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 lambs
1992
Lough, D.S. | Solomon, M.B. | Rumsey, T.S. | Elsasser, T.H. | Slyter, L.L. | Kahl, S. | Lynch, G.P.
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 (SI), 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 < .01) the proportion of total polyunsaturated fatty acids (PUFA) and feeding SL increased (P < .01) the proportion of total PUFA. In s.c. adipose tissue, lambs fed CS had lower (P < .01) saturated fatty acids (SFA) and lambs fed SL had increased (P < .03) PUFA. Feeding CSSL had little effect on fatty acid composition of carcass tissues compared with feeding CS and SL alone. Reducing SFA and(or) increasing PUFA in carcass tissues represents a favorable change in regard to current human dietary guidelines.
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