The captive animals, with their claws removed, were found dead on a farm in the northern Limpopo region on Friday.
They are said to have been injected with an insecticide called Temik, which is commonly used to kill pests such as spider mites.
The incident is believed to be related to a ‘muti killing’ in which body parts were used for ‘healing’ by sorcerers.
Animal rights activists estimate up to 8,000 lions are kept in captivity in South Africa, many of which are “exploited”.
A source last night told Express.co.uk: “Lions are often sold to establishments that offer ‘walking’ experiences with lions.”
She added: “The final journey of most of these hand-raised lions is as a trophy mounted on a hunter’s wall.”
Police have opened an investigation into the horrific incident, which happened near the Stockpoort border crossing.
A spokesman said: “Members of the Lephalale Gauteng Police Force tracked down the suspects.
“The suspects were picked up by a vehicle. The investigation will follow.”
Dr Pieter Kat of the charity LionAid said: “Lion poisoning is a diabolical trend going on across Africa.
“The amputation of the heads and feet of tainted lions is common and is indicative of the black market trade in lion’s paws and teeth.
“Keeping lions in captivity makes these animals very vulnerable to abuse and exploitation.”
Currently, there are many cases of trafficking in wildlife or their parts across national borders. And there have been many species of animals that have fallen into extinction due to being hunted and poisoned too much.