Efficiency of feed additive Nikamax® for artificial infection of broiler chickens with Eimeria spp.

Abstract

The aim of the work was to study the effectiveness of the combined feed additive NIKAMAX® (powder for oral use), produced by JSC Biopharm (Ukraine), the active pharmaceutical ingredients of which are nicarbazine and maduramycin ammonium, for coccidiosis in poultry (broiler chickens) artificially infected with coccidia genus Eimeria. Chickens included in the experiment with artificial infection with coccidiosis were divided into groups on the day of hatching (one experimental group and two control groups). Poultry of the experimental group (group IT) and the first control group (group INT) were inoculated with spore-bearing oocysts of Eimeria acervulina, Eimeria necatrix and Eimeria tenella on the 14th day of life. Eimeria oocysts obtained from local broiler farms were used to inoculate broiler chickens. Identification of coccidiosis patogens was carried out according to species and morphological indexes of Eimeria oocysts. Each chicken of the group IT and the group INT received per os with water a total of 100000 E. acervulina, 10000 E. necatrix and 10000 E. tenella sporulated oocysts. For group IT feed additive NIKAMAX® was used with feed from the 1st day of life at a dose of 0.5 g per 1 kg of feed. This feed additive was not administered for the group INT. Chickens, which were not inoculated and not treated, made up the second control group (group NNT). The primary criteria for demonstrating the effectiveness of the feed additive NIKAMAX® were: intestinal damage index; number of oocysts in feces; poultry mortality and morbidity associated with coccidiosis. Additional indicators of the effectiveness of the feed additive were: average live weight; average daily increase in live weight of poultry; average daily feed consumption, the ratio of the amount of feed consumed to growth; data of bird health monitoring during the experiment. Counting of the number of oocysts in chicken feces was performed before inoculation (0 day), 7, 14 and 21 days after inoculation. To count the number of Eimeria oocysts in feces, the methodology of qualitative studies by Fülleborn and quantitative studies by McMaster was used. To assess the degree of intestinal damage, 5 chickens from each group were slaughtered and dissected on 7, 14 and 21 days after inoculation. Intestinal lesions of chickens with coccidiosis were evaluated on a scale from 0 to 4 points according to the Johnson and Reid method: 0 — no lesion, 1 — very mild, 2 — mild, 3 — moderate, and 4 — severe. Chickens were weighed before inoculation (day 0) and on days 7, 14 and 21 after inoculation. The average daily level of feed consumption was determined for the periods from 0 to 7 days, from 7 to 14 days, from 14 to 21 days and from 0 to 21 days after inoculation. The state of health of all birds included in the study was subject to constant monitoring by a veterinarian. The intensity of invasion in the group IT on the 7th day after inoculation was 3140 oocysts/g of feces and decreased to 2210 oocysts/g of feces (1.42 times) on the 14th day. On the 21st day of the experiment, the excretion of Eimeria oocysts in chickens treated with the feed additive NIKAMAX® decreased to 100 oocysts/g of feces. At the same time, the intensity of invasion in the group INT increased three times from 7 to 21 days after inoculation - from 3760 to 11400 oocysts/g of feces. The decrease in the number of oocysts in the feces of chickens of the group IT is associated with the suppression of the schizogony process by the coccidiostat, what led to less damage of the intestine, compared with the infected but untreated control. If, the indicators of the chickens intestinal damage in the groups IT and INT on the 7th day after inoculation with Eimeria spp. were almost the same, then on the 14th day, the damage of the chickens intestine of the group INT increased, while that of chickens of the group IT decreased. On the 21st day after inoculation, the positive effect of feed additive NIKAMAX® on the degree of damage increases (average score — 0.7 points). Then, as in the infected bird of the group INT, the degree of intestinal damage remained at a high level (average score — 2.4 points). A high mortality rate (53.3%) during the experimental period was recorded among chickens of the group INТ. At the same time, the use of feed additive NIKAMAX® significantly reduced mortality among chickens of the group IТ (10% during the experimental period). The morbidity of poultry in this group also gradually decreased on the 21st day of the experiment, clinical signs of coccidiosis were observed in only one broiler. Addition of feed additive NIKAMAX® to broiler chickens increased the live weight gains of poultry infected with E. acervulina, E. tenella and E. necatrix (group IТ), as well as reduced the feed conversion ratio, compared to the group of infected birds (group INТ) which feed additive was not used. The generalized assessment of the primary and secondary efficiency indicators obtained in the study for artificial infection of E. acervulina, E. tenella and E. necatrix shows that the feed additive NIKAMAX®, manufactured by JSC Biopharm, is an effective coccidiostat for the prevention and treatment of coccidiosis in broiler chickens caused by coccidia of the genus Eimeria