Effect Of Temperature, Humidity And Immune Dose On Eimeria Acervulina Vaccination

Eimeria acervulina ismainly parasitic in the duodenum,with the highest prevalence in the intensive chicken farms.It mainly causes subclinical coccidiosis,which can affect the production performance including weight gain and laying rate of chickens.The immunity establishing of chickens is mainly dependent on the number of progeny oocysts in the E.acervulina vaccine and the degree of oocysts sporulating as well as the number of actual intake of oocysts by the chicken,which are mainly influenced by the immune doses as well as the temperature and humidity.To solve these problems and adjust the immune dose of E.acervulinavaccine,how the vaccine efficacyis affected by the temperature and humidity must be determined.The following tests were carried out to measure the temperature and humidity every day from December 2014 to November 2015.The chicken mental conditions,ooc yst output,intestinal lesion scores and weight gain in the vaccine reactionperiod were evaluated to determine the effect of temperature,humidity and immune doses during the 4 different experimental periods(January,April,July and October).After immunity was established,5x10~4 virulent E.acervulina were used to infect the chicken and the protective efficacy was evaluated.First,the results for temperature and humidity showed that the conditions in April and July were more suitable for oocysts sporulating,in which temperatures were between 24.57℃and 29.45℃,and the humidities were between 67.51%and 69.45%.However,it was not conducive for the oocysts sporulating in October,the average temperature was 23.33℃,and the relative humidity was 54.29%.This was also the case in January,which had low temperatures and humidity(17.68℃and 28.93%,respectively).Second,the mental conditions and intestinal injuries of chickens after the vaccine reaction period showed that there was higher immunization safety with the 1 dose/chicken than 2dose/chicken of the E.acervulina vaccine during April and July.There were no obvious differences in immunization safety between the low dose and high dose of E.acervulina vaccine,but there was significantly higher OPG dur ing the first and second ovulation peaks when using the low dose of E.acervulina vaccine during the January and October.Third,the results for vaccine efficacy showed that there was better vaccine efficacy regarding mental conditions,intestinal injury a nd low OPG when using the high dose(2 dose/chicken)compared to the low dose(1 dose/chicken)of E.acervulina vaccine during January and October.In general,the temperature,humidity and dose has an effect on the immune effect,and these factors influence the protective efficacy against E.acervulina infection.in January and October,the low dose(1 dose/chicken)of E.acervulina vaccination cannot produce strong immunity to provide protective efficacy for chickens because the conditions are not suitable for oocysts sporulation.Therefore,we recommend using the high dose(2dose/chicken)to achieve good protective efficacy.In April and July,both the high dose(2dose/chicken)and low dose(1 dose/chicken)of E.acervulina vaccination can provide protective efficacy for chickens because it is suitable for oocysts sporulating.However,there are more side effects during the vaccine reaction period,and the vaccine cost is high when using the high dose(2dose/chicken).Therefore,we recommend using the low dose(1dose/chicken)of E.acervulina vaccination to provide good protective efficacy in April and July.