Poultry industry in Pakistan is one of the largest agro-based segment that contributing 1.3% in national GDP.There are different factors which contribute in economic losses of poultry industry.
One of them is contamination of poultry feed by mycotoxins which is increasing day by day. Five different species of Aspergillus including Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus, Aspergillus nominus and Aspergillus parasiticus produce different types of toxins. Among these, aflatoxins(AF) are most documented of all mycotoxins.
They were initially identified in England in 1960s and at that time disease due to these toxins was known as turkey X disease because 100,000 turkeys died in England. There are four types of aflatoxins (AFB1, AFB2, AFG1 and AFG2). Among these AFB1 is the most toxic and is aslisted number one carcinogen by World Health Organization (WHO).
Factors responsible for the production of aflatoxins:
25% of world’s cereals production is contaminated with mycotoxins especially with aflatoxins.There are many factors that influence the production of aflatoxins including feed type,storage condition, moisture content in feed and region where feed present.
In poultry feed maize, peanutmeal, soybean meal and other crops are present. Maize and peanut meal are preferred substrate for fungal growth in comparison to others. Due to peanut oil, Aflatoxins, more in broiler feed than layer because in broiler feed peanut meal is more in amount as it is a cheapest source of protein.
Aflatoxins present more in stored feed than in fresh. One key determinant of aflatoxins is moisture content. If moisture contents > 15% chances of aflatoxins contamination are more. Higher temperature is favorable for the production of aflatoxins.
It is noted that aflatoxins are more in tropical region due to suitability of environment like high temperature, relatively high humidity and higher moisture contents.
Pathological effects in poultry:
Fish and poultry are extremely sensitive to AFB1 to dose as low as 15-30ug/kg. Impact on health depends upon amount of toxin ingested and exposure time. The pathological effect of aflatoxins on poultry is mainly related to growth rate. The absolute body weight and weight of liver, bursa and spleen also decrease. The growth rate of chicken decreases due to poor FCR ratio.
Additionally, anorexia, listlessness, decrease in egg production and increase in mortality also observed. Anemia, decrease in immune response, hepatotoxic, mutagenic, carcinogenic and teratogenic effect also related to aflatoxicosis. The target organs for aflatoxicosins are liver, kidney and immune organs. Macroscopically the liver is enlarged in size and pale in color.
Hydropic degeneration, fatty changes, bile duct hyperplasia, portal fibrosis can be seen on microscopic examination. In kidney degeneration of proximal tubules, atrophic glomeruli, cortical fibrosis is obvious. Lymphocytes density decreases in white pulp in splenic tissues and there is reduction in follicular cells of bursa of fabricious.
Preventive measures:
We must take step to reduce the contamination of aflatoxins in feed as animal and human share food chain at different level so it may ultimately harm humans.
Firstly,we have to identify the level of toxin in feed and try to improve the management of feed storage condition by giving optimum temperature, moisture and humidity level.
The best approach to reduce the effect of toxin is the use of toxin-binder in feed. The toxin-binder bind the toxin in feed and reduce absorption of toxin from GIT. Use the toxin-binder that are inert and non toxic and not have any toxicological and pharmacological effect.
Several studies have been done on different feed additives like sodium bentonite, zeolite, aluminosilicate, natural bentonite, yeast and yeast component that allows the removal of aflatoxins without causing losses in nutritive value.
The most widely studied remedial technique against aflatoxins in food is biological control. A number of bacteria, yeast and mold have reported to have potential to degrade aflatoxins.
Authors: Sania Saeed *1, M. Tariq Javed1, Aisha Khatoon 1, Ashiq Ali1, Anum Saeed2,ShunaziaSaquib1, Farwa Rabab 1.
1 Department of Pathology, Faculty of Veterinary Science, University of Agriculture Faisalabad, Pakistan,2 Govt. College University Faisalabad.
* Corresponding Author Email: sania.saeed122@gmail.com