Garlic and rosemary essential oils on weight gain in confined lambs

Abstract

The search for more efficient and sustainable animal production systems has driven the use of natural additives in ruminant feed, replacing growth promoters. Essential oils have gained ground in their ability to influence the rumen microbiota, consequently improving the animal's productive performance and meat quality. Thirty-five uncastrated male lambs of the Texel × Dorper × Santa Inês crossbreed were fed diets containing garlic and rosemary EOs at different doses (0.14, 0.40, and 1.00 mL/L of ruminal fluid). Five diets were tested: without additives; garlic (0.14 and 1.00 mL/L); and rosemary (0.40 and 1.00 mL/L). The diets were formulated with a forage:concentrate ratio of 30:70 and offered ad libitum for 90 days. The experimental design used was completely randomized, the average daily gain was calculated individually for each animal in three distinct periods: 0 to 30 days, 31 to 60 days and 61 to 90 days. The diet with 0.40 mL/L of rosemary essential oil resulted in the highest average daily gains in the periods from 31 to 60 days 0.233 kg/day differing from the others especially from the control diet, which presented the lowest ADG (0.139 kg/day). At 61 to 90 days on this same diet the lambs maintained the highest ADG (0.193 kg/day), significantly higher than the control group and obtained higher dry matter intake, better feed conversion, higher final weight (45.16 kg). Garlic EOs presented intermediate effects and did not differ between the two dosages. It is concluded that the lowest dosage of rosemary essential oil promoted better productive performance of lambs in confinement, standing out as a promising nutritional strategy for intensive systems.