Hepatic hematopoiesis in the alpaca (Vicugna pacos), a species with development in hypoxic environments.

Hematopoiesis occurs in different anatomical niches throughout the life of the individual. The first hematopoietic extra-embryonic stage is replaced by a intra-embryonic stage that occurs in a region that is adjacent to the dorsal aorta. Then, the prenatal hematopoietic function is continued by the liver and spleen, and later by the bone marrow. The objective of the present work was to describe the morphological characteristics of hepatic hematopoiesis in the alpaca and to analyze the proportion of the hematopoietic compartment of the organ and the cell types, at different times of ontogeny. Sixty-two alpaca samples were collected from the municipal slaughterhouse of Huancavelica, Perú. They were processed by routine histological techniques. Hematoxylin-eosin staining, special dyes, immunohistochemical techniques and supplementary analyses by lectinhistochemistry, were performed. The prenatal liver is an important structure in the expansion and differentiation of hematopoietic stem cells. Their hematopoietic activity was characterized by four stages: initiation, expansion, peak, and involution. The liver started its hematopoietic function at 21 days EGA and it was maintained until shortly before birth. Differences were found in the proportion and morphology of the hematopoietic tissue in the different groups corresponding to each gestational stage.

Anatomía macroscópica de los músculos del cuello de la alpaca (Lama pacos) / Gross anatomy of the muscles of the neck of the alpaca (Lama pacos)

Se hizo una descripción anatómica de los músculos del cuello de la alpaca y para lo cual se utilizaron 6 alpacas adultas de la variedad Huacaya. La disección se hizo del plano superficial al profundo, y se observó músculos cutáneos, esqueléticos del plano superficial, esqueléticos profundos dorsales y laterales, esqueléticos profundos ventrales, del aparato hioideo, de la laringe y faringe, y extrínsecos de la cabeza. Se encontró algunas características propias de la especie. Así, no hay división en el rafe clavicular de las porciones cleidobraquial y cleidocervical del músculo braquiocefálico; ni entre las porciones cervical y torácica del músculo trapecio; los músculos esternocefálico y esternohioideo tienen origen común en el manubrio del esternón; el músculo omohioideo se origina en la aponeurosis de la porción cleidomastoidea del braquiocefálico; y los músculos faringeos están fusionados. Los demás músculos presentaron características comunes a otras especies domésticas.

This study was conducted in six adult alpacas (Huacaya breed) to establish anatomical patterns of neck muscles. Dissection was made from the surface to the deep plane, and the muscle distribution was as follow: cutaneous muscles, superficial plane esqueletics muscles, dorsal and lateral deep esqueletics muscles, deep ventral esqueletics muscles, hyoid muscles, laryngeal muscles, pharyngeal muscles and extrinsic head muscles. The study highlighted some specific species characteristics. The division between cleidobraquial and cleidocervical portions of braquiocefalic muscle, and the division between cervical and toracic portions of trapecius muscle were missing. The origen of the esternocephalic and esternohioideus muscles was the same; the origin of the omohioideus muscle was in the aponeurotic of the cleidomastoideus muscle (braquiocefalic); the pharyngeal muscles are only one portion; and the intertransversarius muscles have eight dorsal portions and seven ventral portions. Other muscles have the same characteristic commonly described for domestic mammals.