227 Awardee Talk: Advances in Lipid Nutrition of Modern Sows

Abstract

Abstract The modern lactating sow is a highly productive female capable of producing large quantities of milk to support large, rapidly growing litters. The associated high energy and nutritional demands are challenging to meet, especially during heat stress, when tissue loss is extensive. Supplemental lipids are efficient energy sources with a high energy density and low heat increment associated with digestion and metabolism. Besides serving as concentrated energy sources, unsaturated lipids are important sources of essential fatty acids (EFA; linoleic acid, C18:2n-6; and α-linolenic acid, C18:3n-3). These EFA are precursors of various prostanoids that are important regulators of reproductive processes. Lactating sows fed diets devoid of supplemental lipids exhibited poor reproduction but was significantly improved by inclusion of only 2% unsaturated lipids. It was shown that lactation diets were deficient in both linoleic and α-linolenic acid and tissue reserves were inadequate in mature sows. A multi-trial meta-analysis showed that more sows were successfully bred and maintained pregnancy when they consumed supplemental linoleic acid. Further, increased linoleic acid intake during lactation progressively reduced the number of sows removed from the herd due to reproductive failure (sows not returning to estrus, returning to estrus after breeding, pregnancy loss). Based on dose-response curves, the near maximum response was achieved when sows consumed a minimum of 125 g/d of linoleic acid and 10 g/d of α-linolenic acid during lactation. Recent studies also demonstrated improved subsequent reproduction with supplemental linoleic and α-linolenic acid during lactation, but not during the post-weaning period. Responses appeared to be related to heavier fetoplacental units, elevated allantoic fluid volume, and higher embryo survival measured on day 30 of gestation in sows supplemented with linoleic acid during lactation and early gestation. Research demonstrated the importance of both EFA in lactating sows and their critical role in improving reproduction, thus resolving seasonal anestrus.