Are aflatoxins manageable mycotoxins?

Author: Radka Borutova, DVM, PhD, Business development manager, Nutriad International

The discovery and isolation of aflatoxins was a result of investigations on the mysterious Turkey-X disease of 1960 which resulted in a loss of several thousand turkey poults in the United Kingdom. The cause of the enormous mortality in the turkey poults and of similar outbreaks in other farm animals could be linked to the use of moldy Brazilian peanut meal in the diet of the affected birds. The suspected toxic factor was found to be extractable by using chloroform. Its association with Aspergillus flavus (A. flavus) was established in 1961. In 1962, the name “aflatoxin”, using first letter from “Aspergillus” and the first 3 letters from “flavus” was proposed.

UNIKE®PLUS efficacy against aflatoxins and fumonisins in broiler chicks

A total of 240 male Cobb day-old broilers were randomly allocated to 4 treatments with 6 replicates of 10 birds each. The experiment was 21 days long. Dietary treatments included:

  1. Mycotoxins:    feed contaminated with 1400 ppb of aflatoxins and 25 ppm of fumonisins
  2. Mycotoxins+ 1,5 kg/t UNIKE®PLUS:     contaminated feed with 1,5 kg/t UNIKE®PLUS
  3. Mycotoxins+ 2,5 kg/t UNIKE®PLUS:     contaminated feed with 2,5 kg/t UNIKE®PLUS
  4. Mycotoxins+ 5 kg/t UNIKE®PLUS:       contaminated feed with 5 kg/t UNIKE®PLUS

Feed and water were offered ad libitum during the entire experimental period as typical in battery managed birds except on weighing days when the feed was removed for 6 hours prior to weighing. The feed was contaminated with mycotoxin culture material (75% aflatoxin B1, 24% aflatoxin G1, 1% aflatoxin B2+G2 and 94% fumonisin B1, 6% fumonisin B2).

Parameters measured were:

  • individual body weight
  • feed intake and feed conversion ratio (FCR)
  • individual relative liver weight (expressed as percentage)
  • blood parameters such as total plasma proteins, cholesterol and albumin

The data was analysed by analysis of variance (ANOVA) and the Bonferroni test (p<0.05) was used to compare the means.

At 21 days of age, birds fed diets with mycotoxins presented the lowest body weight as compared to other groups (Fig. 1). The body weight in groups with UNIKE®PLUS was higher and at the inclusion rate of 2,5 and 5 kg/t, the difference with the contaminated group was significant.

Fig 1

No statistically significant difference between treatments for FCR was observed (Fig. 2). However, there was a substantial numerical difference that was dependent on UNIKE®PLUS dose.

Fig 2

Mycotoxins, especially aflatoxins, damage liver and impact protein synthesis as well as fat metabolism. Broilers fed on the diet containing mycotoxins had the highest liver weight and the lowest total plasma protein, albumin and cholesterol levels (Table 1). When added to the contaminated diet, UNIKE®PLUS had a clear dose effect on liver status and several blood parameters. Birds receiving UNIKE®PLUS at levels of 2,5 and 5 kg/t presented significantly improved values in lower relative liver weight and higher blood serum

High levels of aflatoxins in combination with fumonisins can significantly affect animal growth performance and health. The use of UNIKE®PLUS can successfully reduce the negative effects of mycotoxins. In this experiment, broilers fed contaminated diet showed a clear dose response with the inclusion of UNIKE®PLUS. Thus, UNIKE®PLUS is an effective tool in reducing the negative impact of mycotoxins on animal growth performance and health.

Table 1

Conclusion

The best practical way to control mycotoxin levels is to use rapid test kit systems for the analysis of mycotoxins in raw ingredients which are not yet in silos. Different rapid test kit systems are validated for different mycotoxins and commodities offering a very quick and effective way of raw material screening before they enter the feed mill. Once the levels are known, every feed mill can estimate the quality of its raw ingredients in terms of mycotoxin contamination and can effectively and more precisely (by dosage adjustment) apply feed additives during feed production. Another strategy of mycotoxin risk management is to test for the presence of mycotoxins in finished feeds including TMR (total mixed ration) and silages. This method has some advantages and disadvantages. Since each raw ingredient can bring its own mycotoxins into the finished feed, the most important advantage is that the presence of raw ingredients with a low inclusion rate (5-10%) which can still cause significant contamination of the finished feed but can be inadvertently overlooked if not tested can be identified by testing the finished feed. The most important disadvantage is that analysis of finished feed takes quite a long time such that the tested feed is likely to have been fed to the animals by the time the results from the analysis are known. Storage mycotoxin contamination (ochratoxins, aflatoxins) can be prevented by keeping temperature and moisture content in silos low whilst aerating the grain regularly. In cases where perfect storage conditions cannot be guaranteed, the use of mold inhibitors and silage inoculants is highly recommended. The application of specific feed additives (mycotoxin deactivators) which are able to help reduce the negative effects of different mycotoxins in dairy cows is highly recommended.

 

Published on Nutriad Website 08/05/18.