SF6017 - Liquid Feeding of Swine - Potential Positive and Negative Impacts on Pork Safety

Researcher:

Dr. C.F.M. de Lange, Dept. of Animal & Poultry Science, University of Guelph

Objectives:

1. To establish a database of co-products from the food industry that are currently used - or that may be used in the future - in liquid feeding systems for swine, including contents of key pathogens and chemical residues.
   

2. To characterize changes in microflora during fermentation of selected pig feed ingredients (whey, corn distiller solubles and complete pig diets) that may or may not be incubated with beneficial bacteria (probiotics).
   

3. To determine impacts of feeding non-fermented and fermented liquid feed on fecal excretion of pathogens and contamination of pork carcasses with pathogens and selected chemicals.

Expected Benefits:

• The generated information will allow for a more accurate and objective assessment of positive and negative impacts of liquid feeding of swine on safety of Ontario pork products. Moreover, critical control points in pork production and strategies to enhance safety of Ontario pork products will be identified.

Summary of Research Results:

In Ontario about 20% of market pigs are currently raised on computer-controlled liquid feeding systems. Given the benefits of liquid feeding, the number of pigs raised on liquid feeding systems in Ontario is expected to increase rapidly over the next few years. Moreover, the use of liquid co-products from the food industry will increase and liquid feeding will likely include feed fermentation technology. Recent studies suggest that liquid feeding, and especially feeding of fermented feeds, can enhance gut health in pigs, reduce the reliance on in-feed medication in commercial pork production and reduce the contamination of pork products with Salmonella spp. This will directly benefit pork safety. In Ontario a wide range of by-products from the food industry are currently used, or considered for use, in liquid feeding of swine. These co-products from the food or fuel industry may represent environmental hazards if disposed of as waste.

The current evaluation of the main co-products that are used in swine liquid feeding systems in Ontario show that they are safe to feed to animals and that they do not represent a risk to the consumer. The latter is based on contents of pathogens (Salmonella and Yersinia), mycotoxins (vomitoxin and zearalenone) and heavy metals in liquid feed ingredients and mixed liquid diets as well as the use of cleaning agents. In fact, liquid feeds supply more beneficial lactic acid bacteria to pigs than dry feed, which is likely to results in increased gut health, reduced reliance on in feed medication and reduced risk of Salmonella contamination of pigs and pork. Moreover, storage of liquid feed ingredients appears to degrade mycotoxins, which should be explored further. However, the nutrient content of co-products is quite variable and should be monitored based on co-product supplier and routine nutrient analyses.

A combination of different microbes (lactobacillus and bacillus) as inoculants results in a more effective and faster, controlled fermentation of condensed corn distillers' solubles (CDS), while - based on microbial counts and changes in pH - a controlled fermentation of corn steep water and high moisture corn provides little benefit.

Current studies indicate CDS can be an effective pig feed ingredient and that its feeding value can be enhanced by controlled fermentation. When feeding non-fermented CDS slight reductions in pig growth performance were observed as compared to feeding corn and soybean meal based diets. Feeding non-fermented CDS did not influence routine carcass measurements and value, nor aspects of gut health.