Morphometric aspects of the digestive tract of Roeboides xenodon and Orthospinus franciscensis

http://dx.doi.org/10.5007/2175-7925.2014v27n3p139Roeboides xenodon (dentudo) e Orthospinus franciscensis (piaba-facão) são peixes teleósteos de pequeno porte com hábitos alimentares onívoros. Com o objetivo de estudar a morfologia do tubo digestório exemplares de O. franciscensis (n=25) e de R. xenodon (n=16) foram coletados na bacia do rio São Francisco, represa de Três Marias – MG, e fixados em formol a 4%. Em ambas as espécies, o esôfago curto teve início na região cefálica e, após o septo transverso, continuou na cavidade peritoneal até à primeira região do estômago. Em R. xenodon, o esôfago apresentou pregas primárias espessas, estreitas e dispostas longitudinalmente, separadas por sulcos profundos e bordas livres e retas e pregas secundárias entre estas. Em O. franciscensis, o esôfago apresentou pregas primárias espessas e largas, longitudinais, sem sulcos profundos, mas com bordas livres e poucas anastomoses. O estômago é do tipo cecal, em “Y”. Os intestinos apresentaram duas porções: a anterior, mais longa e circunvoluta e a posterior, curta e linear. O início do intestino posterior foi demarcado pela alteração abrupta do padrão da mucosa. O esfíncter anal delimitou posteriormente o tubo digestório. O tubo digestório de ambas as espécies é completo e as adaptações tróficas encontradas no aparelho digestório são condizentes com o hábito alimentar carnívoro.http://dx.doi.org/10.5007/2175-7925.2014v27n3p139Roeboides xenodon (dentudo) and Orthospinus franciscensis (piaba-facão) are small Teleostei with omnivorous feeding habits. In order to study the morphology of the digestive tract, specimens of O. franciscensis (n = 25) and R. xenodon (n = 16) were collected in the São Francisco River, Três Marias - MG and fixed in 4% formalin. In both species, a short esophagus began in the head and after the transverse septum, remained in the peritoneal cavity up to the first section of the stomach. In R. xenodon, the esophagus showed primary thick folds, narrow and longitudinally arranged, separated by deep grooves and free edges and lines. In O. franciscensis, the esophagus displayed longitudinal primary folds, thick and wide, no deep grooves, but with free edges and few anastomoses. The stomach was of the cecal type in “Y.” The intestines consisted of two parts: a longer and more convoluted anterior part and a short posterior section. The beginning of the hindgut was marked by an abrupt change in the pattern of the mucosa. There was an anal sphincter at the distal end of the digestive tract. The digestive tract of both species is complete and adapted to their carnivorous habits

Morphometric aspects of the digestive tract of Roeboides xenodon and Orthospinus franciscensis

Roeboides xenodon (dentudo) and Orthospinus franciscensis (piaba-facão) are small Teleostei with omnivorous feeding habits. In order to study the morphology of the digestive tract, specimens of O. franciscensis (n = 15) and R. xenodon (n = 16) were collected in the São Francisco River, Três Marias - MG and fixed in 4% formalin. In both species, a short esophagus began in the head and after the transverse septum, remained in the peritoneal cavity up to the first section of the stomach. In R. xenodon, the esophagus showed primary thick folds, narrow and longitudinally arranged, separated by deep grooves and free edges and lines. In O. franciscensis, the esophagus displayed longitudinal primary folds, thick and wide, no deep grooves, but with free edges and few anastomoses. The stomach was of the cecal type in “Y.” The intestines consisted of two parts: a longer and more convoluted anterior part and a short posterior section. The beginning of the hindgut was marked by an abrupt change in the pattern of the mucosa. There was an anal sphincter at the distal end of the digestive tract. The digestive tract of both species is complete and adapted to their carnivorous habits