049 Physiological and molecular mechanisms associated with performance, immunometabolic status, and liver function in transition dairy cows fed rumen-protected methionine or choline

Abstract

The onset of lactation in dairy cows is characterized by high output of methylated compounds in milk when sources of methyl group are in short supply. Methionine (MET) and choline (CHOL) are key methyl donors and their availability during this time may be limiting for milk production, hepatic lipid metabolism, and immune function. Supplementing rumenprotected MET and CHOL may improve overall performance and health of transition cows. observed in response to CHOL supplementation, expression of (BHMT) and MTR and BHMT enzyme activity did not change (P > 0.05). Furthermore, overall MTR enzyme activity was lower (23.5 vs. 29.6 nmol product h -1 mg protein -1 ; SEM = 2.9; P = 0.05) in CHOL cows. In terms of AA profile, MET supplementation led to greater (P < 0.01) circulating methionine and proportion of methionine in the essential AA pool, total AA, and total sulfur-containing compounds. Lysine in total AA also tends to be greater (P = 0.08) in these cows, indicating a better overall AA profile. Sulfur-containing compounds (cystathionine, cystine, homocystine, and taurine) also were greater (P < 0.05) in MET-supplemented cows, indicating an enriched sulfur-containing compound pool due to enhanced transsulfuration activity. Circulating essential AA (P = 0.06) and total AA (P = 0.03) concentrations were greater in MET cows due to greater lysine, arginine, tryptophan, threonine, proline, asparagine, alanine, and citrulline. In contrast, tryptophan and cystine were greater. Plasma 3-methylhistidine concentration was lower (P = iv 0.02) in response to CHOL, suggesting less tissue protein mobilization in these cows. Overall, results indicate that MET supplementation improves performance of transition cows through a combination of better immunometabolic status, plasma AA profile, and a reduction in oxidative stress; insufficient regeneration of MET may be one reason for the lack of effect with supplemental CHOL.

Effect of Methionine Supplementation on Serum Metabolism and the Rumen Bacterial Community of Sika Deer (Cervus nippon)

“…Methionine supplementation affected serum immune levels, with a significant increase in the serum IgG level in the HMet group and an increase in the IgM level ( Table 2 ). Previous studies demonstrated that lymphocytes have a higher requirement for methionine, because in lymphocytes precursors such as choline and homocysteine are not met by methionine regeneration through the methionine cycle [ 34 , 35 ]. Wang Han et al also demonstrated that methionine supplementation increased the plasma IgG level in dairy cows [ 36 ].…”

Alterations in Skeletal Muscle mRNA Abundance in Response to Ethyl-Cellulose Rumen-Protected Methionine during the Periparturient Period in Dairy Cows

“…In cows fed typical dry period diets without RPM, concentrations of plasma Met and the nonessential amino acids (NEAA) Asp, Gln, Glu, Cys, Tyr, and Orn as well as glucose decrease continuously from −25 d relative to calving and remain lower in early lactation [26]. Furthermore, when compared to the 3rd week pre-partum, in the 4th week post-partum, skeletal muscle concentrations of essential amino acids (EAA), Gln/Glu, Asp/Asn, Tyr, and Ser were decreased to ∼86% [26]; thus, besides helping cows achieve optimal rates of DMI [6,14,27,28], supplementing Met, first-limiting AA for dairy cows, during the transition period could help prevent drastic decreases in muscle Met. Biologically, the supply of Met in skeletal muscle could play a key role in the initiation of translation, i.e., synthesis of Met-tRNA for binding to the initiation codon AUG [29] especially during a time when the cow still is experiencing a state of negative nutrient balance.…”

“…Statistical p-values for the main effect of time are reported in the figures in the Supplemental File (Figures S1-S7). of essential amino acids (EAA), Gln/Glu, Asp/Asn, Tyr, and Ser were decreased to ∼86% [26]; thus, besides helping cows achieve optimal rates of DMI [6,14,27,28], supplementing Met, first-limiting AA for dairy cows, during the transition period could help prevent drastic decreases in muscle Met. Biologically, the supply of Met in skeletal muscle could play a key role in the initiation of translation, i.e., synthesis of Met-tRNA for binding to the initiation codon AUG [29] especially during a time when the cow still is experiencing a state of negative nutrient balance.…”

Methionine regulates the major physiological functions of animals

“…的合成, 来对动物的免疫状态进行调控 [32] . 对小鼠细 胞蛋氨酸利用的研究发现, 淋巴细胞不能利用高半胱 氨酸和胆碱这些前体物质合成蛋氨酸, 意味着淋巴细 胞在蛋氨酸循环转甲基后不能通过再甲基化途径生成 蛋氨酸对已消耗的蛋氨酸进行补充 [54] ; 同样, 对转基因 奶牛分别饲喂瘤胃保护的蛋氨酸和胆碱, 饲喂蛋氨酸 的奶牛显示更好的免疫代谢状态 [55] ; 因此, 维护机体免 疫系统稳态的蛋氨酸需要量需高于维持生长需要量.…”