Comparison of breeder/layer coccidiosis vaccines: Part 1 -precocity and pathogenicity

Abstract

Coccidiosis control for breeding and laying chickens requires the development of immunity against multiple Eimeria species. Vaccines approved for use in Europe are precocious (attenuated) strains. Only one precocious vaccine (Paracox® 8) was widely available to breeder and layer producers in the European Union (EU) from 1991 until 2015, with registration in all EU member states except Luxembourg. Recently, 2 new products have been introduced to the market: Hipra Evalon® and a 2 part product originally designated as Huveguard® Start (now designated Mmat) and Huveguard® Plus (now designated NB). Nonattenuated (nonprecocious) vaccines, by contrast, are used in other parts of the world, but are not available in the EU. Three precocious vaccines (Paracox® 8, Evalon® and the combined Huveguard vaccines) were compared to each other and to a nonattenuated vaccine from North America (Coccivac® D2) with respect to precocity and pathogenicity. All 3 precocious vaccines demonstrated significantly reduced oocyst output compared to the nonattenuated breeder/layer coccidiosis vaccine. One vaccine (Paracox® 8) demonstrated oocyst output for all species at 96 h (more precocious), while the other 2 vaccines did not have output until 24 or even 48 h later for individual species (less precocious). When tested at 40X the manufacturer’s recommended dose (attempting to simulate the field effect of uneven application), all 3 precocious vaccines demonstrated lower lesion scores and better weight gain over the 7 d post challenge compared to the nonattenuated vaccine.