Meeting Abstract
Previous studies have not adequately quantified or compared the severity of feminization (intersex) between cross and longitudinal sections of testes. In previous studies, intersex severity was ranked on a scale of 0-4: 0 = no oocytes, 1 = one oocyte, 2 = more than one oocyte, 3 = a cluster of oocytes, 4 = multiple clusters of oocytes. This ranking system is ineffective for assessing intersex severity with high counts of oocytes. Our goal was to compare the severity of intersex between two sampling techniques, cross and longitudinal sections of testes. We collected Largemouth Bass (Micropterus salmoides) (n =37) and Spotted Bass (M. punctulatus) (n = 25) from Lake Oliver, a reservoir of the Chattahoochee River, Columbus, GA, USA. Testes from each fish were prepared histologically with one testis cut into three cross sections, while the other was cut longitudinally. After staining with hematoxylin and eosin, the two sectioning techniques showed different intersex severity values. Longitudinal sections of Largemouth Bass revealed an average severity index of 1.67, while cross sectioning yielded an average severity index of only 0.87. In Spotted Bass, the longitudinal sections had a severity index of 1.36, while the cross sections only found an average severity of 1.00. Cross sectioning is the most common sampling technique to assess intersex, but our data suggests that longitudinal sectioning is more descriptive for determining intersex severity. The implications of our findings suggest that assessment of severity in fish populations may be underrepresented in published studies.
