Altered metabolism of carotenoids during pale-bird syndrome in chickens infected with Eimeria acervulina.

The progression of changes in carotenoid metabolism during pale-bird syndrome caused by a coccidial infection was investigated. Male broiler chickens 15 days of age on a yellow corn and soybean meal-based diet were infected with Eimeria acervulina oocysts and their serum, liver, and toe webs were sampled at 0, 4, 6, and 10 days postinfection for HPLC analysis of carotenoids. At 4 days postinfection a drastic reduction (71%) in serum lutein, the main body carotenoid, and smaller reductions in liver (58%) and toe webs (38%) occurred. Derivative forms of lutein, mainly esters, continued to be lost from tissues for 10 days postinfection. These carotenoids were apparently lost via the intestinal tract because birds placed on a white corn and soybean meal-based diet at time of infection had lutein in their jejunal contents even at 7 days postinfection. The loss of carotenoids from the body was accompanied by a decreasing ability to absorb canthaxanthin, a red carotenoid, from the intestinal contents. The absorption of canthaxanthin measured at 0, 3, 4, 5, 6, and 7 days reached its low point of 1% of preinfection ability on Day 5 before a slow recovery commenced. Thus, the pale-bird syndrome caused by E. acervulina appeared to be the result of a loss of previously absorbed carotenoids coupled with drastic malabsorption of dietary carotenoids.