Improved performance of broilers by structural manipulation of feed: Evidence from gizzard development, nutrient digestibility, gut microflora and gene expression

Abstract

The legislation to ban the use of in-feed antibiotics in the poultry industry in European Union and voluntarily removal of antibiotics in animal feed have led to the emergence of wet litter problems, imbalanced gut microflora and reduced nutrient digestibility due to enteric disorders such as necrotic enteritis. Thus, the performance, health and welfare of broilers are affected and the profitability in the industry compromised. There has been a concerted effort to find alternative strategies to modulate gut microflora, augment the immune response and reduce pathogens through management and nutritional intervention, such as the inclusion of fibre and large particle size in diet, in an attempt to improve health and digestive efficiency of broilers. The current thesis examined a variety of strategies to minimise and tackle the issues that raised after the ban of in-feed antibiotics in the poultry industry. Chapter 1 presents the summary of literature related to fiber and ingredient particle size and their potential roles in poultry nutrition and management. Chapter 2 examined the effect of pelleted wheat straw as a bedding material on broiler performance, gut microflora and welfare in contrast to other litter sources commonly used in the broiler industry. The feed conversion ratio (FCR) of birds reared on pelleted straw was improved compared (P<0.05) to that of birds raised on rice hulls. However, it was observed that the birds reared on wood shavings had higher relative gizzard weight at d 24 compared to those reared on pelleted straw (P<0.05). Further, birds reared on pelleted wheat straw had a lower incidence of foot pad lesions than those on chopped straw and shredded paper on d 24 (P<0.001) and 29 (P<0.01). The study demonstrated the potential benefits to using pelleted wheat straw as a bedding material.