Study On Improving The Utilization Efficiency Of Corn Straw Feeding Sheep

A large amount of the agricultural residues（straw,chaff and shell）left are incinerated or accumulated,which has been one of the environment pollution sources.China is an agriculture-based country,which produces a variety of crops in huge amount and thus resulting in a more serious problem of environmental pollution.According to statistics data,suitable feeding crop straw resource was 6.26×10¹¹kg in cereal equivalent form in 2015.It is thus clear that straw feed has great potential for development.Agricultural residue is a major source of ruminant roughage feed.However,straw was limited as ruminant feed due to low protein and mineral contents,poor digestibility and high lignin.Thus,applying scientific methods to remedy or improve nutrient value and degradation rate of straw will be important basis work for enhancing straw resource feed.This research investigate the effect of supplementing with concentrate levels,phosphorus and sulfur levels and edible fungi fermentation on feeding,nutrient value and digestibility.Results showed that:（1）This experiment was conducted to investigate the effects of different concentrate to roughage ratios on the sheep feeding.Five roughage to concentrate ratios were 100:0,80:20,60:40,40:60 and 20:80,respectively.The results showed that dry matter intake,average daily gain（ADG）,apparent digestibility of DM,CP,ADF increased with the increasing of concentrate to roughage ratios.Feed to gain ratio（F/G）was lowest in diet with concentrate to roughage ratios of 40:60.This indicated that supplement with concentrate can improve the apparent digestibility of DM,CP and ADF.The ruminal pH and acetic acid concentration decreased,while the concentration of NH₃-N,propanoic acid,butyric acid and ruminal TVFA increased with increasing of concentrate to roughage ratios.The ruminal TVFA was highest in diet with concentrate to roughage ratios of 40:60.The pH value,shear force,drip loss intramuscular fat content,L^*,a^*,b^*and drip loss were improved through the supplement of concentrate.The concentration of saturated fatty acid（SFA）increased and concentration of polyunsaturated fatty acid decreased with increasing concentrate contents in diet.PUFA/SFA was optimal in diet when concentrate content under 40%.The n-6/n-3 was lowest and obtain first-rate economic benefits in diet with concentrate to roughage ratios of 60:40.（2）This experiment was conducted to investigate the effects of three levels of dietary phosphorus（0.25%,0.35%,0.45%）and sulfur（0.16%,0.36%,0.56%）on feed intake and apparent nutrient digestibility of sheep.Trial was designed as 2×3 design,and divided into 9 groups:A group（0.25%,0.16%）,B group（0.25%,0.36%）,C group（0.25%,0.56%）,D group（0.35%,0.16%）,E group（0.35%,0.36%）,F group（0.35%,0.56%）,G group（0.45%,0.16%）,H group（0.45%,0.36%）and I group（0.45%,0.56%）.The results showed that DM feed intake decreased with increasing of sulfur level diet,under same phosphorus level diet,and vice versa.The variation trend of ADF and NDF is consistent with that of DM.Apparent digestibility of DM and CP were highest in C group,apparent digestibility of NDF was highest in F group.Apparent digestibility of ADF was highest in I group,and the difference was not significant compared with the C group and the F group.The dietary phosphorus intake and total phosphorus excretion were observed to be the highest in D group.The apparent digestibility of phosphorus was positively correlated with the phosphorus level in the diet.The sulfur level addition increased the sulfur intake,urine phosphorus,fecal phosphorus and total sulfur excretion.However,the phosphorus level addition in the diet decreased the sulfur intake,urine phosphorus,fecal phosphorus and total sulfur excretion.The apparent digestibility of sulfur was highest in diet with F group.In conclusion,the phosphorus sulfur level of C group and the F group were the best option for improving the utilization efficiency of corn straw.（3）In this experiment,Pleurotus diamor,Pleurotus citrinopileatus,Pleurotus eryngii and Pleurotus sajor caju were selected to pretreatment corn stover for 21 days under solid state conditions.Comparison between control group and edible fungi group,edible fungi were able to degrade biomass and enhance the nutrient component and in vitro dry matter digestibility（IVDMD）.Pleurotus citrinopileatus degrade maximum cellulose（9.26%）and hemicelluloses（HC）（16.14%）and enhance maximum crude protein（CP）（48.52%）,ether extract（EE）（35%）and amino acid（43.39%）.Pleurotus sajor caju degrade maximum acid lignin（28.59%）and IVDMD（56.94%）.All the fungi pretreatment corn stover were higher antioxidant activity.Pleurotus sajor caju was found to be higher total phenol（7.27 mg/g）and antioxidant activity compared to the other treatment groups.（4）The present study was conducted to investigate the varition pattern of nutritive material（DM,CP,NDF,ADF）of fermented stover,autoclaved stover and control stover of degradation rule in rumen the using nylon bag technique.Six sheep were used to study on the effect of edible fungi fermented straw on rumen degradability using in situ method at incubation times of 0,2,4,6,12,24,48,and 72h.The results revealed that the DM,CP,NDF,ADF of corn stover were higher digestibility by four edible fungi fermented,which were rapidly degraded within 24 to48 h.The digestibility of nutritive material was highest by Pleurotus sajor caju fermentation.Compare to the autoclaved stover,The digestibility of DM,CP,NDF,ADF increased 31.14%,41.75%,30.23%,114.41%,respectively.The degradation model parameters the soluble fractions at time zero（a）,insoluble degradability fractions（b）,rate of degradation（c）and effective degradability（P）were observed to be the optimal nutrition value of corn stover by Pleurotus sajor caju fermentation.DM,CP,NDF,ADF of potential degradability（a+b）increased 72.74%,89.47%,39.95%and 35.2%,respectively,P component increased 22.91%,123.89%,37.14%and 31.72%,respectively.In conclusion,the degradation rule of fermented straw in rumen estimated that Pleurotus sajor caju is an optimal the strain of fermentation.（5）The objectives of this study were to determine an optimal cultivation time for Pleurotus sajor caju fermented corn stover under solid state conditions.The study on an optimal fermentation time for Pleurotus sajor caju fermented corn stover was determined 20 d,25 d,30 d,35 d,40 d,45 d,and 50 d.The results revealed that CP content significantly increased and DM,NDF,ADF,HC,CL and ADL content decreased with the increasing fermentation time.ADL degradation rate was higher HC and CL.The effective degradability of DM,NDF,ADF,HC,CL and ADL were highest at fermentation 35 d by Pleurotus sajor caju,followed by fermentation 30 d or40 d.The effective degradability of CP was highest at fermentation 50 d,followed by fermentation 45 d,40 d and 35 d.In conclusion,the effective degradability of NDF,ADF,HC,CL and ADL were higher than that of fermentation time at 30 d to 40 d.The corn stover can be used as high quality forage by Pleurotus sajor caju fermentation from 30 d to 40 d.