Effect of Prolonged Fasting on Carcass Composition and Blood Fatty Acids and Glucose of Neonatal Swine

Eight littermate pigs from each of four purebred Yorkshire sows were used to determine the relative change in carcass composition and blood fatty acids and glucose in piglets during a 72-hour fast or feeding period at birth and at 1 week of age. Fasted piglets at 72 hours had more moisture content and less percentage glycogen, whereas piglets fed to 72 hours had more percentage crude protein and total lipids but less percentage moisture and glycogen than pigs at birth. Carcasses of fed pigs at 1 week of age were lower in moisture, ash and glycogen and higher in total lipids and crude protein than piglets at birth. The only significant change occurring with fasting the week-old pigs was a decrease in total lipids of fasted pigs. After the 72-hour fasting period, the 3-day-old fasted pigs varied in their fatty acid composition significantly when compared to pigs allowed to suckle. Three-day fed animals decreased in stearic and arachidonic acids as percentage of fatty acids, while 3-day fasted piglets increased in these two fatty acids. The percentages of oleic and linoleic acids increased from birth in 3-day fed piglets, but these two fatty acids decreased in fasted piglets. Fasting had no effect on fatty acid composition of piglets at 1 week of age. Three-day fasted piglets had low blood glucose by 48 hours, whereas other piglets increased in blood glucose and maintained a high level. These data support other evidence of differences in fatty acid metabolism during fasting.