Location: Animal Parasitic Diseases LaboratoryTitle: The use of dual-energy X-ray absorptiometry (DEXA) to assess the impact of Eimeria infections in broiler chicks) Author
Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2013
Publication Date: 6/1/2013
Publication URL: http://handle.nal.usda.gov/10113/56876
Citation: Fetterer, R.H., Miska, K.B., Mitchell, A.D., Jenkins, M.C. 2013. The use of dual-energy X-ray absorptiometry (DEXA) to assess the impact of Eimeria infections in broiler chicks. Avian Diseases. 57(2):199-204. Interpretive Summary: Poultry coccidiosis is the result of several different species of a protozoan intestinal parasite which causes considerable annual losses to the poultry industry. The primary control for the disease is through application of medications in the feed as birds are raised in confinement housing. The control by medications is becoming less effective because of increased resistance to the drugs and less desirable due to concerns about the possibly of drugs remaining in the meat and within the environment. New control methods are needed. In order to more effectively evaluate treatment methods, better techniques are required to measure the impact of parasite infection on the body composition of chickens. The current study adapts a dual x-ray technology (DEXA) that is widely used in human medicine to a study of the changes in body composition of chicken infected with coccidia. The results demonstrated that relatively low levels of infection can alter body composition of chickens including decrease in the lean weight and amount of fat. One of the most predominant changes was a decrease in bone density caused by infection with some of the coccidian species. This observation may be the result of decreased absorption of calcium by the small intestine. Overall, the results clearly demonstrate that DEXA can be a fast and reliable method to evaluate the impact of coccidia infection on body composition of chickens.
Technical Abstract: A number of parameters have been used to assess the impact of coccidosis on chickens in both clinical settings as well as in experimental studies. However a rapid way to determine body composition would be useful to evaluate or compare responses to coccidia and could give further insight into the metabolic impact of infection. The current study evaluates the use of dual X-ray absorptiometry (DEXA) to determine the impact of coccidiosis on body composition in chicks receiving inoculations with single or mixed species of Eimeria. Chicks infected with Eimeria maxima, E. acervulina or E. tenella had altered parameters of body composition as measured by DEXA at 6 days post-infection (PI). The greatest effects were noted in birds infected with E. acervulina or E. maxima where lean mass and fat were reduced about 75 and 85% respectively of control values. In chicks infected with E. tenella, tissue and fat were about 90% of control. Bone mineral content (BMC) was about 75% of control values in birds infected with E. acervulina or E. maxima but only E. acervulina altered bone mineral density (BMD). The decreases in BMC and BMD are likely due to malabsorption. In chicks receiving a mixed coccidian infection all DEXA parameters were significantly decreased at 8 days PI compared to age-matched controls. As with single infections, BMD and BMC were significantly depressed. Values of all DEXA parameters were at about 92% of control values by day 16 PI. Analysis of all birds in the current study indicates DEXA tissue weight slightly underestimated the gravimetrically measured weight by about 3%. The current results demonstrate that DEXA is a potentially important tool for the rapid evaluation of the effect of coccidiosis on broiler chicks and suggest it can be useful for evaluation of vaccines and other controls.