title: Freshwater catfish jundiá (Rhamdia quelen) larvae are prepared to digest inert feed at the exogenous feeding onset: physiological and histological assessments.
abstract: This study assessed the morphological development of jundiá larvae's digestive system and digestive proteolytic activity. Specific serine proteinases activities varied over time, with the highest peak at 12 h after hatching (AH), which corresponded to 296.38 ± 84.20 mU mg⁻¹ for trypsin and 315.45 ± 42.16 mU mg⁻¹ for chymotrypsin. Specific aspartic proteinases activities increased up to the start of weaning, oscillated during that phase, but showed a consistent increase after that, resulting in the highest specific activity at 252 h AH (7.88 ± 0.68 mU mg⁻¹). Gel assays showed different molecular forms, especially of serine proteinases. Histology showed the gastrointestinal tract development onset at 0 h AH and open mouth at 4 h AH. At 16 h AH, the following differentiation of the digestive tract was evident: oropharyngeal cavity, esophagus, liver, pancreas, stomach, and intestine. At 40 h AH, zymogen granules in the pancreas were observed, and at 48 h AH, mucus in the digestive tract and gastric glands in the stomach. Findings indicate that jundiá has a functional stomach before the end of vitelline reserves. Therefore, jundiá larvae are probably capable to digest inert feed at the exogenous feeding onset.
authors.affiliation: Aquaculture Department, Agrarian Sciences Centre, Federal University of Santa Catarina, Rodovia Admar Gonzaga, 1346, Florianópolis, SC, 88034-001, Brazil.
authors.forename: Jenniffer
authors.initials: J
authors.lastname: Silveira
authors.forename: Carlos Peres
authors.initials: CP
authors.lastname: Silva
authors.forename: Eduardo
authors.initials: E
authors.lastname: Cargnin-Ferreira
authors.forename: Daniel
authors.initials: D
authors.lastname: Alexandre
authors.forename: Mariele Abádia
authors.initials: MA
authors.lastname: Elias
authors.forename: Débora Machado
authors.initials: DM
authors.lastname: Fracalossi
mesh_terms: D000821:Animal Feed; D000818:Animals; D017756:Aquaculture; D002397:Catfishes / Q000033:anatomy & histology / Q000502:physiology*; D004063:Digestion; D041981:Gastrointestinal Tract / Q000033:anatomy & histology / Q000201:enzymology*; D007814:Larva / Q000033:anatomy & histology / Q000502:physiology