Plant extracts as natural additives in finishing lamb diet

TThe present study aimed to evaluate the effect of natural additives, oregano essential oil and acacia taniniferous extract, in the diet of feedlot lambs on productive performance and meat quality. Thirty-six male lambs (not-castrated) from crossbreeding Dorper × Santa Inês × Texel, weaned, averring 90 d of age and 27 ± 2.8 kg body weight were used through 53 d of feedlot period in a randomized block design, were weigh at weaning was the block criteria. The lambs were distributed into three treatments with 12 repetitions. All treatments were based on a regular diet (control), where natural plants extracts were designated to following treatments: 1) control (without additive), 2) control diet + oregano essential oil (1 ml/kg of concentrate), 3) control diet + acacia taniniferous extract (5% DM). Diets were formulated as 30:70 forage:concentrate ratio. Lambs were designated to slaughter averring 143 days of age and 42,81 ± 3,97 kg body weight. The nutrient intake and digestibility and productive performance (total body weight gain, average daily body weight gain and production and carcass yield) of lambs fed oregano essential oil were similar to those fed control diet. However, lambs fed acacia taniniferous extract had lower DM intake (DMI), and reduced by 19%, 20% and 50% the total apparent digestibility of DM, OM and NDF, respectively, compared to lambs fed control diet. Meat of lambs fed oregano essential oil was more luminous, however tended to be stronger. Oregano essential oil changed the centesimal composition of meat and TBARS, but increased concentration of DHA fatty acid by 13% compared to control treatment. Acacia taniniferous extract also increased the luminosity of meat, but reduced by 4% meat CP content and TBARS concentration by 28%, in relation to control treatment. Acacia taniniferous extract tended to increase vaccenic acid and omega 3 content. Additionally, taniniferous extract increased by 27% the total CLA, compared to control and oregano essential oil. We can conclude that the inclusion of oregano essential oil in the diet of feedlot lambs does not change productive efficiency and increase the luminosity of meat, although results in stronger meat; whereas the inclusion of acacia taniniferous extract reduce productive performance, but increase the quality of lipid fraction and antioxidant of meat. (AU)