Influence of Photoperiod and Nutrition on Pine Vole Reproduction

Animais de Laboratório: criação e experimentação

“…O controle do fotoperíodo é de extrema importância, pois pode influenciar o ciclo reprodutivo do roedor. Muitas espécies apresentam em seu hábitat natural reprodução estacional e controlada pelo padrão de luminosidade (Hasbrouck, Servello & Kirkpatrick, 1986), sendo necessário reproduzir-se em cativeiro esse padrão luminoso, para se obter reprodução ao longo do ano. Quanto à dieta, podemos constatar que, apesar de cada espécie ter hábitos alimentares específicos na natureza (frugívoros, granívoros, insetívoros e até onívoros), a ração padrão balanceada para roedores de laboratório tem-se mostrado eficiente para suprir as necessidades nutricionais desses animais.…”

The seasonality of reproduction in photoperiod responsive and nonresponsive northern red-backed voles (Myodes rutilus) in Alaska

“…For instance, almost all male prairie voles (Microtus ochrogaster (Wagner, 1842)) housed at 8 8C undergo testicular regression in response to short photoperiods, while those housed at 20 8C on identical day lengths exhibit the normal 20%-40% frequency of nonresponsiveness (Kriegsfeld et al 2000a). Food supplementation and photoperiod have been shown to interact to influence the reproductive condition of pine voles (Microtus pinetorum (LeConte, 1830)) and other small mammals, suggesting a strong nutritional affect (Cengel et al 1978;Hasbrouck et al 1986;Bronson 1989).…”

“…The effect of body condition or nutritional state on the reproductive timing and condition of arvicoline rodents is also not entirely known. Previous studies have shown an influence of nutrition and food availability on reproductive state (Cengel et al 1978;Hasbrouck et al 1986), but body-fat levels do not necessarily correlate to reproductive condition (Batzli and Esseks 1992) and may or may not change seasonally (Cengel et al 1978;Batzli and Esseks 1992;Zuercher et al 1999). We suggest Bronson (1989) for a thorough review on the effects of diet, food restriction, temperature, and other environmental parameters on the reproductive systems of small mammals.…”

“…The high energy costs of winter thermoregulation and summer reproduction create an energetic bottleneck that shapes the seasonality of breeding (Levins 1968;Nelson et al 1998). Reproduction usually occurs during warmer months and longer day lengths in most temperate-zoned and high-latitude arvicoline rodents (Sealander 1967;Batzli and Pitelka 1971;Nelson 1985b;Hasbrouck et al 1986;Negus and Berger 1998;Wallen and Schneider 2000;McNabb 2002). It ceases prior to winter and is usually characterized by regression of reproductive organs.…”