Supplementation with live yeasts and essential oils does not alter blood, fecal and digestible parameters in horses

The aim of this paper was to evaluate the effects of the inclusion of essential oils and live yeasts (Saccharomyces cerevisiae; SC) compound on fecal parameters, apparent digestibility of nutrients and blood parameters of horses. Eight geldings Mini-Horse breed (age 48 ± 6 months and body weight 147 ± 15 kg) were used, randomly distributed in two Latin squares (2 × 2). The individual dry matter intake adopted was 1.75% of body weight. The experimental diet (concentrate: hay as 60:40) was divided into Control group (CO - without additives), live yeast S. cerevisiae group (SC - 2 g/day addition), Essential Oils group (EO - 150 mg/day addition) and Live Yeast + Essential Oils group (LE - both additives). Four periods of 23 days each, being 15 days of adaptation to the diet, 5 days of total collection of feces, and 3 days of washout were performed. Variance and orthogonal contrasts (CO vs others; SC and EO vs LE; EO vs SC) analysis using p < 0.05 as a reference for significant values. The apparent digestibility of nutrients was evaluated through the total collection of feces of each animal by calculating the relationship between the ingested and the excreted nutrients. We were calculated the contents of dry matter (DM), organic matter (OM), crude protein (CP), ethereal extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), and starch. Lipids (triglycerides (TG), total cholesterol (TC) and fractions of high density lipoprotein (HDL), low density lipoprotein (LDL) and very low density lipoprotein (VLDL)) were evaluated into serum, which was obtained during the total collection of feces period. The glycemic and insulinemic responses were evaluated based on the area under the curve of glucose (AUC-G) and insulin (AUC-I). The microbial population (Fibrobacter succinogenes, Ruminococcus flavefaciens and Lactobacillus genus) and pH were evaluated in feces. The treatments did not influence (p > 0.05) the apparent digestibility coefficients of DM, OM, PB, EE, NDF, ADF and starch. No differences (p > 0.05) in blood parameters CT, TG, HDL, LDL, VLDL, AUC-G and AUC-I were observed. There was no effect (p > 0.05) of treatments, time and treatment*time interaction in fecal pH of horses. No differences in the relative population of microorganisms (p > 0.05) between treatments were observed. The use of essential oils and live yeasts (CNCM I-1077), allied or not, in equine diets does not alter blood, fecal and digestible parameters in horses.