Organogenesis of the digestive system in Neotropical carnivorous freshwater catfish Hemisorubim platyrhynchos (Siluriformes: Pimelodidae)

Abstract

The morphological development of the digestive system of Hemisorubim platyrhynchos was studied from the day of hatching until 21 days post-hatching (DPH) using histology, histochemistry and scanning electron microscopy to augment the available knowledge regarding the organogenesis of the digestive system of this carnivorous Neotropical fish. The development of the digestive system was divided into four major stages. Stage I (endotrophic period) starts with hatching and ends with the mouth opening at 2 DPH. The digestive tract originated as a straight undifferentiated tube and ended as an esophagus with goblet cells, an incipient stomach and an intestine divided into the anterior, middle, posterior and rectum. Stage II (endo-exotrophic period) is from the onset of feeding to exhaustion of the yolk at 4 DPH. Stage III is the period in which the larvae rely exclusively on exogenous feeding but still have no functional stomach. Stage IV is an exotrophic period marked by the appearance of gastric glands at 15 DPH. At 20 DPH, the saccular stomach can be observed. Fish growth was largely variable over the time period studied, and the variability was predominant between the period in which the yolk was present and after its exhaustion. The mixed feeding period is short, and the larvae subsequently survive solely by exogenous feeding without a functional stomach for 15 days. During this period, the primary site of digestion is the anterior intestine, which presents with a saccular shape. The accessory glands, liver and pancreas were differentiated at 2 DPH and thus contributed to extracellular digestion. Also observed in the intestine were supranuclear inclusions that could promote intracellular digestion. The rectal columnar epithelium showed scarce goblet cells but had apical mucosubstances that were involved in fecal transit, epithelial protection and in the final absorption of substances. Gastric glands appeared at 15 DPH and, until this period, the larvae should receive live feed and after 15 DPH may be weaned. H. platyrhynchos farmers should also be alert to differences in the size of the fish because this species presents cannibalism and needs to be separated into homogeneous batches.

Development of the digestive system of Argentine hake, Merluccius hubbsi, larvae

“…As reported in larvae of various species such as Dentex dentex L. (Santamaría et al, 2004), Dicentrarchus labrax L. (García‐Hernández, Lozano, Elbal, & Agulleiro, 2001), P. californicus (Gisbert et al, 2004), P. auriga (Sánchez‐Amaya et al, 2007), Engraulis anchoita (Cohen et al, 2014), L. peru (Peña et al, 2017), the number of mucous cells in Argentine hake larvae varied according to the age and the region of the intestinal tract analyzed. The glycosylation pattern of the digestive tract of the larvae of M. hubbsi was similar to other teleost fish such as E. anchoita (Cohen et al, 2014), M. merluccius (Ortiz‐Delgado et al, 2012), Hemisorubim platyrhynchos (Faccioli et al, 2016).…”

“…The organogenesis of the digestive tract has been studied in various teleost species (Cohen et al, 2014; Faccioli et al, 2016; Makrakis et al, 2005; Ortiz‐Delgado et al, 2012; Peña, Dumas, & Contreras‐Olguín, 2017; Teles et al, 2015). Betti (2011) made a first description of the development pattern of the digestive system in M. hubbsi and this study deepens that information.…”

“…The digestive system undergoes major modifications during ontogeny (Makrakis et al, 2005; Zambonino‐Infante et al, 2008). Knowledge about the timing of the digestive system development is crucial to adjust early cultivation conditions and improve survival, growth, and weaning (Faccioli et al, 2016) and in this way to optimize larviculture strategies (Frías‐Quintana et al, 2015).…”

“…GCs with oxidizable vicinal diols are important in the control of the acidity of the mucus secretion (Cohen et al, 2016; Díaz et al, 2005; Mittal et al, 1994) and protect the mucosa against abrasion (Wang et al, 2017). Neutral mucins participate in the formation of the chyme (Murray, Wright, & Goff, 1996; Sarasquete et al, 2001), and may indicate a pregastric digestion (Faccioli et al, 2016; Grau, Crespo, Sarasquete, & Gonzales de Canales, 1992).…”

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

“…Similar to Prochilodus (3 rd DAH) ( Figure 1A), the larvae of several species and orders, such as the Characiformes Brycon orbignyanus (Maciel et al, 2010), the Silurioformes Hemisorubim platyrhynchos (Faccioli et al, 2016), the Perciformes Cichlasoma rophthalmus (Cuenca-Soria et al, 2013) and Symphyosodon sp. (Önal, Çelik, & Cirik, 2010) revealed an undifferentiated digestive tract and a yolk sac during the first days of life.…”