Testicular and Sperm Morphology of Pangasionodon hypophthalmus (Siluriformes: Pangasiidae) Fed With Different Crude Protein Levels.

Panga (Pangasionodon hypophthalmus) is a freshwater fish with increasing production and consumption worldwide. However, the knowledge concerning the nutrition, food management and reproduction in male fish is still scarce, especially regarding the interaction between different protein levels in commercial diets and the reproductive process during gonadal maturation. Thus, the current study aimed to characterise the gonadal and sperm morphology of male P. hypophthalmus fed with two crude protein (C.P.) levels (28% and 36%) in commercial feed. For this, for three months, 50 male specimens were distributed in two excavated tanksand fed with commercial feed with 28% and 36% C.P. The gonads were removed and evaluated by macroscopic, microscopic, histological assessment of the testicular parenchyma and ultrastructural analysis of sperm by Scanning Electron Microscopy. Results showed that fish fed with 36% C.P. had greater testicular weight and gonadosomatic index (GSI) than those fed with 28% C.P. Both crude protein levels contributed to the gonadal maturation of the panga. Fish fed both diets showed similar gonadal and spermatic morphology. However, fish fed with 36% C.P. presented better reproductive performance in terms of total testicular mass gain and GSI parameters compared to fish fed with 28% C.P. Overall, nutritional management with different C.P. levels could contribute to the increase in the reproductive performance of P. hypophthalmus.