Physical and chemical characteristics of fertile and infertile eggs of wild Caiman latirostris

Abstract

In oviparous species, physico-chemical characteristics of eggs are an indicator of maternal physiological traits and environmental conditions of the site where the females develop. In this study, we aim to (a) determine the physico-chemical characteristics of eggs from wild Caiman latirostris populations; (b) evaluate if fertile and infertile eggs differ in physico-chemical characteristics associated with suchest reproductive success; and (c) compare the present results with findings in other crocodilian species to identify characteristics that would be associated with reproductive biology and adaptations to their environments. Eggs were collected and identified, and different morphometric variables (percentage of components, and protein, total lipids and fatty acid composition) were determined. Fertile and infertile eggs did not differ in weight or component (eggshell, yolk and albumen) percentages of total egg weight. Fatty acid profiles of yolk differed between fertile and infertile eggs in C14:0, C16:1 and C17:1. However, the comparison of profiles among clutches showed differences in 12 fatty acids. We also observed differences in percentage of egg components respect to other crocodilian species, particularly of albumen, which had a lower proportion in C. latirostris. Our results suggest that egg infertility may not be related to maternal lipid investment. We propose using yolk of infertile eggs (which is similar to that of fertile eggs) as a non-invasive method to identify and evaluate the difference in FA composition of eggs for breedings female of varyns diets.