The objective of this research was to evaluate the effects of two levels of neutral detergent fiber (NDF) of the diet (25 and 35%) from two forage to concentrate (50:50 and 60:40) ratio on nutrient digestibility, fecal pH and blood parameters as lactate, glucose, urea, creatinine, fibrinogen and alkaline phosphatase, to establish minimum and safe levels of fiber in equines diets. Five horses without defined race, with 6 to 8 years old and average 300 kg BW, were housing in metabolism cages. The animals were distributed to 5 × 5 Latin square design, composed of five diets (two levels of NDF, 25 and 35%, two forage to concentrate ratio, 50:50 and 60:40, and a control diet, with 50:50 forage to concentrate ratio, and five periods. Each period lasted 15 days (10 of adaptation and 5 for collection of feces and blood and pH fecal determination). Neutral detergent fiber levels (25 and 35%) reduced the fiber components digestibility (cell wall fraction) of the diet, however, did not influence the levels of blood parameters as lactate, glucose, urea, creatinine and alkaline phosphatase and fecal pH. Diet with 25% of NDF promoted change in fibrinogen plasma level, therefore, may increase the susceptibility of animals to colic and laminitis problems.
digestibility; glucose; lactate
