JOURNAL OF FISHERIES AND ENVIRONMENTVolume 43, No. 01, Month JANUARY, Year 2019, Pages 40 - 49
Reducing fertilization rate and nitrogen input have no effect on nile tilapia production in periphyton-based culture with supplemental feeding
Wirat Jiwyam, Ratchaneegorn Mapanao, Nudtha Nithikulworawong
Abstract Download PDFNile tilapia, Oreochromis niloticus, with an average individual weight of 87.4 g at a density 3 fish∙m-2 were used to determine growth and production in periphyton-based tanks. The trial was conducted in 10 m2 concrete tanks for a 120-day period. A 10 cm deep layer of soil was placed at the bottom of each tank. Bamboo poles with an approximate submerged surface area of 50% of the total tank surface area were inserted vertically into the soil to act as substrate for periphyton. A biweekly fertilizer dose of triple superphosphate (TSP) and cow manure at the rates of 35 g∙tank-1 and 250 g∙tank-1, respectively, were applied to the experimental tanks. In order to test the effect of reducing nitrogen input, four levels of urea were used with TSP and cow manure; 60, 30, 15 or 7.5 g∙tank-1. The fish were fed daily with a commercial diet containing 30% crude protein at 50% satiation throughout the experimental period. The results indicated that reduction of fertilization rate and nitrogen input have no effect on water quality or production of Nile tilapia in periphyton-based culture. The system gave an average gross yield of 0.86 kg∙m-2 with 92% survival.
Fertilization, Nitrogen input, Periphyton-based, Supplementary feedingProgram