Consumo e digestibilidade aparente dos nutrientes, parâmetros ruminais e balanço de N de cordeiros confinados recebendo dietas com milho e sem forragem com bicarbonato de sódio

Abstract

ABSTRACT: This study evaluated forage-free diets supplemented with sodium bicarbonate (SB) based on ground flint corn on intake, apparent nutrient digestibility, ruminal parameters, and N balance. Four rumen-cannulatedDorper × Santa Inês lambs, with a body weight of 43.4 ± 0.85 kg (mean ± standard deviation) were used. The experimental design was a 4×4 Latin square. Each experimental period lasted 21 days. Experimental diets were: positive control, a diet without SB containing 400 g/kg DM of soybean hulls (CONT), and three diets based on ground flint corn, containing 10 (10SB), 20 (20SB) or 30 (30SB) g/kg DM of SB. Intake of neutral and acid detergent fiber was greater for CONT (P < 0.01) when compared to SB. Intake and apparent nutrient digestibility of dry and organic matter, ether extract, and crude protein did not differ. Intake (P = 0.01) and digestibility (P < 0.01) of non-fiber carbohydrates were greater for SB diets and neutral detergent fiber digestibility was greater (P = 0.03) for CONT. The total digestible nutrients and metabolizable energy were greater for SB (P = 0.04). Rumen concentrations of acetate (P < 0.01), isobutyrate (P < 0.01), butyrate (P < 0.01), isovalerate (P < 0.01), and total short-chain fatty acids (P < 0.01) were greater for CONT. Ruminal pH showed a quadratic (P = 0.05) response to SB levels, with greater values for 20SB. Sodium bicarbonate was efficient in increasing ruminal pH at the level of 20 g/kg DM without interfering with the intake and apparent nutrient digestibility characteristics.