Effects of preservation methods on stable isotope ratios of carbon and nitrogen in muscle tissue of Hemidactylus turcicus

Background/Question/Methods

Stable isotope analysis has been used in many ecological applications, including understanding nutrient cycles, the dietary habit of animals, and migration routes. There has been an increase in demand for this technique in the recent years. However, a standardized methodology for sample preparation in the field has not been well established. Oven drying and freezing are the standard methods for preserving animal tissues but these techniques are sometimes difficult to apply in the field. We examined the effects of preservation method on stable isotope ratios of carbon and nitrogen in muscle tissue of Hemidactylus turcicus. Samples were dried using a slow cooker instead of standard oven drying and the results of carbon and nitrogen isotope ratios were compared. Additionally, samples were stored using solid and liquid NaCl for different periods of time. Both NaCl preserved samples were compared with dry control samples. In addition, the effect of lipid extraction on stable isotope ratio of muscle tissue was examined.

Results/Conclusions

Drying using the slow cooker significantly decreases stable isotope ratios of carbon, while lipid extraction significantly increases stable isotope ratios of carbon. Short-term solid and liquid NaCl preservation of samples (2 weeks and 4 weeks) shows no significant effect on stable isotope ratios of carbon and nitrogen. NaCl preservation may be employed for short-term preservation of gecko tissues in the field.