DEVELOPMENT OF DEFINED CULTURES OF INDIGENOUS CECAL BACTERIA TO CONTROL SALMONELLOSIS IN BROILER CHICKS

An in vitro continuous-flow (CF) culture system was utilized to isolat e and maintain a defined mixed culture of indigenous cecal bacteria fr om adult broilers. The protective effects of the defined CF culture an d dietary lactose on Salmonella typhimurium colonization were evaluate d in broiler chicks. The CF culture was administered to chicks by crop gavage on the day of hatch. Lactose was provided as 5% (wt/wt) of the feed ration. The chicks were challenged orally with 10(4) S. typhimur ium at 3 days of age and evaluated for Salmonella colonization 7 days after challenge. The experiment was repeated in six separate trials us ing newly hatched chicks and CF culture that was maintained in continu ous steady-state conditions from 42 to 190 days. Compared with control s, the mean number of S. typhimurium in the cecal contents of the chic ks given CF culture and dietary lactose decreased significantly (P < . 01) by 4.2 log10 units. Similarly, the numbers of Salmonella cecal cul ture-positive chicks was significantly decreased (P < .01) by 55% in t he chicks given CF culture and lactose. The results indicated that a d efined culture of indigenous cecal bacteria isolated and maintained in CF culture, together with dietary lactose, effectively controlled S. typhimurium cecal colonization in newly hatched broiler chicks.