Histologic and morphometric examination of avian glomeruli from normal and swollen kidneys of broilers at slaughter.

Normal and abnormal kidneys collected from broiler chickens at slaughter (6 to 7 weeks of age and of mixed sex) were evaluated to establish histopathologic and morphometric parameters for broilers. Normal kidneys (group D) had an overall mean glomerular diameter of 67.4 +/- 27.8 microns. Abnormal groups (Groups A, B, and C) had an average glomerular diameter of 75.2 +/- 32.1 microns, which was significantly different (P < 0.01) from that of Group D. All glomerular diameters in Group A (otherwise normal birds with swollen kidneys) were significantly different (P < 0.01) from corresponding diameters in Group D. In Group B (birds condemned for Marek's disease virus), only the mammalian glomeruli were significantly different from Group D mammalian glomeruli (P < 0.01). A significant increase in glomerular density was observed for all abnormal groups and glomerular types. The data indicate that glomerular diameter and cellularity might be practical and sensitive indicators of early glomerular changes that can occur in grossly swollen kidneys. Increased glomerular density indicates tubular loss or increase in glomerular numbers.