EFFECT OF SEASON ON AFLATOXINS LOAD OF SELECTED FEEDSTUFFS FOR PIGS IN THE HUMID TROPICS
1.1 Background of the Study
The consumption of animal protein is very essential for meeting the protein requirement of man for normal growth and healthy development. The protein sources from animal origin are good sources of lysine and sulphur amino acids, which are lower in protein sources from plant origin (Omole, 1991). The shortage of protein, particularly animal protein is prevalent in most parts of Africa where it is estimated that on the average 10 grams of animal protein is consumed per day compared to the recommended daily intake of 35 grams (ILCA,1980; FAO, 1986). The level of animal protein consumption was estimated at 8 grams per caput per day, this is about 20 grams less than the
National Research Council of United States of America’s recommendation (Obioha, 1992; FAO, 1997). Ogini (2001) stated that Nigeria, despite its vast land area of 9,237,680km2 , the greater percentage of her citizens of over 120 million are still battling with abject poverty and hunger. Atsu (2002) reported that there is inadequate intake of animal protein in Nigeria.
The high cost of feeds and feed ingredients, especially the conventional energy and protein feed sources such as maize, wheat, sorghum, soybean cake, groundnut cake and fish meal were as a result of the stiff competition between human consumers for food, for livestock feeds/feeding and industrial raw materials e.g. cereal grains for baby food formulas and biofuel production, especially maize (Agbede et al., 2002; Adegbola and Asaolu, 2008). Maize is a major source of energy in monogastric feeds, especially pigs, poultry and rabbits. In Nigeria, cereal grains are in high demand and its production has never been adequate to meet the needs of the increasing population; consequently there is little or no excess grains for livestock feeding. When available, it is always very expensive
(Rhule,1999). The cost of conventional feedstuffs which are major sources of energy and protein in monogastrics diets has continued to increase (Onu and Madubuike, 2006; Defang et al., 2008) due to their short supply. In 2005 the price of maize rose from about N30 to N70 per kilogram (Rhule,1999). As the competition between man, farm animals and industrial uses for grains continues to increase, substitutes for grains are being increasingly used in poultry and livestock feeding to reduce the high cost of feed (Babatunde and Hamzat, 2005). This continuous increase in the cost of conventional feed ingredients used in formulating poultry and livestock feeds has necessitated an intensive search for cheap alternative feed ingredients that will be able to replace a given portion, if not all of the conventional feed ingredients (Babatunde, 1985; Onyimonyi, 2002; Adesehinwa et al., 2011).
According to Ugwu et al. (2008), the main factors militating against the rapid expansion of animal production industry in Nigeria is the problem of inadequate supplies of feedstuffs at economic prices. The scarcity and high cost of conventional feedstuffs is largely responsible for the present high price of finished animal products such as eggs, meat and milk (Rhule,1999; Adesehinwa et al., 2011). Ijaiya et al. (2004) pointed out that feed cost is perhaps the most expensive input in intensively reared stocks and constitutes about 70 – 80% of the real cost of animal production. Onyimonyi and Onukwufor (2003) had earlier reported that a major solution to the problem of rising costs, scarcity of energy and protein sources for monogastrics is to seek for new and non-conventional feed resources which are able to replace a certain percentage proportion of the known conventional feedstuffs without any deleterious effect on the animal performance. Esonu et al. (2001) indicated that such substitute which have been successfully used to replace the conventional feedstuffs are brewer spent grains, stem/tuber residues and cereal by-products such as wheat offal, rice bran, maize bran as well as bambara nut waste and cassava or yam peels.
Fetuga et al. (1977), Iyayi et al. (2005) and Onyimonyi and Ugwu (2007) had studied the feeding value of such non-conventional feed resources as palm kernel cake, bambara nut offal, rice husk and cassava peels, and that they can be utilized in supplementing a given portion of the conventional feedstuffs. Onyimonyi and Ugwu (2007) further noted that these non-conventional feeding stuffs are commonly found in the South Eastern Nigeria. According to Babatunde and Hamzat (2005), these alternative feedstuffs have proved valuable in supporting the performance of livestocks and poultry and that by utilizing them in ration formulation, it will go a long way in reducing the demand and cost of conventional feedstuffs, which greatly increases the total cost of pork production. Adegbola and Oduozo (1992) reported that some of the limiting factors associated with agro-industrial byproducts and crop residues utilization as animal feeds include: procurement, storage, poor feed intake, high fibre content, toxic and anti-nutrients substances as well as being low in their digestibility which subsequently lowers the animal performance.
According to Serres (1992) pigs are known to be highly prolific and very efficient in converting feed nutrients into high quality animal protein. Adesehinwa (2008) stated that pigs are used to convert a variety of feeds into meat for human consumption. The supply of animal protein by pigs is limited by many factors among which are inadequate nutrition and feeding; poor breeding stocks, poor management practices and housing; disease prevention and control in pig production (Holness,1999).
Pitt and Miscamble (1995) defined mycotoxins as toxic secondary metabolites produced by microorganisms of the fungus kingdom commonly known as moulds. Awan (2001) reported the ability of moulds to produce toxins potentially dangerous to man and animals are common and widespread. Odoemela and Osu, (2008) reported that toxigenic moulds have been found during growth, harvest and storage of different foods and feeds and other agricultural produce. Abarca et al.(2001) stated that there are five major agriculturally important fungal toxins of economic importance namely; aflatoxins, deoxynivalenol, ochratoxin, zearalenone and fumunism, which are produced by fungi invasion of agricultural produces and feed ingredients under favourable conditions of temperature.