Effects of dietary canola seed and soy lecithin in high-forage diets on cholesterol content and fatty acid composition of carcass tissues of growing ram lambs1

Abstract

Phospholipids (soy lecithin) are important in the emulsification of lipids and may escape the rumen and influence the absorption of fatty acids in the small intestine. Our objectives were to determine the influence of dietary canola seed (high in unsaturated fatty acids) and soy lecithin in high-forage diets on total lipid content, cholesterol content, and fatty acid composition of carcass tissues. Forty-three Hampshire or Suffolk-sired ram lambs were weaned at 60 d of age (average 23.6 kg of BW) and assigned to a 2 x 2 factorial arrangement of treatments consisting of 1) basal diet (control = BAS), 2) BAS with 6% whole canola seed (CS), 3) BAS with 4.9% deoiled soy lecithin (SL), and 4) BAS with 6% CS and 4.8% SL (CSSL). The BAS diet consisted of 70% forage and 30% concentrate and contained 15% CP and 2.2 Mcal of ME/kg. Lambs were individually fed and given ad libitum access to feed to an average final BW of 52.1 kg. Longissimus muscle (LM) from the left side of each carcass posterior to the 13th rib (12 to 15 cm in length) was excised and the lean (LM) and corresponding subcutaneous (s.c.) adipose tissue were separated, frozen, and later used for lipid analysis by gas-liquid chromatography. In lean tissue, feeding lambs CS reduced (P less than .01) the proportion of total polyunsaturated fatty acids (PUFA) and feeding SL increased (P less than .01) the proportion of total PUFA. In s.c. adipose tissue, lambs fed CS had lower (P less than .01) saturated fatty acids (SFA) and lambs fed SL had increased (P less than .03) PUFA.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of canola and soya lecithins compared with canola oil and seed on performance, carcass quality and body fat composition of growing bulls

“…As expected from the dietary lipid composition, the proportions of CI6:0 and polyenoic FA were slightly higher and some CI8:1 isomers as well as C20 FA showed a trend towards lower proportions (in part significant) with the use of soya lecithin. Similar effects were reported by Lough et al (1992) for subcutaneous adipose tissue of lambs with C16:0, C20 and C18:2 when canola seed in feed was exchanged by deoiled soya lecithin. In contrast, Lough et al (1992) found higher proportions of CI 8:1 with soya lecithin which might be explained by the associated increase in carcass fatness observed with soya lecithin (Demeyer and Doreau, 1999) whereas in the present experiment fatness was not affected by soya lecithin.…”

“…Similar effects were reported by Lough et al (1992) for subcutaneous adipose tissue of lambs with C16:0, C20 and C18:2 when canola seed in feed was exchanged by deoiled soya lecithin. In contrast, Lough et al (1992) found higher proportions of CI 8:1 with soya lecithin which might be explained by the associated increase in carcass fatness observed with soya lecithin (Demeyer and Doreau, 1999) whereas in the present experiment fatness was not affected by soya lecithin. Using sunflower seed as another source of CI8:2 more clearly increased the CI8:2 proportion in subcutaneous fat and kidney fat when compared with canola seed .…”

“…The FA composition of lecithins is quite variable and substantially differs when the lecithins originate from different plants. Until now, most investigations on lecithins in ruminant nutrition focussed on soya lecithins (e.g., Yoon et al, 1986;Jenkins et al, 1989;Jenkins and Fotouhi, 1990;Lough et al, 1991Lough et al, , 1992. Nowadays, considerable amounts of canola lecithins are also available as potential feedstuffs, but data on the actual feeding value of any type of canola lecithin for growing ruminants are still lacking.…”

Effects of feeding canola screenings on apparent digestibility, growth performance and carcass characteristics of feedlot lambs

“…Consequently, in experiments in which diets were modified to include up to 18% canola seed (Solomon et al 1991;Lough et al 1992;Rule et al 1994;McAllister et al 1999), only minor changes in fatty acid profiles were achieved. By comparison, the dietary treatments in the present study were more extreme (e.g., 95% CS), and the lambs' fatty acid composition was markedly influenced (Table 5).…”

Effects of genotype and plane of nutrition on growth and carcass characteristics of lambs from hill sheep systems

“…Diet type (i.e., roughage-v. concentrate-based) can affect lamb growth rates and carcass characteristics (Chestnutt, 1994;Carson et al, 2001). Furthermore, using concentrate diets high in polyunsaturated fatty acids (PUFA), such as diets supplemented with oilseed meals, can beneficially increase PUFA concentration in meat (Lough et al, 1992;Ponnampalam et al, 2001). However, the effects of using oilseed diets on lamb growth and carcass quality have not been evaluated, and these performance measures are the most important from an economic viewpoint (Conington et al, 2004).…”