Abstract: | The effects of exogenous NO on Eimeria tenella oocysts were studied. The E. tenella oocystsfreshly isolated from feces of experimental chickens infected with E. tenella and sporulated E. tenella oocystswere treated in vitro by the well-known NO-donors, SNP, SPER/NO and GSNO. The results showed thatamong the 3 NO donors, only GSNO had significant effects on the percentage of sporulated oocysts, the inhibi-ting rate of purified oocysts was from 93 to 97%, and reached 100% on the oocysts in the feces of chickenswith E. tenella infection. GSNO also significantly decreased the virulence of E. tenella oocysts, and the oo-cysts treated by 2 -8 mmol L-1 GSNO almost lost their pathogenicity to chickens. |