The Effects of Diet and Other Factors on the Lipid Composition of Ruminant Tissues and Milk

Positional distribution of CLA in TAG of lamb tissues

“…Basal diets supplemented by unprotected polyunsaturated fats in vegetable oils have been shown to have little effect on FA composition of adipose tissue and skeletal muscle sampled from various sites in steers (31). For example, supplementation with 6% safflower oil resulted in a slight increase in the proportion of 16:0 and 18:0.…”

“…The polyunsaturated FA content in tissues of young ruminants has been shown to increase following feeding with milk replacers supplemented with 12.5-70 g sunflower oil d −1 for up to 16 wk (31). The muscle and adipose tissue from animals on this supplemented diet contained up to 40% of 18:2 in the TAG fraction after 30 d. This increase in 18:2 content was accomplished owing to the bypass of the rumen when the esophageal groove was closed while suckling.…”

“…Changes in FA positional distribution as affected by diet also have been shown in bovine and ovine adipose tissues (35)(36)(37) and ovine liver (36), but the mechanism responsible for these diet-induced changes is unknown. In previous studies with ruminants fed a protected supplement, high proportions of additional 18:2 were incorporated into adipose tissues with preferential esterification to the sn-2 position and to a lesser extent the sn-3 position (31,36).…”

Effect of Diet Supplementation with Combinations of Soybean and Linseed Oils on Milk Production and Fatty Acid Profile in Lactating Dairy Ewes

“…The observed decrease of de novo synthesized FA (C4:0 to C15:1) after oil intake was important in all treatments with the lowest values observed in SO100 and LO100. This effect can be explained by the inhibition in the activity of lipogenic mammary enzymes such as acetyl-CoA carboxylase [46] [47]. The reduction was apparently compensated by a concomitant increase in mammary uptake of preformed FA's since milk fat concentration or yield was not decreased (Table 3) despite of the important increase in milk content of trans-10 C18:1 in SO100 and SO75 tretments (Table 4) (Table 4) can be considered important taking into account that its pro-atherogenic role is considered to be very potent [50].…”

Compound‐specific Stable Isotopes in Organic Residue Analysis in Archaeology

“…FAs, which is the most commonly observed class of lipid residue observed in archaeological pottery. Note, 60% of the C 18:0 in ruminant milk is rerouted from adipose tissue and is comprised of carbon originating from dietary glucose and fatty acids, and the remaining 40% (McDonald et al 1988) is directly incorporated from the diet following biohydrogenation of unsaturated fatty acids in the rumen (shown by asterisk), and reflects the inability of the mammary gland to biosynthesise C 18:0 (Christie 1981;Byers and Schelling 1988). sheep/goat and cattle) and porcine (pig) adipose fats are readily distinguishable (Figure 14.18; Evershed et al 1997cEvershed et al , 2003b.…”