Histological development of the digestive system of the Amazonian pimelodid catfish Pseudoplatystoma punctifer

Abstract

The organogenesis of the digestive system was described in the Amazonian pimelodid catfish species Pseudoplatystoma punctifer from hatching (3.5 mm total length, TL) to 41 days post-fertilization (dpf) (58.1 mm TL) reared at 28°C. Newly hatched larvae showed a simple digestive tract, which appeared as a straight undifferentiated and unfolded tube lined by a single layer of columnar epithelial cells (future enterocytes). During the endogenous feeding period, comprised between 20 and 96 h post-fertilization (3.5 to 6.1 mm TL), the larval digestive system experienced a fast transformation with the almost complete development and differentiation of most of digestive organs (buccopahrynx, oesophagus, intestine, liver and exocrine pancreas). Yolk reserves were not completely depleted at the onset of exogenous feeding (4 dpf, 6.1 mm TL), and a period of mixed nutrition was observed up to 6 to 7 dpf (6.8 to 7.3 mm TL) when yolk was definitively exhausted. The stomach was the organ that latest achieved its complete differentiation, characterized by the development of abundant gastric glands in the fundic stomach between 10 and 15 dpf (10.9 to 15.8 mm TL) and the formation of the pyloric sphincter at the junction of the pyloric stomach and the anterior intestine at 15 dpf (15.8 mm TL). The above-mentioned morphological and histological features observed suggested the achievement of a digestive system characteristic of P. punctifer juveniles and adults. The ontogeny of the digestive system in P. punctifer followed the same general pattern as in most Siluriform species so far, although some species-specific differences in the timing of differentiation of several digestive structures were noted, which might be related to different reproductive guilds, egg and larval size or even different larval rearing practices. According to present findings on the histological development of the digestive system in P. punctifer, some recommendations regarding the rearing practices of this species are also provided in order to improve the actual larval rearing techniques of this fast-growing Neotropical catfish species.Keywords: histology, ontogeny, digestive system, catfish, larvae, Amazonia ImplicationsThe aquaculture of Amazonian native species requires the mastering of their biological cycle, especially the improvement of current larval rearing procedures. In this context, the present study provides a detailed and comprehensive description of the development of the digestive tract and accessory glands in the pimelodid catfish Pseudoplatystoma punctifer. This information will provide insight in the digestive physiology of this Amazonian fish species in order to synchronize the stage of larval development with rearing procedures and overcome actual larval rearing bottlenecks (e.g. diet formulation, weaning and cannibalistic behaviour). IntroductionAquaculture in Latin America and the Caribbean is principally known for the salmon industry in Chile and shrimp farming in Ecuador. However, the benefits of this export-oriented and large-scale...

Influence of dietary protein and lipid levels on growth performance and the incidence of cannibalism inPseudoplatystoma punctifer (Castelnau, 1855) larvae and early juveniles

“…This finding is of special relevance considering the high cost of Artemia and the associated costs of nauplii production. The results are also consistent with our hypothesis that Artemia nauplii do not cover the nutritional needs of P. punctifer larvae (Gisbert et al., ), as survival and growth performance of specimens from this group (C) were similar to those of the 30P : 15L group and only higher than the group fed the 30P : 10L diet. These results indicate that the feeding protocol used previously (Gisbert et al., ) allowed larvae to grow normally, but did not let them fully exploit their growth potential.…”

“…The results are also consistent with our hypothesis that Artemia nauplii do not cover the nutritional needs of P. punctifer larvae (Gisbert et al., ), as survival and growth performance of specimens from this group (C) were similar to those of the 30P : 15L group and only higher than the group fed the 30P : 10L diet. These results indicate that the feeding protocol used previously (Gisbert et al., ) allowed larvae to grow normally, but did not let them fully exploit their growth potential. In addition, the large accumulation of lipid deposits found in the intestine and liver suggested a nutritional imbalance with regard to protein and lipid content of the administered compound diet (Gisbert et al., ).…”

“…In addition, the large accumulation of lipid deposits found in the intestine and liver suggested a nutritional imbalance with regard to protein and lipid content of the administered compound diet (Gisbert et al., ). The 45P : 15L diet soon showed an evident positive effect on growth (1 week after weaning) and at the end of the experiment allowed the amelioriation of larval growth performance (six times in terms of WW and two times in terms of TL) and survival (two times) compared to preceding protocols under similar rearing conditions (Gisbert et al., ; M.J. Darias, unpublished data). Nevertheless, parental origin, which significantly affects growth during the early development of this species (Núñez et al., ), might also account for such differences.…”

“…Establishing an adequate feeding protocol adapted to the digestive capacities and nutritional needs during early development while also addressing options to reduce cannibalism is of primary importance to improve survival and growth. We have already described the ontogeny of the digestive system of P. punctifer in order to synchronize the stage of development and maturation of their digestive organs with the feeding protocol and rearing practices (Gisbert et al., ). We found a clear correlation between the feeding protocol and the incidence of cannibalism, suggesting that improving feeding strategies and nutrition could reduce cannibalistic behaviour.…”

EVALUACIÓN DE LA INFLUENCIA PARENTAL EN RELACIÓN AL CRECIMIENTO Y SUPERVENCIA LARVAL EN FAMILIAS DE LA doncella Pseudoplatystoma punctifer

“…A pesar de haberse realizado varios estudios para controlar el ciclo de vida completo de esta especie en ambientes controlados Fernández et al, 2015;Gisbert et al, 2014;Nuñez et al, 2008;Nuñez et al, 2009;Nuñez et al, 2011;Baras et al, 2011;Baras et al, 2012) su acuicultura a gran escala, aún no se ha implementado en el Perú. Una de las limitantes es la baja tasa de supervivencia en la última etapa larval y juvenil así como también la aparición de manera precoz de individuos de mayor tamaño denominados "jumpers" capaces de ejercer depredación sobre las larvas más pequeñas, ocasionando altas tasas de mortalidad.…”