Larval ontogeny and morphology of giant trahira Hoplias lacerdae

Sales²,

et al. 2016

RBT

The early life story of the curimatas Prochilodus argenteus and Prochilodus costatus was studied from hatching until the complete absorption of the yolk, in order to provide knowledge about its growth and behavior, which can be applied to the development of the larval rearing as well as taxonomic characters. The larvae were obtained from artificial reproduction at Hydrobiology and Aquaculture Station of Três Marias, Minas Gerais. Immediately after the hatching approximately 100 larvae of each species were conditioned in two plastic incubators. Larvae behavior was registered daily and were collected 14 larvae of each species to analyze body morphology. On the first day post-hatching the larvae showed elongated and transparent body. The yolk sac was filled with individualized yolk globules. In both species, the embryonic fin rounded the caudal region of the body, the retina showed depigmented and the gut was obliterated. On the second day, larvae have emerged dendritic chromatophores, the mouth was obliterated and the pectoral fin was recorded. The larvae showed 38-43 myomeres in P. costatus and 42-43 in P. argenteus. The gas bladder was inflated and the lumen of the gut was already open. On the third day, the mouth was already open and in a sub terminal position. Retina was pigmented, the gill arches had lamellar protrusions and were partially covered by the operculum. On the fourth day, the pigmentation pattern was maintained with greater intensity; the mouth occupied terminal position, the yolk sac was almost completely reabsorbed and pectoral and caudal fins showed mesenchymal rays. The gut showed broad lumen with folded mucosa and epithelium with striated border. The larvae of both species showed similar swimming behavior during the trial period.

Section: Discussionsupporting

confidence: 85%

Section: Discussionsupporting

confidence: 51%

Early ontogeny and swimming behavior of larvae of the neotropical fish Prochilodus costatus Valenciennes 1850 and Prochilodus argenteus Spix & Agassiz 1829 (Characiformes: Prochilodontidae)

Sales²,

et al. 2016

RBT

Comprehensive Physiology

“…A large number of studies of GI development in at least a dozen fish species have been published in the past decade (59, 67, 96, 104, 187, 191, 200, 213, 224, 225, 240, 260, 264, 269, 273, 281, 327–329, 359, 481, 484, 485) due to their importance in aquaculture, and many studies include newer molecular and gene expression approaches (109, 272). As in birds, a major ontogenetic change in fish is that the source of nutrients and energy necessary to continue larval development changes from the yolk reserves to the ingested food, which is mainly protein and fat in carnivores but higher in carbohydrates in omnivores and herbivores.…”

Section: Matches Of Gi System To Nutritional Changes During Ontogenymentioning

confidence: 99%

Comparative Digestive Physiology

Karasov

Douglas

2013

261

221

In vertebrates and invertebrates, morphological and functional features of gastrointestinal (GI) tracts generally reflect food chemistry, such as content of carbohydrates, proteins, fats, and material(s) refractory to rapid digestion (e.g., cellulose). The expression of digestive enzymes and nutrient transporters approximately matches the dietary load of their respective substrates, with relatively modest excess capacity. Mechanisms explaining differences in hydrolase activity between populations and species include gene copy number variations and single-nucleotide polymorphisms. Transcriptional and posttranscriptional adjustments mediate phenotypic changes in the expression of hydrolases and transporters in response to dietary signals. Many species respond to higher food intake by flexibly increasing digestive compartment size. Fermentative processes by symbiotic microorganisms are important for cellulose degradation but are relatively slow, so animals that rely on those processes typically possess special enlarged compartment(s) to maintain a microbiota and other GI structures that slow digesta flow. The taxon richness of the gut microbiota, usually identified by 16S rRNA gene sequencing, is typically an order of magnitude greater in vertebrates than invertebrates, and the interspecific variation in microbial composition is strongly influenced by diet. Many of the nutrient transporters are orthologous across different animal phyla, though functional details may vary (e.g., glucose and amino acid transport with K+ rather than Na+ as a counter ion). Paracellular absorption is important in many birds. Natural toxins are ubiquitous in foods and may influence key features such as digesta transit, enzymatic breakdown, microbial fermentation, and absorption

Journal of Fish Biology

“…The development of the caudal fin and its supporting elements helps larvae in their initial swimming movements and more active displacement in the water column, indicating the establishment of caudal propulsion (Omori et al, 1996; Osse & Boogaart, 1999). Conversely, the late development of the pectoral fin will assist in the balance and swimming ability of the larvae (maneuverability) throughout the water column (Gomes et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Early ontogeny of the freshwater fish Rhytiodus microlepis (Characiformes, Anostomidae) from the Amazon basin

Santos,

Oliveira,

Silva

et al. 2024

The early development of the freshwater fish Rhytiodus microlepis is characterized by the description of external morphological, meristic, and morphometric changes, as well as the growth patterns, thereby establishing a reference for the identification of its larvae and juveniles. Specimens were collected from the Amazon river channel and floodplain. Ninety‐seven individuals were analysed with standard length varying between 4.31 and 79.23 mm. Rhytiodus microlepis larvae are altricial, with an elongated and fusiform body, anal opening reaching the middle region of the body, and simple nostrils becoming double and tubular during development. The pigments vary from one to two chromatophores in the dorsal region of the head in pre‐flexion and flexion, but later the pigmentation pattern intensifies, transverse bands appear along the body, and a conspicuous spot appears in the basal region of the caudal fin. The total number of myomeres ranges from 49 to 50. During the transition from larval (post‐flexion) to the juvenile periods, the most significant anatomical changes occur, such as the presence of all fins and increased body pigmentation. Integrated myomere count and pigmentation pattern are effective for the correct identification of the initial life stages of R. microlepis from the Amazon basin. Our results expand the knowledge about the early life history of Neotropical freshwater fish species.