Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 1, 2001
Publication Date: N/A
Interpretive Summary: Coccidiosis causes significant economic losses in the poultry industry by reducing weight gains and feed efficiency. The conventional treatment for coccidiosis involves the use of chemicals applied as feed additives. However, drug resistant has become wide spread reducing the efficacy of chemotherapy. It is clear that effective control in the future will be by a combination of chemotherapy and vaccine tailored to the particular needs of the producer. In order to effectively implement these strategies producers will need new methods to evaluate impact of coccidiosis on poultry growth. The current study continues research to determine the mechanisms associated with muscle loss during coccidiosis infection in broiler chickens. Measurement of an amino acid marker of muscle catabolism in muscle and plasma of chickens infected with the cecal parasite Eimeria tenella demonstrated an increase catabolism indicative of breast muscle breakdown. These results indicated muscle breakdown was correlated with intensity and duration of infection. This results shows that muscle catabolism is a general feature of poultry coccidiosis and may form the basis for assessing impact of coccidiosis during poultry production.
To assess muscle breakdown during avian coccidiosis, the level of the non-metabolizable amino acid 3-methyl histidine (3MH) was determined in muscle and plasma from chickens infected with the cecal parasite Eimeria tenella. The change in 3MH level during infection was determined in animals given from 0 to 200,000 sporulated oocysts per bird. The effect of levels of parasitism were evaluated at 6 days post inoculation (DPI). The 3MH levels of plasma and muscle were determined by high pressure liquid chromatography after derivatization with fluorescamine. Weight gains, packed cell volumes (PCV) and gross lesion scores were also determined. Infected birds with significant gross pathology had significantly elevated plasma and muscle 3MH. Plasma and muscle 3MH levels were not correlated with gross lesion scores. However there was an inverse relationship between weight gain and both plasma and muscle 3MH. The results suggested that muscle breakdown, as assessed by plasma and muscle levels of 3MH, was elevated during the acute stage of E. tenella infection, and was most likely associated with anorexia caused by infection. However, the correlation of 3MH levels with severity of infection was not as strong as that previously observed for E. acervulina infection, most likely due to the differences in pathology caused by the two species.