Transplantation of ovaries in Japanese quail (Coturnix japonica).

This study aimed to extend techniques of ovarian transplantation from chickens to Japanese quail. Ovarian tissue was surgically transplanted from chicks obtained from a line of white-breasted (wb/wb) to those of wild-type (+/+) quail at 1-day of age or at 1 week, with or without subsequent administration of the immunosuppressant, mycophenolate mofetil. Only one out of seven quail (14.3%) transplanted at 1-day of age survived the surgery but 14 of 18 quail (77.8%) transplanted at a week of age survived and grew to sexual maturity. In the 8-week progeny test, among those quail that produced offspring, one of four in the non-immunosuppressed group and all five in the immuosuppressed group produced donor-derived offspring. The proportion of donor-derived to host-derived offspring from five quail in the immnuosuppressed group (173/57) was significantly higher than that from one quail that was not immunosuppressed (3/47). These results suggest that quail ovaries can be transplanted at the age of 1 week and that the immnunosuppressant, mycophenolate mofetil, used for mammalian organ transplantation can suppress immunological rejection in birds. These transplantation techniques could provide an efficient means of recovering a line of quail after cryopreservation.

Impact of feed supplementation with antimicrobial agents on growth performance of broiler chickens, Clostridium perfringens and enterococcus counts, and antibiotic resistance phenotypes and distribution of antimicrobial resistance determinants in Escherichia coli isolates.

The effects of feed supplementation with the approved antimicrobial agents bambermycin, penicillin, salinomycin, and bacitracin or a combination of salinomycin plus bacitracin were evaluated for the incidence and distribution of antibiotic resistance in 197 commensal Escherichia coli isolates from broiler chickens over 35 days. All isolates showed some degree of multiple antibiotic resistance. Resistance to tetracycline (68.5%), amoxicillin (61.4%), ceftiofur (51.3%), spectinomycin (47.2%), and sulfonamides (42%) was most frequent. The levels of resistance to streptomycin, chloramphenicol, and gentamicin were 33.5, 35.5, and 25.3%, respectively. The overall resistance levels decreased from day 7 to day 35 (P < 0.001). Comparing treatments, the levels of resistance to ceftiofur, spectinomycin, and gentamicin (except for resistance to bacitracin treatment) were significantly higher in isolates from chickens receiving feed supplemented with salinomycin than from the other feeds (P < 0.001). Using a DNA microarray analysis capable of detecting commonly found antimicrobial resistance genes, we characterized 104 tetracycline-resistant E. coli isolates from 7- to 28-day-old chickens fed different growth promoters. Results showed a decrease in the incidence of isolates harboring tet(B), bla(TEM), sulI, and aadA and class 1 integron from days 7 to 35 (P < 0.01). Of the 84 tetracycline-ceftiofur-resistant E. coli isolates, 76 (90.5%) were positive for bla(CMY-2). The proportions of isolates positive for sulI, aadA, and integron class 1 were significantly higher in salinomycin-treated chickens than in the control or other treatment groups (P < 0.05). These data demonstrate that multiantibiotic-resistant E. coli isolates can be found in broiler chickens regardless of the antimicrobial growth promoters used. However, the phenotype and the distribution of resistance determinants in E. coli can be modulated by feed supplementation with some of the antimicrobial agents used in broiler chicken production.