A B S T R A C TThe influence of dietary supplementation with quebracho tannins (QT) or/and sunflower oil (SF) on growth performance and fatty acid profile in meat of Awassi lambs was studied. Seventy-two lambs were assigned randomly to nine diets (8 per group) in the experiment following a 3 2 factorial design with all possible combinations of two factors, SF and QT each at three levels i.e. 0 (control), 20 or 40 g/kg diet DM. A significant SF × QT interaction was observed on the conjugated linoleic acid content of intramuscular fat (P = 0.007), but not on average daily weight gain (P = 0.11). Addition of QT at 40 g/ kg DM significantly increased average daily gain comparing to control diet. The inclusion of QT in the diet increased the content of the conjugated linoleic acid in the lamb meat above that achieved with SF supplementation only. Addition of the combination of QT and SF to the diet enhanced the content of conjugated linoleic acid (C18:2 c9t11) of the lamb meat. This could be due to the reduction in the bio-hydrogenation of unsaturated fatty acids in the diet. The results suggest that inclusion the combination of QT and SF in lamb diets improved the healthy fatty acids content in the meat without an adverse effect on animal performance.

BACKGROUND: The effect of the inclusion of sunflower oil (SF) and quebracho tannin (QT) in a sheep diet was evaluated. Nutrient digestibility and nitrogen (N) utilization, as well as in vitro ruminal degradation kinetics, were evaluated at three levels [0, 20 and 40 g kg −1 of diet dry matter] of SF and QT in a 3 2 arrangement. The treatments were 0 (control); 20 and 40 g of QT and/or SF kg −1 of the diet. Four intact male sheep (45 ± 1.3 kg) for each treatment were used in the digestibility trial and kept individually in metabolic cages. RESULTS: Nutrient digestibility and N balance were not affected by SF. However, QT at 40 g kg −1 of dry matter decreased (P < 0.05) nutrient digestibility and also increased the proportion of absorbed N. Both SF and QT reduced (P < 0.05) the slowly degraded fraction and rate for organic matter and N. Even though the QT had a negative (P < 0.05) effect on nutrient digestibility, this effect was mild (P > 0.05) when SF was included in the QT-added diets. Moreover, an interaction (P < 0.05) of SF × QT was observed on the synchronization index as an indicator of the efficiency of rumen microbial protein synthesis. CONCLUSION: Supplementation of either SF or QT to sheep diets reduced ruminal organic matter and N degradability, reflecting the compensatory digestion in the post-ruminal track for organic matter feed utilization. Ruminal degradation of OM and N, and SIThe b, c, a + b and u of OM for the tested diets varied (P < 0.05) as a result of the levels of either SF or QT (Table 3). Increasing the level of SF added to the diet reduced (P < 0.05) the b fraction, degradation rate (c) and a + b fraction of OM. Subsequently, the u J Sci Food Agric 2019; 99: 4211-4217