Effective methods of coccidiosis prevention and control remain one of the major challenges in the current poultry production. The results of studies carried out at the Animal Breeding Institute of the National Research Institute in Cracow
indicate that herbal additives may be part of coccidiosis prevention program.
Coccidiosis in chickens is an intestinal parasitic disease caused by single-cell protozoa of Eimeria genus. In chickens there are 7 specific species with different pathogenicity, location in the gastrointestinal tract, and effect on the intestinal tissue. Infection occurs via the faecal-oral route, i.e. after ingestion of an invasive oocyst, which is a common environmental contaminant in birds' habitats. Enterocytes (cells of the intestinal mucosa epithelium) are damaged during the propagation of subsequent stages of the parasite and its release into the intestinal lumen. Interruption of intestinal tissue integrity not only results in impaired digestion and absorption of nutrients from the feed, but also predetermines secondary bacterial infections, causes inflammation, diarrhea, bleeding from the intestinal walls, which in the case of the acute disease may lead to death of an exhausted bird.
Feeding methods, particularly the use of herbal feed additives, are one of the most promising alternative or complementary solutions as opposed to commonly used feed coccidiostats.
"Sporulated oocyst (invasive)"
Studies conducted at the Animal Breeding Institute of the National Research Institute
There are few published results of studies, which aim at seeking substitutes for feed coccidiostats. At the Institute of Animal Breeding of the National Reasearch Institute in Cracow, a series of studies have been performed on the potential coccidiostatic effects of herbal extracts. The purpose of the first stage of the study was to assesses the effectiveness of single extracts obtained from: garlic, rosemary, sage, oregano, nettle, absinthe, pepper, echinacea, thyme and yarrow, under the conditions of experimentally induced clinical coccidiosis (after oral infection of birds with a mixture of oocyst of different Eimeria species
). On the basis of these experimental results, extracts of garlic, sage, oregano, echinacea, thyme had been selected for further studies, and a combination thereof has been prepared. It has been shown that this combination of extracts used in an amount of 1 g/kg of feed mitigates the severity of acute clinical coccidiosis and stimulates compensation growth in recovering chickens. It is worth noting that the growth rate is considered to be a sensitive indicator in assessing the severity of the disease.
Production parameters obtained for the whole rearing period in the group of birds infected with highly pathogenic mixture of oocysts and receiving feed with added extracts were comparable to those obtained using a feed coccidiostat diclazuril, as well as in the group of uninfected birds.
Particularly satisfactory results have been obtained in the farm test carried out on uninfected birds in the conditions of low exposure of chickens to coccidia. The application of the combination of extracts, at each stage of the rearing yielded results comparable to those obtained using a coccidiostat, and significantly higher when compared with a control group not receiving any supplement in the diet. These results indicate that the developed combination of extracts provides an effective protection of chickens in production environments with moderate contamination with coccidia, particularly in the context of subclinical coccidiosis occurrence. There may no apparent symptoms in the course of the disease, however, weight gain is reduced, the utilization rate of feed is lower, and culling rate due to a large differences in the growth of birds is increased. Therefore, subclinical coccidiosis has a highly negative impact on the economic results of rearing.
It is reasonable to believe that the positive effect of the combination of extracts application was not due to its direct effect on the parasite only, but to a multidirectional effect of active substances in the individual extracts, mitigating the adverse effects of coccidiosis, by for example: stabilisation of the intestinal bacterial microflora (bacteriostatic effect of all extracts), stimulation of restoration of intestinal villi damaged by coccidia growth (garlic), alleviating intestinal inflammation through antioxidant action (thyme, oregano, sage, echinacea), or stimulation of immune processes (echinacea, garlic).
The range of feed additives now includes KOKCIDIN
manufactured by INTERMAG, development on the basis of formulation of the combination of herbal extracts tested at the Animal Breeding Institute of the National Research Institute. It is also worth to mention that a test on a combined use of live attenuated vaccine against coccidiosis and KOKCIDIN
was performed in cooperation with the Animal Breeding Institute of the National Research Institute. The test results indicate its usefulness in both unvaccinated chickens feeding, as well as in the case of preventive vaccination against coccidiosis, particularly in the priming period of rearing, i.e. during immunity acquiring period.