Physiological effects of a fish oil supplement on captive juvenile tuatara (Sphenodon punctatus)

Abstract

Tuatara (Sphenodon, Order Sphenodontia) are rare New Zealand reptiles whose conservation involves captive breeding. Wild tuatara eat seabirds, which contain high levels of the long-chain n-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids are absent from the captive diet, and consequently, plasma fatty acid composition of wild and captive tuatara differs. This study investigated the effects of incorporating EPA and DHA into the diet of captive juvenile tuatara (Sphenodon punctatus) in an attempt to replicate the plasma fatty acid composition of wild tuatara. Tuatara receiving a fish oil supplement containing EPA and DHA showed overall changes in their plasma fatty acid composition. Phospholipid EPA and DHA increased markedly, reaching 10.0% and 5.9 mol%, respectively, by 18 mo (cf. ≤0.9% in controls). A reduced dosage from 18 to 24 mo probably still provided a higher n-3 PUFA content than the diet of wild juveniles. The fish oil supplement had no significant effects over 2 yr on growth rate, food conversion efficiency, or metabolism compared with controls; all juveniles survived and grew. Further study is required to determine whether a fish oil supplement would have long-term benefits for captive tuatara.