This study was aimed to explore the comparative acidifying properties of 2‐hydroxy‐4‐(methylthio) butanoic acid (HMTBA) and a combination of DL‐methionine (DLM) and acidifier in male broiler production. A total of 480 1‐day‐old broiler chicks were randomly divided into four treatments: A (low HMTBA, 0.057% HMTBA); B (low acidifier, 0.05% DLM + 0.057% acidifier); C (high HMTBA, 0.284% HMTBA); and D (high acidifier, 0.25% DLM + 0.284% acidifier). At 21 d, growth performance, chyme pH, digestive enzyme activities, and intestinal microflora were measured. The pH of crop, gizzard, and ileum contents was higher in the HMTBA treatment group than in DLM + acidifier treatment group. Furthermore, acidifier supplementation promoted growth of butyrate‐producing bacteria such as Faecalibacterium , whereas high HMTBA (0.284%) inhibited the proliferation of acid‐producing bacteria including Roseburia and Collinsella . The chymotrypsin activity was lower in the HMTBA group than in the DLM + acidifier group. In contrast, high‐level HMTBA group showed higher average daily gain and average daily feed intake than the DLM + acidifier group. These results suggested that HMTBA work through different pathways with DLM plus acidifier.

中文翻译：

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2-羟基-4-(甲硫基)丁酸和酸化剂对肉鸡生产性能、食糜 pH 值和微生物群的影响。

本研究旨在探索 2-羟基-4-(甲硫基) 丁酸 (HMTBA) 和 DL-甲硫氨酸 (DLM) 与酸化剂的组合在雄性肉鸡生产中的比较酸化特性。总共 480 只 1 日龄肉鸡被随机分为四个处理组：A（低 HMTBA，0.057% HMTBA）；B（低酸化剂，0.05% DLM + 0.057%酸化剂）；C（高 HMTBA，0.284% HMTBA）；D（高酸化剂，0.25% DLM + 0.284% 酸化剂）。在 21 天时，测量生长性能、食糜 pH 值、消化酶活性和肠道微生物群落。HMTBA 处理组嗉囊、砂囊和回肠内容物的 pH 值高于 DLM + 酸化剂处理组。此外，酸化剂的补充促进了产丁酸盐细菌的生长，例如Faecalibacterium，而高 HMTBA (0.284%) 抑制了包括Roseburia和Collinsella在内的产酸细菌的增殖。HMTBA 组的胰凝乳蛋白酶活性低于 DLM + 酸化剂组。相比之下，高水平 HMTBA 组的平均日增重和平均日采食量高于 DLM + 酸化剂组。这些结果表明 HMTBA 通过不同的途径与 DLM 加酸化剂一起工作。