Whole Corn Germ as an Energy Source in the Feeding of Feedlot Lambs: Metabolic and Productive Performance

SIMPLE SUMMARY: By-products are the focus of many ruminant nutrition studies in recent decades. These alternative feeds show different concentrations of ideal nutrients for feeding ruminants. These are generally less expensive than common ingredients used in traditional diets (soybean meal and corn). From the corn industry we obtain the by-product whole corn germ (WCG). The highest lipid content of corn is found in WCG (85%), which makes it useful for increasing the energy density of diets. This research aims to evaluate the inclusion in the diet of different levels of WCG, an energy source, on the metabolic and productive behavior of feedlot lambs. Although some changes in nutrient intake and digestibility were observed, the inclusion of WCG in the diet did not promote changes in nitrogen retention, productive performance, and blood parameters. In this way, the use of WCG up to 120 g/kg DM, in the total diet, is recommended as an alternative source of energy for feedlot lambs. ABSTRACT: The aim of this study was to evaluate the dietary inclusion (0, 30, 60, 90, and 120 g/kg DM) of whole corn germ (WCG), an energy source, on the metabolic and productive performance of feedlot lambs. To this end, two complementary experiments were carried out. In Experiment I, we tested the effects of WCG inclusion levels on the metabolism of 10 uncastrated Santa Inês male lambs, which were distributed into two 5 × 5 Latin squares design. Non-fibrous carbohydrates digestibility decreased (p = 0.01), whereas ether extract digestibility increased (p < 0.01) with the inclusion of WCG. Retained nitrogen did not change (p = 0.99) with the WCG inclusion. In Experiment II, we tested the effect of WCG inclusion levels on the production performance of 40 uncastrated Santa Inês male lambs, in a completely randomized design. There was a reduction in the intake of nutritional components (p < 0.05), except EE (p < 0.01), which increased with the increasing WCG levels. Production performance and blood parameters did not change. Based on the observed metabolism, performance, and feed efficiency, the use of WCG at up to 120 g/kg DM, in the total diet, is recommended as an alternative energy source for feedlot lambs.