Negating Anti-nutritional Factors in Poultry Production

27 March 2019

Feed cost is the single largest component in production cost of meat and eggs, accounting for nearly 60-70% of the total costs. At the current raw material situation in India, feed cost has reached the upper range, if not more. Though it would appear a relatively simple task to maintain the quality of feed and its safety, it can be one of the most difficult tasks related to livestock feeding and feed production. Even a minor loss in quality could result in major business setbacks for both poultry growers and feed manufacturers.

The importance of feed safety to ensure food safety, and in turn the health of humans, has been the subject of greater discussion all over the world. In addition to protecting human health, feed safety plays a vital role in maximizing the efficiency of poultry production. This article emphasizes more on the latter aspect.

Anti-nutritional Factors (ANFs)

There are several substances and/or pathogens present in the raw materials (intrinsic or extrinsic), which by themselves or their metabolic products arising in the system compromise feed safety by interfering with nutrient utilization and reduce feed efficiency, and overall animal performance (Table 1). Such agents are called as anti-nutritional factors (ANFs).

Table 1. The list of major anti-nutritional factors in raw materials and feeds

Intrinsic anti-nutritional factors

Extrinsic anti-nutritional factors


Bacterial contamination

Protease inhibitors

Mold contamination


Mycotoxin contamination


Endotoxin contamination

Non-starch polysaccharides

Pesticide contamination

Phytic acid

Insecticide contamination


Dioxin contamination

The natural intrinsic factors, commonly present in higher concentrations in alternate protein meals and cereals, present a variety of toxic effects on nutrient utilization and feed efficiency, besides adversely affecting overall animal performance, when such raw materials are used beyond a level in feed. The most Intrinsic anti-nutrients, however, can be managed by heat treatments and hence less challenging to the modern poultry industry.

The same can’t be said, unfortunately, for extrinsic factors as majority of them are heat-resistant or need impractical and high temperature to destroy them. The most sensitive extrinsic factor for heat treatment is bacteria and hence proper pelleting can reduce the chances of bacterial-contamination of poultry feeds. Molds and yeasts are relatively more tolerant to heat treatment. Most mycotoxins, barring ergot toxins and citrinin, are heat resistant and hence hard to deal with.

Microbial contamination of feed

The contamination of poultry raw materials and feeds with bacteria and molds is very common in the field. Given the high value of producing a hatching egg or a chick, there has been a greater emphasis on the control of bacterial contamination of breeder feed but the same can’t be said for commercial broilers and layers. If a particular bacteria can compromise the performance of breeders, they can certainly affect the performance of broilers and layers and hence equal emphasis should be given. Bacterial contamination of raw materials (more commonly of animal origin) leads to decreased nutritive value, liberation of toxins and heating up of feed, which sometimes ends in automatic combustion.

Molds that infest poultry feeds reduce the feed palatability and nutrient concentration and cause respiratory problems, besides producing mycotoxins, several of which are highly toxic to poultry and livestock. The most common molds found in poultry feeds are Aspergillus, Penicillium and Fusarium. Co-occurrence of mycotoxins in feed, such as aflatoxins, ochratoxins and T-2 toxin, leads to aggravated/cumulative toxicity. Table 2 depicts how various mycotoxins can affect poultry feed efficiency. In addition, chemical toxins/pesticide (more than 900)/fungicide residues are occasionally encountered in feed, which on consumption cause depressed feed efficiency and performance, besides poor egg quality (Table 3).

Table 2. The mode of action of various mycotoxins on poultry feed efficiency

Mycotoxin Group

Mode of Action


Immune suppression, Liver damage, protein synthesis inhibition, poor enzyme functioning


Immune suppression, Liver damage, kidney damage, poor enzyme functioning, intestinal barrier dysfunction

T-2 toxin

Immune suppression, gut damage, increased bacterial translocation, mouth lesions


Immune suppression, intestinal barrier dysfunction


Immune suppression

Table 3. Commonly used pesticides in Indian agriculture






Phenyl mercury acetate (PMA)

Methoxy ethyl mercury chloride (MEMC)

Managing Molds, Bacteria and their Metabolites

Poultry producers should adapt holistic methods to manage molds, bacteria and their metabolites. Some of the key and practical methods are explained briefly below: 

  1. Field Hygiene: The crops while growing can be contaminated with molds and bacteria. Although it is quite difficult to control field contamination, efforts should be made to control such infestation through proper soil cultivation, use of resistant cultivars, and the use of appropriate pesticides and insecticides.
  2. Transportation hygiene: Although clean raw materials are produced in the field, they can get contaminated during transportation from the point of crop production to the feed mill. Longer the distance between these two points higher will be the chances of contamination. Although most of the raw materials used in Indian poultry industry are locally grown, the long distance between the different poultry pockets warrants careful attention to transport hygiene. Trucks should be cleaned regularly with the use of appropriate disinfectants.
  3. Storage hygiene: The poor hygiene contributes to the biggest nutrient loss in Indian feed mills and farms. Most of the raw materials are stored in gunny bags and this makes it impossible to treat the grains to prevent mold and bacterial contamination. Frequent auditing of feed mills and farms is essential to understand the hygiene situation and to take proper actions to prevent the losses. Although the use of silos for raw material storage has increased over the last decade in India, it is critical to maintain proper micro environment within the silo. Aeration, rotation of grains and temperature and moisture monitoring and management within the silos is not always practiced.
  4. Farm hygiene: This is under the supervision of farm veterinarians and proper protocol should be followed for biosecurity, vaccination and litter management. If these are not followed, even the best feed can’t be used effectively by poultry and leads to intestinal disorders and poor feed efficiency.
  5. Feed additive solutions: There has been significant developments over the last three decades on the practical use of feed additives in poultry industry.
    1. Treatment of grains: Many methods were tried in this area, but the most successful to date is the use of organic acids to kill molds and bacteria. This is pretty much a common practice today in poultry industry to use formic and propionic acid-based acidifiers to kill molds and bacteria. Feed millers and integrators have a big challenge of identifying the right products from the plethora of products available in the market.
    2. Feed additives to enhance gut health: Many technologies have been used to achieve good gut health but probiotics and organic acids stand out in terms of having strong research base as well as the field application. Probiotics are more effective in the initial part of life cycle in developing beneficial bacteria in the gut. From there on, organic acids can help in maintaining gut health.
    3. Use of mycotoxin binders: Depending on the type of mycotoxin/s prevalent, the appropriate mycotoxin binder should be selected. Under the Indian conditions, aflatoxins are more prevalent and hence clay binders will do the job. Upon testing feeds for mycotoxins, if other mycotoxins such as ochratoxins and T-2 are present a broad spectrum toxin binder is recommended.

There have been significant developments in genetic improvement in poultry breeds but nutrition is not matching up with their genetic potential. To maximize genetic potential, anti-nutritional factors should be kept at bay. Many physical, chemical and biological methods should be employed to manage anti-nutritional factors. The efforts should be continued to develop quick and simple methods to quantify anti-nutritional factors as well as managing them effectively.

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