JOURNAL OF ANIMAL AND VETERINARY ADVANCES, cilt.8, ss.2477-2484, 2009 (SCI İndekslerine Giren Dergi)
The ontogeny of the exocrine pancreas was studied histological with the expression of digestive protease, trypsin, activity in gilthead sea bream, Sparus aurata, L. larvae from hatching to 30 days after Hatching (DAH). The pancreas was identified as a well developed differentiated cells located dorsal and slightly posterior to the liver at 3 DAH. Incipient pancreas with exocrine polyhedral cells could be observed and first zymogen granules detected at this period. Until the larval metamorphosis, the pancreas became diffuse, spreading throughout the mesentery enclosure the stomach, the upper intestine and the pyloric caeca. The specific activity of trypsin (48.35+/-4.3 mU/mg/protein) and chymotrypsin (205.38+/-46.2 mU/mg/protein) was determined as early as after hatching at 2.27+/-0.14 mm Total Length (TL) of larvae and increased immediately during the following days especially, after exogenous feeding. The highest trypsin and chymotrypsin activity was detected at 25 DAH as 11 8.26+/-10.23 mU/mg/protein and 1067.53+/-118.42 mU/mg/protein, respectively that concurrently detected with Artemia metanauplii introduction. It is concluded that exocrine pancreas organogenesis is the main critical step of the zymogen granules and specific activities digestive proteases, trypsin and chymotrypsin, were present as early as after hatching and continuously increasing with larval period of Sparus aurata.