Probióticos ou fitase na dieta de potros Mangalarga Marchador

In experiment 1, the objective was to assess the effects of probiotic or phytase supplementation on body development of 16 Mangalarga Marchador colts, of 173±8 days (weaning) to 363±12 days of age, and allocated into four treatments groups: A-diet (Cynodon pasture + 1.2 kg/100 kg BW of concentrate + water and mineral salt ad libitum); B-diet+5 g/day of yeast culture (109 CFU/g S. cerevisiae); C-diet+2g/day of bacteria (108 CFU/g B. bifidum, E. faecium, L. acidophilus, L. plantarum) and yeast culture (105 CFU/g S. cerevisiae); and D-diet + 544 FTU/kg concentrate/day of phytase. All foals were randomized, by replicated, using a split-plot arrangement, and results of body weight gains, body measurements, conformation index, blood parameters, means and gains of cortical índex of the right third metacarpus were compared using SNK test (P<0,05) and regression equations (P<0.10). The additives tested did not affect the variables evaluated (P>0.05), except cortical índex gains that was higher in B group at 273 days. The probiotic composed of S. cerevisiae had a positive influence on bone mineralization of foals at 100 days after weaning. In experiment 2, the objective was to assess the viability of microorganisms in commercial probiotics used in horses, one composed of S. cerevisiae Sc47 (lyophilized powder probiotic 1) and another of S. cerevisiae, B. bifidum, E. faecium, L. acidophilus e L. plantarum (paste or powder by spray drying probiotic 2), and stored at two different temperatures (4o C or room temperature); and to assess the in vitro production of antagonistic substances against Salmonella spp. e E.coli.The results were evaluated by descriptive statistics and regression equations. There were differences in the viability of microorganisms according to the method of preservation, being the powder presentation (lyophilized or by drying spray), without (probiotic 1) or with (probiotic 2) cooling, the most appropriate for maintaining viable microorganisms for 12 months after manufacturing. The probiotic 2 in paste should has reduced the validity and be stored at 4oC. The lactic acid producing bacteria produces antagonistic substances that inhibit the growth of pathogens that cause diarrhea in horses, being necessary in vivo studies to future use on horses. In experiment 3, the objective was to study the in vitro enzymatic stability of an commercial exogenous phytase on different pH ranges (2.3, 2.6, 2.9, 4.0, 5.0, 6.0 and 7.0) and on equine peptic and pancreatic digestion. The results were compared using Tukey test (P<0.05) and regression equations. The commercial exogenous phytase retained the enzymatic activity on in vitro conditions of pH variation and the attack of enzymes present in the stomach and small intestine of horses.