1706
Effect of Concentrate Diets Contrasting in Fatty Acid Profiles on Lamb Performance, Carcass Characteristics, Fatty Acid Composition and Wool Production
Knowledge of the health benefits associated with the consumption of n-3 PUFA has led to the selective inclusion of dietary lipids in ruminant diets in attempts to increase tissue incorporation. Increasing the n-3 fatty acid content of ruminant tissues requires the inclusion of dietary lipids that contain unsaturated fatty acids capable of withstanding ruminal biohydrogenation. Tasco® a commercial algal product manufactured from the brown alga Ascophyllum nodosum (TA; 2% DM) was compared to canola (CO), flax (FO) and safflower oils (SO) for effects on performance, fatty acid profiles of skirt muscle, subcutaneous and perirenal adipose tissues and wool yield and quality characteristics of Canadian Arcott lambs. Fifty-six lambs were randomly assigned to four diets. Diets consisted of a pelleted, barley-based finishing diet with lipid sources included at 2% DM. Feed deliveries and orts were recorded daily with lambs weighed weekly and slaughtered once they reached ≥ 45 kg LW. Carcass characteristics and rumen pH were determined at slaughter. Dye-bands were used to determine wool growth, micron and staple length. Data were analyzed using mixed procedure in SAS. No effects were observed on intake, growth, feed efficiency or carcass characteristics. An increase (P<0.05) in staple strength of CO lambs was the only effect observed in wool. Supplementing Tasco® at 2% DM in the diet of Canadian Arcott lambs increased (P≤0.002) the SFA/PUFA ratio in skirt muscle and subcutaneous and visceral adipose tissues in comparison to the supplementation of oils. Additionally, Tasco® supplementation did not improve concentrations of long chain n-3 PUFA or total n-3 concentrations in skirt muscle or adipose tissue when compared to lambs fed canola, flax or safflower oils. In contrast, supplementing FO increased total n-3 accumulation and reduced the n-6/n-3 ratio in all tissues (P<0.001), suggesting that the supplementation of Tasco® did not beneficially alter the FA profile of lamb tissues in comparison to other dietary lipids.
Keywords: fatty acids, lambs, micro-algae