Abstract This study was aimed to investigate the effect of feed supplemented with betaine on broiler chickens’ growth and slaughter performance, breast muscle histomorphometric and physicochemical properties, oxidative status and amino acid content. A total of 1000 1-day-old Ross 308 broiler chickens were divided into four treatments. Control group chickens were fed with standard compound diet (SCD), the chickens from experimental groups B1, B2 and B3 receiving SCD supplemented with 1 g/kg (B1), 2 g/kg (B2) and 3 g/kg (B3) betaine anhydrous, respectively. Each treatment had five replicate pens. Feeding test results showed that betaine reduced broilers’ mortality but increased feed conversion ratio (p < .05). Forty broiler chickens (5 weeks old) were slaughtered and slaughter performance showed that 2 g/kg betaine inclusion improved breast muscle percentage and yield (p < .05). Betaine dosage of 1 g/kg into feed increased breast muscle fibre areas (p < .05). Betaine affected some physicochemical properties: higher a* and the highest drip loss in B2; the highest cooking losses in B1, B2; the highest shear force and fat content in SCD; the highest amounts of ashes in B1, B2 (p < .05). Lower malondialdehyde levels were observed in all betaine-treated groups (p < .05), except B1 fresh meat samples. The highest total amino acid content and a greater amount of essential amino acids were obtained in SCD breast muscles (p < .05), except equally highest amounts of methionine were found in both SCD and B3 samples (p < .05). However, according to our study results, betaine, as a methyl group donor, in broiler chicken diets cannot replace methionine as an essential amino acid. Highlights Betaine is known as functional nutrient in poultry nutrition, which can fulfil the function of a methyl donor. Betaine in animal feed is saving feed costs by replacing choline chloride and methionine.

中文翻译：

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甲基供体甜菜碱对肉鸡生长性能、胸肌品质特性、氧化状态和氨基酸含量的影响

摘要 本研究旨在研究添加甜菜碱的饲料对肉鸡生长和屠宰性能、胸肌组织形态学和理化特性、氧化状态和氨基酸含量的影响。共1000只1日龄Ross 308肉鸡，分为4个处理。对照组鸡饲喂标准复合日粮（SCD），实验组B1、B2和B3的鸡接受SCD补充1g/kg（B1）、2g/kg（B2）和3g/kg（B3）分别为无水甜菜碱。每个处理有五个重复围栏。饲养试验结果表明甜菜碱降低了肉鸡的死亡率，但提高了饲料转化率（p < .05）。屠宰了 40 只肉鸡（5 周龄），屠宰性能表明加入 2 g/kg 甜菜碱可提高胸肌百分比和产量（p < .05）。将 1 g/kg 甜菜碱添加到饲料中可增加胸肌纤维面积 (p < .05)。甜菜碱影响了一些理化性质：较高的a*和B2中最高的滴水损失；B1、B2 的烹饪损失最高；SCD 中最高的剪切力和脂肪含量；B1、B2 中的灰烬量最高（p < .05）。除 B1 鲜肉样品外，所有甜菜碱处理组均观察到较低的丙二醛水平 (p < .05)。在 SCD 的乳房肌肉中获得了最高的总氨基酸含量和更多的必需氨基酸 (p < .05)，但在 SCD 和 B3 样品中发现的蛋氨酸含量同样最高 (p < .05)。然而，根据我们的研究结果，甜菜碱作为甲基供体，在肉鸡日粮中不能替代蛋氨酸作为必需氨基酸。亮点 甜菜碱被称为家禽营养中的功能性营养素，可以完成甲基供体的功能。动物饲料中的甜菜碱通过替代氯化胆碱和蛋氨酸来节省饲料成本。