| 24heads bulls [Simmental (♂) ×local cattle (♀)] with8-11months old,(204.52±32.00) kg weight and similar body condition were selected in this experiment and were divided into four blocks,6heads bulls in each block(initial weight were not significant between group, P<0.05).The experiment was arranged into two factors and multi level block experimental design,and experimental diets were divided into high protein concentrate supplement (HDP,%)diet and low protein concentrate supplement (LDP,%) diet; rumen protected methionine (RPMet) and rumen protected lysine (RPLys) were made by our research group,adding high mount(HRPML,46gRPLys+35.5g RPMet),low mount(LRPML,15.5gRPLys+13.6gRPMet) and none(NRPML)Concentrate supplement feeding amount (DM) were applied according to2%of weight, and were changed every two weeks according to the weight; Napier was coarse material silage and were not limited.Then56d experiment was followed, study on production performance and blood biochemical parameters on growing-finishing beef cattle,conditions of different protein levels diet added different levels mount rumen protected amino acid. The results showed that:(1) Rumen protected amino acid could significantly(P<0.05)improve experimental cattle fattening performance.Rumen protected amino acid had significant effect on average daily weight gain,concentrate feed gain ratio and consumption of crude protein and NEmf on every kilograms of weight gain,had no significant(P>0.05) effect on final weight and concentrate intake. High protein diet extremely significantly(P<0.01) increased experimental the cattle average daily gain extremely significantly(P<0.01), decreased the concentrate feed gain ratio and the coarse material intake,decreased intake,decreased significantly(P<0.05)consumption of NEmf on every kilograms of weight gain,had no significant effece(P>0.05) on final weight and concentrate intake.Rumen protected amino acid had no significant (P>0.05) effect on body size (except chest width final size and the body length volume growth). The level of diet protein had no significant (P>0.05)effect on body size (except bust final size).Rumen protected amino acids and high crude protein diet increased effect on the volume growth of body length, body slanting length,chest girth,chest width and body height. In the experiment Rumen protected amino and dietary protein level had no interaction on cattle production performance (P>0.05).(2) Rumen protected amino acids significantly (P<0.05) reduce serum ammonia content, had no significant effect (P>0.05) on serum urea nitrogen andinsulin. The level of die protein had extremely significantly (P＜0.01) effect on serum ureanitrogen content and significantly (P<0.05) effect on insulin-like growth factors.With dietary protein level increasing, content of serum urea nitrogen and insulin-like growth factors increased. Rumen protected amino acids and diet protein level all had no significant (P＜0.05) effect content of on blood glucose, total protein, albumin, globulin, alanine aminotransferase, aspartate aminotransferase and insulin. In the experiment rumen protected amino and dietary protein level had no interaction on serum routine biochemical indexes, insulin and insulin-like growth factors (P>0.05).(3)Rumen protected amino acids extremely significantly (P<0.01) increased serum methionine content,significantly (P<0.05) increased cystine content,extremely significantly (P＜0.01) decreased content of threonine,significantly (P<0.05) decreased content of phenylalanine, isoleucine and tyrosine, increased contentof lysine content (P>0.05), had no significant effect (P>0.05) on the content of other free amino acids, total mount of serum branched chain amino acids and free amino acids.High protein diet significantly (P<0.05) increased content of arginine,decreased content and total mount of serum branched chain amino acids (P>0.05),had no significant (P>0.05) effect on the content of other free amino acids and total mount of free amino acids. In the experiment of rumen protected amino acids and die protein levels had interaction of content of serum arginine (P＜0.05), had no interaction of content of other free amino acids, total mount of serum branched chain amino acids and free amino acids.Studies have shown that:1.Under the experimental conditions, rumen protected amino acids can improved average daily gain,volumeof body slanting length, content of serum methionine, lysine and tryptophan in varying degrees,coluld decrease concentrate feed gain ratio, consumption of crude protein and NEmf on every kilograms of weight gain, content of serum ammonia and branched chain amino acids.2.Under the experimental conditions, high protein diet can increase average daily gain,content of serum globulin, insulin-like growth factors, methionine,and tryptophanand, decrease consumption of crude NEmf on every kilograms of weight gain, coarse material intake,concentrate feed weight ratio,and content of serum branched chain amino acids.3. Under the experimental conditions, except for content of serum arginine, rumen protected amino acids and die protein levels had no interaction of production performance and other blood biochemical parameters.4.Integrated indicators, adding RPMet and RPLys to growing-finishing beef cattle can promote growth,improve protein metabolism, especially the low protein diet (concentrate supplement CP12.61%) adding46gRPLys and35.5gRPMet showing a good prospect of application. |
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