Effects of Rumen Protected Methionine on Milk Performance and Serum Biochemical Indexes of Milk Goat
LI Li1,2, ZHANG Peihua1,2, LING Hao1,2, CHEN Dong1, WEN Jing3,4, LEI Kun1,2, LIU Ming1
1. College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China;
2. Hunan Co-Innovation Center of Animal Production Safety, Changsha 410128, China;
3. College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling 712100, China;
4. Chengbu Shanmu Animal Husbandry Co., Ltd., Shaoyang 422500, China
Abstract：This experiment was conducted to the effects of adding different protective modes of rumen protected methionine in diets on milk performance and serum biochemical indexes of milk goat. A completely randomized trial design was adopted to select 45 Guanzhong milk goat with the body weight of (52.6±4.9) kg, similar parities and similar lactation age[(120±10) d], randomly divided into 3 groups, and 15 goats in each group. The diet of control group was a basal diet which did not add rumen methionine, the diet of trial Ⅰ group was added 4.5 g/d rumen methionine A (physical coating) based on the basal diet, and the diet of trial Ⅱ group was added 4.5 g/d rumen methionine B (chemical protection) based on the basal diet. The whole experiment lasted for 39 days including 9 days of pretrial period and 30 days of trial period. The results showed as follows:1) the milk to feed ratio of trial Ⅰ group and trial Ⅱ group was significantly higher than that of control group (P<0.01), but the difference between experimental groups was not significant (P>0.05); the milk income and gross returns of trial Ⅰ group and trial Ⅱ group were higher than control group (P>0.05). 2) The milk fat percentage in goat milk of trial Ⅰ group and trial Ⅱ group was 6.75% and 13.18% higher than that of control group, respectively, but the difference was not significant (P>0.05); the milk protein percentage and non-fat solids content in goat milk of trial Ⅰ group and trial Ⅱ group were higher than that of control group, however, the difference was not significant (P>0.05). 3) The contents of serum total cholesterol and urea nitrogen of trial Ⅰ group and trial Ⅱ group were lower than that of control group (P>0.05), and the serum immunoglobulin G content of trial Ⅰ group was significantly higher than that of control group and trial Ⅱ group (P<0.05). To sum up, adding different protective modes of rumen protected methionine (physical coating and chemical protection) can both improve the economic benefit of milk goat. Furthermore, adding rumen protected methionine coated by physical method can promote the body immunity of milk goat, and adding rumen protected methionine protected by chemical method can elevate the milk fat percentage and milk protein percentage of goat milk.
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