Growing conditions, particularly in the western Corn Belt in the last few years, have led to the presence of mycotoxins in field corn. That becomes an issue as hog producers are looking for a safe feed supply, because feeding mycotoxin-contaminated corn in a swine diet can cause health and performance issues in the herd.

Feeding fumonisin-contaminated corn could reduce growth performance and damage the liver, lungs, kidneys and gastrointestinal structures of pigs. In severe cases, it could lead to death.

In a preliminary study conducted at Kansas State University, pigs were fed increasing amounts of corn contaminated naturally by fumonisin to achieve final diet levels of 7 to 35 parts per million of fumonisin. They observed a reduction in growth performance, with a dietary fumonisin level greater than 21 ppm.

From Day 0 to Day 28, feeding pigs diets containing increasing fumonisin decreased (linear, P=0.05) average daily gain, Day 28 body weight and average daily feed intake (linear, P = 0.05), and it worsened (linear, P = 0.01) the feed-to-gain ratio.

Increasing fumonisin linearly (P < 0.05) decreased ADG from Day 7 to Day 14 and Day 21 to Day 28, and linearly (P < 0.05) worsened F:G from Day 0 to Day 7 and Day 7 to Day 14. The decrease in ADG resulted in pigs fed 32.7 and 35.1 ppm fumonisin being 2.8 and 3.4 pounds lighter (P < 0.05), respectively, than pigs fed 7.2 ppm fumonisin on Day 28. There was no statistical evidence for Day 28 body weight differences between diets containing 7.2 to 21.9 ppm fumonisin.

On Day 14, feeding pigs increasing fumonisin increased the (linear, P < 0.001) serum sphinganine-to-sphingosine (Sa:So) ratio from 0.47 to 1.40. Pigs fed 14.7, 21.9, 32.7, and 35.1 ppm of fumonisin had higher (P < 0.05) Sa:So ratio than pigs fed 7.2 ppm of fumonisin. On Day 28, feeding pigs increasing amounts of fumonisin increased (linear, P < 0.001) the serum Sa:So ratio, with pigs fed 21.9, 32.7, and 35.1 ppm of fumonisin having a higher (P < 0.05) Sa:So ratio than pigs fed 7.2 ppm of fumonisin. Pigs fed 32.7 and 35.1 ppm fumonisin had a higher (P < 0.05) Sa:So ratio than pigs fed a lower concentration of fumonisin.

In conclusion, this study found that increasing dietary fumonisin concentration from 7.2 to 35.1 ppm for 28 days worsened growth performance (body weight, ADG, ADFI and F:G), and increased serum Sa:So ratio. By correlating growth performance result with serum Sa:So ratio, there was a threshold of about 20 to 30 ppm of dietary fumonisin that significantly decreased growth performance and increased serum Sa:So ratio.

Therefore, serum Sa:So ratio has the potential to be used as a reliable biomarker for fumonisin intoxication, and diets that contain more than 30 ppm of fumonisin should not be fed to 20- to 60-pound nursery pigs. Furthermore, diets containing greater than 21.9 ppm of fumonisin should be evaluated with caution, as further research is warranted to determine the fumonisin concentration between 21.9 and 30 ppm where the negative effects on pig performance are observed.

Testing commercial products
Blending good-quality corn with corn that is contaminated with fumonisin can be a good way to achieve fumonisin levels that will not adversely affect pig health or performance. During years with widespread poor growing conditions for corn, the supply of good-quality grain to be able to blend may be limited, forcing producers to look to other measures to ensure a safe final feed product.

With that in mind, K-State researchers conducted two studies to determine the efficacy of various commercial products on growth performance of 20- to 50-pound nursery pigs fed diets high in fumonisin concentration.

In Experiment 1, a total of 350 pigs (initially weighing 21.8 pounds) were used. There were five pigs per pen and 14 replicates per treatment. After weaning, pigs were fed common diets for 21 days before the experiment started. Five dietary treatments were used that consisted of a positive control (low fumonisin); a negative control (approximately 50 to 60 ppm of fumonisin); and three other treatments as negative control, with one of three different products from Kemin Industries Inc., NutriQuest; and Biomin America Inc.

Diets were fed in mash form for 14 days and followed with a low-fumonisin mash diet for 13 days as a post-treatment period. For the 14-day treatment period, pigs fed the high-fumonisin negative control, or high-fumonisin diets with the products from Kemin or NutriQuest had decreased (P < 0.05) average daily gain, average daily feed intake and Day 14 body weight, and a poorer (P < 0.05) F:G, compared to the positive control and treatment with the Biomin product.

Pigs fed the high-fumonisin diet with the Biomin product had similar performance to pigs fed the low-fumonisin diet. During the 13-day post-treatment period, pigs previously fed the high-fumonisin negative control, or high-fumonisin diets with the Kemin or NutriQuest products had an improved F:G, compared with pigs previously fed the low-fumonisin diet or high-fumonisin diet with the Biomin product.

Although the performance of the pigs previously fed the high-fumonisin diets without additive or with the Kemin or NutriQuest product improved, their Day 27 body weights were still lower (P < 0.05) compared to pigs previously fed the positive control and high-fumonisin diet with the Biomin product.

In Experiment 2, a total of 300 pigs (initially weighing 23.0 pounds) was used. Procedures were similar to Experiment 1 except for three factors: there were 12 replicate pens per treatment, high-fumonisin diets contained 30 ppm fumonisin and experimental diets were fed for 28 days.

Similar to Experiment 1, for the 28-day treatment period, pigs fed the high-fumonisin negative control, or high-fumonisin diets with the Kemin or NutriQuest product had decreased (P < 0.05) ADG, ADFI and Day 28 body weight, and poorer (P < 0.05) F:G, compared to the positive control and treatment with the Biomin product. Pigs fed the high-fumonisin diet with the Biomin product had similar performance to pigs fed the low-fumonisin diet.

In summary, adding the Biomin product to diets containing 30 to 50 ppm of fumonisin appeared to mitigate the negative effects of fumonisin, while the Kemin and NutriQuest products did not influence pig performance.

Researchers also determined that pork producers can add fumonisin-contaminated corn to swine diets up to about 20 ppm of dietary fumonisin for a short period of time (at least 28 days), without having negative effects on pig performance. But, when facing higher levels (more than 30 ppm), the reduced performance will be expected unless mitigated.

Use of a mitigant feed additive instead of discarding fumonisin-contaminated corn can aid producers if feed supply may run short.

Researchers: Zhong-Xing Rao, Mike D. Tokach, Steve S. Dritz, Jason C. Woodworth, Joel M. DeRouchey, Robert D. Goodband and Hilda Calderon Cartagena, all of Kansas State University. For more information, contact Zhong-Xing Rao or Mike Tokach.