Novel coproducts from corn milling and their use in ruminants’ nutrition

Abstract

The article reviews published data on two novel coproducts originating from corn milling: high-protein distillers' grain (HPDG) and reduced-fat distillers' grain (RFDG). Based on a literature survey over the last decade, this article focuses on their chemical composition and, consequently, nutritive value and on the effects of their inclusion in ruminants' diets on rumen activity and animal performance. Compared to the classic distillers' grains, the two new coproducts expressed lower variability of their chemical composition, nutritive value, and specific feeding characteristics, allowing more targeted feeding strategies (protein balancing, avoidance of milk fat depression, etc.). Thus, HPDG has significantly higher crude protein content (~44%), lower fat content (~4.3%), and lower fibre content (~26.8% neutral detergent fibre (NDF) and ~12.3% acid detergent fibre (ADF)) compared to the classical distillers grains. In the case of RFDG, only the fat content is significantly lower (~4.8%), whereas the crude protein content (~32.1%) and the fibre content (~36.1% NDF and ~14.7% ADF) are only slightly lower compared to the classical distillers grains. On this basis, HPDG can successfully replace classic high-protein meals, such as soybean meal, thus providing high levels of rumen undegradable protein, although it has the same amino acid limitations as the originating raw material, corn grains. The use of RFDG instead of the classical distillers' grains allows much higher dietary inclusion, without adverse effects on rumen metabolism and animal performances. A further development of the two coproducts and further diversification of corn coproducts, allowing better solutions to various feeding situations, is expected.