| dc.description.abstract | Commercial hatcheries are a key part of the poultry industry, and the quality of stock produced is influential to the chick’s life throughout production. Previous studies with broiler hatching eggs have determined that despite the sanitation and vaccination plans currently in place at the commercial level, chicks are leaving the hatchery with a high intestinal tract microbial load. The proper handling and sanitation of eggs at breeder facilities and throughout the duration of the hatching process is critical in lessening the exposure risk of pathogenic bacteria that can penetrate viable eggs and replicate internally. The objectives of this research were to examine the impact of hatchery sanitation methods, such as formaldehyde application, in addition to the use of in ovo injection for vaccine administration on intestinal tract microflora of late incubation embryos and neonatal chicks. Additionally, a study on the membrane microbial distribution of late-stage hatching eggs was performed to evaluate the relationship of internal and external pipping, and the relationship to intestinal tract microbiota.
Microbiological evaluations determined that embryos and newly hatched chicks subjected to formaldehyde application resulted in a reduction of the microbial load while formaldehyde was in use, yet when formaldehyde use ceased, the intestinal tract counts began to approach the counts of the no formaldehyde treatment group. Similar to the intestinal tract microbiota results, the air plate enumeration dropped during treatment for the formaldehyde application group, and approached the non-treated group on 21 d after formaldehyde application ceased. Based on the results, formaldehyde application in the hatchers did not significantly impact the colonization of the chick’s intestinal tract in the late stages of broiler hatching egg incubation.
Microbial evaluations were also performed to determine the effects of in ovo injection on chick intestinal tract microbiota from 19 to 21 d of incubation. The results of the experiment concluded that significant differences existed at 20 d of incubation in Trial 1 with the no in ovo injected treatment group on the TSA aerobic (P= < 0.0001) and TSA anaerobic (P=0.0012) plate counts when compared to the in ovo injected treatment group. Similarly, TSA aerobic plate counts were significantly higher (P= 0.0409) in the in ovo injected treated group. The 21 d results differed between trials. On 21 d of incubation, microbial enumeration of TSA aerobic and anaerobic were not significantly affected by the use of in ovo injection. Trial 1 concluded that in ovo injected eggs on 21 d had a greater enumeration value, while in Trial 2 the no in ovo injected eggs had a greater enumeration value. Results of this experiment conclude that in ovo injection is not a primary source of hatchery contamination due to the elevated microbial counts present in the non-in ovo injection groups for both trials.
A third study performed to evaluate the presence of microorganisms in the eggshell membranes of hatching eggs. Eggshell membranes were extracted from White Leghorn fertile eggs collected from nest and floor locations. Enumeration of the microorganisms in the membranes concluded that there were no differences between the eggs from the nest and floor. Eggshell membranes at day of lay were contaminated with both aerobic and anaerobic bacteria, and fungi regardless of the location the eggs originated. A comparison of eggshell membrane microbial counts and gastrointestinal microbiota was performed in late-stage Ross 708 broiler hatching eggs. The objective was to determine if there was a link between contaminated membranes and the pipping process. Results concluded that the same bacteria were found in the membrane and intestinal tract on most samples; however, additional research is warranted. | |
