Proteína dietética para equinos de concurso completo de equitação

Abstract

The aim of this study, first of all, was to evaluate the impact of dietary protein levels in nutrients digestibility, water and nitrogen balance in eventing training horses, and also intended to evaluate the physiological response of horses, tested for physical effort in high speed treadmill, and their interactions, related to dietary protein and free amino acid concentrations in blood serum. Were used 24 Brazilian Sport Horses, males and females, aged between eight and fifteen years old, body weight (BW) between 432 and 560 kg and body condition score between 5.0 and 5.5. The weekly training, consisted on average of 30% walk, 30% trot, 10% gallop and 30% jump. Horses were used in a randomized design, with four treatments, six repetitions and two treadmill tests. The analyzes of the results were performed in split plot scheme. Diets were composed of 7.5, 9.0, 11.0 and 13.0% crude protein (CP). A digestion assay was performed with partial feces collection, over four days, followed by one day of total urine collection. The treadmill tests were: warming up (6 minutes) and galloping from 6.0 m/s with increase 1.0 m/s in the speed every 1 minute to reach 10 m/s. During the tests, it was measured heart rate (HR). The blood samples were collected at fasting, before the test, during and at the end of the treadmill test, and at 10, 30, 60 minutes, 12 and 24 hours after the test, for analysis of lactate, urea, uric acid, creatinine, glucose, hemogasometry and acid-base balance and amino acids. Regression analysis were performed, when the diet had a significant effect (P<0.05). The dry matter intake average was 1.7% of BW. Crude protein and nitrogen (N) intake showed a linear increase, as a function of increasing CP level in the diets. A quadratic response (P=0.01) were observed on the CP and NDF digestibility coefficients, with maximum estimated level of digestibility at 11.6% and 11.4%, respectively, CP in diet. The 11.0% CP level diet showed more adjusting results, considering the responses related to NI, NA and the estimated NR to NA ratio. The performance variables V200, VL4 and lactate concentration, were not affected by the training or the diet. The concentrations of urea during and after the exercises were influenced by the dietary CP. Dietary CP did not affect performance variables, neither the acid-base or electrolyte balance of horses. The diets had not an acidogenic effect. The treadmill speed workout can induced measurable changes in serum concentrations of free amino acids in eventing horse training. To accomplish, the levels of amino acid intaked in the present study, do not seem to influence the metabolic responses to physical test.