Análises morfológicas e histoquímicas da ontogenia do sistema digestório de Pseudoplatystoma reticulatum, Leiarius marmoratus e das progênies do cruzamento entre estas espécies
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Data
2020-02-20
Autores
Oliveira, Yasmim Alves Araújo de
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Universidade Estadual Paulista (Unesp)
Resumo
Pseudoplatystoma reticulatum, Leiarius marmoratus e o híbrido resultante do cruzamento entre essas espécies apresentam características zootécnicas interessantes e promissoras para o cultivo em piscicultura. Porém, a larvicultura dessas espécies apresentam altos índices de mortalidade, pois nesse período as larvas não estão totalmente desenvolvidas e não possuem o sistema digestório completamente formado. Pesquisas relacionadas ao desenvolvimento do sistema digestório de larvas tem sido uma ferramenta importante para o conhecimento sobre os períodos de alimentação endógena, exógena e mista. Neste sentido, este trabalho teve como objetivo analisar e comparar as características anatômicas, histológicas e histoquímicas do sistema digestório de Pseudoplatystoma reticulatum, Leiarius marmoratus e do híbrido, nas fases inicias de desenvolvimento após eclosão. As amostras foram fixadas em solução de karnovsky (paraformoldeído 4% + glutaraldeído 2% + tampão fosfato Sorensen 0,1 M, pH 7,2), e processadas para análise anatômica, histológica e histoquímica. As larvas de P. reticulatum, L. marmoratus e híbrido eclodiram 24 horas após a fertilização. As larvas recém-eclodidas apresentaram-se pouco desenvolvidas e com escassez de cromatóforos. A cavidade bucofaríngea pôde ser observada, mas não foi possível diferenciar os componentes do tubo digestivo. As reservas de vitelo foram observadas até o 3º DPE em P. reticulatum e em L. marmoratus e no Híbrido até o 4º DPE. Para os três modelos biológicos, as primeiras células caliciformes do esôfago foram observadas ao 1º DPE. O epitélio de revestimento do esôfago foi caracterizado como estratificado pavimentoso e com a presença de células caliciformes. Com o desenvolvimento dos animais, as células caliciformes foram reativas ao PAS, AB, PAS+AB. Com relação ao estômago, em P. reticulatum e L. marmoratus as primeiras estruturas foram visualizadas no 3º DPE, a formação das glândulas gástricas foi observada a partir do 15º DPE e 14º DPE, respectivamente. No Híbrido as primeiras estruturas do estômago foram visualizadas ao 4º DPE e até o 12º DPE não foram observadas a formação de glândulas gástricas. O epitélio de revestimento do estômago foi caracterizado como simples colunar com ausência de células caliciformes. Foi observada intensa reação ao PAS no epitélio de revestimento do estômago ao 3º DPE para larvas de P. reticulatum, no 5º DPE para larvas de L. marmoratus e 4º DPE para o Híbrido, indicando a presença de mucosubastâncias neutras. Quanto ao intestino, este apresentou epitélio simples colunar e células caliciformes sendo mais concentradas na região posterior. As células caliciformes do intestino apresentaram reação positiva ao PAS e PAS+AB, indicando a presença de mucosubastâncias neutra e ácida. Sobre a formação das glândulas anexas, o fígado teve sua diferenciação observada no 1º DPE e o pâncreas ao 2º DPE. No início da alimentação exógena as glândulas anexas já se encontravam bem desenvolvidas.
Pseudoplatystoma reticulatum, Leiarius marmoratus and the hybrid resulting from the cross between these species show interesting and promising zootechnical characteristics for fish farming. The main bottleneck of larviculture today is the high mortality rate in the early stages of life, because in this period the larvae are not fully developed and do not have a fully formed digestive system. Research related to the development of the digestive system of larvae, has been an important tool for understanding the periods of endogenous, exogenous and mixed feeding. In this sense, this work aimed to analyze and compare the anatomical, histological and histochemical characteristics of the digestive system of Pseudoplatystoma reticulatum, Leiarius marmoratus and the hybrid, in the early stages of development after hatching. The samples were fixed in a karnovsky solution (paraformoldehyde 4% + glutaraldehyde 2% + phosphate buffer Sorensen 0.1 M, pH 7.2), and processed for anatomical, histological and histochemical analysis. The larvae of P. reticulatum, L. marmoratus and hybrid hatched 24 hours after fertilization. The newly hatched larvae were poorly developed, with a shortage of chromatophores. The buccopharyngeal cavity could be observed, but it was not possible to differentiate the components of the digestive tract. Calf reserves were observed until the 3º DPE in P. reticulatum and in L. marmoratus and in the hybrid until the 4º DPE. For the three biological models, the first goblet cells of the esophagus were observed at the 1º DPE. The esophageal lining epithelium was characterized as a stratified pavement and with the presence of goblet cells. With the development of the animals, the goblet cells were reactive to PAS, AB, PAS + AB. Regarding the stomach, in P. reticulatum and L. marmoratus the first structures were seen on the 3ºDPE, the formation of the gastric glands was observed from the 15º DPE and 14º DPE, respectively. In the hybrid, the first stomach structures were visualized at the 4º DPE and until the 12º DPE the formation of gastric glands was not observed. The stomach lining epithelium was characterized as a simple columnar with no goblet cells. An intense reaction to PAS was observed in the stomach lining epithelium at the 3º DPE for P. reticulatum larvae, at the 5º DPE for larvae of L. marmoratus and 4º DPE for the hybrid, indicating the presence of neutral mucosubstances. As for the intestine, it presented simple columnar epithelium and goblet cells being more concentrated in the posterior region. Goblet cells in the intestine showed a positive reaction to PAS and PAS + AB, indicating the presence of neutral and acid mucosubstances. Regarding a formation of the attached glands, the liver had its differentiation observed in the 1º DPE and increased the 2º DPE. At the beginning of exogenous feeding as attached glands are already being found well developed.
Pseudoplatystoma reticulatum, Leiarius marmoratus and the hybrid resulting from the cross between these species show interesting and promising zootechnical characteristics for fish farming. The main bottleneck of larviculture today is the high mortality rate in the early stages of life, because in this period the larvae are not fully developed and do not have a fully formed digestive system. Research related to the development of the digestive system of larvae, has been an important tool for understanding the periods of endogenous, exogenous and mixed feeding. In this sense, this work aimed to analyze and compare the anatomical, histological and histochemical characteristics of the digestive system of Pseudoplatystoma reticulatum, Leiarius marmoratus and the hybrid, in the early stages of development after hatching. The samples were fixed in a karnovsky solution (paraformoldehyde 4% + glutaraldehyde 2% + phosphate buffer Sorensen 0.1 M, pH 7.2), and processed for anatomical, histological and histochemical analysis. The larvae of P. reticulatum, L. marmoratus and hybrid hatched 24 hours after fertilization. The newly hatched larvae were poorly developed, with a shortage of chromatophores. The buccopharyngeal cavity could be observed, but it was not possible to differentiate the components of the digestive tract. Calf reserves were observed until the 3º DPE in P. reticulatum and in L. marmoratus and in the hybrid until the 4º DPE. For the three biological models, the first goblet cells of the esophagus were observed at the 1º DPE. The esophageal lining epithelium was characterized as a stratified pavement and with the presence of goblet cells. With the development of the animals, the goblet cells were reactive to PAS, AB, PAS + AB. Regarding the stomach, in P. reticulatum and L. marmoratus the first structures were seen on the 3ºDPE, the formation of the gastric glands was observed from the 15º DPE and 14º DPE, respectively. In the hybrid, the first stomach structures were visualized at the 4º DPE and until the 12º DPE the formation of gastric glands was not observed. The stomach lining epithelium was characterized as a simple columnar with no goblet cells. An intense reaction to PAS was observed in the stomach lining epithelium at the 3º DPE for P. reticulatum larvae, at the 5º DPE for larvae of L. marmoratus and 4º DPE for the hybrid, indicating the presence of neutral mucosubstances. As for the intestine, it presented simple columnar epithelium and goblet cells being more concentrated in the posterior region. Goblet cells in the intestine showed a positive reaction to PAS and PAS + AB, indicating the presence of neutral and acid mucosubstances. Regarding a formation of the attached glands, the liver had its differentiation observed in the 1º DPE and increased the 2º DPE. At the beginning of exogenous feeding as attached glands are already being found well developed.
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Palavras-chave
Híbrido, Ontogenia, Alimentação exógena, Diferenciação de órgãos, Hybrid, Ontogeny, Exogenous feeding, Organ differentiation