Effect of dietary unsaturated fatty acids and stage of lactation on milk composition and adipose tissue in swine.

Abstract

Sows fed a corn-soybean meal diet containing 10% corn oil from the 109th day of gestation and throughout lactation were compared to those fed an isocaloric, isonitrogenous diet low in fat. Milk samples were taken mechanically within 24 hr. after farrowing and at five weekly intervals thereafter for determinations of major components and fatty acids. Samples of subcutaneous adipose tissue were taken for fatty acid analyses from the backs of sows at 1, 3 and 5 weeks of lactation and from their nursing pigs at 3 and 5 weeks of age. Colostrum contained significantly more crude protein and less ash, lactose, calcium and phosphorus than later milk and was more acidic. Colostral fat contained significantly higher percentages of oleic and linoleic acids than later milk. The feeding of corn oil significantly increased the percentage of linoleic acid in both colostral- and milk-fat. Linoleic acid reached a high of 35% of the total fatty acids by the fifth week of lactation. The only changes in fatty acid percentages in sows' adipose tissue were slight changes in myristic and linolenic acids. However, by 3 weeks of age nursing pigs' adipose tissue fatty acids closely resembled those in the milk being consumed. The adipose tissue from nursing pigs from control and corn oil-fed groups contained 9.6 and 21.4% linoleic acid, respectively. There were no differences in pig weight gains to 5 weeks of age.