Wheat DDGS Offers Potential for Future of Pig Feeding
UK - Distillers dried grains with solubles made from wheat (wDDGS) offer potential to reduce reliance on imported feed ingredients without compromising the performance or health of UK pigs and poultry, according to the results of a four-year project which were presented last week. This important co-product from the bioethanol industry could make a significant impact in improving the sustainability of these sectors by reducing greenhouse gas emissions. Senior editor of ThePigSite, Jackie Linden, reports.
4 May 2015
7 minute read
By: Making pig production more sustainable is all about the front end, according to Nigel Penlington [pictured above], Environment and Buildings Manager for the British Pig Executive (BPEX).
Introducing the event, ‘The Future of Feed’ on new advances in co-products for pigs and poultry at Stoneleigh last week, he explained that feed has the biggest impact on sustainability.
Like many countries, the UK relies heavily on imported feed ingredients for livestock and so in 2010, a consortium of leading pig processors, manufacturers of distillers dried grains with solubles (DDGS), feed and nutrition companies and researchers began working on the Environmental and Nutritional Benefits of Bioethanol Coproducts (ENNBIO) project.
Funded by the LINK programme from the Defra, the members of the consortium contributed to the project, which explored the feasibility of using DDGS derived from wheat (wDDGS) as a replacement for imported proteins such as soybean meal. WDDGS is a co-product from the production of the renewable fuel, bioethanol.
Results of Feeding Trials
The studies into the feeding of wDDGS to pigs and poultry were presented to the meeting by Professor Julian Wiseman of the University of Nottingham.
Experiments in pigs: Nottingham University
Based on the experiences with broilers, Dr Wiseman explained that for pigs, his first investigation was into the amino acid digestibility of wDDGS.
In an experiment in the US comparing different w-DDGS products, the digestibility values for most of the amino acids were again lower than expected at around 60 to 70 per cent, particularly for lysine, which was only about 30 per cent digestible. Over-heating of the material was again thought to be the cause.
Based on this data, a small-scale feeding trial was carried out at Nottingham University, looking at the performance and carcass quality of entire male grower-finisher pigs (35 to 105kg liveweight). The diets contained zero, 10, 20 or 30 per cent w-DDGS and were balanced for net energy and digestible lysine.
There were no effects of wDDGS level on killing-out percentage, P2 backfat measurement, meat pH or the levels of skatole or indole (natural chemicals associated with boar taint).
So, summarising his work, Dr Wiseman said that wDDGS is potentially a valuable raw material in diets for non-ruminants, at an inclusion level of 30 per cent for growing-finishing pigs.
“WDDGS cannot replace soybean meal in poultry and pig diets but it can be used as a means of reducing reliance on this imported ingredient,” concluded Dr Wiseman.
Commercial pig trial with wDDGS
Following on from the experience at Nottingham, a second, larger trial was carried out at Harper Adams University, sponsored by Tulip Ltd, explained Jen Waters of Tulip.
Again, levels of wDDGS used were zero, 10, 20 and 30 per cent in the two diets (grower and finisher), with all diets balanced for net energy and digestible amino acids.
The inclusion level of wDDGS had no significant effects on the growth rate or FCR of the pigs although there were positive trends in both phases, particularly in the grower period (40 to 60kg).
With killing-out percentage and meat pH, there were no differences between the pigs linked to wDDGS inclusion level and Ms Waters said there were no negative issues.
So, she concluded wDDGS can be fed at up to 30 per cent in grower and finisher diets for pigs and because there were indications that this level gave the best results, the inclusion level could be increased, providing it is still cost-effective. There were no detrimental effects on farm performance, slaughter characteristics or meat quality, she confirmed.
Ms Waters added: “So wDDGS works as well on a big scale as well as a small scale.”
Commercial Feed Formulation with wDDGS
A key aspect in the incorporation of any raw material into a diet is to understand fully the nutrients it provides, said Dr Steven Jagger of AB Agri by way of introduction to his presentation to the meeting.
He explained that during the ethanol production process, the wheat is ground and cooked, water is added and then enzymes and yeast are added for the fermentation stage. Finally, it is distilled to drive off the ethanol, which is collected as the main product.
What remains after separation are the wet distillers grains and the syrup. These are dried together in order to obtain the co-product, wDDGS.
This is the crucial stage for its value as a feed ingredient: if the wet material is overheated, the amino acids can react with any residual sugars in what is called the Maillard reaction, the result of which is a reduction in digestibility, particularly of lysine, Dr Jagger said.
He then presented data from several sources, showing the reduction in digestibility of lysine in wDDGS.
He went on to explain a number of ways in which lysine digestibility can be predicted from the levels of crude protein or acid detergent fibre - both of which can be determined quite easily by chemical methods.
Finally, as with maize DDGS, the colour (luminance) of the product can give a rough indication of lysine digestibility.
Dr Jagger showed some examples of different cost scenarios and how they would affect the inclusion level of wDDGS in commercial pig diets.
Up to 30 per cent wDDGS can be included in grower and finisher diets for pigs, Dr Jagger concluded. He stressed that it is important to know accurate digestibility values for the product, and that the ability to predict these values is key.
He identified stage of production, relative raw material prices and amino acid digestibility as the main factors that affect the financial value of wDDGS in pig feeds.
Future of the Bioethanol Industry in the UK
£750 million was invested by private sources in the UK following the legislation set for biofuels in 2009 under the Renewable Energy Directive, and this included the establishment of three biorefineries in country, producing bioethanol and animal feed, according to Mark Chesworth, managing director of one of those companies, Vivergo Fuels.
As well as providing many thousands of jobs, directly and indirectly, and offering a new demand stream for arable farmers, EU ethanol production displaced 26.5 million barrels of oil in 2013, which may only be around two per cent of the total requirement but it does contribute to energy security and the balance of payments.
Vivergo is based on Humberside, explained Mr Chesworth. His company produces 420 million litres of bioethanol a year and 400,000 tonnes of animal feed, which is enough protein to feed around 20 per cent of the UK dairy herd – the main market for this co-product until now.
Looking to the future, he said, his company aims to have a measurable positive impact on the future sustainability of UK food and farming by offering a cost-effective replacement for imported proteins.
