,Unclassified Prevotellaceae had an increasing trend（P=0.085）,and there was no significant difference for other genera（P>0.05）.In conclusion,the addition of 17.5%fermented Flammulina velutiformis residue in the basal diet to replace a part of concentrate did not affected the rumen bacterial community composition,but changed the rumen fermentation parameters.