Inhibitory effect of dietary anacardic acid supplementation on cecal lesion formation following chicken coccidial infection

Two experiments were conducted to determine the effects on male chicken performance of anacardic acid and cashew nut shell oil as feed supplements during an experimental coccidial infection. Seven-day-old chicks wer e fed a corn-soybean diet containing anacardic acid at 0, 0.4 or 0.8% (Experiment 1), or cashew nut shell oil at 0, 0.1, 0.2 or 0.4% (Experiment 2) for 10 days. On the third day of each experiment, half of the birds fed each diet were individually inoculated orally with 2 × 10³ or 5 × 10⁴ (Experiment 1) and 1 × 10⁴ or 1 × 10⁵ (Experiment 2) Eimeria tenella oocysts. In Experiment 1, body weight gain and cecal length decreased significantly according to the level of oocyst inoculation, while oocyst production per cecum (log value) and cecal lesion score significantly increased. Dietary anacardic acid supplementation had no effect on these parameters except for that of lesion score, which was improved (i.e. decreased) by anacardic acid supplementation of 0.8% at the inoculation level of 2 × 10³ oocysts, and of 0.4 and 0.8% for the higher inoculation (5 × 10⁴ oocysts). Results of Experiment 2 also showed that cashew nut shell oil affected neither cecal length nor oocyst production per cecum (log value) at either of the inoculation levels, but the lesion score was improved by cashew nut shell oil supplementation at 0.2 and 0.4% in the diet at the inoculation level of 1 × 10⁴ oocysts and at 0.4% for the higher inoculation. The present study provides the first evidence of the reducing effects of anacardic acid and cashew nut shell oil on the severity of cecal lesions in chickens during an experimental coccidial infection.