Effects Of Mannan Oligosaccharide Added In Compound Chemical Treatment Straw Diet On Production Performance And Meat Quality Of Tan Sheep

As people pay more and more attention to environmental protection and food safety issues,the focus of animal husbandry production has been also changed from output to quality.Livestock and poultry feed is the key in the production of green livestock products,and how to solve the series of hazards caused by the application of antibiotics is a major challenge facing livestock production,and also a breakthrough in the feed industry.Mannose oligosaccharide has the effects of improving animal daily gain and feed conversion rate,enhancing animal immune function and antioxidant capacity and reducing the incidence of disease.It is a green and safe feed additive that can replace antibiotics.In this experiment,Ningxia Tany sheep was selected as the experimental animals,Twenty healthy 4-month-old Tan sheep of similar weight were selected and randomly divided into 4 groups(5 in each group).The ratio of concentrate to roughage of basic diet was 30:70,and compound chemically treated straw and untreated alfalfa were mixed as 60:40 as roughage.The control group was fed basal diet and 4.5 g/d rumen protected methionine,and the experimental Ⅰ,Ⅱ,and Ⅲ groups were added with 1.0%,2.0%,and 3.0%mannose oligosaccharide under the basic diet conditions respectively.The pre-feeding period was 20 days and the trial period was 60 days.Through the feeding test,digestion and metabolism test and slaughter test,the effects of mannose oligosaccharide on digestion and metabolism,serum biochemical indexes,immune function,antioxidant capacity,rumen fermentation and flora structure,growth performance and meat quality of Tan sheep were studied.The results showed:1.The digestibility of NDF and ADF was the highest(P<0.05)when the amount of mannose oligosaccharide in diet was 1.0%.The addition of mannose oligosaccharide in the diet can increase the nitrogen deposition,nitrogen deposition rate and apparent biological value of protein in experimental sheep(P<0.05).The effect on energy metabolism of Tan sheep was not significant,but Tan sheep with 1.0%mannose oligosaccharide had the highest digestive energy and total digestibility(P>0.05).2.After feeding mannose oligosaccharide,the serum total cholesterol and triglyceride content of Tan sheep was decreased(P<0.05);The mean value of the total antioxidant capacity of group Ⅱ increased(P<0.05),but the mean serum malondialdehyde concentration of the test sheep and the total antioxidant capacity activity of the test group Ⅲ on the 30th and 60th days decreased(P<0.05);The content of IgM of the test groups Ⅱ and Ⅲ was higher than that of the control group at 30 days and 60 days after the feeding of manno-oligosaccharide(P<0.05),the content of IgG,IgM and IgA in the test group were higher than that of the control group at 60 days(P>0.05).3.Mannan oligosaccharide can reduce the pH and NH3-N concentration of rumen fluid in test sheep,but the concentration of acetic acid in test group II increased(P<0.05).At the phylum level,Firmicutes,Proteobacteria and Bacteroidetes are the dominant phylum in the rumen of Tan sheep.The addition of manno-oligosaccharide increased the relative abundance of the Proteobacteria(P<0.01).The effect of Bacteroides and Firmicutes abundance was not significant(P>0.05).At the genus level,the addition of 1.0%mannose oligosaccharide increased the relative abundance of Prevotellaceae UCG-001(P<0.01)related to starch degradation and Ruminococcaceae_UCG-002(P<0.05)related to fiber degradation.It showed that mannose oligosaccharide can increase the abundance of rumen fiber-degrading bacteria and starch-degrading bacteria,and improve feed utilization.4.Manno-oligosaccharide had an increasing trend for the total and daily weight gain of the experimental sheep(P>0.05).When the addition amount was 1.0%,the experimental sheep had the best weight gain,16.02%higher than the control group,the lowest feed-to-weight ratio,and the highest breeding economic benefits.5.The slaughter performance and nutrient composition of the sheep in the control group were not significantly different from those in the other groups(P>0.05),but the shear force,water loss rate and the yellow value of meat color(b*)was lower than that of the control group(P<0.05).In summary,under the conditions of this experiment,the addition of mannose oligosaccharide had a positive effect on the performance and meat quality of Tan sheep.Among them,the addition of 1.0%mannose oligosaccharide had the best effect and the highest economic benefit.