Research review
In 2022, Irish Farmers Monthly spoke to Professor O’Doherty about PigNutriStrat, a research project he is leading with Teagasc Moorepark and South East Technological University (SETU) to develop solutions to prevent and manage diseases in pigs in order to reduce antibiotic use. The research is funded by the Department of Agriculture, Food and the Marine and is looking at everything from biosecurity right up to nutrition of sows and pigs post-weaning and the economics of these changes, he explains.
The key focus in the last few years, he says, has been investigating alternatives to in-feed antibiotics, and zinc oxide in pig diets. “Zinc oxide is a heavy metal and was also increasing antimicrobial resistance and has been banned since 2022. We are now looking at ways of improving performance without the use of additives, and while a number of feed additives are available, none has delivered the same performance as zinc oxide or in-feed medication. One of the reasons for this is that the pigs don’t eat enough directly after weaning.” This, he says, is due to the immaturity of the gastrointestinal tract, and the solution may lie in offering feed that addresses this issue.
Acidified Cereals
“Over the last few years, Ruth Connolly and Shane Maher (PhD students) have been looking at acidified cereals in pig diets. Rather than drying the cereal, we add an organic acid blend to cereals at harvest time. In comparison to dried cereals, we have seen very good results in terms of improved average daily gain in the region of about 13-14 per cent, less diarrhoea in weaned pigs, and improved food conversion ratios. Throughout the life cycle of the pig, we are getting in the region of 6-7kg increase in body weight at slaughter from organic acid-treated cereals.”
The organic acid blend added to the cereals is a combination of propionic acid with a blend of salts (MycoCURB). “It doesn’t reduce the pH of the feed or have any detrimental effects on feed bins.”
The question the research is now answering is, why? “Firstly, we have seen that the organic acid-treated cereals improves the ileal nitrogen and gross energy digestibility of the diet as well as improving the total tract nutrient digestibility of the diet: in the region of 7-8% improvement in digestibility. Secondly, we see a very different microbiome in pigs: a different microbial population in the gastro-intestinal tract and an increase in beneficial bacteria, particularly Faecalbacterium, in the pigs that have been fed the acidified cereal diets. We also see a lot less inflammation in the gastro-intestinal tract.”
They are, he says, healthier pigs. “The main stressful point around pig production is weaning, and zinc oxide and infeed medication are used around this time. You see a very strong relationship between the presence of pathogenic bacteria, like E. coli in the gut of the pig and the levels of diarrhoea. What we are seeing with acidified cereals is an increase in the beneficial bacteria, like Faecalbacterium, and a reduction in pathogenic bacteria in these weaned pigs.”
Native beans
In a parallel study, in conjunction with SFI Biorbic Centre and Adesco, Professor O’Doherty along with Shane Maher (PhD student) has been researching native beans as an alternative protein source for pigs. The vicia faba, also known as the broad bean, fava bean, faba bean, field bean, bell bean, or tic bean, performs well in the Irish climate as the crop is tolerant of wetter conditions and cool summer temperatures. In dry seasons and on light soils, beans can suffer from drought.
“We have been using native beans as a protein source in place of soya bean meal and it’s been going quite well. Beans haven’t been used to a major extent in Ireland, mainly because soya beans always worked.” According to Teagasc, annual production has increased from 3,000ha to 11,000ha in recent years aided by a protein crop support scheme.
“Beans are 27-29 per cent protein, soya bean meal is about 48 per cent protein, so they are a good alternative source of proteins. “In the Biorbic project, we are looking at levels of beans that can be used along with the acidified cereals, and studying if can we use the organic acids treatment at harvest to improve the nutritional value of those beans.”
WHAT ARE ANTI-NUTRITIONAL FACTORS?
Anti-nutritional factors (ANFs) are compounds present in foods that can reduce nutrient utilisation or food uptake, which leads to impaired gastrointestinal functions and metabolic performance.
Source: Nutritional Composition and Antioxidant Properties of Fruits and Vegetables, 2020 Amit K. Jaiswal
Can we expect to see organic acid-treated cereals used across Ireland? “For an industry to take it up, they like to see a lot of evidence. When I began looking at this work, I hoped to get the same performance from treated grain as dried grain. However, to my surprise, we are getting in the region of 6-7kg increase in body weight at slaughter from organic acid-treated cereals and we are also reducing the carbon footprint of pork.”
Carbon footprint
Acidified cereals and native beans meet another objective of the research: finding alternatives that have a lower carbon footprint. “You aren’t using kerosene to dry the cereal, instead you are preserving the cereal using an organic acid blend, so you are lowering the carbon footprint for pig production. We are seeing a 10-15 per cent reduction in carbon footprint. That’s a huge advantage in working towards our carbon neutral goals.”
According to Teagasc, more than 1.2 million tonnes of imported protein feed could be displaced by native beans which would contribute hugely to our efforts to reach our climate targets. “Soya beans are grown in the US, Brazil and Argentina so they have to be imported and that’s a huge carbon footprint. We would expect the beans to be grown here which will have a major impact on our carbon footprint. They can also be a source of protein for ruminants – anything that will reduce our carbon output. The effect on the carbon footprint of pork on an acidified cereal and bean diet is massive, you could be talking about a 50 per cent reduction.”