The influence of coccidiostatic Baycox on the course of coccidiosis in broiler chicken

The purpose of the research is to identify species of Eimeria spp. in chicken broilers suspected to be infected with coccidia and to determine the effect of coccidiostatics in the course of coccidiosis. Materials and methods . The study involved 20 six-week-old broiler chickens obtained from a farm heavily affected by coccidia (natural infection – a high oocyst incidence). Each group yielded 10 randomly picked chickens to be used in the experiment. The birds were divided into 2 groups 10 chickens each: control (I); Baycox-treated (II); Baycox was applied for 2 days in a concentration of 25 ppm in drinking water. Samples of broiler chickens’ droppings were tested qualitatively by the flotation method (Willis-Schlaaf) and then quantitatively by the McMaster technique. The chickens were killed 6 days post-treatment and their intestinal mean total lesion scores (MTLS) were graded 0 to 4 on an arbitrary scale described by Johnson and Reid (1970). Results and discussion . As a result of the research, six species of protozoa of the genus Eimeria were identified: E. acervulina, E. tenella, E. brunetti, E. maxima, E. mivati, E. necatrix , while E. necatrix and E. maxima were the dominant species. This proves the presence of such species as E. mivati, E. acervulina (76.34%) in the anterior segment of the intestine and E. necatrix, E. maxima (83.34%) – in the middle segment of the small intestine. Infections of E. brunetti broilers amounted to 51.11%. The most pathogenic species of E. tenella residing in the cecum was found in 37.53%. MTLS in the group of chickens that received Baycox was 0.33. The post-treatment oocyst indices in the second group amounted to 1 (1–50 oocysts in 1 g of faeces), in the control group MTLS was very high (2,5), the oocyst index exceeding 3.


Introduction
As an environmental disease, coccidiosis continues to be a significant health problem in poultry production. According to prof. Jeffers, it is the most common disease in poultry [9]. The course of the infection of this dangerous disease is the result of many environmental factors. The outbreak of the disease may contribute to frustrating the breeder's effort by direct losses (chicken sickness and falls) as well as indirect losses manifested by worse production effects.
Seven coccidial species have been described in chickens, of which five -Eimeria tenella, E. necatrix, E. brunetii, E. acervulina and E. maxima -are considered pathogenic species. The pathogenicity of E. mitis and E. praecox is ambiguous -by many researchers they are classified as non-pathogenic [5,14], however, more and more data indicate the impact of these species on the profitability of production, as infection, despite the absence of disease symptoms and falls, leads to a deterioration of the economic results of breeding [5,11].
The problem of coccidiosis prevention in Poland is generally not covered by any coordination. Dispersion of feed and premix producers, the declining profitability of this industry and extremely fierce competition do not encourage activities on the coordination of activities in the field of rationalization of coccidiosis chemoprophylaxis programs. The current policy, or rather the lack of a policy regarding the use of coccidiostats in poultry production, leads to losses caused by these parasites, and they result directly from lower economic effects [3].
The aim of the present research was to identify species of Eimeria spp. in chicken broilers suspected to be infected with coccidia and to determine the effect of coccidiostats in the course of coccidiosis.

Materials and methods
Animals. The study involved 20 six-week-old broiler chickens obtained from a farm heavily affected by coccidia (natural infection -a high oocyst incidence). The chickens were kept in an electrically heated poultry house and fed ad libitum with appropriate feed and water. The basic diet contained 18% total protein, 8% fat, 4% crude fibre, 0.4% methionine, 0.3% cysteine, 18% tryptofan, 0.9% lysine, 1% calcium, and 0.5% phosphorus. Each group yielded 10 randomly picked chickens to be used in the experiment. The birds were divided into 2 groups 10 chickens each: control (I); Baycox-treated (II); Baycox was applied for 2 days in a concentration of 25 ppm in drinking water.
Parasitologcal analysis. More specifically, fecal samples were qualitatively analyzed by using the Willis-Schlaaf flotation with saturated NaCl solution and a McMaster method with a detection level of Eimeria spp. oocysts per gram of feces was performed with saturated NaCl solution [4]. The procedures of propagation and harvesting of oocysts, and preparation of oocysts followed by recommendations Eckert [4]. The chickens were killed 6 days post-treatment and their intestinal mean total lesion scores (MTLS) were graded 0 to 4 on an arbitrary scale described by Johnson and Reid (1970) (Fig.1) [10].

Results and discussion
As a result of the research, six species of protozoa of the genus Eimeria were identified: E. acervulina, E. tenella, E. brunetti, E. maxima, E. mivati, E. necatrix, while E. necatrix and E. maxima were the dominant species (table 1). In the digestive tract of chicken broilers, anatomical changes were particularly frequent in the anterior and middle sections of the small intestine. This proves the presence of such species as E. mivati, E. acervulina (76.34%) located in the anterior segment of the intestine and E. necatrix, E. maxima (83.34%) located in the middle segment of the small intestine. Infections of E. brunetti broilers amounted to 51.11%.
This specie is localized in the rectum and the steak. The most pathogenic species of E. tenella residing in the cecum was found in 37.53% (Table 1).
The analysis of the obtained results showed that in most cases broilers were affected by mixed infections with the predominance of five and six species. They were confirmed in 66.4% of the tested chickens.
In half of the farms studied, dangerously high degree of infection with chickens coccidia was demonstrated.
Baycox is a well-known coccidiostatic particularly useful for controlling poultry coccidiosis. MTLS in the Baycox-treated group was 0.33. The post-treatment oocyst indices in these groups TREATMENT AND PREVENTION amounted to 1 (1-50 oocysts in 1 g of faeces). The control group MTLS was very high (2,5), the oocyst index exceeding 3 (more than 300 oocysts in 1 g of faeces) ( Table 2, 3).
Coccidiosis remains one of the major threats for poultry industry throughout the world [7]. The disease is traditionally controlled by the use of chemoprophylactic measures including anticoccidials in feed that inhibit the developmental stages of Eimeria.
The dominance of individual species of coccidia is variable and depends not only on the area, but may also change over time in the same area. From scientific reports from various countries, incl. The Czech Republic, France, the Nether-  Table 3 Prevalence of coccidia in broilers after Baycox treatment lands, Iran, Korea, Norway, Romania and Turkey show that the most common species of coccidia, similarly to our country, were E. acervulina and E. tenella [6,8,12,13,15]. The research was conducted in Russia. Coccidiosis is a serious problem in broiler chicken production in Poland. Coccidiostatics are used to combat this disease. In last time additionally for coccidiosis control compounds are applied, which stimulated the non-specific resistance system.
In Poland the most frequently diagnosed species were E. tenella (64%), E. acervulina (32%), E. maxima (8%), and E. necatrix (4%). Most cases were caused by a single species of coccidia (92%), and in 8% of cases two species of coccidia were found [5]. On the other hand, studies by Doner and Szeleszczuk showed that in the country broiler chickens were infected with several species (E. acervulina, E. mitis and E. maxima), and infections with E. tenella constituted 29% [2,3].

Conclusion
Despite the introduction of new diagnostic techniques into coccidiosis research, the disease remains a problem in the poultry industry. In Poland, there is no nationwide program of prevention, based on the use of coccidiostatics and vaccines against coccidiosis.