Introduction
Mycotoxins are secondary metabolites of low molecular weight produced by a wide range of fungi, principally molds. There are over 200 species of molds that produce mycotoxins. Aflatoxins (AF), zearalenone (ZEN), ochratoxin A (OTA), fumonisin (FUM), trichothecenes such as deoxynivalenol (DON) & T-2 toxin are some of the mycotoxins that can significantly impact the health and productivity of poultry species. These toxins are found as natural contaminants in many feed ingredients of plant origin like cereals, seeds, fodder etc; hence mycotoxins seem to be the most relevant with respect to feed contamination and have a significant economic impact on the livestock industry.
Many published scientific studies and surveys regarding mycotoxin contamination for India are usually limited to a single ingredient, very small time period or have a small sample size for the study. In order to have a better understanding mycotoxin prevalence in animal feed ingredients in India, the present study was done for 10 months in which a total of around 540 raw ingredients samples across India were collected and analysed for Aflatoxin (AFLA), Fumonisin (FUM), Ochratoxin (OTA) and T-2 Trichothecene (T2).
In India, the commonly used ingredients for feed formulation in poultry diets are Corn, Corn Gluten Meal, Soya Bean Meal, Rice Polish, Mustard De Oiled Cake (Mustard DOC) and Dried Distillers Grains (DDGS); hence these were considered for the present study.
Analytical samples
A total of 540 samples, including 126 corn samples, 69 corn Gluten Meal, 57 DDGS, 72 Mustard DOC, 70 Rice Polish, 95 SBM and 51 other samples like fish meal, MBM, groundnut cake, Deoiled Rice bran (DORB) were sourced directly from animal farms and feed production sites from different regions. The origin of these samples was diverse, covering all the regions across India.
Ideal sampling methods were adopted during the sample collection. All the samples that were received for the study were grounded and homogenized. A subsample was then taken for the subsequent analytical process.
A choice was made to screen the mycotoxins which included Aflatoxin, Fumonisin, Ochratoxin, and T2, or analyze to the only Aflatoxin in selected samples.
Mycotoxin analysis
ELISA analysis was performed with a commercially available test kit (Vertex® brand of diagnostics from Neogen®). These kits are often viewed as the gold standard by the food industry for mycotoxin testing approved by GIPSA and AOAC. By running multiple controls and establishing a standard curve through a reader, samples can be plotted against the curve to determine the concentration of analyte present.
The overview of the survey results are as follows:
- Prevalence of major mycotoxins
Mycotoxin survey was conducted for the different feed ingredients collected from all over India. The followed guidelines of 2006/576/EC, EFSA and US FDA were followed for citing the maximum tolerance limit of various mycotoxins in Poultry.
Three levels of contamination have been defined for each mycotoxin.
- Non-contaminated Ingredients: Level of mycotoxins were found to be below LOD (limit of detection). These ingredients were considered as normal samples.
- Contaminated ingredients: Level of mycotoxins were more than LOD but less than maximum tolerance limit (above risk level). These ingredients were considered as positive samples.
- Above Risk Level: Level of mycotoxins were found to be more than tolerance limits & can impose a serious threat on consumption.
Various studies have established that ingredients having below LOD mycotoxin can also exert the negative impact on animal performance due to synergistic & additive effects of multiple mycotoxins.
A total of 540 raw ingredient sample were analyzed for the survey. The percentage of contaminated samples and risk levels for each mycotoxin is represented in Figure 1.
Aflatoxin & T2 were most prevalently found mycotoxin in ingredients with 42% and 40% above risk (tolerance) level respectively. 21% of the ingredients were found to be normal and 38% of the samples were contaminated with aflatoxin. Only 16% of ingredients were without T2 contamination and 57% were contaminated with T2. Ochratoxin contamination was found in 75% of samples and with 8% sample above the risk level. The fumonisin contamination was the least in 17% of samples and with 10% samples above the risk levels.
After getting the overall mycotoxin contamination pattern, we analyzed the levels of mycotoxins in each feed ingredient. The resulting patterns are depicted from Figures 2 to 7 showing normal samples, contamination samples and above tolerance level for each mycotoxin.
Aflatoxin contamination was found to be higher for corn and 52% samples were above risk level that was very critical as corn is predominantly used in animal feed. Ochratoxin, followed by fumonisin is having comparatively less contamination. (Figure 2)
Corn Gluten Meal samples were found infested with all types of mycotoxins studied. T2 & aflatoxin were found to be predominantly followed by fumonisin&Ochra. High contamination could be due to improper processing and poor storage. (Figure 3)
In general, DDGS samples were found to be the most contaminated with mycotoxins. 98% samples were above risk level for aflatoxin & T2, in which not a single sample was without contamination. Even 71% DDGS samples were contaminated with ochratoxin having 27% above the risk level (Figure 4).
In Mustard DOC, T2 mycotoxin contamination intensity was highest, 59 % samples were above risk level for T2. (Figure 5). Mustard DOC is a comparatively clean ingredient in term of aflatoxin, Ochratoxin &fumonisin contamination.
Rice Bran samples were contaminated with 60%, 76% and 84% with aflatoxin, ochratoxin & T2 respectively having 27%, 9% and 16% above the risk level . (Figure 6)
SBM is always a good source of protein and widely used in poultry feed. Our study reveals that 28% samples were above the risk level for T2. SBM is a comparatively clean ingredient in term of mycotoxin infestation. (Figure 7)
After having trend analysis of mycotoxin prevalence of each selected ingredient it was concluded that aflatoxin remains a major concern for all ingredients and can impose serious health issue. CGM & DDGS were infested considerably high with aflatoxin and T2 mycotoxins. SBM & MDOC is a comparatively clean ingredient in term of aflatoxin infestation. Level of Fumonisin is comparatively lower than other mycotoxins in all selected ingredients.
- Presence of multiple mycotoxins in feed ingredients
Multi mycotoxin contamination is an area of concern since it increases the adverse impact of toxins because of their synergistic effect. 95% of analyzed samples were found co-contaminated with mycotoxins and only 5% of samples were normal samples having a level of mycotoxin less than LOD. 17.22 % were contaminated with a single mycotoxin, 30% had a presence of two mycotoxins, 35% were contaminated with three mycotoxins and 13% of samples tested positive for all the tested mycotoxins as shown in Figure 8.
- Regionwise mycotoxin infestation:
Feed Ingredients were received from the variable regions of India for mycotoxin analysis to get a pattern of mycotoxin prevalence.
The results of the analysis are displayed in Figure 9-12:
Samples received from the eastern region of India comprising of the states Bihar, Jharkhand, Orissa, West Bengal reflected a high contamination (above risk level) with T2 followed by aflatoxin. All DDGS & CGM samples were above the risk level for T2 & Aflatoxin.(Figure 9)
The results of the samples received from the northern region of India, which comprises of Punjab, Haryana, Uttar Pradesh, Uttarakhand, Himachal Pradeshstates indicatedcontamination by T2 and Aflatoxin. Here also, all DDGS and CGM samples were above the risk level for aflatoxin and T2. SBM wasa comparatively clean ingredient. (Figure 10)
In South Region, which comprises of Andhra Pradesh, Karnataka, Kerala, Tamil Nadu & Telangana states, T2 was a major cause of concern for CGM, DDGS & MDOC in southern India as well. Rice polish and SBM were comparatively clean ingredients. (Figure 11)
In West Region, which comprises of Goa, Gujrat, Maharashtra, Chhattisgarh, Rajasthan, Madhya Pradesh; DDGS was highly infested with aflatoxin and T2 (Figure 12).
Conclusions
This report of the survey showed the prevalence of mycotoxins in common feed ingredients used in the livestock production industry in India. In the feed ingredients samples tested, the levels of mycotoxin were higher than the risk levels guidance values. Among all feed ingredients, the level of aflatoxin contamination was high. The feed ingredient corn gluten meal had a high infestation of mycotoxins. More than 96% of the feed ingredients were co-contaminated with mycotoxins.
Region wise mycotoxin survey of the feed ingredients from all the Northern, Southern, Western and Eastern regions of India had shown a presence of multiple infestations of mycotoxins.
Analysis of the mycotoxin risk is critical for providing recommendation and advice on the quality control of the various raw material and ingredients. A special focus needs to be given to prevent the adverse impact of mycotoxins on animal health and performance. The mycotoxin survey conducted by Provimi (India) is going to be an important tool to approach the mycotoxin risk management for the poultry producers in India.
References are available upon request.
