The feeding habits of 100 silver catfish, Chrysichthys nigrodigitatus (Lacépède, 1803) from Oyan dam were investigated. Stomach contents were identified and analyzed by occurrence methods and the prominence of Individual food items was determined by the ranking index. Only 15% of the specimens had empty stomachs while 21% had full stomach, others had stomachs in varying degrees of fullness. Sand was 11% of total volume in the stomach of chrysichthys nigrodigitatus species, which suggests a benthic feeding habit. The high percentage occurrence of Insects (arthropod) established Chrysichthys nigrodigitatus as an omnivore.
Assay was conducted to determine the distribution and specific activities of digestive enzymes in different gut regions of chrysichthys nigrodigitatus. Amylase, lipase and protenase were present in different gut and regions at varying quantities and with specific activities. Amylase is high in the stomach, while lipase and protenase in the posterior region. There were significant differences (P<0.05) in specific activities of digestive enzymes. The wide distribution of enzymes in Chrysichthys nigrodigitatus specimen reflects its ability to digest the carbohydrate, protein and lipid portion of its food. The viscerosomatic and hepatosomatic indices were carried out for Chrysichthys nigrodigitatus analyzed based on the total body weight and organ weight of the fish with condition factor (K) ranging between 1.87 and 1.99 respectively.
The coefficient factor of the length weight relationship, linear equation shows a correlation between weight and length, with correlation (r=0.78) indicating a strong association between the two variables and the regression co-efficient of determination R2=0.611 indicating that 61.1% of the variations recorded in weight can be explained by length.