According a reply by the government to a question in the Assembly, nine tigers and 11 lions in the park died of various diseases and ailments between January 2010 and March 2011.
Of the nine tigers, six were from safari and three rescued from European circuses. They were housed in the Born Free Foundation at the BBP.
Of the six safari tigers, three died of salmonella bacteria infection and three of pneumonia and neurological disorder and brain haemorrhage.
Of the three Siberian Tigers, rescued from European circuses, one was killed by cyanide poisoning. The other two succumbed to age related problem.
The zoo authorities, however, have claimed that the birth of five cubs recently has stabilised the population.
Of the 11 lions rescued from various circuses across the country, all aged above 15 years, have died due to age related problems like multi-organ failure, tuberculosis and paralysis.
The park has said that the rescue centre is practically an old age home for animals.
Following the deaths, steps have been taken to enhance the quality of food. The authorities have also stated that proper hygiene and cleanliness procedure in and around the animal enclosure has been ensured as per the advice of veterinary experts.