Search

BACKGROUND Tannins are polyphenolic compounds able to modify the ruminal biohydrogenation ( BH) of unsaturated fatty acids, but their activity may vary among different tannin sources. The effect of rockrose ( Cistus ladanifer) on BH has never been compared with other more common tannin sources. Tannin extracts (100 g kg−1 substrate dry matter) from chestnut ( CH), quebracho ( QB), grape seed ( GS) and rockrose ( CL) were incubated in vitro for 6 h with ruminal fluid using as substrate a feed containing 60 g kg−1 of sunflower oil. A control treatment with no added tannins was also included. RESULTS Compared with the control, GS and CL, but not CH and QB, increased ( P < 0.05) the disappearance of c9, c12-18:2 with a consequent larger production of c9, t11-18:2 and t11-18:1. However, no differences among treatments ( P > 0.05) were observed for the disappearance of c9-18:1 and c9, c12, c15-18:3. The production of 18:0 was not different ( P > 0.05) among treatments, although its proportion in the total BH products was lower ( P < 0.05) for GS than for the other treatments. CONCLUSION Condensed tannins from GS and, to a lesser extent, from CL stimulate the first steps of BH, without a clear inhibition of 18:0 production. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Thirty-six Merino Branco lambs were assigned to six dietary treatments: control diet (C) consisting of 90% dehydrated lucerne and 10% wheat bran; C with 6% of oil blend (CO); C with 2.5% of grape seed extract (GS); GS with 6% of oil blend (GSO); C with 25% of Cistus ladanifer (CL), and CL with 6% of oil blend (CLO). Meat lipid and colour stability was then evaluated during 7 days of storage. The effect of inclusion of grape seed extract and C. ladanifer in diets on meat sensory properties was also evaluated. Meat antioxidant potential, determined after oxidation induction by a ferrous/hydrogen peroxide system, decreased with oil supplementation (P<0.001), but inclusion of grape seed extract and C. ladanifer in diets protected the meat against lipid oxidation (P=0.036). Meat colour was not affected by diets. Inclusion of grape seed extract and C. ladanifer in diets did not change the sensory properties of meat., (Copyright © 2012 Elsevier Ltd. All rights reserved.)