Essentially, modern layer industry tends to improve on the production level by employing appropriate genetic crossbreeding, adequate rearing conditions and good nutrition. One of the major challenges faced by poultry industry in the developing world including Nigeria is the issue of improving efficiency of production. In an attempt to address this very issue, series of efforts have been made by researchers. These involved the incorporation of antimicrobials and other natural products, such as yeasts to animal feeds (Muihead, S.2005.). Live yeast addition to animal feed has been known to improve the nutritive quality of feed and performance of animals [Glade, M.J.,Martin, S.A.2001]. Non-antibiotic growth promoters, such as organic acids and probiotics are already well established in animal nutrition (Windisch, W.2008).
Introduction Probiotics are bacteria, fungi or yeasts that have favourable effects on hosts by improving the characteristics of intestinal microflora (Fuller, 1989). Probiotics can be classified into colonizing species (Lactobacillus sp., Enterococcus sp. and Streptococcus sp.) and free, non-colonizing species (Bacillus and Saccharomyces cerevisiae). Probiotics display several ways of action: antagonistic action towards pathogenic bacteria by secretion of products that inhibit their development, such as bacteriocins, organic acids and hydrogen peroxide; or competition for locations to adhere to the intestinal mucous membranes; or competition for nutrients (Patterson and Brukholder, 2003). They reduce the risk of disease (Line et al., 1998; Mountzouris et al., 2007), improve the function of the immune system (Zulkifliet al., 2000; Hossain et al., 2005) and influence morphology and function of intestines (Uscebrkaet al., 2005; Yang et al., 2009). In mice, probiotics, especially Streptococcus thermophilus, increase body weight by enhancing digestion and absorption, and inhibit the synthesis of cholesterol, so that cholesterol levels drop and prevent atherosclerosis and coronary heart disease (Sanders, 2000).
Probiotics can be included in pellets, capsules, paste, powder, curd or granules, which can be given to animals directly or through food. Nearly all probiotics currently on the market contain lactobacilli and/or streptococci, few contain bifid bacteria.
1.1 AIMS AND OBJECTIVES
The aim of this project work is to investigate the effect of direct fed on heamathology and serum biochemistryof layer chicks.
- To examine the effect of yeast on the serum of layer chick.( low density lipoprotein, cholesterol, high density lipoprotein and total protein)
- To evaluate the probiotic effect on their heamathology( heamoglobin, red blood cell, white blood cell, lymphocytes, platelet, and the mean cell volume