Influence of Two Dairy Fats on Lipid Synthesis in the Pig: Comparative Study of Liver, Muscle and the Two Backfat Layers

Abstract

The development of pig adipose tissues is influenced by several factors such as localisation and dietary fat. The neck and backfat subcutaneous adipose tissues consist of two layers with different chemical compositions, and it is not yet known whether such variations are due to differences in lipogenic enzyme activities or to other factors. The aim of the present study was to compare the lipogenic activities of tissues from different sites (Longissimus dorsi muscle, liver, subcutaneous backfat) and between the outer and inner backfat layers. The effects of dietary fat from two animal sources on the lipogenic activities and fatty acid composition of these tissues were also compared. 28 Large White × Pietrain cross-bred swine, averaging 75 (initial) to 108 kg (final) live weight, were allocated into 2 groups. They were fed diets with the same energy and lipid contents but provided either by goat’s milk or cow’s milk. The lipid content and fatty acid composition of the tissues were determined and the following lipogenic enzymes activities measured: acetyl-CoA carboxylase (CBX); glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme (ME). Both groups showed similar average daily gain, carcass composition and tissue lipid contents. Lipogenic activities were highest in backfat (p < 0.001), intermediate in Longissimus dorsi muscle and lowest in liver. The lipogenic activities in backfat tissue were greater (p < 0.001) in the inner than in the outer layer in both groups. Animals fed on goat’s milk exhibited greater (p < 0.05) CBX and ME activities in the backfat, and CBX (p < 0.05) activity in the Longissimus dorsi muscle. In backfat tissue of animals fed on goat’s milk, CBX, G6PDH (p < 0.01) and ME (p < 0.05) were greater in the inner than in the outer layer, whereas in animals fed on cow’s milk the inner backfat layer exhibited the slightly higher (p < 0.05) lipid content. Differences in CBX activity between the two dairy diets tended to be greater (p < 0.001) in the inner backfat than in the outer layer. This suggests that the inner layer might be more sensitive to dietary source fat. It is concluded that the layers of pig subcutaneous backfat should not be considered as a single entity, but rather as two separate tissues.

Rates of Change in Tissue Fatty Acid Composition When Dietary Soybean Oil Is Switched to Olive Oil

“…Fatty acid compositions of three different tissues and, in particular, the MUFA and PUFA content are highly dependent on the fat composition of the diet by de novo synthesis or by elongation from fatty acids provided by the dietary fats. [16][17][18] This was profoundly significant with linoleic acid and oleic acid in our data. Therefore, the steady state composition of fatty acids in tissues, i.e., the proportions of SFA, MUFA, and PUFA could be maintained by different esterifying enzymes actions, i.e., on site remodeling of fatty acid esters in accordance with the PI is calculated as an index of substrate availability for maximal rates of oxidation with two or more double bonds and is based on the formula of in vitro experiment.…”

Selective mobilization of fatty acids in adipose tissue of heavy pigs

“…The outer layer is richer in unsaturated fatty acids (Malmfors et al, 1978) and in collagen tissues with greater organization of the connective structure surrounding the adipocytes (Lo Fiego et al, 1987) that gives it a greater consistency compared with the inner layer. The lipogenic activities are greater in the inner layer than in the outer layer (Camara et al, 1996;Warnants et al, 1999).…”

“…The subcutaneous fat of pigs is constituted by two (Camara et al, 1996) or more layers (Apple et al, 2009) with different chemical compositions and different metabolic activity. In fact it should not be considered as a single entity, but rather as two separate tissues (Camara et al, 1996).…”

“…In fact it should not be considered as a single entity, but rather as two separate tissues (Camara et al, 1996). The outer layer is richer in unsaturated fatty acids (Malmfors et al, 1978) and in collagen tissues with greater organization of the connective structure surrounding the adipocytes (Lo Fiego et al, 1987) that gives it a greater consistency compared with the inner layer.…”

Dietary fat source regulates ob gene expression in white adipose tissue of rats under hyperphagic feeding

“…It has been shown that dietary fatty acid composition can influence different integrating processes of lipid metabolism, such as adipose tissue lipolysis (Awad & Chattopahyay 1986a,b;Raclot et al 1997;Portillo et al 1999b), lipogenesis (Perdereau et al 1992;Camara et al 1996;Portillo et al 2001), lipoprotein lipase activity (Murphy et al 1993;Raclot et al 1997), thermogenic capacity (Takeuchi et al 1995;Kawada et al 1998;Takahashi & Ide, 2000;Rodríguez et al 2002) and fatty acid oxidation (Leyton et al 1987). The potential influence of dietary fatty acids on expression of ob gene and secretion of leptin remains to be elucidated.…”