SUMMARY There is considerable interest in the development of reduced protein diets with supplemental amino acids (AAs) for broiler chickens due to economic, environmental, health and bird welfare advantages. Lowering levels of protein, or using local sources, which may be more poorly digested or have an unbalanced AA profile, has implications for both animal performance and health. However, reduced protein diets may result in AA redistribution away from growth and production processes, towards intestinal cells involved in immune and inflammatory responses. Certain gut diseases are related to higher protein diets, and low protein formulations can reduce the risk of such problems. However, in low protein diets, a reduced or unbalanced supply of AA in the diet can be deleterious to the immune system. Therefore, an ideal dietary AA profile is crucial for broiler chicken gut health, especially in Antibiotic growth promoter (AGP) free situations. All AA are in ratio to dietary Lys, and when Lys concentration is increased, both essential and non-essential AA concentrations need to be increased accordingly. Currently when dietary standardised ileal digestibility (SID) for Lys is 1.3%, the SID of total sulphur-containing AA may need to increase to 0.975%, Arg to 1.43%, Thr to 0.884%, Val to 1.04%, Ile to 0.884% and Phe to 0.845%. In wheat-soy based diets, reduced protein diets may lead to deficiencies in His and Ala, potentially affecting chicken gut health. Possibly the SID of His needs to increase to 0.53%. Some non-essential AA profiles need to increase, such as SID of Gly to 0.884%, Glu to 3.54% and Ala to 0.845%. Compared with DL-Methionine and DL-HMTBA, L-Met is the natural form of Met and its relative biological value has remained controversial due to unsuitable statistical models and other limiting AA influence. Increasing AA levels in reduced protein diets has been shown to maintain growth and ensure less incidence of gut disorders.

中文翻译：

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氨基酸营养与鸡肠道健康

总结 由于经济、环境、健康和家禽福利方面的优势，人们对为肉鸡开发含有补充氨基酸 (AAs) 的低蛋白日粮产生了相当大的兴趣。降低蛋白质水平，或使用可能更难消化或具有不平衡 AA 特征的本地来源，对动物的性能和健康都有影响。然而，减少蛋白质饮食可能导致 AA 从生长和生产过程重新分配到参与免疫和炎症反应的肠细胞。某些肠道疾病与高蛋白饮食有关，低蛋白配方可以降低出现此类问题的风险。然而，在低蛋白饮食中，饮食中 AA 的供应减少或不平衡可能对免疫系统有害。所以，理想的日粮 AA 配置对肉鸡肠道健康至关重要，尤其是在不含抗生素生长促进剂 (AGP) 的情况下。所有氨基酸都与日粮赖氨酸成比例，当赖氨酸浓度增加时，必需和非必需氨基酸浓度都需要相应增加。目前，当赖氨酸的日粮标准回肠消化率 (SID) 为 1.3% 时，总含硫 AA 的 SID 可能需要增加到 0.975%，Arg 到 1.43%，Thr 到 0.884%，Val 到 1.04%，Ile 到 0.884% Phe 为 0.845%。在以小麦大豆为基础的饮食中，减少蛋白质饮食可能导致 His 和 Ala 缺乏，从而可能影响鸡肠道健康。可能他的 SID 需要增加到 0.53%。一些非必需的 AA 配置文件需要增加，例如 Gly 的 SID 到 0.884%，Glu 到 3.54% 和 Ala 到 0.845%。与 DL-蛋氨酸和 DL-HMTBA 相比，L-Met 是 Met 的自然形式，由于不合适的统计模型和其他限制性 AA 影响，其相对生物学价值仍然存在争议。在减少蛋白质的饮食中增加 AA 水平已被证明可以维持生长并确保减少肠道疾病的发生率。