Effects Of Different Nitrogen Sources On Fattening Performance,Immune Parameters And Blood Biochemical Indices Of Mongolian Lambs

The purpose of this thesis was to study the effects of different resources of protein-feed on fattening performance,immune parameters and blood biochemical indices of mongolian lambs,data presented here to support the maximization of economic benefits,as well as exploring suitable protein source feed,reducing lamb feeding cost.Four to five-month-old Mongolian lambs were selected and randomly divided into 5 treatment groups(n=10 per groups)according to the principle of no significant difference in body weight.Treatments contains the following: Soybean meal group(control group);Soybean meal group +1.5 % urea(U1.5);Soybean meal group+1 % urea(U1);Soybean meal group +1 % urea + rumen protected amino acid group(AC);Miscellaneous meal group + 1 % urea(MG).In addition to the content of protein decreased 1%(AC),all of diet design principles were followed equal energy and nitrogen principles.Sheep were raised in single column,an acclimation period of 15 days were allowed for lamb adaptation to the pen,followed by a formal experimental session(60days).The results showed that :(1)Growth performance : Compared with the control group,the average daily gain of MG group(d1-30)was significantly lower than the control group at the beginning of the experiment(P < 0.05)and F/G was decreased by 32.88%.On d31-60,there were no significant differences in ADG,ADFI and F/G among all treatments(P > 0.05).At the beginning of the experiment,the average daily gain of MG groups(d1-60)was reduced by 13.59% compared with the control group.(2)Slaughter performance : The eye muscle area of U1 group and AC group was significantly higher than that of control group(P < 0.01).The eye muscle area of U1 group was significantly higher than that of U1.5 group(P < 0.01).(3)Meat quality : The muscle p H of AC group and U1 group was significantly higher than that of other groups at 45 min after slaughter(P < 0.05),and the muscle p H of U1 group was significantly lower than that of control group at 24 h after slaughter(P< 0.05).The drip loss of the U1 group was significantly lower than that of the control group(P < 0.05),and the shear force of the U1 group was significantly lower than that of the U1.5 group(P = 0.09).The crude fat content of U1.5 group and U1 group was significantly higher than that of AC,MG and control group(P < 0.05),and the fat content of U1 group was significantly higher than that of MG group and control group(P< 0.05).The contents of Met and Cys in muscle of each group were significantly lower than those in the control group(P < 0.05).The contents of Leu in muscle of AC group and MG group were significantly higher than those in the control group(P < 0.05).The contents of Tyr and Ile in MG group were significantly lower than those in the control group(P < 0.05).The content of BCAA in MG group was significantly higher than that in the control group(P < 0.05).(4)Serum biochemical indexes : On the 0 th day of the experiment,the Glu content of U1 group was significantly lower than that of control group(P < 0.05).On the 30 th day of the experiment,the ALB content of U1.5 group,U1 group and AC group was significantly lower than that of the control group(P < 0.01).The AST content in U1.5group,U1 group and AC group was significantly lower than that in MG group(P <0.05).TG content in U1 group,AC group and MG group was significantly lower than that in control group(P < 0.05).TP content in AC group and MG group was significantly lower than that in U1 group(P < 0.05).The content of ALT in MG group was significantly higher than that in control group(P < 0.05).On the 60 th day of the experiment,the ALP content of U1.5 group,U1 group and AC group was significantly lower than that of the control group(P < 0.01).GLU content in U1.5 group and U1 group was significantly higher than that in AC group and MG group(P < 0.05).The content of TG in AC group was significantly higher than that in other groups(P < 0.01).Feeding Mongolian lambs with different nitrogen sources had no significant effect on BUN and Scr content(P > 0.05).There was no significant effect on BUN concentration at each time period(P > 0.05).The BUN content in the U1.5 group before eating was significantly lower than that in the control group(P = 0.07).The effect of different urea additions on BUN levels was the same.There was no significant effect on Scr concentration before and after eating(P > 0.05),and the trend of Scr level was the same.Except for 6h after eating,the Scr levels in other time periods were U1.5 group,control group and U1 group.There was no significant effect on the Amon level before and after each time period(P > 0.05),and the trend of influence on the Amon level was the same.(5)Serum immune indexes : On the 30 th day of the experiment,the Ig M content of U1 group was significantly lower than that of U1.5 group and control group(P < 0.01).The content of AST(MG)was significantly higher than other treatments.Ig G content in U1 group was significantly lower than that in U1.5 group(P < 0.01).The content of Ig A in MG group was significantly lower than that in U1.5 group,U1 group and control group(P < 0.05).On the 60 th day of the experiment,the Ig G content of the U1.5 group was significantly higher than that of the control group(P < 0.05).The content of Ig A in MG group was significantly lower than that in U1.5 group and control group(P < 0.05).(6)In conclusion,the growth performance(U1.5),the dressing percentage(U1),eye muscle(U1)and fat deposits(U1)was higher than the control group,the fattening performance of AC group was no difference than the control,it indicated that(U1)the supplement of rumen protected amino acid on the diet containing urea could maintain the normal growth of lambs.Compared with the control and U1 group,the growth performance of MG was decreased,and the content of Ig A on the late stage of the experiment was significantly decreased,the results showed that the use of 1% urea and miscellaneous group to completely replace soybean meal have adverse effects on growth performance and the body may have inflammatory reactions.To sum up,the optimum production performance was obtained by adding 1.5% urea.