Effect of zeolite on the water quality and growth performance of Red Hybrid Tilapia (Oreochromis sp.)

Water quality is one of the factors that affects fish production which varies by species and must be monitored to ensure fish growth and survival. This present study was conducted to assess the effect of zeolite on the water quality and growth performance of red hybrid tilapia (Oreochromis sp.). Different particle size and dosage of zeolite were investigated according to split plot design to investigate the optimal dosage and particle size required for a good water quality and high growth performance of fish for the 60 days experiment periods. The main plot of this experiment was particle size of zeolite with two different levels M1 (> 0.5mm < 2.0 mm) and M2 (> 2.0 mm < 4.0 mm) meanwhile dosage of zeolite assigned as sub plot with four different levels S1 (5 g/L), S2 (10 g/L), S3 (15 g/L) and S4 (20 g/L). Water quality analyses were examined according to APHA (1999) standard method. Efficiency analysis of zeolite adsorbents was conducted for selected toxic pollutants which is ammonia, nitrite, nitrate, total phosphorus, and orthophosphate. Growth performance parameters of fish were monitored through weight and length. At the end of the experiment, histopathological changes of fish liver were examined to identify the toxicity effect of zeolite. Based on ANOVA result, particle size and dosages of zeolite do affect the water quality and growth performance of red hybrid tilapia (Oreochromis sp.) with significant difference (p < 0.05). However, dosage of zeolite was highly significant at (p < 0.001) compared to the particle size of zeolite for most water quality parameters as well as growth performance parameters. Besides, treatment with smaller particle size and 15 g/L of zeolite (M1S3) were recorded as the best water quality level and the best remediation efficiency with removal percentages of 99.71 %, 86.49 %, 81.58 %, 49.76 % and 55.81 % for ammonia, nitrite, nitrate, total phosphorus, and orthophosphate compared to other treatments. Same results were obtained for growth performance parameters of red hybrid tilapia. Final weights and lengths, weight gain, ADW and SGR of fish in treatment M1S3 were recorded as the highest values. Meanwhile, growth performance in control group without zeolite showed a very low performance compared to treatment group with a significance difference (p > 0.05) and this was due to polluted water conditions and poor water quality. For histopathological analysis, greater cell changes > 70 % showed in the fish liver tissues from control group without addition of zeolite was due to high concentration of ammonia. The liver cell of treatment fish exposed to zeolite M1S2, M1S3, M1S4, M2S3 and M2S4 exhibited slightly histopathological changes (0 % < 25 %) whereas liver cell of fish treated from zeolite treatment M1S1, M2S1 and M2S2 suffered mild histopathological changes (25 % < 50 %). In conclusion, addition of zeolite is significant for the improvement of water quality and growth performance of red hybrid tilapia (Oreochromis sp.) with suggested dose of 15 g/L and smaller particle size of zeolite for optimum fish farming production.