Sporulation of Eimeria maxima oocysts in litter with different moisture contents

The aim of this study was to determine if the sporulation of Eimeria maxima oocysts was affected by the moisture content of the litter. Fresh feces were collected from chickens experimentally infected with E. maxima. The feces were mixed with dried wood shavings and different amounts of water to obtain final moisture contents of 16, 42, and 62% and a final oocyst concentration of 5,000 per g of mixture. The samples were kept at 23 C and 75% relative humidity and were thoroughly aerated every 12 h. Oocysts kept under ordinary laboratory sporulation conditions in 2% wt/vol aqueous potassium dichromate at 27 C were used as a standard for optimal sporulation. The proportion of sporulated oocysts was determined microscopically every 12 h. Sporulation of E. maxima was most efficient under the driest conditions studied (16% moisture content), and poorest in the samples with the highest moisture content (62%). Even though the differences may not have resulted from a direct effect of humidity on the oocysts, but more likely resulted from limited oxygen in the moister substrates, it is clear that sporulation is not favored by moist litter.