| Rape straw is the remaining part of the stalk after harvesting rapeseed,which is one of the main crop straws in China.Rape straw is a kind of ideal feed ingredients,because of it is rich in crude protein,crude fiber and crude fat and other nutrients.But for a long time,rape straw is mainly burned and returned to the field,which not only wastes a lot of available resources,but also produces a lot of greenhouse gases,causing serious environmental pollution.As rape straw is poor edible and inconvenient storage,hitherto it has not been reasonably exploited and utilized.Therefore,it is very important to exploit a suitable method to treat rape straw and improve its feeding value for solving these problems of "competition between human beings and livestock for grain" and environmental pollution.Microbial fermentation of rapeseed straw is one of the main methods to produce high quality straw feed,which is easy to operate,green and efficient.Therefore,microbial fermentation was used to prepare rapeseed straw,and the fermentation conditions were optimized to determine the optimum fermentation conditions.The effects of the proportion of fermented rape straw on Goat Growth performance,serum biochemical index,nutrient digestibility and rumen fermentation were studied through the feeding experiment.In addition,the optimum amount of fermented rape straw was further explored.This study provides a reference for the development and utilization of rape straw resources and promoting the development of animal husbandry.Experiment one:The effect of different conditions on the nutritional value of rape strawThe purpose of this experiment was to explore the effects of different fermentation conditions on the nutritional value of rape straw.The rape straw was treated by sealing fermentation with green xylase,Candida utilis and Staphylococcus pentosae.We optimized fermentation conditions through adjusting the ratio of cellulase,glucose,urea,inoculation and water.The contents of DM,CP,EE,Ash,NDF,ADF,and NH3-N,microbial quantity and pH value,amino acid and mycotoxin in rape straw were determined after fermentation.The results showed that the content of CP and EE increased significantly(P<0.05),and the content of NDF and ADF decreased significantly(P<0.05).After fermentation,the third group had the best results.The degradation rate of NDF was 29.1%,the degradation rate of ADF was 29.7%.Compared with other groups,the content of CP was significantly higher in the third group(P<0.05).In the fermentation groups,a certain number of microorganisms could be retained,and the pH value was between 3.2 and 4.0.Total acid content increased by 334%,essential amino acid content increased by 140%,and proline content increased by 547%.No toxin components were detected whenever before and after fermentation of rape straw,which indicated that rape straw treated with fermentation met the national health standards and could be used as roughage for ruminant feeding.Experiment two:Effect of fermented rape straw addition ratio on growth performance,nutrient digestibility and serum biochemical indexes of goatsThe purpose of this experiment was to explore the effects of different proportion of fermented rape straw on growth performance,nutrient digestibility and serum biochemical indexes of goats.Sixty healthy goat ewes with similar body condition(15.00+2.00 kg)at 3 months old were randomly divided into four groups,and fed with 0,10,20 and 30%fermented rapeseed straw for 60 days,respectively.Relevant growth indexes were measured after feeding.The results showed that ADG and ANG in all experimental groups were higher than that of the control group.Compared with other groups,ADG,ANG and DF in 20%fermented rape straw addition group were the highest(P<0.05).The results of apparent digestibility of nutrients showed that CP and ADF were the highest in the 20%adding ratio group(P<0.05),while NDF was the highest in the 30%adding ratio group(P<0.05).In addition,the apparent digestibility of DM and EE in the experimental group was higher than that in the control group(P>0.05).The results of serum biochemical indicators showed that the contents of TP and GLU were the highest in the 20%adding ratio group(P<0.05),and GPT,AKP and TC were the highest in the 30%adding ratio group(P<0.05).Compared with the control group,the contents of AKP and Bun in the 10%adding ratio group were lower(P>0.05).The results of antioxidant indexes showed that the activity of GSH-Px was the highest in the 20%proportion group(P>0.05).Adding fermented rape straw increased the activity of SOD in serum.The activity of CAT in the 10%proportion group was the highest(P<0.05).The activity of CAT increased with the increase of the proportion of fermented rape straw addition,and the experimental group was higher than the control group(P<0.05).Overall,adding 20%fermented rape straw to the diet can increase daily gain,decrease feed-Weight ratio,and improve nutrient digestibility and antioxidant capacity of goats.Experiment three:Effect of fermented rape straw addition ratio on rumen fermentation of goatThe purpose of this experiment was to explore the effects of different proportion of fermented rapeseed straw on rumen fermentation in goats.Sixty healthy goat ewes with similar body condition(15.00± 2.00 kg)at 3 months old were randomly divided into four groups,and fed with 0,10,20 and 30%fermented rapeseed straw for 60 days,respectively.Within 8 hours after feeding,we collected rumen fluid by using gastric catheter every two hours.In addition,we continuously monitor pH value,NH3-N concentration,VFA concentration and cellulase activity in rumen for 3 days.The results showed that the pH value of rumen juice in each experimental group was lower than that in the control group at each time point.There is no significant difference on the pH value of rumen juice during four groups(P>0.05),which were between 6.2 and 7.0.The of in rumen juice of the three experimental groups have similar change pattern.Within 2 hours after feeding,NH3-N concentration increased first,following decreased gradually.In the 30%addition ratio group,NH3-N concentration in rumen juice was the highest at 0 h and 2 h(P<0.05).The contents of acetic acid,propionic acid and TVFA in the 20%supplementation group were higher than those in the control group(P>0.05).Compared with the control group,the activity of carboxymethyl cellulase and cellobiose in the 20%ratio group were the highest with increased by 11.19%and 33.33%,respectively(P<0.05).The activity of microcrystalline cellulase in the experimental group was lower than that in the control group(P<0.05).Taken together,the 20%addition ratio group can maintain the steady state of rumen environment and improve the degradation efficiency and nutrient absorption rate of rumen cellulose. |
