DON contamination in feed represents great impact on performance and economic viability within the pig industry. The contamination of feed ingredients with mycotoxins continues to be a great problem in animal diets, especially for the pig industry. Research carried out recently focused on deoxynivalenol (DON) which is the most common mycotoxin in pig feed. It usually contaminates corn, wheat, barley and other important feed ingredients that suffer from Fusarium fungus infection. There are limits to the amount of DON allowed in pig feed due to the fact that even small amounts of this mycotoxin have negative effects on pig performance. According to previous studies 85% of all grain samples and 90% of finished feed simples in North America contained DON. Advances in mycotoxin analysis have shed light on the severity of mycotoxin contamination, revealing a worse scenario than was anticipated. As a result production costs associated with mycotoxin contamination and its control continue to increase.
Contaminated grains are usually destined for use in livestock feed despite the fact the best strategy for livestock producers should be to avoid mycotoxin contaminated grain for animal feeding. However, due to the current high incidence and levels of contamination this is not an option. As a result, different strategies have been proposed for minimizing or eliminating the negative effects of mycotoxin contamination in animal feed. A majority of these strategies, base themselves on the deactivation of mycotoxins through binding agents like silicate clays and activated carbon.These adsorbents can be included in feed in the form of non-nutrient additives. However despite these efforts, current feed additives are not very effective when it comes to mitigating mycotoxins’ negative effects, or they simply don’t have the capacity to neutralize al lot the existing types of mycotoxins. Recent studies have examined the inclusion of different additive combinations like: yeast/yeast products, preservatives, antioxidants, amino acids, and probiotics. These have shown promising results in DON-contaminated diets for weaned piglets and grower pigs.
There is a considerable amount of research regarding DON in pigs as they are one of the most susceptible livestock species to its negative effects. However, most of the previous studies have been carried out in young animals based on the idea that the negative effects of mycotoxin contamination are greater at this stage. On the other hand, most of such studies have examined the impact of mycotoxins over relatively short periods of time. Therefore plenty of ground still needs to be covered. In an attempt to make a better assessment of the problem, a study carried out by researchers from the Prairie Swine Center sought to answer the following questions:
Studies (materials and methods)
Two growth performance studies were conducted to examine the impact of long-term feeding of graded levels of DON in finisher (75 – 120 kg) and grower-finisher (35 – 120 kg) pigs.
For both studies, pens housing the groups of studied animals were assigned to 1 of 4 dietary treatments. Dietary treatments consisted of a control diet containing no DON or a diet containing 1, 3, or 5 ppm DON (DON1, DON3, or DON5). I
Individual pig body weight and per pen feed intake were measured weekly for the duration of the studies (42 d for Study 1 and 77 d for Study 2) to determine average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (gain:feed; GF).
It was revealed that finisher pigs presented a fast negative response to > 1 ppm DON intake, resulting in reduced average daily gain and feed intake. As well as a decrease in body weight within the first week of the trial. This body weight reduction was maintained throughout the study. However, after a 4 week period, feed intake and average daily gain of all pigs presented a recovery The response to DON intake in grower-finisher pigs was slower and more subtle which resulted in variability over time and across treatments. Overall there was reduction in average daily gain, feed intake, and body weight in pigs fed > 1 ppm DON. Impact of dietary DON content on feed efficiency was not evidenced in either study.
In summary, these studies provide evidence to support a higher limit for DON of 1 ppm in finisher pig feed in order to prevent performance reductions. Despite an initial performance reduction, pigs exhibited the capacity of adapting to a DON intake of > 1 ppm and < 5 ppm.
The negative effects of DON intake appear to be due largely to reduced feed intake. This is supported by lack of negative effects of DON intake on nutrient utilization, health status, and carcass quality.
Feeding diets containing > 1 ppm DON will result in reduced margin over feed cost. This reduction is greater when DON is first introduced in the finisher period compared to the grower period.
Producers may be able to feed DON-contaminated diets, up to 5 ppm, while making adjustments (e.g., reduced ingredient/feed cost, increased days to market, mycotoxin mitigating feed additives) for the negative impact of DON intake on growth performance.
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