Gérmen de milho integral extra gordo em substituição ao milho moído em dietas para ovinos

Abstract

The effect of replacing ground corn with extra fat whole corn germ (0; 25; 50; 75 and 100% in dry matter - DM) was evaluated on consumption and apparent digestibility of DM and nutrients, ingestive behavior, rumen dynamics, water balance, ruminal and blood parameters and nitrogen utilization efficiency. Five male sheep, castrated in the rumen, with an average body weight of 67.56 + 9.13 kg were distributed in a 5x5 Latin Square experimental design. The consumption of MS matter and nutrients were not influenced by the substitution levels, except the consumption of ether extract (EE) which increased linearly (0.018; 0.032; 0.050; 0.073 and 0.075 kg/day, respectively) while the coefficients of apparent digestibility of crude protein (CP) and EE increased linearly. The time spent on rumination, feeding and leisure and the efficiency of feeding and rumination according to the consumption of DM and neutral detergent fiber (NDF) were not influenced. The water balance was not altered, except for the excretion of water via feces, which decreased linearly (0.487; 0.423; 0.398; 0.364 and 0.373 kg/day, respectively). There was no effect of the substitution levels in the pool of DM, NDF and indigestible neutral detergent fiber (NDFi), however, the EE pool increased linearly (13.0; 17.42; 22.19; 23.3 and 25, 1g, respectively). Passage (Kp), intake (ki) and digestion (kd) rates of MS and NDF, and NDFi passage rate (Kpi) were not influenced. The substitution levels did not influence the ruminal pH, but over the collection times, it showed a quadratic behavior, with a minimum value estimated at 5.91, 3.38 hours after feeding. There was no effect on ammoniacal nitrogen (NAR) due to the substitution levels, however, a decreasing linear effect was observed depending on the collection times (20.3; 21.6; 16.2; 13.4 and 12.1 mg/dL, respectively), showing interaction between the replacement levels and collection time. Quadratic behavior was observed for acetate, with a maximum concentration of 60.26 mmol/L at the level of 32.05% and a decreasing linear effect for butyrate (9.5; 10.3; 10.0; 8.6 and 6.1 mmol/L), depending on the replacement. The concentrations of acetate and propionate, acetate: propionate ratio and the total of short-chain fatty acids showed a quadratic behavior according to the collection times, with a maximum of 58.19; 23.25; 2.57 and 90.49 mmol/L, estimated at 3.34; 3.43; 3.60 and 3.34 hours after feeding, respectively. There was no effect (P> 0.05) of substitution levels on nitrogen utilization efficiency; however, a decreasing linear effect of nitrogen excreted in the faces was observed (6.27; 5.63; 5.26; 5.24 and 4.72 g / day, respectively). In addition, it was observed that cholesterol and triglycerides increased linearly, with mean values of 67.45 and 15.34 mg / dL, respectively, while glucose and fructosamine levels had no effect. The levels of substitution of ground corn with extra fat whole corn germ (GMIEG) do not negatively influence the variables evaluated. Therefore, it is recommended that GMIEG be replaced entirely with ground corn.