Effect of Eimeria acervulina infection on nutrient retention with special reference to fat malabsorption in chickens

Nutritional balance studies were conducted to determine the effect of Eimeria acervulina infection on the retention of nutrients and the efficiency of utilization of protein and energy in the diet during the course of intestinal coccidiosis in chickens. Both light and electronmicroscopic studies were conducted to elucidate the pathogenesis of fat malabsorption in the infected chickens. The infection with E. acervulina during the acute phase of the disease (day 4 to day 8 postinfection) caused a reduction (P smaller than 0.01) in the retention of percent protein, percent ether extract and percent gross energy of the diet with a concomitant increase (P smaller than 0.01) in the concentration of ether extract and gross energy of the excreta. The metabolizable energy value of the diet was also depressed during this phase. During the recovery phase of the disease (day 9 to day 13 postinfection) infected chickens voided excreta containing a slightly greater concentration of ether extract when compared to the controls but differences in the retention of percent protein and percent gross energy were no longer observed. An increased retention of percent phosphorus also occured during the recovery phase. Studies involving the carcass composition revealed that the efficiency of utilization of protein and metabolizable energy of the diet for tissue deposition was reduced (P smaller than 0.05) during day 0 to day 8 postinfection but only the efficiency of metabolizable energy utilization was found to be depressed (P smaller than 0.05) when data for day 0 to day 14 postinfection were analyzed. Both light and electronmicroscopic studies of the duodenal villi of infected chickens during day 5 to day 6 postinfection revealed accumulation of large globules of fat in the villus epithelial cells parasitized by the gammonts of E. acervulina indicating a possible blackade of "fat exit" from these cells.