The effects of dietary arginine supplementation on blood biochemistry values in Japanese Black fattening cattle

Arginine, an amino acid with various physiological effects, has been shown to promote growth hormone secretion in humans.However, its physiological effects in cattle have been less clarified.Therefore, we examined the effects of feeding cattle with arginine on their serum biochemical values.Twenty castrated, fattened Japanese black cattle aged 10 months were divided into two groups of 10: one fed with feed containing crystalline L-arginine at 20% (50 grams per animal per day) for 3 months from the start of the study (Arg group) and the other without L-arginine (control) .Blood samples were collected before, at the end of and 3 months after the feeding period, i.e., at 10, 13 and 16 months of age, respectively, and were analyzed for serum vitamin A, vitamin E, total cholesterol, urea nitrogen, total protein, albumin, free arginine and IGF-1.Serum free arginine showed a significant interaction between the two groups, simple main effect analysis revealed significantly higher serum free arginine in Arg-fed cattle at 13 months of age compared to those at 10 and 16 months of age as well as control cattle at 10, 13 and 16 months of age.As for serum IGF-1, the Arg group showed significantly greater values than the control group at 13 and 16 months.These results indicate that feeding Japanese black cattle with arginine in the amount used in this study increases serum free arginine and IGF-1 levels.Further studies are necessary to understand how arginine can increase IGF-1 secretion in cattle.