Using a direct-fed microbial in broiler breeders to reduce broiler progeny lameness
Owen, Ashley Laine
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Bacterial chondronecrosis with osteomyelitis is a substantial problem in the poultry industry today. Many studies have been undertaken to determine the cause of BCO and how to reduce it in broiler chickens. Some studies have suggested the original bacterial contamination that causes BCO comes from the broiler breeder flock and unsanitary hatcheries. Figuring out a way to reduce this bacterial contamination is crucial in the fight to reduce BCO in broilers. This thesis focuses on the feeding of probiotics in broiler breeders to reduce bacterial contamination on the egg shell, therefore passing less harmful bacteria to the offspring. Four treatment groups were used. Chicks from control fed hens were assigned to a control diet (CT-CT) or a Bacillus subtilis (BSS) diet (CT-BSS). While chicks from probiotic fed hens were assigned to a control diet (BSS-CT) or a BSS diet (BSS-BSS). During the study, at 28 days, a wire-floor ramp was placed in all pens in between feed and water to force broilers to traverse in order to eat and drink. This ramp system has been used in previous studies to induce BCO in order to study its pathogenesis. During the course of the study, any visually lame and dead broilers were removed, leg lesions scored and bacteria swabs taken. At the end of the study, 56 days, 30 remaining healthy broilers from every pen were evaluated to determine if BCO lesions were present and the severity of lesions. Broilers from BSS-CT treatment group had significantly lower FCR and higher average body weight gain. Broilers from the same treatment also had significantly lower BCO lesion incidence and the severity of these lesions were also significantly lower than that of the control treatment. This data suggests that feeding broiler breeders a probiotic will have a positive effect in reducing bacterial contamination of broiler egg shells, therefore reducing broiler progeny lameness.