Morphometric alterations in hepatocytes and ultrastructural distribution of liver glycogen in pacu (Piaractus mesopotamicus Holmberg, 1887) during food restriction and refeeding

The morphometric alterations in hepatocytes and the ultrastructural distribution of tissue glycogen in pacu (Piaractus mesootamicus) were studied following food restriction and refeeding. Fish (200-300g) were allocated to control and experimental groups. The experimental group was sampled after 0, 2, 7, 30 and 60 days of food restriction and after 7 and 30 days of refeeding. The control group, which was fed daily, was sampled on the same days. The morphometric results were analyzed by ANOVA in a 2x7 (feeding x days) factorial design and the averages compared by the Tukey test. Transmission electron microscopy showed liver glycogen mobilization during food restriction. The levels of glycogen did not return to normal after up to 30 days of refeeding. There was a decrease in the cytoplasmic area and volume after seven days without food whereas changes in the nuclear area and volume appeared after two days of food restriction. Recovery of the nuclear and cytoplasmic area and volume occurred after 7 days and 30 days of refeeding, respectively. These results indicate tha liver glycogen supplies at least part of the energy requirement during food restriction in juvenile pacu. Thirty days of refeeding were not enough to re-establish the pre-restriction carbohydrate levels, probably because of the extra energy demand associated with the high metabolic rate that occurred during the compensatory process of refeeding at elevated ambient temperatures. However, the recovey seen in the morphometric parameters of the hepatocytes indicated a functional re-adjustment of the liver stimulated by the restored food supply.

Estudos hematológicos e hormonal de frangos de corte tratados com contaminantes do milho: Crotalaria spectabilis e Senna occidentalis / Hematological and hormonal studies from broiler chickens fed with corn contaminants: Crotalaria spectabilis e Senna occidentalis

Crotalaria spectabilis (crotalária) e a Senna occidentalis (fedegoso) podem crescer em plantaçöes de milho e, durante a colheita, este cereal pode ser contaminado com as sementes dessas plantas, que apresenta toxicidade para os animais. O objetivo deste estudo foi investigar os parâmetros morfométricos dos eritrócitos, as variáveis hematológicas e a concentraçäo plasmática hormonal dos frangos de corte tratados com raçäo de dois níveis de energia, que foi adicionada de 0,1 por cento e 0,5 por cento de sementes de Crotalaria spectabilis e Senna occidentalis, respectivamente. Cento e oitenta frangos de corte foram divididos em seis grupos, de acordo com uma análise fatorial 3 x 2 (controle, crotalária e fedegoso como tratamentos principais e dois níveis de energia, 2.900 e 3.200 kcal ME/kg de raçäo). Os resultados deste experimento mostraram que o efeito tóxico da crotalária determinou uma reduçäo no número de hemácias, no valor do hematócrito e do VCM, nao influenciando os parâmetros morfométricos avaliados. A semente de crotalária induziu, também, aumento na incidência de ascite, em funçäo de sua toxicidade hepática. Já a semente de fedegoso näo mostrou toxicidade suficiente para induzir ascite nos frangos