A STUDY ON THE EFFECT OF AMMONIA ON THE MATURATION OF GONADS IN COMMON CARP (CYPRINUS CARPIO) L., 1758.

This study was carried out on 100 of healthy live common carp, (Cyprinus carpio) with an average body weight of 54.64+ 5.96 g and average total length 15.18 0.69cm. The fish were reared in aerated metalic tanks with flow rate of 8 L/h water. Fish were exposed to 1, 5, 10, and 20 ing/L ammonia-N for 9 weeks. Gonad specimens were taken from the fish and immediately weighed and fixed for histological sections and examined with light microscopy. The gonado-somatic index (GSI) decreased significantly (P < 0.05) with the increase of ammonia concentration. The percentage decrease of GSI was 28.94, 28.73, 49.18 and 55.28 % for 1, 5, 10 and 20 mg/L aminonia-N, respectively. The decrease of GSI was correlated with the increase of ammonia-N levels (r = -0.9193). The histological examination showed no remarkable changes in the oogenesis and spermatogenesis, at Img/L ammonia, but at higher concentrations of anmonia-N (5, 10 and 20 mg/L) there was a significant reduction (P<0.01) in the nunber of yolk vesicles and mature stages of the oocytes in the ovary and there was an inhibition in the spermatogenesis.