The impact of cooling and Moringa supplementation on oxidative stress in serum and milk, including milk cytokines, in heat stressed lactating sows and their litters

Abstract

Heat stress (HS) poses a significant challenge to the United States swine industry. Sows and their piglets are particularly vulnerable to HS, as the periparturient phase is characterized by heightened metabolism and increased oxidative stress and inflammation. The study examined the effects of using conductive electronic cooling pads (ECP) and dietary supplementation with 4% Moringa (M) leaf powder on controlling oxidative stress and inflammation caused by HS in sows and their piglets. Forty-eight late gestation sows were assigned to four treatment groups: HS-fed corn-soybean meal (HS + CS), ECP-fed corn-soybean meal (ECP + CS), HS + M, and ECP + M. Blood was collected from sows on gestation (G) day 112, and lactation (L) day 14 and L20, and from piglets (2 males and 2 females) in each litter on postnatal (PN) day 1 and PN20. Colostrum was collected within 2h of birth of the first neonate, and mature milk was collected on L14. Piglet fecal samples were collected on PN14 to measure calprotectin concentration as a marker of intestinal inflammation. Biological antioxidant potential (BAP), derivatives of reactive oxygen metabolites (dROMs). and oxidative stress index (OSi) were measured in blood and milk samples using a Free Radical Elective Evaluator. Milk samples pooled by day of lactation and treatment group were analyzed using cytokine array. Levels of inflammatory cytokines in colostrum were affected by Moringa supplementation and cooling, but not mature milk. Notably, the anti-inflammatory cytokines interleukin (IL)-10 and IL-1ra were 2.14 and 1.57 Log₂ higher in the colostrum of HS + M compared to other groups. The OSi of colostrum was higher (P = 0.0002) than mature milk. Level of BAP in sow serum was greater in ECP + CS and HS + M (P = 0.0291) compared to other groups. Moringa had an overall effect of increasing dROMs (P = 0.0035) and levels of OSi were lowest in ECP + CS (P = 0.0296) sow serum. Treatments did not affect piglet serum oxidative index (P > 0.05) or calprotectin levels (P > 0.05). Findings support further studies to investigate the efficacy of using ECP and Moringa supplementation to mitigate inflammation and oxidative stress imposed by heat stress conditions in lactating sows.

Keywords: Moringa; cooling pad; heat stress; lactation; oxidative stress; sow.