Lipogenesis and Lipolysis in Adipose Tissue of Ad Libitum and Restricted-Fed Beef Cattle during Growth1

Abstract

Lipogenic and lipolytic capacities were measured in subcutaneous (backfat) and omental adipose tissue of beef steers weighing 113, 231, 363 and 505 kilograms. A comparison also was made between ad libitum-fed and restricted-fed steers during fattening. Maximum lipogenic capacity in both adipose sites of the ad libitum-fed animals was with the 363-kg steers, and the minimum with the 505-kg steers. Even though restricted-fed steers had equal fat accumulation, fatty acid synthesis capacity was lower in adipose of restricted-fed steers compared with ad libitum-fed steers, except for omental adipose of the 505-kg steers. During growth from 113 kg, rates of basal lipolysis in backfat and omental adipose tissue of ad libitum-fed steers increased at 231 and 363 kg and again at 505 kilograms. Hormone-stimulated lipolysis rates tended to decrease with increasing body weight. Except for stimulated lipolysis in omental adipose in the 363-kg steers, both stimulated and basal lipolysis rates decreased with restricted feeding. Basal lipolysis did not differ markedly between adipose sites, but stimulated lipolysis was greater in backfat than in omental in both the ad libitum- and restricted-fed steers. Lipogenic capacity was significantly correlated with stimulated lipolysis, but not with basal lipolysis. Copyright © 1975. American Society of Animal Science . Copyright 1975 by American Society of Animal Science.