Baliña Sofía, Temperoni Brenda, López Greco Laura Susana, Tropea Carolina
Biol Bull. 2018 Jun;234(3):139-151. doi: 10.1086/698266. Epub 2018 Jun 1.
Maternal provisioning is particularly important in invertebrates with abbreviated development because large energy reserves must be provided for the developing embryo. In this context, the objective of the present study was to analyze in an aquatic invertebrate with direct development the effect of temperature on female biochemical composition and reserve allocation to maturing ovaries, which determine egg quality. A decapod crustacean, the freshwater shrimp Neocaridina davidi, was used as experimental model. Newly hatched juveniles were exposed to 28 °C or 33 °C. Females showed mature ovaries and spawned at 28 °C (control ovigerous females), but no ovigerous female was found at 33 °C. After a 200-day period, half of the females at 33 °C were transferred to 28 °C, where they rapidly showed mature ovaries and spawned (transferred ovigerous females). Ovigerous females and females that did not spawn at 28 °C (control non-ovigerous females) and at 33 °C (high-temperature non-ovigerous females) were sacrificed to determine their biochemical composition. The number, volume, weight, and biochemical composition of the eggs from transferred and control ovigerous females were also analyzed as indicators of their quality. Female biochemical composition was not influenced by temperature, because control and high-temperature non-ovigerous females had similar lipid, protein, and glycogen contents. However, ovarian maturation and spawning were inhibited at 33 °C, which indicates a negative effect of this temperature on nutrient transfer to the oocytes. This effect was rapidly reversed after females were moved to 28 °C; the eggs from control and transferred ovigerous females were of similar quality, except for a lower protein content in the latter. The present results provide valuable information on reserve allocation to reproduction under thermal stress.
在发育过程缩短的无脊椎动物中，母体营养供应尤为重要，因为必须为发育中的胚胎提供大量能量储备。在此背景下，本研究的目的是分析温度对一种直接发育的水生无脊椎动物雌体生化组成以及向成熟卵巢储备分配的影响，而卵巢储备分配决定了卵的质量。一种十足目甲壳动物——淡水虾秀丽白虾被用作实验模型。刚孵化的幼体被置于28℃或33℃环境中。雌虾在28℃时卵巢成熟并产卵（对照抱卵雌虾），但在33℃时未发现抱卵雌虾。200天后，将33℃环境中的一半雌虾转移至28℃，它们很快卵巢成熟并产卵（转移抱卵雌虾）。处死抱卵雌虾以及在28℃（对照非抱卵雌虾）和33℃（高温非抱卵雌虾）下未产卵的雌虾，以确定其生化组成。还分析了转移抱卵雌虾和对照抱卵雌虾所产卵子的数量、体积、重量和生化组成，作为卵子质量指标。雌体生化组成不受温度影响，因为对照非抱卵雌虾和高温非抱卵雌虾的脂质、蛋白质和糖原含量相似。然而，33℃时卵巢成熟和产卵受到抑制，这表明该温度对营养物质向卵母细胞的转移有负面影响。雌虾转移至28℃后，这种影响迅速逆转；对照抱卵雌虾和转移抱卵雌虾所产卵子质量相似，只是后者蛋白质含量较低。本研究结果为热应激下繁殖储备分配提供了有价值的信息。
