Duttlinger Alan W, Kpodo Kouassi R, Schinckel Allan P, Richert Brian T, Johnson Jay S
Purdue University, Department of Animal Sciences, West Lafayette, IN.
USDA-ARS Livestock Behavior Research Unit, West Lafayette, IN.
Transl Anim Sci. 2020 Aug 26;4(3):txaa157. doi: 10.1093/tas/txaa157. eCollection 2020 Jul.
Supplementing nursery diets with 0.20% L-glutamine (GLN) may provide similar growth and health benefits as dietary antibiotics, but it was unknown if greater inclusion levels may provide additional benefits. Therefore, the study objective was to evaluate the impact of replacing dietary antibiotics with increasing GLN levels on growth performance, therapeutic antibiotic treatment rates, welfare measures, and production costs in pigs after weaning and transport. We hypothesized that withholding dietary antibiotics may negatively impact performance and increase therapeutic treatment rate, and that diet supplementation with 0.20% to 1.00% GLN may incrementally improve productivity and reduce therapeutic antibiotic treatment rates compared with dietary antibiotics. Mixed sex pigs ( = 308; 5.64 ± 0.06 kg body weight [BW]) were weaned (19.1 ± 0.2 d of age) and transported in central Indiana in 2017. Pigs were blocked by BW and allotted to one of seven dietary treatments ( = 8 pens/dietary treatment): dietary antibiotics (positive control [PC]; chlortetracycline [441 mg/kg] + tiamulin [38.6 mg/kg]), no antibiotics or added GLN (negative control [NC]), 0.20% GLN, 0.40% GLN, 0.60% GLN, 0.80% GLN, or 1.00% GLN fed for 14 d. From d 14 to 35, pigs were provided nonantibiotic common diets in two phases. Overall, average daily gain (ADG) was reduced ( = 0.01; 17.7%) from d 0 to 14 in NC, 0.20% GLN, 0.60% GLN, 0.80% GLN, and 1.00% GLN pigs compared with PC pigs, but no ADG differences were detected between 0.40% GLN pigs and PC pigs. Increasing GLN in the diet tended to increase ADG (linear; = 0.10). Overall, d 35 BW was greater ( = 0.01) in 0.80% GLN and PC pigs compared with NC, 0.20% GLN, and 0.60% GLN pigs, and was greater for 0.40% GLN and 1.00% GLN pigs vs. 0.20% GLN pigs. However, no d 35 BW differences were detected ( > 0.05) between PC, 0.40% GLN, 0.80% GLN, and 1.00% GLN pigs. Increasing GLN in the diet tended to increase (linear; = 0.08) d 35 BW. Overall, income over feed and therapeutic injectable antibiotics cost (IOFAC) for enteric and unthrifty challenges were greater ( = 0.02) in 0.80% GLN pigs compared with NC, 0.20% GLN, and 0.60% GLN pigs, but no IOFACs for enteric and unthrifty challenges differences were detected between 0.80% GLN pigs and 0.40% GLN, 1.00% GLN, and PC pigs. In conclusion, GLN supplemented pigs had improved performance after weaning and transport compared with the NC pigs with 0.40% GLN being the most effective level.
在保育猪日粮中添加0.20%的L-谷氨酰胺（GLN）可能会带来与日粮抗生素相似的生长和健康益处，但更高添加水平是否会带来额外益处尚不清楚。因此，本研究的目的是评估用不同GLN水平替代日粮抗生素对断奶和运输后仔猪生长性能、治疗性抗生素使用率、福利指标和生产成本的影响。我们假设不添加日粮抗生素可能会对生长性能产生负面影响并增加治疗性抗生素使用率，并且与日粮抗生素相比，在日粮中添加0.20%至1.00%的GLN可能会逐步提高生产性能并降低治疗性抗生素使用率。2017年，在印第安纳州中部对混合性别的仔猪（n = 308；体重[BW]5.64±0.06千克）进行断奶（19.1±0.2日龄）并运输。仔猪按体重进行分组，然后分配到七种日粮处理之一（每个日粮处理8个栏）：日粮抗生素（阳性对照[PC]；金霉素[441毫克/千克]+噻嘧啶[38.6毫克/千克]）、不添加抗生素或GLN（阴性对照[NC]）、0.20%GLN、0.40%GLN、0.60%GLN、0.80%GLN或1.00%GLN，饲喂14天。从第14天到第35天，仔猪分两个阶段饲喂无抗生素的普通日粮。总体而言，与PC组仔猪相比，NC组、0.20%GLN组、0.60%GLN组、0.80%GLN组和1.00%GLN组仔猪在第0天至第14天的平均日增重（ADG）降低（P = 0.01；降低17.7%），但0.40%GLN组仔猪与PC组仔猪之间未检测到ADG差异。日粮中GLN添加量增加有使ADG升高的趋势（线性；P = 0.10）。总体而言，与NC组、0.20%GLN组和0.60%GLN组仔猪相比，0.80%GLN组和PC组仔猪在第35天的体重更大（P = 0.01），0.40%GLN组和1.00%GLN组仔猪相对于0.20%GLN组仔猪体重更大。然而，PC组、0.40%GLN组、0.80%GLN组和1.00%GLN组仔猪在第35天的体重差异未达到显著水平（P>0.05）。日粮中GLN添加量增加有使第35天体重升高的趋势（线性；P = 0.08）。总体而言，与NC组、0.20%GLN组和0.60%GLN组仔猪相比，0.80%GLN组仔猪因肠道和生长不良问题产生的饲料收益与治疗性注射用抗生素成本（IOFAC）更高（P = 0.02），但0.80%GLN组仔猪与0.40%GLN组、1.00%GLN组和PC组仔猪在因肠道和生长不良问题产生的IOFAC方面未检测到差异。总之，与NC组仔猪相比，添加GLN的仔猪在断奶和运输后的生长性能有所改善，其中添加0.40%GLN的效果最为显著。
