Submitted to: Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/4/2006
Publication Date: 12/18/2006
Citation: Hume, M.E., Clemente-Hernandez, S., Oviedo-Rondon, E. 2006. Effects of feed additives and mixed Eimeria species infection on intestinal microbial ecology of broilers. Poultry Science. 85:2106-2111. Interpretive Summary: The evaluation of changes in the kinds of intestinal bacteria found in poultry is necessary to understand the effects of chemicals that are added to feed to fight disease and/or increase growth. These studies determined changes in the kinds of bacteria populations in the intestine of broiler chickens fed diets containing antibiotics and two oil blends A and B and subsequently infected at 19 days of age with a common poultry intestinal parasite (Eimeria). Infection with the poultry parasite caused drastic shifts in the kinds of bacteria seen in each portion of the intestine examined. Parasite infection in broilers treated with the essential oils resulted in comparatively smaller changes in the kinds of bacteria present than those seen in the untreated infected broilers. We concluded that infection with the parasite caused drastic shifts in the kinds of digestive bacteria in chickens. Additionally, treatment with the essential oils lessened the drastic shift in bacteria caused by the parasite. This research has interest for poultry digestive bacteria researchers, producers, and anti-coccidia manufacturers and suppliers.
Technical Abstract: These studies examined the effects of combinations of antibiotic, ionophore, and essential oil treatment and Eimeria infection on the dynamics of intestinal microbial communities (MC) in broilers chickens. Five treatments were analyzed: 1. Unmedicated-Uninfected (UU) control; 2. Unmedicated-Infected (UI) control; 3. feed additives BMD®+Coban® 60 (AI); 4. essential oil (EO) blend Crina® POULTRY (CP); and 5. EO blend Crina® ALTERNATE (CA). The EO blends were added at 100 ppm to the same basal diets. Chicks were gavage-infected at 19 d of age with E. acervulina, E. maxima, and E. tenella. Duodenal (D), ileal (I), and cecal (C) samples were taken from 12 birds per treatment just before and 7 d after challenge, pooled in 6 samples, and frozen. Denaturing gradient gel electrophoresis was used to examine PCR-amplified fragments of the bacterial 16S ribosomal DNA variable region. Results are presented as percent similarity coefficients (SC). Dendrograms of amplicon patterns indicated MC differences due to intestinal location, feed additives, and cocci challenge. EO blends CP and CA did affect MC in all gut sections. Each EO had different effects over MC and they differed in most instances from the AI group. The cocci-challenge caused drastic MC population shifts in D, I, and C sections (36.7., 55.4., and 36.2% SC, respectively). Diets supplemented with CP supported higher SC between pre- and post-challenge MC (89.9, 83.3, and 76.4%) than AI (81.8., 57.4 and 60.0%). We concluded that mixed coccidia challenge causes drastic shifts in MC. These EO blends modulate MC better than AI avoiding drastic shifts after a mixed challenge. Correlations between MC dynamics and host responses are discussed.