Fat Metabolism in Growing Swine: A Review

Abstract

At birth, piglets have little body fat that can be mobilized. The influx of high-fat milk causes a rapid increase in body fat stores and a depression of lipogenic enzyme activity. Conversely, lipolytic enzyme activity increases after birth. Changing the fat intake of sucking piglets affects the amount of fat deposition. The length of the sucking period also influences body composition at weaning. Weaning produces a pronounced but temporary decrease in total body lipid, despite an increase in fat synthesis. The effect of weaning on lipolysis is not clear due to a lack of experimental data. During the growing period, fat continues to build up even though lipogenic enzyme activity tends to decline with age. The composition of the diet, the sex of the animal and genetic factors have all been shown to influence the rate of lipogenesis. Fewer reports have been published in which factors affecting lipolysis have been studied and the results are often less conclusive. However, the combined activities of lipogenic and lipolytic processes do not account for the large quantity of body fat found in growing pigs. Key words: Swine, fat, lipogenesis, lipolysis, diet, sex.

Lipogenic enzyme activities in subcutaneous adipose tissue and skeletal muscle from neonatal pigs consuming maternal or formula milk

“…Although it is usually accepted that fatty acid synthesis is limited in suckling newborn mammals [4,15,38], the present data indicate that lipogenesis is not limited by enzyme activities or glucose transporter and that these parameters are regulated by early nutrition. The activities of lipogenic enzymes are lower in this study than in weaned pigs [3,28] but they are significant.…”

“…Body fat in the neonate is thought to be primarily derived from dietary fat since it is usually accepted that fatty acid synthesis is negligible in suckling newborn mammals [4,15,38]. Nevertheless, the detection of lipogenic enzymes in adipose tissue [27] and in skeletal muscle [28] of suckling pigs suggests that the activities of these enzymes may be significant for fatty acid synthesis.…”

Effect of sex, dietary glycerol or dietary fat during late fattening, on fatty acid composition and positional distribution of fatty acids within the triglyceride in pigs

“…Limiting the concentration of linoleic acid (C18:2n-6) in pig fat improves fat consistency, decreases the susceptibility to oxidation and development of undesirable flavor and reduces the incidence of technological problems, such as those related to water migration (López-Bote, 1998;López-Bote et al, 2002;Isabel et al, 2003). A reduction in C18:2n-6 concentration is achieved through the incorporation of saturated fats or other ingredients that enhance endogenous fat synthesis during the fattening diets period (Farnworth and Kramer, 1987;Wood et al, 2004;Duran-Montgé et al, 2008).…”

Backfat and carcass composition of piglets fed milk replacers containing vegetable oil compared with sow-reared piglets

“…In sow-reared piglets the time between birth and weaning is one of rapid fat accretion (Farnworth and Kramer, 1987) when adipocytes increase in size and lipid content (Moody et al, 1978). By using an artifi-icial rearing system using milk replacer, in which the level and type of fat can be controlled, feeding regimes may be developed that optimize desired growth or compositional characteristics.…”