RESUMO O objetivo da presente pesquisa foi avaliar o efeito da inclusão de semente de linhaça na dieta sobre a qualidade seminal e o perfil metabólico de machos caprinos. Foram utilizados 16 machos da raça Saanen, distribuídos aleatoriamente em quatro grupos, recebendo níveis de inclusão de semente de linhaça (0, 4, 8 e 12%) na dieta, durante um período de 60 dias. As coletas e as avaliações seminais foram realizadas duas vezes por semana. Os animais foram submetidos a coletas quinzenais de sangue, durante todo o período experimental. Os dados foram avaliados por ANOVA e pela análise de regressão a 5% de significância. Houve comportamento cúbico para motilidade espermática progressiva, que apresentou o maior valor (82,30%) com a adição de 9,92% de semente de linhaça na dieta (P<0,05). Houve comportamento cúbico para concentração plasmática de triglicerídeos, e o nível de 8% de semente de linhaça na dieta apresentou média de 43,32mg dL-1, acima dos valores normais para a espécie caprina (P<0,05). A inclusão de semente de linhaça na dieta de machos caprinos proporcionou melhora na produção espermática e na qualidade seminal. No entanto, devem-se considerar os possíveis efeitos dos níveis superiores a 4% de semente de linhaça sobre o perfil metabólico dos animais.

ABSTRACT This study aimed to evaluate the effect of flaxseed inclusion in the diet of male goats through the semen quality and metabolic profile. Randomly allocated 16 Saanen males were placed into four groups receiving flaxseed inclusion levels (0, 4, 8 and 12%) in the diet over a period of 60 days. The collections and seminal evaluations were performed twice a week. The animals were subjected to biweekly blood collections from the beginning to the end of the trial period. The data were evaluated by ANOVA and regression analysis at 5% significance. A cubic behavior for motility, with the highest value (82.30%) with the addition of 9.92% of flaxseed in the diet (P< 0.05) was detected. A cubic behavior for plasma triglyceride concentration and the level of 8% of flaxseed in the diet averaged 43.32mg dL -1 above normal values for goats (P< 0.05) was detected. The inclusion of flaxseed in the diet of male goats improved sperm production and quality. However, one should consider the possible effects of the levels above 4% of flaxseed on the metabolic profile of the animals.

RESUMO: A dessecação da cultura do feijão destinado à produção de sementes, com a utilização de herbicidas, é uma alternativa de manejo, pois permite a colheita quando as sementes apresentam elevado vigor, germinação e massa seca, porém essa técnica pode ocasionar prejuízos às sementes. Objetivou-se com este trabalho avaliar a qualidade fisiológica de sementes de feijão, do tipo carioca, com a aplicação de doses de herbicidas dessecantes em diferentes épocas, visando a antecipação da colheita. As plantas de feijão carioca, cultivar Pérola, foram dessecadas quando as sementes apresentavam 42% e 30% de teor de água, com amonio-glufosinate, saflufenacil e diquat, nas doses de 0%, 50%, 75% e 100% em relação à dose média recomendada para dessecação, respectivamente para cada um dos herbicidas. O tratamento controle, sem aplicação do dessecante, foi colhido na mesma data das dessecações. Já o tratamento adicional, também sem aplicação do dessecante, foi colhido apenas quando as sementes apresentavam o teor de água de 18%. As variáveis analisadas foram germinação, primeira contagem de germinação, índice de velocidade de germinação, teste de frio, envelhecimento acelerado, comprimento de plântula e radícula e massa seca. Os herbicidas aplicados na primeira época (42% de água), nas maiores doses, prejudicam a qualidade fisiológica das sementes, e a colheita das sementes com teores de água de 30% e 42%, sem a utilização de dessecantes, promove elevado vigor e germinação. Resultados satisfatórios foram constatados quando se aplicou o saflufenacil na 0 época 2 (30% de água), utilizando 50% da dose média recomendada deste herbicida.

ABSTRACT: The use of herbicides for bean crop desiccation aiming seed production, is an alternative management because it allows harvesting when the seeds present high vigor, germination and dry mass, however this technique can cause damages to the seeds. The objective of this study was to evaluate the physiological quality of bean seeds, of the Carioca type, with the application of desiccant herbicides doses at different periods, aiming at the anticipation of the harvest. The bean plants, Pérola cultivar, were desiccated when the seeds had 42 and 30% water content, with ammonium glufosinate, saflufenacil and diquat at doses of 0, 50, 75 and 100% in relation to the recommended average dose for desiccation, respectively for each of the herbicides. The control treatment without desiccant application was harvested on the same date as desiccation. The additional treatment, also without desiccant application, was harvested only when the seeds had a water content of 18%. The variables analyzed were germination, first germination count, germination speed index, cold test, accelerated aging, seedling and radicle length, and dry mass. The herbicides applied in the first period (42% water), at the highest doses, impair the physiological quality of the seeds, and the seeds with water contents of 30 and 42%, without the use of desiccants, promote high vigor and germination. Satisfactory results were obtained when the saflufenacil herbicide was applied in period 2 (30% water), using 50% of the recommended average dose of this herbicide.

This review addresses the mechanisms of methylmercury (MeHg)-induced neurotoxicity, specifically examining the role of oxidative stress in mediating neuronal damage. A number of critical findings point to a central role for astrocytes in mediating MeHg-induced neurotoxicity as evidenced by the following observations: a) MeHg preferentially accumulates in astrocytes; b) MeHg specifically inhibits glutamate uptake in astrocytes; c) neuronal dysfunction is secondary to disturbances in astrocytes. The generation of reactive oxygen species (ROS) by MeHg has been observed in various experimental paradigms. For example, MeHg enhances ROS formation both in vivo (rodent cerebellum) and in vitro (isolated rat brain synaptosomes), as well as in neuronal and mixed reaggregating cell cultures. Antioxidants, including selenocompounds, can rescue astrocytes from MeHg-induced cytotoxicity by reducing ROS formation. We emphasize that oxidative stress plays a significant role in mediating MeHg-induced neurotoxic damage with active involvement of the mitochondria in this process. Furthermore, we provide a mechanistic overview on oxidative stress induced by MeHg that is triggered by a series of molecular events such as activation of various kinases, stress proteins and other immediate early genes culminating in cell damage.

Glutamate receptors have been implicated in memory formation. The aim of the present study was to determine the effect of inhibitory avoidance training on specific [3H]-glutamate binding to membranes obtained from the hippocampus or parietal cortex of rats. Adult male Wistar rats were trained (0.5-mA footshock) in a step-down inhibitory avoidance task and were sacrificed 0, 5, 15 or 60 min after training. Hippocampus and parietal cortex were dissected and membranes were prepared and incubated with 350 nM [3H]-glutamate (N = 4-6 per group). Inhibitory avoidance training induced a 29% increase in glutamate binding in hippocampal membranes obtained from rats sacrificed at 5 min (P<0.01), but not at 0, 15, or 60 min after training, and did not affect glutamate binding in membranes obtained from the parietal cortex. These results are consistent with previous evidence for the involvement of glutamatergic synaptic modification in the hippocampus in the early steps of memory formation.