On the relationship between rabbit age and lens dry weight:improved determination of the age of rabbits in the wild

[摘要] Purpose: Eye lens dry weights are commonly used for estimating theage of animals in the wild, but reported relationships are variable. Thepurpose of this study was to determine why different relationships havebeen reported using data available for the same species of rabbits.Methods: Published results that relate lens weight to age for wildEuropean rabbits from four locations in Australia and cottontail rabbitsfrom two locations in the United States have been reexamined. Inaddition, the effects of variations in lens preparation have been testedwith fresh eyes.Results: It was found that, in previous studies, the logistic typerelationship between lens weight and age was interpreted inappropriatelythrough the use of age constants, which imply that lens growth commencesbefore conception. Using gestational time as the constant yields asingle formula for each species, and this is consistent with most of thepublished data. Variations in fixation and drying conditions may beresponsible for small differences between different populations.Conclusions: When using lens dry weights as a measure of age, it isrecommended that eyes be fixed for at least four weeks and the fixedlenses be dried for two weeks at 85 °C or, preferably, three days at100 °C. Any formula, relating age and lens dry weight for anyspecies, must take into account the fact that lens growth commencesduring gestation not before or after.

[学科分类] 生物化学/生物物理