Histological development of digestive tract in discus, Symphysodon spp. larvae

Abstract

The present study provides information on the histomorphological development of digestive system of discus, Symphyosodon spp., larvae during the first month of life. Discus larvae are altricial at hatching, with an undifferentiated digestive tract and a large yolksac, which is completely consumed within 7 days. The mouth opens 3 days after hatching (DAH) and the larvae starts feeding on AF Artemia at 4 DAH when offered. At 3 DAH the digestive tract is differentiated with distinct esophagus, stomach anlage, and mid-and hindguts. At 5 DAH, discus larvae is an active feeder, equipped with partly developed jaws and ossified gill arches and an inflated swim bladder. The liver and pancreas are present and supranuclear inclusion vacuoles (SIV) appear in the hindgut for the first time. Gastric glands in stomach were first observed 7 DAH and proliferated by 11-13 DAH. SIV were a common feature in the midgut and hindgut epithelium until 15-23 DAH. Therefore, exclusive use of artificial diets should be postponed until 2-3 weeks after hatching.

Morphological and morphometric aspects of early life stages of piabanhaBrycon gouldingi(Characidae)

“…Önal et al . () classified larvae with a large yolk sac and an undifferentiated gut at hatching, as those of B. gouldingi, as altricial larvae.…”

Gross morphology and histology of the alimentary tract of the convict cichlid Amatitlania nigrofasciata

“…Most of the detailed studies on the piscine AT focus on commercial aquaculture species, such as rainbow trout Oncorhynchus mykiss (Walbaum 1792) (Ezeasor & Strokoe, 1981;Ostos-Garrido et al, 1993;Khojasteh et al, 2009) and species of tilapia (Gargiulo et al, 1998;Abdulahadi, 2005). Only a few studies deal with the digestive tract of aquarium fish species (Hale, 1965;Caceci, 1984;Önal et al, 2010).…”

Characterization of the initial ontogeny ofLeiarius marmoratus(GILL, 1870): larvae to juvenile

“…According to descriptions reported by Nakatani et al (2001), in Pimelodidae it is common for hatched larvae to exhibit a lack of pigmentation in the eyes and to have an incomplete digestive system, with mouth and anal openings still closed, as observed in newly hatched larvae of Brycon gouldingi (Önal, Çelik, & Cirik, 2010).…”

“…According to descriptions reported by Nakatani et al (), in Pimelodidae it is common for hatched larvae to exhibit a lack of pigmentation in the eyes and to have an incomplete digestive system, with mouth and anal openings still closed, as observed in newly hatched larvae of Brycon gouldingi (Önal, Çelik, & Cirik, ). The eyes pigmentation and functionality of mouth and intestine occurred at the transition between yolk stage and pre‐flexion, together with the end of yolk reserve consumption and the beginning of exogenous feeding, which adds the statements of Lasker, Feder, Theillacker, & May, that mouth opening and pigmentation of the eye are directly related to the onset of exogenous feeding, and are events that occur simultaneously during development.…”