“…Conjugated linoleic acid is an intermediate product of the biohydrogenation, therefore its high concentration in DHA group was logical, since the degradation of the docosahexaenoic acid in the rumen is the slowest. The concentration of the conjugated linoleic acid in goat milk fat was relatively high also in ALFA group, knowing that the biohydrogenation of the -linoleic acid is the fastest (Gulati et al, 1999), what we also observed in an increased concentration of C 18:1 in ALFA group. The conjugated linoleic acid is synthesised in the mammary gland of lactating animals and in the muscles of young animals.…”
Section: Composition Of Fatty Acids In Goat Milksupporting
“…Conjugated linoleic acid is an intermediate product of the biohydrogenation, therefore its high concentration in DHA group was logical, since the degradation of the docosahexaenoic acid in the rumen is the slowest. The concentration of the conjugated linoleic acid in goat milk fat was relatively high also in ALFA group, knowing that the biohydrogenation of the -linoleic acid is the fastest (Gulati et al, 1999), what we also observed in an increased concentration of C 18:1 in ALFA group. The conjugated linoleic acid is synthesised in the mammary gland of lactating animals and in the muscles of young animals.…”
Section: Composition Of Fatty Acids In Goat Milksupporting
“…The endogenous synthesis of C 20:5 (n-3) and C 22:6 (n-3) from C 18:3 (n-3) may therefore provide an explanation for the presence of long-chain n-3 PUFA within plasma of Megalac-supplemented ewes. Rates of biohydrogenation (Gulati et al, 1999;Sinclair et al, 2005) and transfer into milk (Shingfield et al, 2003) are comparable between C 20:5 --Approaching significance (P , 0.1).…”
Supplementation of pregnant ewes with long-chain n-3 polyunsaturated fatty acids (PUFA) demonstrably improves indicators of neonatal lamb vigour, potentially improving the number of lambs reared per ewe. The present study investigated the effect of supplementing ewes with fish oil and vitamin E (a-tocopherol acetate) throughout both pregnancy and lactation on the performance of lactating ewes and sucking lambs. Forty-eight ewes were supplemented with one of four concentrates containing either Megalac or fish oil plus a basal (50 mg/kg) or supranutritional (500 mg/kg) concentration of vitamin E from 6 weeks pre-partum until 4 weeks post partum in a two-by-two factorial randomised-block design. All concentrates were formulated to contain approximately 60 g/kg supplemental fatty acids. Ewes were housed, penned on sawdust and offered straw ad libitum. Blood samples were taken from ewes and lambs at intervals throughout the experiment and milk samples were obtained at 21 days into lactation. There was no notable effect of dietary vitamin E concentration upon ewe or lamb performance. Ewe dry-matter (DM) intake and yield were unaffected by dietary treatment, although ewes fed fish oil lost less weight during lactation (21.88 kg compared with 23.97 kg for Megalac-supplemented ewes; P , 0.01). Milk fat concentrations (67.3 g/kg compared with 91.8 g/kg; P , 0.01) and yields (6.65 g/h v. 9.26 g/h; P , 0.01) were reduced in ewes fed fish oil and these decreases were associated with lower litter-growth rates (0.49 g/day compared with 0.54 g/day; P , 0.05). Milk protein yield was increased by fish oil supplementation (3.82 g/h) compared with Megalac supplementation (3.28 g/h; P , 0.05); moreover, there was an interaction between fat source and vitamin E concentration in that both protein concentration and yield were significantly lower in milk from ewes fed treatment with Megalac 1 basal vitamin E (MB) compared with the other three treatments. Fish oil supplementation increased the concentrations of C 18:1 trans-, cis-9, trans-11 conjugated linoleic acid (CLA), C 20:5 (n-3) and C 22:6 (n-3) within ewe plasma, milk and lamb plasma. The mechanisms by which fish oil supplementation affects milk composition warrants further investigation.
“…The BH of these PUFAs n-3 can be influenced by the concentration of the FO in the diet (Ashes et al, 1992). Results from a dose-response experiment with FO (Gulati et al, 1999) showed a greater capacity of sheep …”
Enhancing healthy fatty acids (FAs) in ewe milk fat and suckling lamb tissues is an important objective in terms of improving the nutritional value of these foods for the consumer. The present study examined the effects of feeding-protected lipid supplements rich in unsaturated FAs on the lipid composition of ewe milk, and subsequently in the muscle and subcutaneous adipose tissues of lambs suckling such milk. Thirty-six pregnant Churra ewes with their new-born lambs were assigned to one of three experimental diets (forage/concentrate ratio 50 : 50), each supplemented with either 3% Ca soap FAs of palm (Control), olive (OLI) or fish (FO) oil. The lambs were nourished exclusively by suckling for the whole experimental period. When the lambs reached 11 kg BW, they were slaughtered and samples were taken from the Longissimus dorsi and subcutaneous fat depots. Although milk production was not affected by lipid supplementation, the FO diet decreased fat content ( P < 0.001), whereas the OLI milk FA profile resembled that of the Control diet. In contrast, although FO drastically diminished the contents of stearic and oleic acids ( P < 0.001), all the saturated even-numbered carbon FAs from 6:0 to 14:0 increased ( P < 0.05). FO also produced the highest levels of c9,t11-18:2 (2.21%) and n-3 FAs, 20:5 n-3 (0.58%), 22:5 n-3 (0.48%) and 22:6 n-3 (0.40%). The high levels of trans-11 18:1 (7.10%) obtained from the FO diet would suggest that Ca soaps only confer partial protection in the rumen. In contrast, the lack of significant differences in trans-10 18:1 levels ( P > 0.05) and other trans-FAs between Control and FO treatments would indicate that FO treatment does not alter rumen biohydrogenation pathways under the assayed conditions. Changes in dam milk FA composition induced differences in the FA profiles of meat and fat depots of lambs, preferentially incorporated polyunsaturated FAs into the muscle rather than storing them in the adipose tissue. In the intramuscular fat of the FO treatment, all the n-3 FAs reached their highest concentrations: 0.97 (18:3 n-3), 2.72 (20:5 n-3), 2.21 (22:5 n-3) and 1.53% (22:6 n-3). In addition, not only did FO intramuscular fat have the most cis-9, trans-11 18:2 (1.66%) and trans-11 18:1 (3.75%), but also the lowest n-6/n-3 ratio (1.80) and saturated FA content were not affected. Therefore, FO exhibited the best FA profile from a nutritional point of view.
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