摘要
The objective of this study was to determine the effect of supplemental lysine (Lys), methionine (Met) or both amino acids added in the form of rumen-protected (RP) tablets with copolymer coating to a diet of dairy cows on yield and composition of milk and concentration of plasma amino acids (AA). The experiment was carried out on four high-yielding lactating Holstein cows with average milk production of 33.5 kg/day in the form of Latin square design. The four treatments were as follows: C – control without AA supplementation, L – control plus supplement of RP Lys, M – control plus supplement of RP Met and ML – control plus supplement of RP Met and Lys. The experiment was divided into 4 periods. Each period (14 days) consisted of 10-day preliminary period and 4-day experimental period. Cows were fed a diet based on maize silage, lucerne hay and supplemental mixture. Average milk yield recorded in ML was 34.18 kg and was higher than that recorded in L or M (32.46 kg and 32.13 kg, respectively P < 0.05) and tended to be higher than in C (33.33 kg, P > 0.05). The content of protein and casein was higher in L and ML in comparison with C (P < 0.05) and tended to be higher than in M (P > 0.05). Protein yield in ML (1 054 g/day) was higher than that found in C, L or M (990, 998 or 968 g/day, respectively, P < 0.05). The same response was found for casein yield (P < 0.05). Although the proportion of individual casein fractions was not affected by the treatment, the yield of α- and β-casein differed (P < 0.05) while the yield of κ-casein was not affected by the treatment. Concentrations of blood metabolites, except for betahydroxybutyrate (BHB), were not changed. Plasma Met concentrations were increased (P < 0.05) in the M and ML group. Similar, but insignificant increases (P > 0.05) were also observed in plasma Lys in the L and ML group.
摘要译文
本研究的目的是确定补充赖氨酸（Lys），蛋氨酸（Met）或两种氨基酸以瘤胃保护（RP）片剂的形式加入共聚物涂层对奶牛日粮产量和成分的影响。牛奶和血浆氨基酸浓度（AA）。该实验在四只高产泌乳荷斯坦奶牛上进行，平均产奶量为33.5千克/天，采用拉丁方设计。四种治疗方法如下：C - 对照无AA补充，L - 对照加RP Lys补充，M - 对照加RP Met补充和ML - 对照加RP Met和Lys补充。实验分为4个时期。每个时期（14天）包括10天的初步期和4天的实验期。给奶牛喂食基于玉米青贮饲料，苜蓿干草和补充混合物的饮食。 ML中记录的平均产奶量为34.18 kg，高于L或M记录的产奶量（32.46 kg和32.13 kg，分别为P <0.05），并且趋于高于C（33.33 kg，P> 0.05）。 L和ML中蛋白质和酪蛋白含量高于C（P <0.05），且高于M（P> 0.05）。 ML（1054g /天）中的蛋白质产率高于C，L或M中的蛋白质产率（分别为990,998或968g /天，P <0.05）。酪蛋白产量的反应相同（P <0.05）。虽然单个酪蛋白组分的比例不受处理的影响，但α-和β-酪蛋白的产率不同（P <0.05），而κ-酪蛋白的产率不受处理的影响。除β-羟基丁酸（BHB）外，血液代谢物的浓度没有变化。 M组和ML组血浆Met浓度升高（P <0.05）。在L和ML组的血浆Lys中也观察到类似但不显着的增加（P> 0.05）。
J. Třinácty; L. Křížová; M. Richter; V. Černy; J. Říha. Effect of rumen-protected methionine, lysine or both on milk production and plasma amino acids of high-yielding dairy cows[J]. Czech Journal of
Animal Science, 2009,54(6): 239-248