Effects Of Rumen-passing Amino Acids And Fatty Acids On Tan Sheep Feeding On A Low Protein Diet

In this study,FOM,RDP and RENB values were calculated based on the principle of rumen energy and nitrogen balance through in vitro fermentation experiments.The CP degradation rate and OM fermentation rate of feed materials such as corn,bran,soybean meal,flax meal,silage corn,corn straw,wrapped alfalfa and alfalfa were determined.Reducing the ratio of RDP in the diet or increasing the content of FOM was to improve energy and nitrogen balance;Adding rumen lysine and rumen methionine and rumen fat was to study the nutrition regulation of dietary energy and nitrogen balance to enhance the efficient breeding of Tan sheep through feeding experiments,digestion and metabolism experiments and slaughter experiments with the condition of low-protein diets.27 healthy and disease-free Tan sheep with well-developed body condition weighed(22±1.00)kg.They were selected,numbered and randomly divided into 3 groups with 9 sheep in each group.The control group was fed the basal diet.The test group Ⅰ was fed with 7.5g/d rumen-passing lysine(RPLys)+ 4.5g/d rumen-passing methionine(RPMet),while the test group Ⅱ was fed with 2.4%rumen-passing fat powder(RPF).The nutrient levels of the experimental Tan sheep were similar.The pre-feeding period lasted 10 days,and the trial period lasted 60 days.The main findings are as follows:(1)Various indicators of feed raw materials were measured by in vitro fermentation test.The FOM values of bean curd residue,silage corn and wrapped alfalfa were lower,while bran and alfalfa had higher FOM values;the RDP value of corn stalk was the lowest,and soybean meal was the highest.(2)Adding RPLys+RPMet to low-protein diets increased the apparent digestibility of nutrients,and the apparent digestibility of neutral detergent fiber in test group Ⅰ was significantly higher than that in control group and test group Ⅱ by 33.59%and 34.1 7%,respectively(P<0.01);the apparent digestibility of acid detergent fiber was the highest in test group Ⅰ,which was 60.59%and 38.49%higher than that in the control group(P<0.05).(3)Adding RPLys+RPMet to low-protein diets had significant effects on rumen fermentation and nitrogen emission of Tan sheep.Adding RPLys+RPMet and RPF to the low-protein diet can improve the rumen environment index,and the ammonia nitrogen content in the control group and the test group Ⅰwere significantly higher than that of the test group Ⅱ on the 40th day(P<0.05).The concentrations of acetic acid,propionic acid and butyric acid in test group Ⅰ increased.The sediment nitrogen and nitrogen biological value of Tan sheep in low protein diet supplemented with RPLys+RPMet and RPF were higher than those in energy nitrogen balance group.The addition of RPLys+RPMet RPF both reduced nitrogen emission and increased nitrogen deposition rate.But adding RPLys+RPMet was more favorable for nitrogen deposition.(4)Adding RPLys+RPMet to low-protein diets had a positive effect on the immunity and antioxidant of Tan sheep.On the 20th day,the activity of GSH-Px in test group Ⅰ was significantly higher than that in other groups(P<0.05).Overall,with the increase of the test days,the activities of GSH-Px and T-SOD in the serum of Tan sheep tended to increase gradually,the concentration of MDA decreased gradually,and the antioxidant capacity of Tan sheep gradually increased.The contents of IgA and IgM showed an increasing trend,which effectively improved the immunity of Tan sheep.(5)The low-protein diet supplemented with RPLys+RPMet and RPF had no significant effect on the head weight,hoof weight and tail fat weight of Tan sheep(P>0.05),but the addition of RPF significantly increased the eye muscle area(P<0.01).adding RPF group could significantly increase live weight,carcass weight,fur weight,net meat weight,bone weight,carcass weight,bone-meat ratio and slaughter rate(P<0.05).The low-protein diet supplemented with RPF had a better effect on muscle tenderness,and the increase in fat content made the meat tender.The supplementment of RPLys+RPMet significantly increased the content of crude protein and increased the water retention of the meat.In summary,using the rumen-passing technology,adding RPLys and RPMet to low-protein diets can improve the apparent digestibility of nutrients in Tan sheep,increase nitrogen deposition,and effectively improve the antioxidant and immune capacity of Tan sheep.The addition of Fat(RPF)can improve slaughter rate and muscle fat content of Tan sheep.In the low-protein diet,the feeding effect was significantly improved by regulating the energy-nitrogen unbalanced diet through two control methods.