Abstract: 【Objective】 This study was conducted to evaluate the prophylactic and therapeutic efficacy of sodium humate (HNa) against Eimeria tenella (E.tenella) infection in broiler chickens. 【Method】 A comprehensive evaluation was conducted through in vitro spore inhibition tests and in vivo intervention tests in animals. In vitro experiments were conducted with three concentration treatment groups of HNa 0.4,0.5 and 0.6 mg/mL.10% DMSO was used as the negative control,and 2.5% potassium dichromate was used as the positive control.2.0×10⁵ unsporulated oocysts of Eimeria tenella were added to each test tube and incubated at 28 ℃ for 3 days.The inhibitory effect of HNa on oocyst sporulation was observed at different time (24,48 and 72 h). In vivo experiments,180 12 days old SPF chicks were divided into 6 groups:Blank control group,infection control group,diclazuril group (0.2 mL/L),and HNa low (400 mg/kg),medium (500 mg/kg) and high (600 mg/kg) dose groups,with 3 replicates in each group and 10 chicks in each replicate.The chicks in blank control group were not infected with coccidia and no medication was given. In infection control group,chicks were infected with coccidia and no medication was given.In diclazuril group,chicks were infected with coccidia and were given diclazuril in drinking water at a dose of 0.2 mL/L from 14 to 21 days of age. Chicks in HNa low,medium and high dose groups were infected with coccidia and given corresponding doses of HNa mixed with feed at 12-21 days of age.At 14 days of age,chicks in blank control group were gavaged with 1 mL of cold boiled water per chick,while chicks in the other groups were gavaged with 1 mL of coccidia oocyst fluid containing 2.0×10⁴ spores.The experiment ended at 21 days of age.This study monitored the growth performance of broiler chicks,cecal lesion scores,oocysts per gram of feces (OPG),anticoccidial index (ACI) and pathological damage in cecal tissues. 【Result】 In vitro experiments showed that the sporulation rate of 0.5 mg/mL HNa treatment group was significantly lower than that of other treatment groups at 24,48 and 72 h (P＜0.05).In the in vivo experiment,HNa medium dose group showed the best therapeutic effect.After 7 days of infection,the average weight gain of the chicks in this group was significantly higher than that of infected control group (P＜0.05),and was higher than that of low and high HNa dose groups (P＞0.05).The scores of cecal lesions and OPG were significantly lower than those in infection control group (P＜0.05).ACI was 164.58,which belonged to the moderate anti coccidiosis effect,second only to diclazuril group (ACI 182.33).The histopathological observation results showed that different concentrations of HNa could effectively reduce the shedding of cecal villi and inflammatory infiltration in chicks. 【Conclusion】 HNa could effectively reduce the in vitro sporulation rate of Eimeria tenella,improve ACI,and alleviate pathological tissue damage in the cecum.Under the conditions of this experiment,the optimal dosage for prevention and treatment was 500 mg/kg.

Key words: sodium humate; chicken coccidiosis; Eimeria tenella; anticoccidial index