Buffering assessment of pawpaw (Carica papaya) leaves and stem for fish production in Port Harcourt, Nigeria

Organic materials are alternatives to chemicals for safe and healthy fish production. This study aimed at comparing the buffer efficiency of pawpaw leaves and stem with calcium carbonate on acidic borehole water at different dosages for aquaculture. Forty-eight, 25-litres shaded plastic tanks of three replicates per treatment were used. The tanks were 20 litres filled with experimental water (pH 4.7). There were sixteen treatment (T) levels (T0 to T16). T1 to T15 were classified into three groups of three dosage levels (G) (2.4g [ G1], 6g [ G2] and 12g [ G3]) per pawpaw leaves and stem [ dried leaves (DL), fresh leaves (FL), dried stem (DS) and fresh stem (FS)] and calcium carbonate (CA). pH and temperature were monitored once daily while dissolved oxygen, alkalinity and calcium were measured weekly for thirty-one (31) days using standard method. Data were analyzed for analysis of variance, Duncan Multiple Range and descriptive statistics. At the end of the study period, the minimum (4.7) and maximum (7.30) pH were recorded in T0 and T11 respectively. Water pH progressively increased from Day 1 to Day 31 in all the treatment levels. The order of buffer efficiency of pawpaw leaves and stem at the end of the experiment in all the treatment groups was FS< DS< FL< DL. pH values ranged between 6.41 +/- 0.01 (T4) and 7.03 +/- 0.02 (T11) on Day 28 and were within the acceptable range of 6.5-9.0. This study therefore suggests the use of DL, FL, DS and FS for fish production. It is free of cost and safe for fish production and human consumption.