| Cotton industry is the pillar industry in Xinjiang,China.In 2022,cotton production in Xinjiang accounted for more than 90% of the total of China.Cotton straw is the main byproduct of cotton.The output of cotton straw in Xinjiang was huge,exceeding 20 million tons,especially concentrated in Kashgar,Aksu,Bayingol and other places.Aiming at the problems of hard texture,poor taste and low direct feeding efficiency of cotton straw,the method of bacteria-enzyme synergism fermentation was discussed to explore new feed resources,so as to realize efficient utilization of cotton straw.The feeding value of its was verified through feeding mutton sheep trial,which provided a scientific evidence for the promotion and utilization of fermented cotton straw(FCS)in the mutton sheep industry.The cotton straw was fermented by mixture of lactic acid bacteria,yeast and bacillus for 56 days and fed to mutton sheep after the nutrients and feed hygiene indices were measured.Sixty four-month-old ram(Duolang sheep♂×Karakul sheep♀)in great condition(BW 28.82±3.35 kg)were randomly divided into 5 groups,4 replicates per group,3 sheep per replicate.The groups were CON(Control group),LFC(Low-proportion fermented cotton straw group,FCS-14.50%),HFC(High-proportion fermented cotton straw group,FCS-29.00%),MIC(Microbial group,compound probiotics include Bacillus licheniformis,Bacillus subtilis & yeast)and MEY(Microbial and enzymatic preparation group,include compound probiotics,cellulase,xylanase,β-glucanase,amylase & protease).The trial lasted for 11 weeks,including 2 weeks for transitional trail,2 weeks for adaption and 7 weeks for growth trial,which were divided into two stages: 4 weeks in the first stage(day 1-day 28)and 3 weeks in the second stage(day 29-day 49).The body weight of each sheep was weighed before morning feeding on the day 1,day 28 and day 49 of the growth trial,and the feed intake was weighed daily in order to calculate the ratio of feed and gain(F/G).Blood and rumen fluid samples were collected on the day 28 and day 49 of growth trial for the serum indices and rumen microbial diversity measurement.The main results are as follows:1.Through bacteria-enzyme synergism fermentation,the nutrient level of cotton straw has been significantly improved(P<0.05),crude protein level increased by 1.46%,and the levels of neutral detergent fiber as well as acid detergent fiber decreased by 12.60% and10.87%,respectively;The level of feed hygiene has been significantly improved(P<0.05),the residues of Aflatoxin B1,vomitoxin,zearalenone,free gossypol decreased by 27.58%,51.06%,22.00% and 45.83%,respectively.2.In the second stage of growth trial,the ratio of feed and gain(F/G)of the LFC group was 6.21,significantly lower than that of the CON group(9.55)(P<0.05).LFC group had the lowest F/G of the whole period(5.53).3.At the end of the trial,the levels of total cholesterol(TC),triglyceride(TG),urea(UREA),and beta-hydroxybutyrate(BHBA)in each treatment group were significantly lower than those in the CON group(P<0.05),and the MEY group was the lowest;the levels of acetoacetyl coenzyme A(Ac Co A)and growth hormone(GH)in each treatment group were significantly higher than those in the CON group(29.98 mmol/L and 3.49 ng/m L)(P<0.05),and MEY had the highest value(66.00 mmol/L and 9.32 ng/m L).4.At the end of the trial,there were significant differences in superoxide dismutase(SOD),malondialdehyde(MDA)and total anti-oxidation capacity(T-AOC)between groups(P<0.05).The levels of SOD and T-AOC in each treatment group were significantly higher than those in the CON group(P<0.05),the maximum value was in the MEY group.Among them,the T-AOC levels of MEY and CON were 14.65 U/m L and 6.64 U/m L,respectively.The MDA level in treatment group was significantly lower than that in the CON group(P<0.05),and the minimum value was in the MEY group.5.At the end of trial,the p H value of rumen fluid in each treatment group was higher than that in the CON group,and the maximum value was in the MEY group,the p H value in each group was within the normal range.Effects of fermented cotton straw on rumen microflora diversity of mutton sheep were observed.Fermented cotton straw made the rumen microbial community richness and diversity higher than CON,MIC and MEY group.Rumen microflora of mutton sheep in different groups was significantly separated(P<0.05).6.The abundance of Prevotella in the LFC,HFC group was higher than that in other groups;the abundance of Oscillospiraceae＿NK4A214＿group in each treatment group(except MEY group)was higher than that in the CON group.In summary,the diet with low--proportion fermented cotton straw has the best short-term(about 50 days)fattening effect of mutton sheep,and improve the utilization rate of fat,protein and the antioxidant capacity of mutton sheep.Fermented cotton straw may enhance the production performance of mutton sheep by increasing the abundance of bacteria related to the utilization of protein,carbohydrate and other nutrients. |
