This study evaluated the effects of feeding pigs low protein (LP) diets for different lengths of time after weaning on indices of protein fermentation, the incidence of post-weaning diarrhoea (PWD), growth performance, and total-tract apparent digestibility. Sixty weaner pigs weighing 6.1 ± 0.13 kg (mean ± SEM) were used in a completely randomised design having five treatments: (i) a high protein diet (HP, 243 g/kg CP) fed for 14 d after weaning (HP14); (ii) a low protein diet (LP, 173 g CP/kg) fed for 5 d after weaning (LP5); (iii) LP diet fed for 7 d after weaning (LP7); (iv) LP diet fed for 10 d after weaning (LP10), and (v) LP diet fed for 14 d after weaning (LP14). All diets were supplemented with lysine, methionine, tryptophan and threonine, with all LP diets additionally fortified with crystalline isoleucine and valine to conform to a proposed ideal amino acid (AA) pattern. A second-stage diet (215 g CP/kg) was fed to pigs at the conclusion of each treatment. None of the diets contained antimicrobial compounds. Feeding a LP diet, regardless of duration of feeding, decreased plasma urea nitrogen (p < 0.001) and faecal ammonia-nitrogen (p < 0.001) contents. Feeding a LP diet, irrespective of feeding duration, decreased the incidence of PWD at day 8 after weaning (p = 0.044), and pigs fed diets LP7, LP10 and LP14 had firmer faeces (p = 0.030, p = 0.047 and p = 0.007, respectively) between days 10 and 12 after weaning. Treatments LP5, LP7, LP10 and LP14 did not reduce (p > 0.05) growth performance up to 106 days after weaning compared to pigs fed the HP diet. Total-tract apparent digestibility of dry matter, energy and crude protein were similar (p > 0.05) between treatments. Our data suggest that feeding a LP diet, supplemented with AA to conform to an ideal AA pattern, for 7–10 days after weaning can reduce PWD in pigs fed antibiotic-free diets without compromising production.

中文翻译：

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低蛋白日粮对仔猪血浆尿素氮、粪便氨氮、腹泻发生率及断奶后生产性能的影响

本研究评估了断奶后不同时间饲喂低蛋白（LP）日粮对蛋白质发酵指数、断奶后腹泻（PWD）发生率、生长性能和全道表观消化率的影响。60 头重 6.1 ± 0.13 kg（平均值 ± SEM）的断奶仔猪用于完全随机设计，有五种处理：（i）高蛋白日粮（HP，243 g/kg CP），断奶后饲喂 14 天（HP14）；(ii) 断奶后饲喂 5 天的低蛋白日粮（LP，173 g CP/kg）（LP5）；(iii)断奶后饲喂7天的LP日粮(LP7)；(iv) 断奶后饲喂 10 天的 LP 日粮 (LP10)，和 (v) 断奶后饲喂 14 天的 LP 日粮 (LP14)。所有日粮都补充赖氨酸、蛋氨酸、色氨酸和苏氨酸，所有 LP 饮食都额外添加了结晶异亮氨酸和缬氨酸，以符合建议的理想氨基酸 (AA) 模式。在每次处理结束时给猪喂食第二阶段日粮（215 克 CP/kg）。没有一种饮食含有抗微生物化合物。饲喂 LP 日粮，无论饲喂时间长短，都会降低血浆尿素氮 (p < 0.001) 和粪便氨氮 (p < 0.001) 含量。饲喂 LP 日粮，无论饲喂时间长短，都可降低断奶后第 8 天 PWD 的发生率（p = 0.044），饲喂 LP7、LP10 和 LP14 日粮的猪粪便更硬（p = 0.030、p = 0.047 和 p = 0.007） ，分别）断奶后第 10 天和第 12 天之间。与喂食 HP 饮食的猪相比，LP5、LP7、LP10 和 LP14 处理在断奶后长达 106 天没有降低（p > 0.05）生长性能。不同处理间干物质、能量和粗蛋白的全消化道表观消化率相似（p > 0.05）。我们的数据表明，在断奶后 7-10 天内饲喂 LP 日粮并添加 AA 以符合理想的 AA 模式，可以减少饲喂无抗生素日粮的猪的 PWD，而不会影响生产。