USE OF ACTIVE AND INACTIVE YEASTS IN LAMB DIETS: INTAKE, DIGESTIBILITY, AND METABOLISM

This study aims to evaluate the use of active, inactive plus active, and inactive yeasts on the consumptionof dry matter, water, and the apparent digestibility of dry matter, urinary parameters, and serummetabolites of lambs. Twenty crossbred lambs (Dorper x Santa Inês) were used, with an initial averagebody weight of 31.89 kg and seven months of age, distributed in a completely randomized design.Treatments were Control group (without yeasts); Active Flora® (ICC), live yeast plus inactivated yeast(Saccharomyces cerevisiae, 2.0 x 1010 UFC g-1) in the dose of 0.003 kg of animal dry matter -1 day-1,;Milk Sacc X® (Alltech®), active yeast - Saccharomyces cerevisiae strain 1026, 5.0 x 108 UFC g-1 - atthe dose of 0.0015 kg of animal dry matter-1 day-1; and Rumen Yeast® (York Ag Products INC.), inactiveyeast - Saccharomyces cerevisiae,1.5 x 104 UFC g-1 - in the dose of 0.0045 kg of animal dry matter-1day-1. Variance analysis and the SNK (Student-Newman-Keuls) test were performed considering 5%significance. For glycemic concentrations over time, regression analysis at 5% significance wereperformed. The fecal score, as a non-parametric variable, was assessed by the Kruskal and Wallis testat a 5% significance level. There was a statistical difference (P< 0.05) in fecal dry matter (FDM), wherethe Active Flora® treatment was inferior to the others. The use of different yeasts did not change theintake and digestibility of dry matter, water, urinary parameters, and serum concentrations of energy,protein, and liver metabolites (P> 0.05). The average dry matter intake was 1.16 ± 0.16 kg day-1, whereasthe dry matter digestibility was 85.40 ± 2.73%. It was concluded that active and/or inactive yeasts canbe used as additives in the diet of lambs, maintaining the intake and digestibility of dry matter withoutcausing metabolic disturbances.