How much MYCOFIX® do I have to add to be SAFE???
Published: April 16, 2008
By: Verena Starkl - Biomin GmbH
Last November, one of Argentina’s largest table egg producers conducted a trial using Mycofix® Select in the diet of laying hens at a concentration of 750g for 2 weeks and 500g per ton of feed for an additional 3 weeks. November/December is usually not considered very “dangerous” period of the year for mycotoxin contamination of the raw materials. Argentina has a significant advantage compared to other countries with capacity to produce corn and soya. Thus, especially big farmers, often have the freedom to selectively purchase which ingredients and quality for their diets. Because of their experiences regarding mycotoxin contamination, 750g and 500g of Mycofix® Select were chosen as sufficient to protect the animals from negative effects of low mycotoxin contamination found during this period of the year.
The trial was conducted in a house with 100 000 laying hens starting at 29 weeks of age. Previous symptomatic experiences presumed the diets were contaminated with probable low levels of trichothecenes (T-2 toxin and associated lesions), and probable aflatoxins or fumonisins (liver damages). At the beginning of the trial laying hens were only 84% rate of lay and following 5 weeks of treatment brought performance to 90%. Weekly mortality decreased from 0.12% to 0.11%. Mean body weights increased from 1515 gram to 1610 gram along with egg weight increasing from 59 gram to 60,5 gram. Twenty percent of the flock had oral lesions at the beginning of the trial. These lesions were measurably reduced to 16% after 5 weeks treatment. Livers from this flock were described as friable at the beginning of the trial and had completely disappeared at the conclusion of this five week period! Because of these dramatic changes the veterinarian responsible recommended the continued use of Mycofix® Select. The egg-producer chose to include 500g Mycofix® Select per ton of feed as insurance on a regular basis in his diets. Under field conditions and at low inclusion rates Mycofix ® Select worked to the satisfaction of the egg producer.
Approximately at the same time and on the other side of the world – Professor Chang-Won Kang at the Animal Resources Research Center, College of Animal Husbandry, Konkuk University, Seoul, South Korea a further layer trial was performed. This trial, however, used contaminated feed and with a high inclusion rate of Mycofix® Select to counteract high contamination levels of deoxynivalenol (DON) and zearalenone (ZON). Two-hundred, eighty-eight Hy-Line Brown pullets at the beginning of lay (19 weeks of age) were used, randomly mixed and divided into 24 groups. Out of the 24 groups 6 treatments with 4 replicates, 12 birds each were grouped. During 11 weeks layers were fed different diets according to the trial set-up shown in table 1.
Table 1: Trial set-up layer trial Korea.
The objective of the trial was to measure the impact from a defined concentration of deoxynivalenol (5000ppb) and zearalenone (1000ppb) on laying hens. The experiment sought to find a possible increased interaction of DON in the presence of ZON, and learn the capacity of Mycofix® Select to counteract diverse mycotoxin challenges. Exploring scientific literature one can find very different contamination rates of both DON and ZON that did NOT cause any adverse effects in layers. Even among researchers, opinions differ. In laying hens, Kubena et al. (1987) did not find any effect – neither in quality, nor quantity of the eggs - of 18ppm deoxynivalenol using white Leghorn chickens.
In this trial layer hens were fed contaminated diets through 6 consecutive 28 day-periods and no changes compared to control birds fed without DON were found! Trenholm et al. (1981) fed naturally contaminated DON wheat diets to adult female Leghorn chickens for 10 weeks and observed no marked changes in feed consumption, weight gain, or egg production. Hamilton et al. (1981 a,b 1983, 1985a), in contrast, reported that naturally contaminated wheat diets containing 350ppb or 700ppb of DON, fed for 10 weeks, caused a significant decrease in egg numbers, shell weight, and shell thickness. Whereas other parameters measured were not affected. To underline the difficulty of predicting situations based on known contaminations of feed, please be aware that Professor Hamilton et al. (1983) in further studies observed, using naturally contaminated wheat diets containing as much as 4900ppb DON were fed for 24 weeks (!) to laying hens and did not find any of the previously mentioned parameters statistically impacted by deoxynivalenol!
Chickens are generally considered not sensitive to zearalenone. Researchers all over the world fed high levels to layer hens without proving any impact. Marks and Bacon (1976) reported no negative impact on egg production up to 100ppm of ZON. Finally, a synergistic effect of DON and ZON was suggested by Branton et al. (1988) who studied the effect of naturally contaminated grain sorghum on egg production. He found an impact at a low contamination of DON (appr. 300ppb) when accompanied by ZON (appr. 1100 ppb).
The layer hen trial carried out in Korea was performed with DON and ZON since their impact on laying hens is generally considered as negligible. Therefore, egg productivity was measured as egg production rate (%), egg weight (g/egg), egg mass (g/day/bird), and egg quality was measured as egg shell strength (kg/cm2), egg shell thickness (mm/100), egg shell color (S.C.), egg yolk color (R.C.F.) and haugh unit. Birds were checked daily for occurrence of oral lesions. Relative weights of liver and spleen were recorded at the end of the trial. Blood profile including total cholesterol HDL-C, LDL-C, GOT and GPT was made. Feed intake was calculated every second week.
Results until week 5 of trial did not show any statistically significant differences in none of the measured parameters and therefore are neither displayed nor discussed in the following. Most important results after eleven weeks of trial are summed up in the following tables 2 - 6.
Layer hens were 19 weeks old, at laying start at an egg production between 7,32% and 13,00%. There was no significant impact on feed intake during the whole trial period.
Table 2: Impact of DON and ZON on feed intake and impact of Mycofix® Select to counteract.
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In accordance with other researchers we could confirm that DON does not have an impact on feed intake of layer hens (table 2). In general highest effect of mycotoxin appeared as expected around laying peak. Egg production (table 3) during this period was strongly affected by mycotoxins and this negative impact was completely overcome by inclusion of Mycofix® Select in the diet. Differences in egg weight (g/egg table 4) were seen but less frequent and less intense than the differences that were seen in egg mass (g/day/bird). As can be seen in table 3 egg production and table 5 egg mass of birds (T2, T4) fed mycotoxins without Mycofix® Select for 8 weeks were significantly decreased compared to control birds and birds fed with the contaminated diet in which Mycofix® Select counteracted the mycotoxin hazard.
There was no difference in productive performance between group T2 (5 ppm deoxynivalenol) and the group where deoxynivalenol and zearalenone combined were fed (T4). On contrary, results of some weeks even show significant improvement when the diet was contaminated not only with DON but also with ZON (eg. egg mass and egg weight week 8, egg production and egg mass week 9, egg weight week 10 tables 3, 4, 5). Furthermore it has to be mentioned that several times group T5 (DON and ZON contamination treated with Mycofix® Select) showed even better results than the control group (eg. egg mass week 9, on egg production week 10, table 3, on egg mass week 9, table 5)!
Although not statistically significant - a very positive impact of Mycofix® Select on the haugh unit was observed during each week of the trial (table 6). Highest haugh unit was always analyzed in group T1 – the group where Mycofix® Select was used. Apart from haugh unit no other quality parameter seems to be influenced by the different diets. There was no statistically significant difference between the groups within the first 8 weeks and no persistent, significant differences were seen in the last 3 weeks of the trial. Therefore these data are not shown in this newsletter.
There were no differences in final body weight and mortality rate between the groups. Neither relative weight of liver nor of spleen was influenced by the dietary treatments. There was also no statistical significance regarding the measured biochemical parameters.
Table 3: Impact of DON and ZON on egg production and impact of Mycofix® Select to counteract.
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Table 4: Impact of DON and ZON on egg weight and impact of Mycofix® Select to counteract.
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Table 5: Impact of DON and ZON on egg mass and impact of Mycofix® Select to counteract.
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Table 6. Impact of DON and ZON and impact of Mycofix® Select on the haugh unit of eggs.
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Conclusion
Taking as examples different experiments performed both on the field and under scientific conditions by Biomin® and showing results of independent, international research done in the field I tried to explain that it is hardly possible to predict animal health and productivity on the field on basis of mycotoxin analysis. Even results of the different literature cited show that even if only taking into account results of lab research it is already impossible to set a level of safety of mycotoxins as effects of mycotoxins seem to depend on a whole variety of factors which we probably might not even have defined yet. In some investigations animals seem to be sensitive in others the same animals under similar conditions seem to be completely tolerant against high levels of mycotoxins. Thinking of the different conditions that every producer might face even within his own farm unfortunately it is impossible to exactly interprete the results of mycotoxin analysis and predict what is going to happen with the animals. However, as clearly shown in the field trial we did in Argentina, Mycofix® Select used as an “insurance” even with low levels of not defined mycotoxins leads to improvement and success.
The scientific trial showed that our product is not only effective under filed conditions but also leads to statistically significant improvement in egg production. Therefore Mycofix® Select gives the farmer the most efficient tool to improve and stabilize performance of birds facing a multiple mycotoxin challenge!
Literature
Branton S.L., Deaton J.W., Hagler W.M. Jr., Maslin W.R., and Hardin J.M. (1989) Decreased Egg Production in Commercial Laying Hens Fed Zearalenone- and Deoxynivalenol-Contaminated Grain Sorghum Avian Disease 33:804-808.
Kubena, L.F., Harvey, R.B., Corrier D.E., and Huff W.E. Effects of Feeding Deoxynivalenol (DON, Vomitoxin)-Contaminated Wheat to Female White Leghorn Chickens from Day Old Through Egg Production (1987) Poultry Science 66:1612-1618.
Hamilton, R.M.G., Trenholm H.L. and Thompson B.K. (1983) Effects of feeding chicks and laying hens diets that contain vomitoxin (deoxynivalenol) contaminated wheat. Proc. Annu. Nutr. Conf. Feed Manuf. 19:48-55.
Hamilton, R.M.G., Thompson B.K. and Trenholm H.L., Fiser S., Greenhalgh R.. (1985a) Effects of feeding white Leghorn hens diets that contain deoxynivalenol (vomitoxin-)contaminated wheat. Poultry Sci. 64:1840-1852.
Hamilton, R.M.G., Thompson B.K. and Trenholm H.L.. (1981a) The effect of vomitoxin contaminated wheat on the palatability of laying diets by white Leghorn hens. Poultry Sci. 60: 1665-1666. (Abstr.)
Hamilton, R.M.G., Thompson B.K. and Trenholm H.L.. (1981b) Feed intake, egg production and shell quality
of hens given diets that contained vomitoxin contaminated wheat Poultry Sci. 60:1666. (Abstr.)
Marks, H.L. and Bacon, C.W. (1976) Influence of Fusarium infected corn and F-2 on laying hens. Poult. Sci. 55:1864-1870.
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