| Methionine(Met)is an essential amino acid in animal body and a substrate for protein synthesis.It can be used as a methyl donor to participate in DNA,RNA and protein methylation,polyamines,creatine and other substances formation.N-carbamoylglutamate(NCG)can promote the synthesis of arginine in animal body,and arginine in the body.It is involved in the synthesis of proteins,urea,creatine and polyamines in tissues and cells.Polyamines and creatine,as the co-metabolites of Met and NCG,play an important role in the growth and development of the body and protein synthesis.Sixty healthy castrated beach lambs with the same genetic background and good physical condition were randomly divided into four groups:control group(CK),NCG(N),RP-Met(RPM)group and NCG+RP-Met(NRM)group.There were 3 repeats(columns)in each group,and 5 sheep in each repeat.The experiment lasted for 100 days.The effects of NCG and RP-Met on the production,meat quality and antioxidant properties of Tan sheep were studied.The results showed that dietary supplementation of NCG and RP-Met could improve carcass traits,digestibility,meat quality and antioxidant capacity of House-fed Tan sheep.Compared with CK group,N group,RPM group and NRM group significantly increased the average daily gain and decreased the feed-Weight ratio(P<0.05),and NRM group had the best effect of average daily gain and the lowest feed-Weight ratio.The carcass weight,slaughter rate and net meat rate of NRM group were significantly higher than those of other three groups(P<0.05),followed by RPM group and N group.The digestibility of dry matter,crude protein and organic matter of Tan sheep in N,RPM and NRM groups were significantly increased(P<0.05),and the digestibility of NRM group was significantly higher than that of N and RPM groups.Compared with CK group,NRM group had a tendency to reduce subcutaneous fat deposition;GR value and eye muscle area of N group,RPM group and NRM group were significantly lower than those of control group(P<0.05),and pH 45 and 24 were significantly higher than those of control group(P<0.05).The water loss rate of NRM group was significantly lower than that of N group and RPM group(P<0.05).There was a significant difference in serum urea nitrogen and cholesterol content among the treatment groups(P<0.05).The NRM group had the highest urea nitrogen content and the lowest cholesterol content.Compared with CK,the content of T-AOC in muscle of Tan sheep in NRM group increased(P>0.05),and the content of CAT in muscle of Tan sheep in NRM group was significantly higher than that in N group and RPM group(P<0.05).There was significant difference in SOD content among the treatment groups,which was higher than CK group,and the highest SOD content was found in RPM group(P<0.05).The serum T-AOC content of each treatment group had no significant difference,but it was higher than CK group and had an upward trend(P>0.05).In summary,dietary supplementation of NCG and RP-Met improved the average daily gain and reduced feed-Weight ratio of House-fed Tan sheep,improved slaughter performance,carcass weight and slaughter rate,increased digestion and absorption of feed nutrients,and effectively improved muscle nutrients of House-fed Tan sheep,and regulated fat deposition of House-fed Tan sheep.It can obviously improve the physical and chemical properties of mutton,increase the total protein content in serum and reduce the content of urea nitrogen and cholesterol.At the same time,NCG and RP-Met participate in the oxidative metabolism pathway in the body of House-fed Tan sheep,and improve the antioxidant capacity of serum and muscle. |
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