THE ENUMERATION AND MITIGATION OF MICROBIAL LOADS ON HATCHING EGGS, EMBRYOS AND NEWLY HATCHED CHICKS

Abstract

Commercial hatcheries are an integral part of poultry production, and the quality of hatchlings produced at the hatchery can have important impacts throughout the rest of the production chain. Microbial contamination of hatching eggs is known to have negative economic effects due to hatchability loss, chick quality decline, and transmission of pathogens to the grow-out farm. Reducing microbial load on eggs prior to incubation has been shown to be an effective strategy to reduce egg and newly hatched chick contamination. Therefore, one objective of this research was to assess the naturally occurring microbial loads on hatching eggs, developing embryos, rotten eggs, and newly hatched chicks. Secondly, research was conducted to determine if egg sanitization prior to incubation could mitigate the microbial loads on chicken hatching eggs and in the intestinal tract and yolk sacs of newly hatched chicks. Evaluation of naturally occurring microbial loads on hatching eggs indicated that Clostridium spp. were detected on eggs and developing embryos throughout incubation. Furthermore, rotten egg microbial loads were observed at high concentrations for aerobic and anaerobic bacteria. The sampling of the intestinal tract of newly hatched chicks obtained from commercial hatcheries indicated high intestinal microbial loads, whereas chicks that were incubated in a laboratory setting had significantly lower intestinal counts. However, yolk sac microbial loads were similar between commercial and laboratory incubated chicks. Egg sanitization experiments demonstrated that both formaldehyde fumigation and the H2O2/UV advanced oxidative process (AOP) method were effective for reducing eggshell surface and intestinal microbial loads without negative effects to hatchability, chick quality, and chick livability after a 7 d grow-out. While egg sanitization prior to incubation can be an effective tool to reduce microbial loads on eggs entering the hatchery environment, additional research is warranted to investigate methods to further mitigate the microbial contamination of chicks produced under commercial conditions.