Differential digestive and metabolic profile of juveniles and adults of the estuarine-dependent marine fish Mugil liza (Mugilidae) cohabiting inside a southwestern Atlantic coastal lagoon

ALBANESI,C.; GONZÁLEZ CASTRO, M.; LÓPEZ MAÑANES, A,A.

CANADIAN JOURNAL OF ZOOLOGY

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Lugar: Otawa; Año: 2023 vol. 101 p. 1079 - 1092

0008-4301

AbstractIntegrative studies on intraspecific differences of digestive enzymes, energy reserves, and morphological/somatic traits injuveniles and adults of estuarine-dependent marine fish while inhabiting inside a coastal lagoon are lacking. This study wascarried on juveniles and adults of Mugil liza Valenciennes, 1836 inhabiting inside Mar Chiquita Coastal Lagoon (Argentina).Both stages exhibited amylase, maltase, sucrase, lipase, trypsin, and aminopeptidase-N activities in the intestine, which wereactive over a wide range of pH and temperatures and exhibited Michaelis–Menten kinetics. Adults exhibited higher intestinalcoefficient (31%), higher amylase (32%), and lower maltase (82%) and lipase activities (38%). Glycogen concentration in liver andmuscle was similar, while free glucose concentration was higher in adults (772% and 400%, respectively). In adults, retroperitonealfat (absent in juveniles) constituted the main triglycerides (TAG) storage site, while TAG concentration in liver andmuscle was lower (86% and 80%, respectively) than that in juveniles. No differences were found in protein concentration inany storage organ. The results show that juveniles and adults exhibit a digestive and metabolic profile at the biochemicallevel and intraspecific differences in key components of carbohydrate and lipid metabolism that could support preparationfor reproductive migration of adults outside the coastal lagoon.Key words: digestive enzymes, energy reserves, Mugil liza, fish, juveniles, adults