Effects of Citrus aurantium dulcis essential oil and Yucca schidigera saponins on broiler performance and health

Avian coccidiosis is an economically relevant infection for the poultry industry, usually prevented by synthetic coccidiostats. The increasing resistance of avian coccidia prompted the search for new prevention methods. Yucca schidigera’s (Ys) steroidal saponins reduce the oocyst cycling and improve the chicken's performance. Citrus spp. essential oil (EOs) possesses gastroprotective ulcer healing actions, and intense antiparasitic activity, due to the presence of d-limonene. The anticoccidial activity of Citrus aurantium L. var. dulcis (Ca-EOs) and its potential association with Ys saponins has not been tested yet in chickens. This study aimed to evaluate this combination on chickens naturally exposed to coccidia. One-d-old female broiler chicks (n=140) unvaccinated against coccidiosis were divided into 4 experimental groups (n=35 each), maintained on natural light/dark photoperiod, watered, and fed ad libitum with a diet free of coccidiostats. The trial lasted 9 weeks, from 1 (t0) to 63-d-old (t9). The treatments (Tr) included: control group (Ctrl); Tr1 (Ca-EOs 5%, 1mL/L); Tr2 (Ys 100% pure extract, 0.05mL/L); Tr3 (EOs+Ys, 1.05mL/L) administered in water in bell-shaped tanks. Performances and coccidia oocysts count were evaluated weekly. At t9 all groups were slaughtered and serum biochemical parameters were evaluated. Data were analyzed using STATA software. Results showed no differences among the groups in feed daily intake, feed conversion ratio, and mortality rate. The body weight showed differences (p < 0.05) among all treatments, with Tr2 and Tr3 maintaining greater body weight during and to the end of the trial (3186.7±195.8 and 3274.1±346.7 kg respectively) compared to Ctrl and Tr1 (2626.7±204.7 and 2948.8±397.5 kg respectively). No oocysts were observed in the first 4 weeks in all groups. From 4th to 9th week, Tr1, Tr2, and Tr3 showed significantly lower oocysts than Ctrl (p < 0.05). The oocyst count was significantly lower in Tr1 than Tr2 and Tr3 (p < 0.05), with a proportional decrease from 4th to 9th week in Tr3. Differences among the treatments were detected in serum AST, cholesterol, total protein, albumin, Ca, and P, with the higher value recorded in Tr2 and Tr3 groups (p < 0.05), albeit within the physiological range. These preliminary data indicate that Y. schidigera confirms its anticoccidial activity, that Citrus spp. EOs can reduce coccidia life-cycle with coccidiostat effects, and the effects increase when Ys and EOs are combined.