Effects increasing dietary L-glutaine to replace antibiotics on pig health and performance following weaning and transport.

Authors: DUTTLINGER, ALAN - Purdue University; KPODO, KOUASSI - Purdue University; SCHINCKEL, ALLAN - Purdue University; RICHERT, BRIAN - Purdue University; Johnson, Jay

Submitted to: Translational Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2020
Publication Date: 8/26/2020
Citation: Duttlinger, A.W., Kpodo, K.R., Schinckel, A.P., Richert, B.T., Johnson, J.S. 2020. Effects increasing dietary L-glutaine to replace antibiotics on pig health and performance following weaning and transport.. Translational Animal Science. https://doi.org/10.1093/tas/txaa157.
DOI: https://doi.org/10.1093/tas/txaa157

Interpretive Summary: Pigs in the United States are transported following weaning to different production facilities in an effort to reduce illness. Unfortunately, the weaning and transport process reduces piglet health and welfare. Traditionally, swine producers have used dietary antibiotics to help pigs overcome the stress of weaning and transport. However, in recent years, United States pork producers have sought out antibiotic-free nutritional additives to improve piglet health and performance following common production stressors. Previous research by the USDA-ARS determined that supplementing newly weaned and transported pig diets with 0.20% L-glutamine could improve growth performance and health to a similar extent as dietary antibiotics. However, it was unknown whether increasing the inclusion rate of L-glutamine would further improve this response. Therefore, the study objective was to evaluate the impact of replacing dietary antibiotics with increasing levels of L-glutamine on growth performance, health status, and production costs following weaning and transport in pigs. It was determined that pigs provided 0.40%, 0.80%, and 1.00% L-glutamine supplementation had similar growth performance and health after weaning and transport compared to dietary antibiotic supplemented pigs. However, 0.40% L-glutamine supplementation in the present study was the optimal level while the experimental diets were fed and 0.80% L-glutamine was the optimal level for the duration of the trial when common diets were fed when considering the production costs. Based on the results from the present study, it appears that 0.40% L-glutamine may be the optimal level of inclusion to improve pig welfare and performance immediately following weaning and transport while 0.80% L-glutamine supplementation may provide the most long-term economic benefit.

Technical Abstract: Previous research indicates that supplementing nursery diets with 0.20% L-glutamine (GLN) provides similar growth and health benefits as dietary antibiotics, but it is unknown whether greater inclusion levels will provide additional benefits. Therefore, the study objective was to evaluate the impact of replacing dietary antibiotics (A) with increasing levels of GLN on growth performance, health status, and production costs in pigs following weaning and transport. We hypothesized that withholding A would negatively impact performance and health, and that diet supplementation with 0.20% to 1.00% GLN would incrementally improve health and productivity compared to A. Mixed sex pigs (N = 308; 5.64 ± 0.06 kg BW) were weaned (19.1 ± 0.2 d of age) and transported in central Indiana during the autumn of 2017. Pigs were blocked by BW and allotted to 1 of 7 dietary treatments (n = 8 pens/dietary treatment); A [chlortetracycline (441 ppm) + tiamulin (38.6 ppm)], no antibiotics or added GLN (NA), 0.20% GLN, 0.40% GLN, 0.60% GLN, 0.80% GLN, or 1.00% GLN fed for 14 d. On d 15 to 35, pigs were provided NA diets in two phases. Data were analyzed using PROC MIXED in SAS 9.4. Overall, ADG was reduced (P = 0.04; 6.4%) in NA pigs vs. 0.40% GLN or A pigs. Increasing GLN in the diet tended to increase (linear; P = 0.10) ADG. Average daily feed intake was reduced (P = 0.04; 6.9%) in NA pigs vs. 0.40% GLN or A pigs. Overall, d 35 BW was greater (P = 0.01) in 0.80% GLN and A pigs compared to NA, 0.20% GLN, and 0.60% GLN pigs, but no BW differences were detected between 0.80% GLN and A and 0.40% GLN and 1.00% GLN pigs. In addition, d 35 BW was greater (P = 0.01) for 0.40% GLN and 1.00% GLN pigs compared to 0.20% GLN pigs. Increasing GLN in the diet tended to increase (linear; P = 0.08) d 35 BW. Overall, income over feed and therapeutic injectable antibiotics cost for enteric and unthrifty challenges was greater (P = 0.02) in 0.80% GLN pigs compared to NA, 0.20% GLN, and 0.60% GLN pigs, but no income over feed and therapeutic injectable antibiotics cost for enteric and unthrifty challenges differences were detected between 0.80% GLN pigs and 0.40% GLN, 1.00% GLN, and A pigs. In conclusion, GLN supplemented pigs had improved performance and health after weaning and transport compared to the NA pigs with 0.40% GLN being the optimal level while the experimental diets were fed or 0.80% GLN being the most optimal level for the duration of the trial.