Environmental and nutritional benefits of bioethanol co-products (ENBBIO)

The ENBBIO consortium included AHDB Beef & Lamb, AHDB Cereals & Oilseeds, AHDB Dairy, AHDB Pork, AB Agri Ltd, AB Vista Feed Ingredients, ADAS UK Ltd, Aunir, Ensus Ltd, Evonik Industries AG, Glencore, Hook2Sisters, Marks and Spencer, Noble Foods, Premier Nutrition, Sciantec, the Scotch Whisky Research Institute, Scotland’s Rural College, Syngenta, Tulip, and University of Nottingham.

Abstract

The ENBBIO LINK project was devised to bring together all sectors of the bioethanol, livestock and arable industries to investigate the value of wheat DDGS produced by the growing bioethanol industry, for all sectors of UK livestock production. The non-ruminant programme was designed to examine the nutritional value of wheat distillers dried grains with solubles (wDDGS) in poultry and pigs. Nine separate trials were undertaken based on a range of objectives/methodologies. A largescale commercial broiler trial (H2S) revealed that there were no differences in liveweight but better feed conversion ratio (FCR) with wDDGS, although these diets were more expensive as a result of having to include higher levels of pure amino acids; however cost /kg gain was lower and Production Efficiency Factor (PEF) higher. The trial has shown that the addition of up to 100g/kg wDDGS into a balanced broiler diet had no detrimental effects on the technical performance of the birds.

An initial layer trial (Nottingham) reported that including wDDGS at up to 180g/kg in diets that were isoenergetic and balanced for digestible amino acids had no effect on performance and egg shell quality; there were no effects of treatment on gut environment/microflora. The next commercial layer trial (Noble) reported that, with an inclusion of 75g/kg wDDGS with the nutritional matrix values ascribed to the raw material in the formulations by Premier Nutrition, there was no practical difference between the trial and control flocks. wDDGS can be safely used in layer diets, in part substituting for imported soya. Whether it is actually used or not will depend on the relative values of the product and other raw materials used in least cost formulated layer diets. Growing/finishing pigs are able to tolerate levels of wDDGS up to 300g/kg in pelleted balanced diets in terms of performance and carcass quality without a significant reduction in performance. In a final commercial growth trial (Tulip, Harper Adams), the inclusion of wDDGS at any of the levels in the pelleted diets did not have any negative effects for on farm performance, slaughter characteristics or meat quality. The highest inclusion at 300g/kg showed best performance in a number of areas including daily liveweight gain, FCR and slaughter weight. It can, therefore, be concluded that feeding pigs during the growing and finishing stages with up to 300g/kg wDDGS included in the pelleted diets is an acceptable level.

The ENBBIO ruminant studies achieved their primary objective, which was to evaluate wDDGS from UK bioethanol production in terms of nutritional value and animal responses to inclusion in typical ruminant diets. The first dairy trial gave an apparent limitation of wDDGS inclusion of ~200g/kg of diet dry matter. Digestibility studies confirmed that there was no significant effect of wDDGS inclusion level on dry matter digestibility. A second dairy trial re-examined the effect of inclusion level of wDDGS. For this trial, diets were formulated with ME values and degradation characteristics determined in advance for the actual batch of wDDGS to be tested. With an accurate ME value, there was no effect of wDDGS inclusion level on intake or performance. In a survey of wDDGS use on commercial beef farms, inclusion levels of 125g/kg and 300g/kg of the diet supported good performance levels.

An important element of the ENBBIO project was to quantify the potential environmental benefits of bioethanol production, focussing on the utilisation of the co-products and their value in the animal feed supply chain. Using 3 Mt of wheat grown on 405 kha of UK arable land to produce DDGS, in addition to the bioethanol produced, would potentially substitute for ca. 1Mt of three major commodities used in animal feeds i.e. soyfbean meal (SBM), sunflower meal (SFM) and wheat. The extent to which of DDGS will substitute for other commodities, particularly plant proteins, will inevitably show some variation over time, for instance as economic scenarios and the relative prices of different feed ingredients change. An estimated 389kt of SBM could be substituted, which equates to 150kha land area spared.

Another element of work within the ENBBIO project was to identify and create options by which industries producing DDGS might enhance the quality and value of their DDGS. A general recommendation is that this will happen most effectively in the context of integrated approaches that allow additional product revenue streams and more efficient operation. A long-term view in which DDGS is produced in increasingly integrated biorefineries will provide helpful guidance and direction for the development of the industry. The opportunity to extract arabinoxylan is particularly promising; it would enhance the nutritional quality and commercial scope of DDGS while producing an additional high value product. The project demonstrated great value for wDDGS in its current form as well as potential for further improvements.