Carbohydrases and glycogen reserves in prejuveniles of Mugil liza (Actinopterygii; Fam. Mugilidae) upon different postprandial times and refeeding

ALBANESI,C.; MENDEZ, E.; MICHIELS, M.S.; GONZALEZ CASTRO, M. *AMBOS AUTORES CONTRIBUYERON DE IGUALMENTE A ESTE TRABAJO; LÓPEZ MAÑANES, A.A:.*AMBOS AUTORES CONTRIBUYERON DE IGUALMENTE A ESTE TRABAJO

Conferencia; VII CONFERENCIA LATINOAMERICANA SOBRE CULTIVO DE PECES NATIVOS ANAIS; 2022

EQUIPO ORGANIZADOR RONALD KENNEDY LUZ GISELE CRISTINA FAVERO CINTIA LABUSSIÈRE NAKAYAMA

To establish the postprandial dynamics and adjustments after feeding, fasting/ refeeding of digestive enzymes and energy reserves in fish under aquaculture allows to determine the transition from feeding to food deprivation and to minimize costs of maintenance. Mullets are cultured in extensive, semi-intensive or intensive systems. The southern population of Mugil liza is distributed from the state of São Paulo, Brazil (23 °S) to Argentina (47 °S). The tolerance to different external condition supports its use in aquaculture. Studies on the dynamics of key digestive and energy reserves upon food deprivation/ refeeding are lacking. The aim was to analyze at different times after feeding and after refeeding, amylase, maltase and sucrase in intestine and glycogen and free glucose concentration in liver and muscle in prejuveniles. Prejuveniles were collected (Total length: 50.5 ±5.1 mm, total weight: 42.1±4.3g) after recruitment into Mar Chiquita Coastal Lagoon, Argentina. The animals were maintained in aquarium water aerated and filtered (170L; 18 psu 20°C) and fed twice a day (TetraMin food) ad libitum. Determinations were done immediately (t0) and at 24, 72, 144 and 240h after feeding. At 240h, fish were re-fed and the corresponding determinations were done after 72h. The intestine, liver and muscle were homogenized in 50 mM Tris/HCl, pH 7.4 (intestine and liver: 4 ml of tissue g-1; muscle: 8 ml oftissue g-1). Amylase (μg maltose x min-1 x mg protein-1) was assayed by hydrolysis of starch in 50mM phosphate buffer pH 7,4 (30ºC). Sucrase and maltase (μg glucosa x mg prot-1 x min-1) by hydrolysis of the corresponding substrate in 0.1 M maleate pH 6,4 (37°C). Glycogen (mg x g tissue-1) was determined by hydrolysis with α-amyloglucosidase (0,2ml/ml). Free glucose was determined without α-amyloglucosidase. Analysis of variance (one-way ANOVA ) was used to estimate the statistical significance of the differences and P