Reduced ribonucleotide reductase RRM2 subunit expression increases DNA damage and mitochondria dysfunction in woody breast chickens.

OBJECTIVE: The aim of this study was to investigate the roles of ribonucleotide reductase subunit M2 (RRM2; subunit of ribonucleotide reductase) in severe woody breast (WB) and normal breast muscles. ANIMALS: 40 8-week-old male Ross-708 broiler chickens. METHODS: Quantitative PCR was performed to determine gene expression, and commercial ELISA/assay kits were used to obtain several enzymatic activities. RESULTS: Results showed that RRM2 activity (P = .0002) and RRM2 (P = .05) and hydroxymethylbilane synthase expression (impaired oxygen transport and metabolism, P = .002) were reduced in WB, while caveolin-3 (defected membrane integrity, P = .09), endoglin (increased fibrosis, P = .06), and secreted protein acidic rich in cysteine (metabolic dysregulation, P = .09) expression tended to increase in WB. WB tended to have increased levels of homocysteine (P = .06), aspartate aminotransferase mitochondria (P = .02), pyruvate kinase (P = .04), DNA damage (P = .06), creatine kinase (P = .05), and triglyceride (P = .002) but decreased ATPase activity (P = .01), all indicating mitochondria dysfunction and tissue damage. CLINICAL RELEVANCE: In this study, differences in various enzyme activities and increased DNA damage suggest that RRM2-mediated mitochondrial abnormalities may play a role in WB myopathy.

Research Note: Bacterial composition of settled dust during growout of broiler chickens.

Dust present in poultry houses can disseminate bacteria in air and deposit them on surfaces. This study evaluated bacteria in settled dust during growout of broilers from 2 flocks (Flocks A and B). Dust samples for bacteria analyses were obtained during 6 wk of growout (Flocks A and B) and 1 wk after flock termination (Flock B) by environmental swabbing and collecting dust in petri dishes from multiple locations inside the poultry house. For weekly swabbing, dust deposited during each wk of the sampling period (noncumulatively, n = 12/wk) and cumulatively (n = 12/wk) throughout the sampling period was collected. Swabbed dust samples were analyzed for counts (log10 CFU/28 cm2) of aerobic bacteria, E. coli, coliforms, and Salmonella recovery. For petri dish dust collection, dust was collected in weekly and bi-weekly time spans during the sampling period and then analyzed for Salmonella recovery. Data were analyzed by one-way ANOVA and Fisher's Exact Test and means were separated using LSD. Only aerobic plate counts changed over time in dust during growout (Flocks A and B; P < 0.0001). In noncumulatively settled dust, aerobic bacteria (Flocks A and B; P < 0.0001), E. coli (Flock A; P = 0.0432), and coliforms (Flock B; P = 0.0303) varied during growout with peak counts on wk 5 or wk 6, wk 4, and wk 4, respectively, after bird placement. Salmonella recovery did not vary in cumulatively (3/72, 10/84) and noncumulatively (0/12, 10/84) settled dust during growout in both flocks. In dust sampled by bi-weekly collection in petri dishes, Salmonella recovery was highest (5/6) between wk 2 to wk 4 for Flock B (P = 0.0118). Overall, this study displayed that settled dust bacteria levels can fluctuate during broiler growout, and dust can contain Salmonella.

Impact of poultry litter Salmonella levels and moisture on transfer of Salmonella through associated in vitro generated dust.

Dust present in poultry houses can contain high concentrations of microorganisms and has the potential to include pathogens from the litter. The objective of this study was to examine in vitro the potential for litter to dust transfer of aerobic bacteria, Salmonella, E. coli, and coliforms, and the role of the litter moisture on this process. Poultry litter was inoculated with 102 to 109 CFU/mL of Salmonella Typhimurium to evaluate litter to dust transfer of bacteria (Experiment 1). To evaluate the effect of litter moisture on litter to dust microbial transfer (Experiment 2), litter was inoculated with 109S. Typhimurium with increasing amounts of sterilized water added for moisture adjustment. Dust was generated by blowing air in a direct stream onto inoculated litter while simultaneously collecting dust through impingement. Following litter and dust sample collection, microbial analyses for aerobic plate counts (APC),Salmonella, E. coli, and coliforms were conducted. Both experiments were repeated 5 times and their data analyzed by one-way ANOVA and simple logistic regression. In Experiment 1, APC of litter (log10 CFU/g) and dust samples (log10 CFU/L) were 10.55 and 4.92, respectively. Salmonella ranged from 1.70 to 6.16 log10 CFU/g in litter and only one dust sample had 1.10 log10 CFU/L of Salmonella. As Salmonella levels in litter increased, the probability of obtaining a dust Salmonella positive result also increased. In Experiment 2, attained moisture percentages were 13.0, 18.2, 23.0, 28.2, and 33.3%. Litter recovery for APC, Salmonella, E. coli, and coliforms counts did not differ (P > 0.05) with increasing moisture levels. Dust sample bacterial counts significantly decreased with increasing moisture levels (P < 0.0001). Results from this in vitro study indicate that there is potential for Salmonella to be present in generated dust and the higher levels of Salmonella in litter increase the likelihood of detecting Salmonella in dust. Additionally, with higher litter moisture percentage, prevalence of Salmonella in generated dust was decreased.