Inclusion of the Cistus ladanifer L. plant and its condensed tannin extract in lamb diets - Effects on animal antioxidant status and oxidative stability of meat

This study evaluated whether the incorporation of condensed tannin (CT) extract from Cistus ladanifer in lamb diets induces the same antioxidant protection as the C. ladanifer plant. How dietary CT can enhance the antioxidant status of animals and the oxidative stability of their products was also explored. Thirty-six lambs were used to evaluate the effect of three levels of C. ladanifer CT (without CT enrichment, medium, and high level of CT) and two ways of CT supply (C. ladanifer plant or C. ladanifer CT extract) on meat lipid and colour stability, and antioxidant status of muscle, rumen, abomasum, and faeces. The presence of CT monomers in muscle and CT content in digestive contents and faeces was evaluated. Cistus ladanifer plant and CT extract did not improve the lipid stability and antioxidant status of meat, but both CT sources enhanced the meat colour stability over storage time. Condensed tannin monomers were not identified in muscle. Intake of α-tocopherol decreased with inclusion of CT sources in diets. However, muscle α-tocopherol content was not affected by diets, suggesting that CT increase the α-tocopherol availability in muscle. Both CT sources increased antioxidant activity in the digestive contents, although, in the abomasum, C. ladanifer plant resulted in higher antioxidant activity than CT extract for the same CT level in the diet. No CT were detected in the faeces and both CT sources had a minor effect on the antioxidant activity, which could indicate the CT transformation in the gastrointestinal tract.