Anátomo-clínica e Biologia em frangos de corte experimentalmente infectados com Eimeria acervulina e suplementados com betaína

Abstract

Purposing to evaluate the anatomy-clinics and biology in broilers chicks experimentally infected with Eimeria acervulina and supplemented with betaine, a study was carried out. Thus, 390 broiler chicks Cobb were housed in battery cages distributed in a randomized block design composed of five treatments, six replicates with 13 chicks each, including a positive control, a group treated with the salinomycin plus potassium penicillin G and three levels of betaine in the feed 0.05%, 0.10% and 0.15%. A soybean-maize based diet was prepared according the nutritional requirements of broiler chickens; food and water were given ad libitum. Chicks 14 days old were individually infected orally with 2 x 105 sporulated oocysts of E. acervulina. Weight gain, feed consumption, oocyst output and clinical signs were performed during 1-7 and 7-14 days after inoculation (DAI). After, from 0-7 and 7-14 DAI weight gain, feed consumption, oocyst output, plasma proteins and clinical signs were evaluated. At 0, 4, 7 and 14 DAI one bird from each replicate were euthanatized to perform lesion score and collection of blood and intestinal tissues for histopathology and villous measuring. Laboratorial analyses were made using saturated sugar centrifugation technique following oocyst counting and measurements with an ocular micrometric. Biology of the parasite was evaluated throughout the sporulation time, pre-patent and paten periods of infection, morphology of endogenous stages and oocyst and relationship with the mathematical cons tant Phi. It was not observed anatomy-clinics differences (p>0.05) between birds of different treatments due to all parameters used, however the response with betaine was similar to treatment with salinomycin and potassium penicillin G, indicating there are possibilities to use betaine to substitute these drugs. Nevertheless, betaine show ability to decrease oocyst output against control group but fewer than salinomycin. Regarding the biology of the parasite, although betaine affected the form and size of oocysts, little influence was observed in the endogenous stages according to measurements of trophozoites and macrogametes. Within the morphology it was observed a great relationship between the development of sporocysts of E. acervulina and the mathematical constant Phi.