Growth, survival, and myogenic gene expression in the post-larvae of Colossoma macropomum provisioned with Artemia nauplii.

Artemia nauplii are widely used as fish larvae feed due to its beneficial nutritional characteristics for larval development; however, efficient feeding strategies are needed to balance its high costs. Therefore, we evaluated the effects of different densities of Artemia nauplii (100, 250, 500, 750, and 1000 nauplii/post-larvae) on the growth, survival, water quality, and myogenic gene expression of tambaqui (Colossoma macropomum) post-larvae cultivated in a recirculating aquaculture system. After 2 weeks of trial, there was a significant decrease in dissolved oxygen concentration with the increase in nauplii density, but it did not interfere with larval performance and survival. In the first week, larvae fed with fewer than 500 nauplii/post-larvae presented slower growth, while in the second week, larvae fed with 1000 nauplii/post-larvae had the highest final weight and length. Regression analysis suggests that the optimum feeding density of Artemia nauplii during the first week is 411 nauplii/post-larvae, while for the second week, the growth increased proportionally to the feeding densities. The relative expression of the myod, myog, and mstn genes was higher in larvae fed with fewer than 500 nauplii/post-larvae. Although low-growing larvae showed increased expression of myod and myog genes, responsible for muscle hyperplasia and hypertrophy, respectively, mstn expression may have played a significant inhibitory role in larval development. Further research is needed to better determine the effects of the live food on the zootechnical performance and the expression of the myogenic genes in the initial phase of the life cycle of the tambaqui post-larvae.

Hematology and biochemistry of buffalo (Bubalus bubalis): influence of sex and age on reference values.

This research aimed to obtain a hematological and biochemical profile of buffalos (Bubalus bubalis) bred in a region of the Brazilian Legal Amazon. A total of 73 animals of mixed races, divided into three groups, were studied: group 1 (G1) comprised animals up to 11 months old; in group 2 (G2), subjects were 12 to 23 months old; and, in group 3 (G3), they were 24 months old and older. We performed the hematological analysis manually, and, for the biochemistry, we used biochemical analyzers. Age of the animals has influenced the monocyte count. The counting of these cells was higher (p > 0.05) in younger animals (G1). There was no difference (p > 0.05) in hematological parameters concerning sex. In regard to biochemistry, we found that age influenced results for albumin and urea. Animals from G1 had higher albumin values when compared to G2 and G3. Serum urea values were higher in animals from G3. Regarding the serum mineral parameters, there were no significant results when the different age groups and both sexes were compared. Thus, the hematological and biochemical values obtained can work as a reference for the bubaline species of animals bred in the studied region, under the same management and breeding conditions. Sex and age of the animals are necessary for the interpretation of the tests.

Mesenchymal stem cells in dogs with demyelinating leukoencephalitis as an experimental model of multiple sclerosis.

Researchers have used dogs with neurological sequelae caused by distemper as an experimental model for multiple sclerosis, owing to the similarities of the neuropathological changes between distemper virus-induced demyelinating leukoencephalitis and multiple sclerosis in humans. However, little is known about the role of mesenchymal stem cells in treating such clinical conditions. Therefore, we investigated the use of mesenchymal stem cells in four dogs with neurological lesions caused by the distemper virus. During the first year after cellular therapy, the animals did not demonstrate significant changes in their locomotive abilities. However, the intense (Grade V) myoclonus in three animals was reduced to a moderate (Grade IV) level. At one year after the mesenchymal stem cell infusions, three animals regained functional ambulation (Grade I), and all four dogs started to move independently (Grades I and II). In two animals, the myoclonic severity had become mild (Grade III). It was concluded that the use of mesenchymal stem cells could improve the quality of life of dogs with neurological sequelae caused by canine distemper, thus presenting hope for similar positive results in human patients with multiple sclerosis.

Effect of age and sex on bone markers in Chlorocebus aethiops raised in captivity.

BACKGROUND: The objective was to evaluate the procollagen type I N-propeptide (PINP), osteocalcin (OC), ß-crosslaps (ß-CTX), and parathyroid hormone (PTH) in relation to age and sex of Chlorocebus aethiops in captivity. METHODS: Seventy-three monkeys were divided into four age groups: AG1 (juvenile); AG2 (young adult); AG3 (adult); and AG4 (senile). An electrochemiluminescence immunoassay with an Elecsys 2010 analyzer was used to determine the serum markers of bone. RESULTS AND CONCLUSIONS: Sex did not influence the results of the markers. However, the variables PINP, OC, and ß-CTX were negatively correlated with age (r = -0.643; r = -0.711; r = -0.488; P < 0.001, respectively), and PTH was correlated positively with age (r = 0.418, P < 0.001). The data obtained can be used as biomarkers of bone metabolism reference intervals in healthy C. aethiops in captivity.

Sexual dimorphism of sharks from the amazonian equatorial coast / Dimorfismo sexual de tiburones de la costa ecuatorial amazónica / Dimorfismo sexual de tubaróes da costa equatorial amazónica

Sexual dimorphism is a widespread feature in several groups of vertebrates. Chondrichthyans differ sexually due to the presence of the clasper, a structure for internal fertilization, and other sexual differences in secondary characteristics. Nevertheless, studies assessing these variations are fairly rare. The main goal of this study is to identify differences in sexual dimorphism in three species of sharks from the Carcharhinidae family (Rhizoprionodon porosus, Carcharhinusporosus and Isogomphodon oxyrhynchus) using morphometric tools. A total of 213 specimens were captured in the Amazonian Equatorial Coast and analyzed using 65 morphometric characters. Discriminant analysis and The Student's t-test were used to demonstrate the morphological differences among sexes. Sexual dimorphism was reported at different levels for the three species. This study suggests that the most likely explanation for the presence of these variations is related to their reproductive characteristics and mating behavior.

El dimorfismo sexual es una característica presente en diversos grupos de vertebrados. Machos y hembras de Chondrichthyes se identifican fácilmente por la presencia de una estructura para la fertilización interna, el clasper, y otras pequeñas diferencias en las características secundarias. Sin embargo, los estudios que evalúan estas variaciones en la morfología entre los sexos son poco frecuentes. El objetivo de este trabajo es identificar el dimorfismo sexual en tres especies de tiburones de la familia Carcharhinidae (Rlhizoprionodon porosus, Carcharhinus porosus y Isogomphodon oxyrhynchus) con el uso de herramientas morfométricas. Se capturaron un total de 213 ejemplares en la costa Ecuatorial Amazónica y fueran analizados utilizando 65 caracteres morfométricos. Fueran aplicadas análisis discriminantes y prueba t-student para mostrar las diferencias morfológicas entre los sexos. Se observó dimorfismo sexual en diferentes niveles para las tres especies. Sugerimos que la explicación más probable para la presencia de estas variaciones está relacionada con las características reproductivas y el comportamiento de cópula.

O dimorfismo sexual é uma característica presente em vários grupos de vertebrados. Machos e fèmeas de Chondrichthyes são facilmente identificados pela presenca de uma estrutura para a fertilização interna, o clasper, além de outras diferencas em características secundárias. No entanto, estudos que avaliam estas variacóes na morfologia externa entre os sexos são raros. O principal objetivo deste estudo é identificar dimorfismo sexual em très espécies de tubarão da familia Carcharhinidae (Rhizoprionodon porosus, Carcharhinus porosus e Isogomphodon oxyrhynchus) através do uso de ferramentas morfométricas. Um total de 213 espécimes foi capturado na costa Equatorial Amazónica e analisado através de 65 caracteres morfométricos. Análises discriminantes e teste t-student foram aplicados para evidenciar as diferencas morfológicas entre os sexos. Nós observamos dimorfismo sexual, em diferentes níveis, para as très espécies estudadas e sugerimos que a causa mais provável para a presenca de tais variacóes está relacionada a características reprodutivas e comportamentos copulatórios.