This study was conducted to investigate the effects of dietary complexity and l-Thr supplementation on energy and nutrient utilization in nursery pigs. Thirty-two nursery pigs (7.23 ± 0.48 kg) were randomly assigned to a 2 × 2 factorial treatment arrangement based on diet complexity (complex vs. simple) with different levels of l-Thr supplementation. The complex diet contained animal protein sources (e.g., fish meal and plasma) and a dairy product (e.g., dried whey) to mimic a conventional nursery diet. The simple diet was formulated with corn, wheat, and soybean meal. Both diets were supplemented with l-Thr to contain either 100% or 115% (SUP Thr) of the estimated standardized ileal digestible Thr requirement for 9 kg body weight pigs (NRC, 2012). The pigs were individually housed in metabolism crates and fed an experimental diet ad libitum for a 7-d adaptation period and 5 d of total but separate urine and fecal collection. On day 14, all pigs were euthanized to determine body composition. The diet complexity, l-Thr supplementation, and their interactions were considered main effects. Pigs fed the complex diet tended to exhibit greater (P < 0.10) apparent total tract digestibility (ATTD) of ash and urinary energy output than those fed the simple diet. The complex diet had greater (P < 0.05) digestible energy and net energy contents than the simple diet. Furthermore, the complex diet-fed pigs had lower (P < 0.05) plasma urea nitrogen concentration on day 14 than simple diet-fed pigs. The SUP Thr decreased (P < 0.05) ATTD of acid detergent fiber but trended (P < 0.10) toward a decrease in urinary nitrogen (N) output and an increase in N retention and body N mass. In conclusion, the simple diet for nursery pigs had lower digestible and net energy contents than a complex diet. The SUP Thr can improve N utilization and body protein deposition, irrespective of diet complexity.

中文翻译：

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日粮复杂性和 L-苏氨酸补充：对保育猪营养消化率、氮和能量平衡以及身体成分的影响。


本研究旨在调查日粮复杂性和 L-Thr 补充对保育猪能量和营养利用的影响。将 32 头保育猪（7.23 ± 0.48 kg）根据日粮复杂性（复杂与简单）随机分配至 2 × 2 析因处理安排，并添加不同水平的 L-Thr。复杂的饮食包含动物蛋白来源（例如鱼粉和血浆）和乳制品（例如乳清粉）以模仿传统的保育饮食。简单的饮食由玉米、小麦和豆粕配制而成。两种日粮均添加了 l-Thr，含量达到 9 公斤体重猪的标准化回肠可消化 Thr 需求量的 100% 或 115% (SUP Thr)（NRC，2012）。将猪单独圈养在代谢栏内，并在 7 天的适应期中随意饲喂实验饮食，并收集 5 天的全部但单独的尿液和粪便。第 14 天，对所有猪实施安乐死以确定身体成分。饮食复杂性、l-Thr 补充及其相互作用被认为是主要影响。饲喂复杂日粮的猪往往比饲喂简单日粮的猪表现出更高的（P < 0.10）灰分表观总消化道消化率（ATTD）和尿能量输出。复合饮食比简单饮食具有更高的消化能和净能含量（P < 0.05）。此外，第14天，复合日粮喂养的猪的血浆尿素氮浓度低于简单日粮喂养的猪（P < 0.05）。 SUP Thr 降低了酸性洗涤纤维的 ATTD (P < 0.05)，但趋势是 (P < 0.10) 尿氮 (N) 输出量减少，氮保留量和身体氮量增加。 总之，保育猪的简单日粮的可消化能和净能含量低于复合日粮。无论饮食复杂程度如何，SUP Thr 都可以提高氮利用率和体内蛋白质沉积。