Temperature, humidity and ammonia are important environmental parameters modulating the gut microbiome of broilers under “Raised Without Antibiotics” production

Authors: JOHNSON, JASMINE - University Of Georgia; ZWIRZITZ, BENJAMIN - University Of Veterinary Medicine; Oladeinde, Adelumola - Ade; MILFORT, MARIE - University Of Georgia; FULLER, ALBERTA - University Of Georgia; Looft, Torey; BOSCH, ANNA MARIE - University Of Georgia; ZOCK, GREGORY - University Of Georgia; SOMMERS, MARLO - University Of Georgia; TU, SUPANON - Khon Kaen University; Plumblee Lawrence, Jodie; Cudnik, Denice; AGGREY, SAMUEL - University Of Georgia

Submitted to: World Poultry Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/29/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The chicken gut microbiome consists of all microorganisms including bacteria, viruses, protozoa, and fungi present in the gastrointestinal tract (GIT). The gut microbiome plays key roles in nutrition absorption, development of immunity, and disease resistance. Gut microbiome may have positive or negative effects on feed efficiency, productivity, and health of chickens. However, we do not know how the poultry house environmental parameters (temperature, ammonia, humidity) modulate the bacterial community residing in the GIT. In this study, we raised six hundred Cobb-500 broiler chicks in floor pens with clean pine shavings in two houses (300 birds/house; 25 per pen) for 49 days under environmental conditions reflecting those of commercial “Raised Without Antibiotics (RWA)” broiler production. We performed 16S rRNA gene sequence surveys on the meconium of day-old chicks, the ceca when the birds were 14, 28, 42 and 49- days old and on weekly litter samples. Furthermore, we tested the effect of an 8-h feed withdrawal period prior to slaughter on the microbiome of 240 birds (120 birds/house). We also monitored the temperature, relative humidity and ammonia levels in the house and the moisture, pH and culturable E. coli in the litter. The bacterial communities in the meconium, ceca and litter were significantly different from each other throughout the study (p < 0.05), and the ceca had the highest alpha diversity. The top genera in the meconium was Enterococcus and from the ceca was Bacteriodes. For the litter, the top genera changed from day 7 to day 49. The bacterial community in the ceca and litter were significantly different between houses (house 1 and 2) from day 28 – day 49 (p < 0.02). Temperature and morning (7 – 10 am) relative humidity had a significant correlation on the ß-diversity of the ceca. In addition to house temperature, relative humidity and ammonia, the pH and moisture of the litter were the important parameters correlating with the ß-diversity of the litter. An 8-h feed withdrawal before slaughter had no significant correlation (p> 0.05) with the bacterial community of the ceca. Together, our results indicate that the environmental conditions in the farmhouse significantly correlated with the gut microbiome of broiler chickens. Broilers in house 1 had significantly different ceca/litter microbiome and higher live weights than broilers in house 2 upon harvest.