blended and filtered to remove debris then centrifuged at a speed sufficient to pellet the remaining fecal material for e tenella a similar procedure is used except that cecal cores are taken at 6 days post infection the pellet is resuspended in a saturated salt solution in which the oocysts float and most of the contaminating debris can be removed by centrifugation the oocyst suspension is then diluted to lower the salt concentration the oocysts are washed repeatedly to remove the salt and resuspended in potassium dichromate solution 2 5 w v the oocyst suspension is incubated at 29 u00b0 c with shaking e g 140 rpm for approximately 72 hours to induce sporulation of the oocysts alternatively the oocysts can be treated with sodium hypochlorite and then sporulated the number of sporulated oocysts ml is determined by direct count using a hemocytometer and the culture is stored preferably under refrigeration until needed the oocysts can be used in accord with the present vaccination method preferably in a dose comprising from 10 2 to 10 8 oocysts per egg more preferably the dose comprises from 10 2 to 10 5 oocysts per egg to prepare sporocysts the potassium dichromate is removed from the oocyst suspension described above by repeated washing of the oocysts which involves collection of oocysts by centrifugation and resuspending in deionized or distilled water when the dichromate has been removed as judged by the lack of yellowishorange coloration the oocyst suspension is mixed with an equal volume of sodium hypochlorite bleach and incubated at room temperature for 15 minutes the bleach is then removed by repeated washings and the oocysts are resuspended in physiological saline or deionized water oocysts can be broken to release sporocysts using a variety of.