A comparative study to investigate the efficiency and sustainability of Oreochromis niloticus culture together with Ipomoea aquatica and Centella asiatica using simple aquaponic technique

Abstract

Aquaponics is the practice of combining soilless plant culture with fish to produce symbiotic systems in which plants filter the water in an aquaculture system and fish waste fertilizes the plants that are growing in those systems. This approach produces fish and vegetables in a controlled environment while decreasing waste production and allows for the sustainable production of both fish and plants. The present study aims to intensify the culture practices of Oreochromis niloticus (GIFT tilapia) fish with Ipomoea aquatica (Kankun) and Centella asiatica (gotukola) plant culture in the same system as a simple aquaponic system. Experimental set up was adjusted to evaluate the growth performance and the survival rate of O.niloticus grown together with the two plant species separately in the outdoor experimental tanks, while determining the water quality changes during the experimental period. The treatments of this experiment were, Treatment 01 (T1): O. niloticus cultured with I. aquatica and Treatment 02 (T2): O. niloticus cultured with C. asiatica and control treatment (TC ): O. niloticus cultured without an aquaponic system. A Completely randomized design was used to all treatments with three replications and the experiment was conducted for a period of 12 weeks. Plants were grown using plastic rafts floated on the surface of the experimental fish tanks. The Results indicated that weight gain, length gain, and specific growth rate found in O. niloticus cultured with I. aquatica (30.842 ± 0.22 g, 11.957 ± 0.01 cm, and 3.758 ± 0.03%) and O. niloticus cultured with C. asiatica (28.594 ± 0.79 g, 8.90±0.01 cm, and 2.686 ± 0.04%) were higher than O. niloticus cultured without aquaponic (25.836 ± 0.51 g, 5.780 ± 0.01 cm, and 2.508±0.01%) (One-way ANOVA, p < 0.05). Vegetable yields were 0.120 kg/84 days for I. aquatica and 0.091 kg/84 days for C. asiatica. Water quality parameters such as total ammonia (mg/l) concentration of O. niloticus cultured using aquaponics (T1: 0.356 ± 0.01 and T2: 0.396 ± 0.01) were better than those without aquaponics (0.450 ± 0.03) indicating that the plants grown in the system have efficiently absorbed the waste products created by the fish and uneaten foods of the same system. Other water quality parameters, such as pH, DO, temperature, nitrate, and nitrite concentrations were within the acceptable and safe limits for the growth and survival of O. niloticus. It can suggest that aquaponic systems can contribute to enhance the growth performances of Nile tilapia. Further, it provides an additional income by selling both plants and fish as harvest from the same system.