Maximização de dietas a base de palma forrageira e cana-de-açúcar para ovinos

Abstract

The aim of this study was to evaluate the effects of the substitution of sugarcane with Opuntia ficus-indica MILL on the intake, digestibility of nutrients, ingestive behavior, nitrogen balance, water intake and excretion, microbial protein synthesis, intake and concentration of minerals in the plasma of the sheep. Five sheep were used, distributed in a latin square design, receiving five levels of substitution of sugarcane with N. cochenillifera (0; 180; 360; 540 and 720g/kg). There was a quadratic effect for dry matter, organic matter, crude protein, neutral detergent fiber, non-fibrous carbohydrates, indigestible neutral detergent fiber and total digestible nutrients, with maximum values of 1163; 1083; 179.8; 325.0; 586.3; 160.0 and 888.0 g/d-1, estimated with 433.4; 402.8; 434.2; 338.9; 397.1; 248.5 and 380.9 g/kg of substitution levels, respectively. The digestibility of dry matter and nutrients were not altered. Rumination time decreased, while idle time and rumination efficiency increased linearly. Nitrogen consumption, fecal excretion and nitrogen balance showed a quadratic behavior, with maximum values of 28.79; 4.25; 13.2 g/day, estimated with 425.9; 531.3 and 310.7g/kg of substitution levels, respectively. Urine nitrogen excretion and ureic nitrogen concentration in the plasma increased linearly. However, the urea nitrogen in the urine did not change. The efficiency and synthesis of microbial protein were not altered. The intake of Mg, Ca, P, Na and K increased linearly, as well as their plasma concentrations, except for the plasma Ca concentration. The total water consumption and that via food and N. cochenillifera increased linearly, while the voluntary water intake showed a quadratic effect, with a minimum consumption value of 0.505 L-1, estimated at 508.7 g/kg substitution level. The excretion of water via faeces and urine increased linearly. In order to maximize the energy intake, it is recommended to replace 380.9g/kg of sugarcane with N. cochenillifera in sheep feed.