Egg Windowing and Plastic Culture System in Caiman latirostris Embryos, Improving Hatching Success and Offer Potential Management Applications.

Abstract

The shell of crocodilian eggs is highly fragile, especially during the early stages of development, making them susceptible to cracking during laying or collection, often resulting in embryo mortality. While numerous studies have explored various techniques for artificially incubating eggs to improve hatching success, particularly concerning issues with eggshells, there is limited information available on this topic for crocodilians. The objective of this research was to assess the hatching and survival success of cracked eggs using the windowing method and ex ovo incubation of Caiman latirostris (C. latirostris) embryos in a culture vessel. We used fertile eggs with cracked shells for the windowing eggs (WE) and ex ovo incubation (EE) treatments, and fertile noncracked eggs shell as control treatment. To ensure contamination-free incubation, all eggs were cleaned with alcohol. In the WE treatment, an eggshell section was removed, while in the EE treatment, embryos were removed from the eggshells. Each treatment was incubated in a culture vessel containing an aqueous antimicrobial solution at 31 ± 1°C. After 38 days of incubation in the culture vessel, the hatching success rates were as follows: 66.67% for WE, 0% for EE, and 100% for the control. Subsequently, the survival of hatchlings from the WE and control groups was 100%. The results suggest that incubation in artificial culture vessels enhances the viability and hatching success of C. latirostris cracked eggs. It works as an effective antimicrobial barrier maintaining sterile conditions and does not interfere with embryonic development. Moreover, the WE method offers unique possibilities for the monitoring of developmental studies and other manipulations of crocodilian embryos. However, the EE method is not advisable, as it does not reproduce the conditions inside the egg.