BANGKOK, Dec 8 (Reuters) - Thailand"s supreme court on Wednesday sentenced construction tycoon Premchai Karnasuta to two and a half years in prison without probation on charges related to the poaching of protected animals, a prosecutor told Reuters. Premchai, president of Thai construction company Italian Thai Development Pcl (ITD.BK), was found guilty of possessing a firearm without a permit, enabling poaching and possessing the carcass of a protected animal, said prosecutor Phanomrit Homnitsakul.