Understanding the early ontogenetic stages of Mugil liza (Mugilidae): morphological traits and digestive/metabolic profile of pre-juveniles after recruitment

ALBANESI, C;; GONZÁLEZ-CASTRO, MARIANO; LÓPEZ-MAÑANES, A.

JOURNAL OF FISH BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021 vol. 98 p. 643 - 654

0022-1112

Mugilidae Family is mostly constituted by diadromous species, whose reproductionoccurs in offshore waters. Pre-juveniles shift their diet in the surf zone(zooplanctophagous to iliophagous). Later, during their recruitment into estuaries, willexperiment huge changes in their digestive system. However, digestive and metaboliccharacteristics and some morphological traits upon recruitment are unknown forMugilidae. We performed comparative studies on early and late pre-juveniles of Mugilliza recruited in Mar Chiquita Coastal Lagoon (37°32′?37°45′S; 57°19′?57°26′W,Argentina). We determined digestive enzymes activities (intestine), energy reserves(liver/muscle), total/standard length, total weight, intestinal coefficient, hepatosomaticindex and retroperitoneal fat. Pre-juveniles exhibited amylase, maltase, sucrase,lipase, trypsin and APN activities, which were maintained over a wide range of pH andtemperature and exhibited Michaelis-Menten kinetics. In late pre-juveniles, amylase(422±131μmol maltose x min -1 x mgprot -1 ), sucrase (86±14 mg glucose x min -1x mg prot -1 ), trypsin (84±9 μmoles x min -1 x mg prot -1 ) and APN (0.58±0.08μmoles x min -1 x mg prot -1 ) activities were higher (42, 28, 35 and 28%,respectively) than in the early stage. Also, intestinal coefficient was higher in late (3.04)than early (2.06) pre-juveniles. Moreover, liver appeared to be a main site of glycogenand triglycerides storage of late pre-juveniles, being muscle the site of storage in earlypre-juveniles, which exhibited higher glycogen, free glucose and protein concentration(92, 82, 32%, respectively). The results suggest that pre-juveniles of M. liza exhibit anadequate digestive battery to perform complete hydrolysis of various dietarysubstrates, availability of energy reserves and morphological characteristics to supporttheir feeding habit and growing after recruitment. Our results represent an importantcontribution to increase the knowledge about ecology and digestive physiology of prejuvenilesof Mugilidae in the wild.