<b>Development of the digestive system in larvae of the Neotropical fish <i>Prochilodus argenteus</i> (Characiformes, Prochilodontidae)

Abstract

The development of the digestive system in larvae of the Neotropical fish P. argenteus was analyzed histologically. On the 3 rd day after hatching, the digestive system comprised oropharyngeal cavity, esophagus and simple undifferentiated tube. Since secreting cells, positive to Alcian Blue (AB), were found in the esophagus, digestive activity in the initial phase had occurred. On the 18 and 28 th days after hatching, the esophagus was positive for AB and Periodic Acid Schiff (PAS) stain. The stomach was fully differentiated, with the cardiac, fundic and pyloric regions. Different regions of the epithelium were characterized by basic and acidic secreting cells (AB and PAS positive). On the 18 and 28 th days after hatching, the intestine was long, coiled and divided into proximal, middle and distal segments with pyloric ceca. Secreting cells in different regions of the gut were either positive or negative for AB and PAS. Results showed that larvae of P. argenteus exhibited digestive activity on the third day after hatching, with fully differentiated stomach and intestines on the 18 and 28 th days and their different regions featuring secreting cells.

Systematic evaluation of the gut microbiome of swamp eel (Monopterus albus) by 16S rRNA gene sequencing

“…This difference may be associated with the specific physiological structure of the swamp eel’s intestine. Unlike omnivorous and herbivorous fish with usually long and coiled intestines (Pereira et al, 2015; Santos et al, 2016), swamp eel is carnivorous with an intestine that is short and straight. The midgut is thought to be the organ where the majority of digestion occurs (Egerton et al, 2018).…”

Ontogenetic development of the gastrointestinal tract of African lungfish larvaeProtopterus aethiopicus(Heckel 1851): A light microscopy study

“…The 3D reconstruction model enables us to understand the morphology of the digestive organs and also provides a deeper insight into the mechanisms of feeding and digestive physiology during ontogeny (Kamisaka and Rønnestad, 2011). This morphological assessment is critical in evaluating the changes in the gastrointestinal tract development and also the larvae's ability to utilize food (Santos, Pedreira, Santos, & Souza, 2016). Morphology and spatial organization of the gastrointestinal tract can be a challenge to understand on the basis of 2D histological sections or drawings, especially when the elongated gut gets more coiled in the peritoneal cavity as the larvae develops (Kamisaka and Rønnestad, 2011).…”

Peer Review #1 of "Systematic evaluation of the gut microbiome of swamp eel (Monopterus albus) by 16S rRNA gene sequencing (v0.2)"

“…This difference may be associated with the specific physiological structure of swamp eel's intestine. Unlike omnivorous and herbivorous fish which usually have long and coiled intestines (Pereira et al, 2015;Santos et al, 2016), swamp eel is carnivorous which intestine is short and straight. And, generally, the mid-gut is thought to be the organ where the majority of digestion occurs (Egerton et al, 2015).…”