You can feed fusarium contaminated barley to pigs

Pearling Fusarium-Contaminated Barley Yields A Feedstuff Suitable For Use In Starter Pig Diets

While the full extent of the fusarium problem in the 2005 Manitoba cereal grain crops has yet to be determined, preliminary reports highlight the potential for significant infection rates. For pig producers, this could mean another season of coping with DON. The mycotoxin DON (deoxynivalenol or vomitoxin), when present in swine diets above 1 to 2 ppm, can suppress feed intake and lead to reductions in average daily gain and increase days to market. At the University of Manitoba’s Department of Animal Science, we have been conducting research to A) better understand how fusarium-contaminated cereal grains impact swine performance and B) develop strategies to reduce the negative impacts observed when feeding these grains.

With respect to point B, we have focused our attention on the use of pearling techniques, or abrasive dehulling, to remove DON (and other mycotoxins) from the grain. Our initial studies with a laboratory-scale pearling machine showed that pearling was quite effective at removing DON from hulled barley: The removal of 15% of the outer kernel, approximately equal to the hull fraction, resulted in the removal of 65% of the DON. Similar results were obtained when we tested a commercial-scale pearling unit. The commercial-scale unit provided an opportunity to assess the impact of pearling on the feeding value of fusarium-contaminated hulled barley. We showed that pearling 1) removed the feed refusal factor from contaminated barley and 2) increased the digestible energy value of barley by an average of 15%, due to the removal of the fibrous hull fraction. The next phase in our studies included the investigation of whether DON-contaminated barley, once it had been pearled, could serve as a suitable feed ingredient for starter pigs.

Does the pearling of DON-contaminated barley yield a suitable feed ingredient for starter pigs?

The effect of commercial pearling of DON-contaminated barley diets was evaluated with respect to the performance of early-weaned pigs. Three sources of barley were used, each with a different level of initial DON contamination: Barley 1 = 1.2 ppm (low); Barley 2 = 4.4 ppm (medium); and Barley 3 = 7.6 ppm (high). Each barley source was subjected to a commercial pearling procedure, using a Satake cereal grain abrader, to remove approximately 20% of the outer portion of the grain. As a result, the final DON levels in the pearled barley samples were: Barley 1 = 0.42 ppm; Barley 2 = 1.54 ppm; Barley 3 = 2.70 ppm. These barley samples were used in the formulation of two phase diets for starter pigs. Phase I diets contained 44% pearled barley, 25% soybean meal (48% crude protein), 15% dried whey, 10% lactose, 6% spray dried plasma, 1.8% vegetable oil, plus supplemental lysine, methionine, and a vitamin-mineral premix to provide sufficient nutrients to meet or exceed the requirements of the young pig.

The phase II diets consisted of 67% pearled barley, 27% soybean meal, 1.5% vegetable oil, plus supplemental lysine, methionine, and a vitamin-mineral premix to provide sufficient nutrients to meet or exceed the requirements of the young pig. As a control, corn-based diets were formulated to the same nutrient specifications for the two phases.

The study involved 96 piglets (48 males and 48 females) weaned at 17 ± 1 d of age. The animals were assigned to the four dietary treatments in a completely randomized design, and the experiment lasted for 4 weeks: Phase I = weeks 1 and 2; Phase II = weeks 3 and 4. Each dietary treatment was randomly assigned to six replicate pens with four pigs per pen and balanced for initial body weight and sex. Feed intake, average daily gain and feed conversion efficiency were determined by phase. The results of the study appear in the figures below.

In phase I and overall, feed intake was lower in the pearled barley-based diets as compared to the corn based diets, however this did not translate to reductions in average daily gain. In fact, there was a tendency for average daily gain to be higher in the pearled-barley rations during phase II, especially for the diets based on the higher DON sources (Barley 2 and 3). These results translated to significantly improved rates of feed conversion efficiency for the pearled-barley diets during all phases of the study.

Based on these results, we conclude that the commercial pearling of DON-contaminated, hulled barley yields a feed ingredient that is well tolerated by young pigs. The removal of the mycotoxins, in particular DON, as well as the fibrous hull fraction creates a feed ingredient that supports average daily gains and feed efficiency values that are similar, if not better, than a corn-based control. Therefore, the pearling or dehulling of barley should be considered as an effective strategy to increase the utilization of fusarium-contaminated grains by the swine industry.

Pearling requires capital inputs (pearling machine, grain handling and storage), as well as the input of energy. However, the costs associated with pearling should be offset by the reduction in transportation costs associated with the importation of DON-free grains, as well as the improvement in the digestible energy value that is obtained through the removal of the fibrous hull fraction (ie: less added oil required in the diets). Further work to optimize the process, as well as the determination of the cost-effectiveness of the procedure will indicate the economic conditions when this process is viable at the commercial level.

Authors: James D. House, Ntinya Johnson and Martin Nyachoti
Department of Animal Science, University of Manitoba and David Abramson - Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, MB
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