COMPARATIVE STUDIES IN VITRO AND IN VIVO TRIALS OF SOME FEED ADDITIVES (GARLIC POWDER AND GARLIC OIL) IN SHEEP RATIONS

Feed additives utilization from natural locally resources are an important strategy to increase animal production in developing countries. Many investigations were conducted using nutritional additives at in vitro level. While, few in vivo studies are available on the effect of such additives on animal and the relationship between the results at in vitro and in vivo trials. Therefore, garlic cloves (Allium sativum) in various combinations, were processed either as a powder or its oil to formulate a supplemented diets for Barki rams. These diets were used to determine in vivo digestibility and to record these results in comparison with in vitro digestibility procedures. Sixteen Barki rams with an average live weight (40.47±0.99 kg) were allocated into four treatment groups and were individually kept in metabolic cages. The experimental diets were :1) a basal diet without additive (control); 2) a basal diet supplemented with 20g garlic powder/ kg DM; 3) a basal diet supplemented with 40g garlic powder/kg DM; 4) a basal diet supplemented with 2 ml oil/kg DM. In vitro dry matter digestibility were strongly correlated (r = 0.77) with their mates by in vivo trial. A rumen fermentation pattern, nitrogen utilization and some blood parameters was asses as well. Ruminal pH and volatile fatty acids (VFAs) were not affected by the supplementation of garlic powder and garlic oil in the diets, while ruminal ammonia significantly decreased compared to control diet. Either treated or untreated diets showed no differences of nitrogen (N) intakes, digested and excreted as g /kg BW among the experimental groups. Also, N balance (g /Kg BW) is a similar resulting between the experimental diets. The use of garlic additives in sheep diets improved blood total protein, but decreased triglycerides and urea blood concentration. As conclusion, garlic powder and garlic oil supplementation can be recommended for sheep diets to enhance rumen fermentation and blood parameters however, there is a need for long-term feeding trials and rumen microbial studies should be conducted for better understanding of their impacts in feed metabolism and rumen outputs.