Effect of sodium bentonite and vegetable oil blend supplementation on growth, carcass quality and intramuscular fatty acid composition of lambs

Abstract

Abstract The effect of dietary sodium bentonite and a blend of sunflower and linseed oils at 1:2 (v/v) on growth, carcass and meat quality and fatty acid (FA) composition of longissimus dorsi muscle of lambs was studied. Thirty-two Merino Branco lambs with initial live weights (LW) of 16.2 ± 2.93 kg were divided according to a completely randomized experimental design within a 2 × 2 factorial arrangement of treatments in order to evaluate effects of the vegetable oil blend supplementation (0 g/kg versus 60 g/kg DM) and sodium bentonite inclusion in diets (0 g/kg versus 20 g/kg DM). The basal diet consisted of pellets with 750 g dehydrated lucerne/kg DM and 250 g manioc/kg DM. The experimental period was 6 weeks. Bentonite affected neither daily LW gain, dry matter (DM) intake, nor carcass composition. However, bentonite decreased the a* meat colour parameter (redness; P =0.004). Oil supplementation affected neither daily LW gain, nor DM intake. However, it increased fat proportion in chump and shoulder cuts ( P P P P P =0.007), mostly by increasing proportions of n -3 PUFA and biohydrogenation derived PUFA. Oil supplementation decreased n -6 long chain PUFA ( P n -3 long chain PUFA was not affected by oil supplementation, so the increase in n -3 PUFA from 1.99 g/100 g of total FA to 4.23 g/100 g of total FA ( P P n -3 long chain PUFA concentration from 20 to 31 mg ( P cis -11 18:1 which decreased, and cis -13 18:1 and trans -8, cis -10 18:2 which were unchanged. Conjugated linoleic acid increased with oil supplementation from 0.50 to 1.72 g/100 g of total FA ( P trans -11 18:1, but prevented the increase of trans -10 18:1 in meat from oil supplemented lambs ( P Trans -11, cis -15 18:2, cis -9, cis -15 18:2 and cis -9, trans -11, cis -15 18:3 increased with dietary bentonite inclusion.