Temperature and circadian effects on metabolic rate of South American echimyid rodents, Trinomys setosus and Clyomys bishopi (Rodentia: Echimyidae)

Basal metabolic rate (BMR) represents the lowest level of metabolic activity capable to sustain homeostasis in an endotherm and is an important tool to compare metabolic rates of different species. Echimyidae is the most specious family within caviomorph rodents, however, little is known about the biology of its species, such as Trinomys setosus (Desmarest, 1817) and Clyomys bishopi (Ávila-Pires & Wutke, 1981), a ground and an underground dwelling echimyid, respectively. The ambient temperature and circadian effects on metabolic rate were evaluated through closed-system respirometry for these two species, as well as the circadian effects on CO2 production and respiratory exchange ratio (RER). Trinomys setosus and C. bishopi showed the lowest metabolic rates (0.56 ± 0.02 mLO2.h-1.g-1 and 0.53 ± 0.03 mLO2.h-1.g-1, respectively) at 32 °C and during the light phase. Under laboratory conditions, T. setosus showed metabolic rate variation compatible with nocturnal activity, whereas C. bishopi activity cycle remains unclear. Both species showed BMR lower than expected by allometric regressions for rodents.

Temperature and circadian effects on metabolic rate of South American echimyid rodents, Trinomys setosus and Clyomys bishopi (Rodentia: Echimyidae)

Basal metabolic rate (BMR) represents the lowest level of metabolic activity capable to sustain homeostasis in an endotherm and is an important tool to compare metabolic rates of different species. Echimyidae is the most specious family within caviomorph rodents, however, little is known about the biology of its species, such as Trinomys setosus (Desmarest, 1817) and Clyomys bishopi (Ávila-Pires & Wutke, 1981), a ground and an underground dwelling echimyid, respectively. The ambient temperature and circadian effects on metabolic rate were evaluated through closed-system respirometry for these two species, as well as the circadian effects on CO2 production and respiratory exchange ratio (RER). Trinomys setosus and C. bishopi showed the lowest metabolic rates (0.56 ± 0.02 mLO2.h-1.g-1 and 0.53 ± 0.03 mLO2.h-1.g-1, respectively) at 32 °C and during the light phase. Under laboratory conditions, T. setosus showed metabolic rate variation compatible with nocturnal activity, whereas C. bishopi activity cycle remains unclear. Both species showed BMR lower than expected by allometric regressions for rodents.(AU)

NET ENERGY FOR MAINTENANCE AND ALLOMETRIC EXPONENT FOR POULTRY

E importante uma determinação de um expoente alométrico adequado que considere o crescimento, a maturidade e o status produtivo das aves, e represente melhor o seu tamanho metabólico é importante para expressar de uma forma mais acurada as exigências de energia liquida de mantença para aves em crescimento, aves adultas produtivas e não produtivas. Um estudo de meta analises foi conduzido com o objetivo de estabelecer o coeficiente alométrico para aves de diferentes categorias (aves em crescimento, adultas produtivas e não produtivas), e estimar a energia liquida de mantença. Com esse intuito, um total de 124 dados (produção de calor no jejum, peso corporal, idade, ano de publicação e temperatura), foram analisados tanto na qualidade dos dados quanto nos procedimentos estatísticos de valores influentes e valores atípicos. A agrupação dos dados foi realizada de acordo com a categoria e conferidas pelo analises de clusters. O procedimento do analises dos dados individuais para ajustar o modelo (a×BW

It is important to determine an adequate exponent that considers the growth, maturity and the productive status in poultry and has a better representation of metabolic size, to have a more accurate expression of the net energy requirements for growth, adult productive and adult non-productive birds. This study was performed to establish the allometric coefficient of different birds categories (growth birds, adult productive and non-productive birds), and estimate the net energy to maintenance. A total of 124 data (fasting heat production, body weight, age, year of publication and temperature) was submitted to several quality and statistical analyses of outlier and leverage points. The criterium to classify the date per category was performed by the cluster analyses. The model a×BW