Effects Of Supplementing 2-Hydroxy-4- (Methylthio) Butanoic Acid Isopropyl Ester On Finishing Performance, Boold Index Levels And The H-FABP Gene MRNA Expression Finishing Cattle

The effects of 2-hydroxy-4-(methylthio) butanoic acid isopropyl ester(HMBi) on finishing performance in dairy calves;carcass characteristics, boold indexes and the H-FABP gene mRNA expression in finishing cattle were studied in the experiment, which provided the experimental basis for the application of HMBi on beef cattle.Section one:The effects of 2-hydroxy-4-(methylthio) butanoic acid isopropyl ester (HMBi) on productive performance, serum biochemical indexes and serum hormone levels in Dairy Calves were studied in the experiment. Twelve Snow Dragon Black cattle and Xuzhou cattle hybrid generation calves (average age 4.5 month) were selected and randomly divided into control group and treatment group with 6 head in each group, according to the principles of same age and body weight, feeding at the same conditions. Control group fed a based diet (0 g HMBi) while treatment group supplement 4 g/d HMBi per head. Fecal morphology and feed intake were recorded everyday during the experiment and body weight, body height, body length, heart girth, circumference of cannon bone and other body sizes were recorded at 1 st d,28th d and 49th d. Blood samples were collected at the time of the start and the end of the treatment. Result as follows:Compared with control group, the body weight had no significant change (P<0.05); The roughage feed intake were significantly incerased at 1-7 d (P<0.05); the diarrhea rates were extremely significant decreased (P<0.05). The Chest depth were significantly higher than that in control group at 28th d (P<0.05). The concentrations of serum TG were significant lower than that of control group (P<0.05). The concentrations of BUN in treatment had significant decreased after the experiment (P<0.05).The serum IGF-1 levels in the treatment group had significant increased after the experiment (P<0.05). HMBi supplementation in dairy calves can improve the chest depth, decreased the diarrhea rates and the content of serum TG, while had no significant effects on serum Hormone Levels.Section two:Sixteen Xuzhou cattle (average age 4-5 year old) were selected and randomly divided into control group and treatment group with 8 head in each group, according to the principles of same age and body weight. Control group fed a based diet (0 g 2-hydroxy-4-methylthio butanoic acid isopropyl ester, HMBi) while treatment group supplement 8 g/dHMBi per head. Slaughter performance, carcass characteristics and serum biochemical indexes were test after slaughter. Result as follows:Compared with control group, the hot carcass weight, dressing percentage, mesenteric weight, back fat, the calculated yield grade and KPH% increased (P>0.05); the 12th rib fat thickness and rib eye area decreased. the meat color, fat color, shearing-force and cooking-loss had no significant change (P>0.05); but marbling score were higher than that in control group (P>0.05).The concentrations of serum total protein (TP), globulin (GLO) and blood urea nitrogen(BUN) in both groups significantly decreased after the experiment (P<0.05), The concentrations of serum Triglycerides(TG)were significant lower than that of control group (P<0.05). The concentrations of serum glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in treatment increased by 9.20% and 2.10%, respectively; while serum malondialdehyde (MDA)decreased by 7.17%. HMBi supplementation in finishing cattle had no significant effects on serum hormone levels (P>0.05). HMBi supplementation in finishing cattle have a tendency to improve the marbling score of beef, decrease the content of serum TG, while had no significant effects on hormone levels.Section three:This study was conducted to investigate the effect of HMBi on beef chemical composition, intramuscular fat content (IMF) and the H-FABP gene mRNA expression in finishing cattle. Test design and test material were same with the test two. Result as follows:compared with control group, the ether extract (EE) of longissimus dorsi (LM) was higher than that in control and the crude ash (ASH) was significantly higher than that in control group (P<0.05); the chemical composition of gluteus medius (GM) had no significant change. The H-FABP gene mRNA expression in longissimus dorsi (LM) and gluteus medius (GM) were higher than that in control (P>0.05). It is concluded that HMBi supplementation in finishing cattle can improve the EE, ASH of beef, while have no significant effects on the IMFand the H-FABP gene mRNA expression.