A second round of USDA pig trials suggest dietary L-glutamine could substitute for some antibiotic use for enhancing immunity and performance following stressful events.
Last year, the USDA’s Agricultural Research Service (ARS) reported results of initial trials showing potential benefits of feeding glutamine in controlled settings. The researchers published their findings in the Journal of Animal Science, while noting a need for further testing in commercial environments.
The researchers note that L-glutamine is a conditionally essential amino acid that is a major energy source for rapidly dividing cells including enterocytes and lymphocytes. It serves as an immunomodulator that inhibits pro-inflammatory cytokines. Previous research has indicated that including dietary L-glutamine as a growth promoter can improve productivity in healthy and unstressed pigs. Little is known though, about its effects on the health of piglets following typical production stressors. So, the researchers set out to compare L-glutamine supplementation with dietary chlortetracycline and no supplement, in post-weaning pigs during a period of simulated transport and heat stress.
In the more recent, larger-scale trials, researchers transported groups of piglets 12 hours from their weaning location to a nursery barn. During the nursery phase, the researchers fed one group of pigs a supplement containing chlortetracycline while another group received glutamine and the third group served as controls. The trial included two replicates with 480 pigs, one replicate shipped during the summer of 2016 and the other during spring of 2017.
Overall, the researchers found the glutamine groups performed similarly to the antibiotic groups, with both outpacing the control pigs.
Key findings include:
- Glutamine-fed piglets gained weight as well as the antibiotic group but showed fewer signs of intestinal damage from pathogens.
- Glutamine group members were somewhat less aggressive in pens with mixed litters than those given the antibiotic.
- Compared to the control group, glutamine- and antibiotic-treated piglets showed lower blood plasma levels of tumor necrosis factor alpha (TNF-alpha), a biochemical marker of inflammation and immune system activity.
- The meat quality of market-ready pigs from the glutamine group was no different than that of the antibiotic or control group.
The researchers published their results in the May 29 issue of the Journal of Animal Science.
For more about glutamine and other potential alternatives to antibiotics in livestock production, see these articles from BovineVetOnline: