Effect of omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation to lactating sows on growth and indicators of stress in the post-weaned pig

Authors: MCAFEE, JOHN - University Of Tennessee; KATTESH, HENRY - University Of Tennessee; LINDEMANN, MERLIN - University Of Kentucky; VOY, BRYNN - University Of Tennessee; KOJIMA, CHERLY - University Of Tennessee; Sanchez, Nicole; Carroll, Jeffery - Jeff Carroll; GILLESPIE, BARBARA - University Of Tennessee; SAXTON, ARNOLD - University Of Tennessee

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2019
Publication Date: 9/23/2019
Citation: McAfee, J.M., Kattesh, H.G., Lindemann, M.D., Voy, B.H., Kojima, C.J., Sanchez, N.C., Carroll, J.A., Gillespie, B.E., Saxton, A.M. 2019. Effect of omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation to lactating sows on growth and indicators of stress in the post-weaned pig. Journal of Animal Science. 97(11):4453-4463. https://doi.org/10.1093/jas/skz300.
DOI: https://doi.org/10.1093/jas/skz300

Interpretive Summary: Stress can decrease pork production and jeopardize animal welfare. However, best management practices to decrease stress in pregnant sows and new born piglets is poorly understood. This research represents a collaborative effort by scientists from the University of Tennessee, the University of Kentucky, and ARS' Livestock Issues Research Unit to determine if feeding pregnant sows a protected form of fish oil during late gestation and throughout lactation would reduce the stress and inflammation response as well as promote growth in pigs upon weaning. The results of the study indicated that the inclusion of a 1% fish oil supplement in the sows’ diet from gestation into late lactation does have some effects on indicators of stress and inflammation in their offspring postweaning. Not only did pigs fed the 1% fish oil diet gain more weight but they also had lower concentrations of blood markers associated with the inflammatory and stress responses associated with weaning. These data will be of interest to scientists in the fields of stress physiology, nutrition, and immunology as well as swine veterinarians and producers.

Technical Abstract: Dietary n-3 PUFA are precursors for lipid metabolites that reduce inflammation. Two experiments were conducted to test the hypothesis that enriching the sow diet in n-3 PUFA during late gestation and throughout lactation reduces stress and inflammation, and promotes growth in weaned pigs. A protected fish oil product (PFO; GromegaTM) was used to enrich the diet in n-3 PUFA. In the initial experiment, time-bred gilts were fed a gestation and lactation diet supplemented with 0 (control; n = 5), 0.25 (n = 4), 0.5 (n = 4) or 1% (n = 5) PFO from 101 ± 2 d of gestation to d 16 of lactation. Adding 1% PFO to the diet increased the n-3:n-6 PUFA ratio in colostrum and milk compared to controls (P = 0.05). A subsequent experiment was performed to determine if supplementing the sows’ diet with 1% PFO improved growth and reduced circulating markers of acute inflammation and stress in their offspring. Plasma was harvested from piglets (16 /treatment group) on d 0 (d of weaning) and d 1 and 3 postweaning. Pigs from the 1% PFO treatment group weighed more (P = 0.03) on d 3 postweaning and had a greater (P ' 0.05) n-3:n-6 PUFA ratio in plasma on each day sampled compared to 0% PFO controls. There was an overall treatment effect on plasma total cortisol (P = 0.03) and haptoglobin (P = 0.04), with lesser concentrations in pigs on the 1% PFO diet. Plasma corticosteroid-binding globulin (CBG) concentrations were not different between treatment groups but were lesser (P ' 0.001) on d 1 and 3 when compared to d 0. The resultant free cortisol index [FCI (cortisol/CBG)] was lesser (P = 0.02) on d 1 and 3 for pigs from the 1% treatment group compared to the controls. An ex vivo lipopolysaccharide (LPS) challenge of whole blood collected on d 0 and 1 was used to determine if 1% PFO attenuated release of inflammatory cytokines (IL-1ß, IL-6, and TNF-a). Pigs from the 1% PFO treatment group tended (P = 0.098) to have a lesser mean concentration of TNF-a in response to LPS compared to controls. These results suggest that providing a PFO supplement as 1% of the diet to sows beginning in late gestation and during lactation can increase the n-3:n-6 PUFA ratio in their offspring, which may improve growth and reduce the acute physiological stress response in the pigs postweaning.