Intake, digestibility, water balance, ruminal dynamics, and blood parameters in sheep fed diets containing extra-fat whole corn germ

Abstract

We evaluated the effects of replacing ground corn with extra-fat whole corn germ (EFCG; 0%, 25%, 50%, 75%, and 100%) on the intake and concentration of soluble nutrients of dry matter and its components, ingestive behavior, water balance, ruminal dynamics, and blood parameters in sheep. Five rumen-fistulated sheep with an average body weight of 67.56 ± 9.13 kg were assigned to a 5 × 5 Latin square experimental design. The experimental period lasted five consecutive 22-day periods divided into 14-day adaptation and 8-day sampling periods. The diets were composed of corn silage and cactus cladodes as roughage and soybean meal, ground corn, EFCG, urea, and mineral premix as concentrate. The forage: concentrate ratio was 70:30. There were no differences in nutrient intake, except for ether extract. However, the concentration of digestible crude protein (CP; P = 0.038) and ether extract (EE; P < 0.001) increased. The replacement levels did not influence ingestive behavior, nor rumination efficiencies. Water intake and excretion were unaffected, except for excretion by feces (P = 0.040), which decreased. There was no effect of treatments on the dry matter (DM), neutral detergent fiber (NDF), and indigestible neutral fiber detergent (NDF) pools; however, the pool of EE (P < 0.001) increased. The rates of passage (Kp), ingestion (Ki), and degradation (Kd) of DM and aNDF, as well as the passage rate (Kpi) of iNDF, were uninfluenced. Levels of cholesterol (P < 0.001) and triglycerides (P = 0.001) increased. It was concluded that ground corn can be fully replaced by EFCG without affecting intake and concentration of digestible dry matter and its components, water balance, ingestive behavior, rumen dynamics, and glucose and fructosamine serum concentrations. On the other hand, the replacement increased ether extract intake and consequently, cholesterol and triglyceride serum concentrations. Therefore, we recommend total replacement of ground corn by EFCG in diets for sheep. However, further investigations are needed on animal performance and sensory and biochemical characteristics of meat and milk.