ARS | Publication request: Evaluation of quail and chicken embryos for the detection of botulinum toxin serotypes A, B, E and F activity.

Submitted to: Interagency Botulism Research Committee
Publication Type: Proceedings/Symposium
Publication Acceptance Date: August 13, 2008
Publication Date: September 14, 2008
Citation: Buhr, R.J., Bourassa, D.V., Cox Jr, N.A., Richardson, L.J., Phillips, R.W., Kelley, L.C. 2008. Evaluation of quail and chicken embryos for the detection of botulinum toxin serotypes A, B, E and F activity. Interagency Botulism Research Committee. P-40, p. 226.

Technical Abstract: Comparison of quail (Coturnix japonica) and chicken (Gallus domesticus) embryos for the detection of BoNT/A activity was conducted using equal dosages of toxin/g of embryo (quail at 7 g and chickens at 48 g). Quail embryos were injected at 0, 0.5 to 50 ng adn chicken embryos at 0, 3.4 to 342 ng and embryo viability was reassessed daily. Four days PI quail embryos injected at 0 ng hatched 90%, 0.5 ng and 1 ng at 35%, 10 ng at 5%, adn 5 ng , 20 ng or 50 ng at 0%. Chicken embryos injected at 0 ng hatched at 100%, 3.4 ng at 50%, 6.8 ng at 56%, 34 ng at 55%, 68 ng at 5%, 137 ng at 40%, adn 342 ng at 0%. Depressed embryo viability was detected at 1 day PI for quail but not until 3 days PI for chickens. Both quail and chicken embryos can detect BoNT/A activity at 70 ng/kg. BoNT/A, B, E and F evaluated in the University of Georgia (UGA) randombred quail control line, and BoNT/A and F in the Louisiana State University (LSU) High and Low blood corticosteroid response and Control quail lines. The vaiability of UGA embryos injected with 0 ng of toxin was 90% at 3 days PI. Embryos injected with BoNT/A at doses from 1, 5, 10, 20 to 40 ng had consistently low viability for all dosages at 20, 0, 25, 10 and 20%. Those embryos injected with BoNT/F at dosages of 1, 5, 10, 20 to 40 ng had progressively lower viability with increasing dosages from 80, 50, 30, 40 to 10% viable. Embryos injected with trypsin activated BoNT/E had viabilities of 10, 20, 0 and 0%. The LSU Low stress response line was 50% more sensitive to BoNT/A and 18% more sensitive to BoNT/F than the LSU High stress response or the LSU Control quail lines (which did not differ in viability). For the BoNT/A injected embryos the High response quail line exceeded the Control line in viability when injected at 2.5 ng (20%) adn 5 ng (10%). For the BoNT/F injected embryos the High response quail line exceeded the Control line in viability by 20% when injected at 1 ng but was 20% lower in viability when injected at 5 ng.