Effects of natural dietary supplement combinations in Eimeria challenged Ross 308 broilers on body weight gain, feed conversion ratio and oocyst excretion.

Abstract

In the poultry industry, a worldwide substantial economic loss is caused by coccidiosis, a disease in broilers caused by protozoan parasites of the genus Eimeria spp. These parasites cause damage by penetrating the epithelial cells of the intestinal tract in broilers, leading to a reduced body weight gain (BWG), increased feed conversion ratio (FCR), and enhanced mortality rates in flocks. Coccidiostats are mainly used to control coccidiosis, but increasing resistance to these anticoccidial feed additives is reported, reducing its efficacy.The development of natural alternatives is boosted by increasing objections of consumers and legislative restrictions against coccidiostats.The aim of this study is to investigate the ability of different combinations of natural feed additives to support intestinal health and recovery from a mixed Eimeria infection. The effects on intestinal health were evaluated based on BWG, FCR and Eimeria oocyst shedding. Materials and methods: 720 Ross 308 day‐old male broilers were obtained from a commercial hatchery (day 0), and randomly assigned to six treatment groups (trt 1‐6) with each six replicates. All broilers were inoculated with sporulated oocysts of E. acervulina, E. maxima and E. tenella on day 7. Four treatment groups (trt 1‐4) received a basic diet supplemented with several natural dietary ingredients. The diet was substituted with different combinations of natural supplements in the starter, grower 1,grower 2 and finisher feed, supplied respectively from day 0, 9, 18 and 28 onwards. The positive control (PC, trt 5) consisted of broilers receiving a diet with the anticoccidial drug diclazuril. The negative control (NC, trt 6) received a diet without any additives. On day 9, 18, 28 and 35, birds were weighed and feed intake (FI) was measured. Fecal droppings were collected to quantify total oocyst shedding and of oocysts of E. maxima using the McMaster method.Results were statistically analyzed using linear mixed models. Results: No significant differences were observed in BWG and FI between the experimental groups, regardless of dietary phase. Some significant differences in FCR were found between the broilers receiving natural dietary supplements and the controls, but generally FCR was worse compared to the group treated with coccidiostats. Total oocyst excretion was higher for trt 1‐4 compared to the PC at day 14, 22 and 28. At day 35, the PC had no oocyst output, and oocyst output in other groups was low, with the NC and trt 4 having slightly higher outputs than trt 1‐3. In addition, trt 1‐4 showed generally a similar oocyst excretion of E. maxima compared to the PC from the age of 22 days onwards. Conclusion: The natural dietary supplements used in this study did not induce a significant beneficial effect on the BWG, FI and FCR. Total oocyst excretion was not reduced compared to the positive control between day 14 and 28 but trt 1‐3 showed some promising effects on reduction of E. maxima oocyst output.