Anatomical and histological characterization of the digestive canal of the golden kingklip (Genypterus blacodes) / Caracterización anatómica e histológica del canal digestivo del congrio dorado (Genypterus blacodes)

Given the importance of the Golden kingklip (Genypterus blacodes) as an alternative to the production of salmonid species for worldwide diversification of aquaculture this study researched the morpho-histology of the digestive canal, providing a uniform nomenclature and basic information to support their nutritional management in captive conditions. The objective was to describe the normal morphology of the digestive canal. Twelve wild specimens were collected and dissected. Samples of the esophagus, stomach, liver, pyloric blind and intestines were obtained. An anatomical and histological description was performed. The digestive canal presented a short tubular esophagus, a slightly dilated, J-shaped stomach and thick walls. The stomach had a cardiac region that ended in a pyloric sphincter from which the intestine of thin walls. The intestine presented an anterior, middle and posterior segment. The anterior region of the first segment of the middle intestine presented 4-5 pairs of pyloric cecum. The middle intestine represented approximately 30 % of the total length of the digestive canal, with a smaller diameter compared to the first segment. The posterior intestine was separated from the middle intestine by a thick and powerful sphincter. The liver was large and elongated, and located in the peritoneal cavity located to the left plane and ventral to the swim bladder. The gallbladder was located lateral to the hepatic anterior wolf. The bile duct led to the duodenal region of the anterior intestine. Ventrally, the rectum ended in the anus, located in front of the anal fin. In general, the histological structures were variable according to the segment studied, a mucous tunic was recognized that presented a simple columnar epithelium, a lamina propria composed of loose connective tissue, a muscular layer of the mucosa composed of smooth muscle tissue and a submucosal layer composed of loose connective tissue, a circular and longitudinal stratum of muscular tunic, which had striated musculature and an adventitial tunic composed of a simple squamous epithelium. In conclusion, Golden kingklip (Genypterus blacodes) presents a digestive system typical of a carnivorous benthic fish adapted to feed on fish and crustaceans.

Dada la importancia del Congrio colorado (Genypterus blacodes) como alternativa a la producción de especies salmonídeas para la diversificación mundial de la acuicultura, el objetivo del presente estudio es describir la morfología normal del canal digestivo de esta especie, proporcionando una nomenclatura uniforme e información básica para apoyar su manejo nutricional en condiciones de cautiverio. Doce especímenes silvestres fueron colectados y disecados. Se obtuvo muestras del esófago, estómago, hígado, ciego pilórico e intestinos. Se realizó una descripción anatómica e histológica. El canal digestivo presentó un esófago tubular corto, un estómago ligeramente dilatado, con forma de J y paredes gruesas. El estómago presentaba una región cardíaca que terminaba en un esfínter pilórico desde el cual el intestino de paredes delgadas. El intestino presentaba un segmento anterior, medio y posterior. La región anterior del primer segmento del intestino medio presentó 4-5 pares de ciegos pilóricos. El intestino medio representó aproximadamente el 30 % de la longitud total del canal digestivo, con un diámetro menor en comparación con el primer segmento. El intestino posterior estaba separado del intestino medio por un esfínter grueso y poderoso. El hígado era grande y alargado, y ubicado en la cavidad peritoneal ubicado al plano izquierdo y ventral a la vejiga natatoria. La vesícula biliar se ubicó lateral al lobo anterior hepático. El ducto biliar desembocó en la región duodenal del intestino anterior. Ventralmente, el recto terminó en el ano, ubicado frente a la aleta anal. En general, las estructuras histológicas fueron variables según el segmento estudiado, se reconoció una túnica mucosa que presentaba un epitelio columnar simple, una lámina propia de la mucosa compuesta por tejido conectivo laxo, una capa muscular de la mucosa compuesta por músculo liso tejido y una capa submucosa compuesta de tejido conectivo laxo, un estrato circular y longitudinal de túnica muscular, que tenía musculatura estriada y una túnica adventicia compuesta por un epitelio plano simple. En conclusión, Congrio colorado (Genypterus blacodes) presenta un sistema digestivo típico de un pez bentónico carnívoro adaptado para alimentarse de peces y crustáceos.

Modulation of murine blastocyst hatching in vitro by glutamine and tryptophan

Enrichment of culture media with amino acids improves embryo development. However, little is known about the specific action of each amino acid during embryogenesis. The present study was undertaken to examine the effect of L-glutamine (Gln) and tryptophan (Trp) on mouse embryo hatching, expansion and viability in vitro. Blastocysts were collected from 6- to 8-week-old female BALB/c mice (N = 30) and cultured in M2 medium containing either 0.125, 0.25 or 0.5 mM Trp, 1 mM Gln, or M2 alone. Gln significantly increased (100 percent; P < 0.05) blastocyst hatching at 24 h compared to M2 alone or Trp; moreover, Trp inhibited blastocyst hatching when compared to M2 alone (P < 0.05) at 72 h. In contrast, the percentage of embryos reaching the state of expanded blastocyst at 48 h was significantly higher in medium with 1 mM Gln (66.6 percent; P < 0.05) or with 0.125 mM Trp (61.1 percent; P < 0.05). Unexpectedly, Trp increased the percentage of degenerated blastocysts after 48 h (67.7 percent; P < 0.05), while Gln preserved blastocyst viability. These results suggest that Gln may enhance blastocyst hatching, expansion and viability in vitro.

Blastocyst-endometrium interaction: intertwining a cytokine network

The successful implantation of the blastocyst depends on adequate interactions between the embryo and the uterus. The development of the embryo begins with the fertilized ovum, a single totipotent cell which undergoes mitosis and gives rise to a multicellular structure named blastocyst. At the same time, increasing concentrations of ovarian steroid hormones initiate a complex signaling cascade that stimulates the differentiation of endometrial stromal cells to decidual cells, preparing the uterus to lodge the embryo. Studies in humans and in other mammals have shown that cytokines and growth factors are produced by the pre-implantation embryo and cells of the reproductive tract; however, the interactions between these factors that converge for successful implantation are not well understood. This review focuses on the actions of interleukin-1, leukemia inhibitory factor, epidermal growth factor, heparin-binding epidermal growth factor, and vascular endothelial growth factor, and on the network of their interactions leading to early embryo development, peri-implantatory endometrial changes, embryo implantation and trophoblast differentiation. We also propose therapeutical approaches based on current knowledge on cytokine interactions.