EVALUATION OF THE OPTIMUM INCLUSION LEVELS OF MYCOFIX AND BIOTRONIC SEAS FEED ADDITIVES ON THE PERFORMANCE OF BROILER CHICKENS

CHAPTER ONE

1.0 INTRODUCTION

Feed represents the greatest single expenditure associated with poultry production. Nutritional research in poultry has therefore centered on issues related to identifying barriers to effective digestion, utilization of nutrients, and on approaches for improving feed utilization (Ravindran, 2010). The quality of feed ingredients is very important as this will determine the quality of the feed and the end-products.Hence a more precise evaluation of the quality of dietary raw materials is needed (Kersten et al., 2005). Feed materials may be contaminated at any time during growing, harvesting, processing, storage and distribution of the feed. Feeds may contain diverse microflora that are acquired from multiple environmental sources, including dust, soil, water, and insects (Maciorowski et al., 2006).

Mycotoxins are a historical problem in poultry, first recognised in the 1960s as the cause of ‘turkey X disease’ in England which resulted in the death of 100,000 turkey poults and many ducks, chickens and pheasants (Siska, 2013). Mycotoxins are toxins formed during fungi growth, myco means mould and toxin represents poison (Annongu, 2012). Mycotoxins are highly toxic secondary metabolic products of mould on almost all agricultural commodities worldwide. They occur under natural conditions in feed. Several studies proved that economic losses occur at all levels of food and production, including crop and animal production, processing and distribution (Robens and Cardwell, 2003; Wu, 2007; Bryden, 2012). According to the Food and Agriculture Organization (FAO), 25% of the world‟s crop harvests are contaminated with mycotoxins (FAO, 2012). There are currently more than 400 mycotoxins known. There are six major classes of mycotoxins that frequently occur namely, aflatoxins, trichothecenes, fumonisins, zearalenone, ochratoxin and ergot alkaloids (CAST 2003). They are formed by different kinds of fungi and each fungi species can produce more than one type of mycotoxin. Surveys of mycotoxin levels in poultry feeds often reveal the presence of a number of different toxins; most samples in a recent survey contained at least 10 contaminants. Contamination of feeds with mycotoxins is a worldwide problem, in poultry particularly those produced by the genera, Fusarium, Aspergillus and Penicillium (Siska, 2013).