Biopolymer-encapsulated calcium peroxide tablets for slow sustained release of dissolved oxygen in fish tank

Abstract

Dissolved oxygen (DO) is a critical water quality parameter for intensive aquaculture activities in tanks. For better fish survivability slow and sustained release oxygen formula is needed to maintain the optimum DO level for long time as traditional oxygen release tablets are fast-releasing and a repetitive application is required under emergency conditions and also during live fish marketing and transportation. In the present study, calcium peroxide tablets coated with a biopolymer, cellulose acetate and the performance of these coated tablets is tested for their superior oxygen release properties in fish tanks. The result revealed that coated oxygen tablets with cellulose acetate prolonged (43 % higher) the duration of oxygen release as compared to non-coated calcium oxide tablets in tanks without fish. Whereas in tanks with fish (Labeo catla fingerlings) addition of two coated tablets prolonged the optimum DO level for 3 h which is 33 % higher than the non-coated tablets. An addition of 10 noncoated tablets in fish tank created a hyperoxic condition and the DO level increased above 12 ppm, leading to agitated fish behavior. However, same level of coated tablets addition maintained the DO level above 5 ppm for 16 h and did not render any abnormal fish behaviour. Hence it can be concluded that cellulose acetate-coated calcium peroxide tablets can be utilised for intensive aquaculture for better performance and safe application for increasing the DO level during an emergency.