Alan W Duttlinger,，Kouassi R Kpodo，Donald C Lay，Jr.，Brian T Richert，Jay S Johnson
试验数据显示，抗生素组（5.6%、18.5%）和谷氨酰胺组（3.8%、11.4%）14d体重、0～14d日增重显著高于对照组（P=0.01），而这两组之间无显著差异。抗生素组0～14d日采食量显著高于对照组（9.3%，P＜0.04）；谷氨酰胺组与其它两组无显著差异。随着日粮处理的停止，各处理组之间生产性能没有显著差异（P＞0.05）。在第13d，与对照组相比，抗生素组和谷氨酰胺组肿瘤坏死因子α显著降低（36.7±6.9和40.9±6.9 pg/ml VS. 63.2±6.9 pg/ml；P=0.02）。 与抗生素组相比，谷氨酰胺组猪的侵略性行为有减少的趋势（P = 0.09；26.4%）；对照组与抗生素组和谷氨酰胺组之间没有显著差异。春季时仔猪抱团、活动和采食/饮水行为整体高于夏季（P＜0.02；179%、37%和29%）。当以热胴体重为协变量时，春季时眼肌深度和瘦肉率显著高于夏季（P = 0.01；4.0% 和1.1%）。
Replacing dietary antibiotics with 0.20% L-glutamine in swine nursery diets: impact on health and productivity of pigs following weaning and transport
Antibiotic use has been limited in U.S. swine production. Therefore, the objective was to determine whether supplementing L-glutamine at cost-effective levels can replace dietary antibiotics to improve piglet welfare and productivity following weaning and transport. Based on previous research, we hypothesized that withholding dietary antibiotics would negatively affect pigs while diet supplementation with 0.20% L-glutamine (GLN) would have similar effects on pig performance and health as antibiotics. Mixed sex piglets (N = 480; 5.62 ± 0.06 kg BW) were weaned (18.4 ± 0.2 d of age) and transported for 12 h in central Indiana, for 2 replicates, during the summer of 2016 and the spring of 2017. Pigs were blocked by BW and allotted to 1 of 3 dietary treatments (n = 10 pens/dietary treatment/replicate [8 pigs/pen]); antibiotics (A; chlortetracycline [441 ppm] + tiamulin [38.6 ppm]), no antibiotics (NA), or GLN fed for 14 d. On days 15 to 34, pigs were provided common antibiotic-free diets in 2 phases. Data were analyzed using PROC MIXED in SAS 9.4. Day 14 BW and days 0 to 14 ADG were greater (P = 0.01) for A (5.6% and 18.5%, respectively) and GLN pigs (3.8% and 11.4%, respectively) compared with NA pigs, with no differences between A and GLN pigs. Days 0 to 14 ADFI increased for A (P < 0.04; 9.3%) compared with NA pigs; however, no differences were detected when comparing GLN with A and NA pigs. Once dietary treatments ceased, no differences (P > 0.05) in productivity between dietary treatments were detected. On day 13, plasma tumor necrosis factor alpha (TNF-α) was reduced (P = 0.02) in A (36.7 ± 6.9 pg/mL) and GLN pigs (40.9 ± 6.9 pg/mL) vs. NA pigs (63.2 ± 6.9 pg/mL). Aggressive behavior tended to be reduced overall (P = 0.09; 26.4%) in GLN compared with A pigs, but no differences were observed between A and GLN vs. NA pigs. Huddling, active, and eating/drinking behaviors were increased overall (P < 0.02; 179%, 37%, and 29%, respectively) in the spring replicate compared with the summer replicate. When hot carcass weight (HCW) was used as a covariate, loin depth and lean percentage were increased (P = 0.01; 4.0% and 1.1%, respectively) during the spring replicate compared with the summer replicate. In conclusion, GLN supplementation improved pig performance and health after weaning and transport similarly to A across replicates; however, the positive effects of A and GLN were diminished when dietary treatments ceased.