Energy metabolism in the starved new-born lamb

Abstract

New-born lambs were treated in one of three ways: (a) killed within 2 hr of birth; (b) starved at 23°C in 'still air'; (c) starved at approximately 9°C in moving air. Starved lambs became hypothermic and hypoglycaemic and lapsed into coma or convulsions shortly before death, which occurred between 16 hr and 5 days. Survival was generally longer when starvation was at the higher temperature. The size of the energy reserves was estimated from the fat and glycogen content of lambs killed at birth or near death from starvation; protein utilization during starvation was estimated from nitrogen excretion in the urine and the increase in urea in the blood. Fat and carbohydrate reserves appeared to be exhausted near death from starvation. Fat was the largest source of energy, and there was twice as much fat available at birth in lambs from well-fed ewes as in lambs from poorly fed ewes. Carbohydrate reserves in the liver and muscle appeared unaffected by pre-natal nutrition. Protein utilization increased progressively throughout starvation at a rate independent of pre-natal nutrition, and the total amount of protein utilized depended on the period of survival. Total energy reserves in lambs from well-fed and poorly fed ewes were approximately 1000 and 400 kcal respectively estimated as above or from calorimetric studies during starvation.