Advances in Meat Research: Growth Regulation in Farm Animals (Volume 7)

Growth regulation in farm animals is a topic of interest to animal scientists and livestock producers, and also of fundamental importance to muscle biochemists and meat scientists. Recently the increased consumer awareness of the importance of reducing fat consumption by humans has increased the emphasis on production of leaner meat. Reduction of fatness in farm animals can be achieved either by limiting feed intake or by metabolic regulation of the growth process to produce more lean or muscle tissue while simultaneously decreasing the fat content of the carcass by other means, such as raising of intact males in place of castrates, and administration of hormones and other compounds to stimulate growth and muscle deposition. The opening chapter provides an overview of growth to explain the mechanics of the growth process. Following this, the topics include hormonal regulation of growth application of genetic and transgenetic principles to control growth and effects of nutrition for a period of time toward subsequent gains upon refeeding, the effects upon the composition of the gains, and the eating quality of the meat produced. Regulation of adipose tissue metabolism and accretion is covered as is protein synthesis, accretion and degradation. These are important topics that discuss basic mechanisms involved in tissue metabolism of fat and protein deposition and mobilization and will ultimately determine the amount of muscle and fat deposited in the bodies of farm animals. The effects of sex and castration are also dealt with, followed by a chapter on the influence of testosterone and the other sex hormones upon body weight gains and their composition. The effects of ionophores and antibiotics and related compounds upon growth are also discussed. Insulin and insulin-like growth factors are also covered from the standpoint of their effects on gains in weight and meat quality. Other topics discussed from the standpoint of growth regulation include growth hormone releasing factor, the effects of photoperiod and serotonin, and the effects of the B-agonists upon growth and composition. The final three chapters discuss the effects of growth and composition on meat quality and some possible future developments in controlling growth.