Methionine plays a vital role in protein synthesis, and regulation of antioxidant response in ruminants. This study aimed to assess the effects of dietary supplementation with -acetyl--methionine (NALM), which serves a source of rumen-protected methionine, on growth performance, carcass traits, meat quality, and oxidative stability. Sixty Angus heifers (initial body weight = 408 ± 51.2 kg, 15–18 months) were stratified by body weight and randomly assigned to four dietary treatments: a control group (0% NALM), and experimental groups receiving diets containing 0.125%, 0.25%, and 0.50% NALM (dry matter (DM) basis), respectively. The experiment included a 2-week adaptation and a 22-week data and sample collection period. Results indicated that blood urea nitrogen in the plasma of the 0.25% NALM group was lower compared to the control and the 0.50% NALM groups ( = 0.02). The plasma methionine ( = 0.04), proline ( < 0.01), and tryptophan ( = 0.05) were higher in the 0.25% and 0.50% NALM groups, as well as the methionine and proline in the muscle of the 0.25% NALM group ( 0.01). The muscle pH ( < 0.01) was increased by supplementing 0.25% and 0.50% NALM in diets but decreased the lactate ( 0.01). The 0.25% NALM group also increased * ( 0.05), decreased * ( = 0.05), drip loss ( = 0.01), and glycolytic potential in the muscle ( < 0.01). The total antioxidant capacity, superoxide dismutase, glutathione peroxidase, catalase, and glutathione in muscle of 0.25% NALM group were higher than that of the control ( < 0.01), and the malondialdehyde and protein carbonyl were lower ( < 0.01). In conclusion, the dietary supplement with NALM improves meat quality by enhancing the antioxidant effect of lipids and proteins.

中文翻译：

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N-乙酰基-L-蛋氨酸膳食补充剂通过育成安格斯小母牛的氧化稳定性改善肉质


蛋氨酸在反刍动物的蛋白质合成和抗氧化反应调节中起着至关重要的作用。本研究旨在评估膳食补充剂 - 乙酰 - 蛋氨酸 (NALM)（瘤胃保护蛋氨酸的来源）对生长性能、胴体性状、肉质和氧化稳定性的影响。 60 头安格斯小母牛（初始体重 = 408 ± 51.2 kg，15-18 个月）按体重分层，并随机分配到四种饮食治疗组：对照组（0% NALM）和接受含有 0.125%、0.25 NALM 饮食的实验组。分别为 % 和 0.50% NALM（干物质 (DM) 基础）。该实验包括 2 周的适应期和 22 周的数据和样本收集期。结果表明，0.25% NALM 组血浆中的血尿素氮低于对照组和 0.50% NALM 组（= 0.02）。 0.25% 和 0.50% NALM 组的血浆蛋氨酸 ( = 0.04)、脯氨酸 ( < 0.01) 和色氨酸 ( = 0.05) 较高，0.25% NALM 组肌肉中的蛋氨酸和脯氨酸较高 ( 0.01 ）。在日粮中添加 0.25% 和 0.50% NALM 可以提高肌肉 pH 值 ( < 0.01)，但会降低乳酸 ( 0.01)。 0.25% NALM 组还增加了 * ( 0.05)、减少了 * ( = 0.05)、滴水损失 ( = 0.01) 和肌肉中的糖酵解潜力 ( < 0.01)。 0.25%NALM组肌肉总抗氧化能力、超氧化物歧化酶、谷胱甘肽过氧化物酶、过氧化氢酶、谷胱甘肽均高于对照组（<0.01），丙二醛和蛋白羰基含量较低（<0.01）。总之，含有 NALM 的膳食补充剂通过增强脂质和蛋白质的抗氧化作用来改善肉质。