Apparent Nutrient Digestibility of Farm-made and Commercial Tilapia Diets in Nile Tilapia (Oreochromis niloticus L.)

Abstract

Aims: To determine the apparent digestibility of gross nutrients in a farm-made tilapia grower diet, ARDECFEED and those of two commercial ones, RAANAN and COPPENS in Oreochromis niloticus with a view of establishing whether all the diets would be well utilized by O. niloticus, the most cultured fish in Ghana. Study Design: Completely Randomized Design. Place and Duration of Study: The Aquaculture Research and Development Centre (ARDEC), Akosombo, of Water Research Institute (WRI) of Council for Scientific and Industrial Research (CSIR), Ghana, in November, 2015. Methodology: Each of the diets was finely milled separately and subsequently sieved. Exactly 0.5% of chromic oxide (Cr2O3) was incorporated into 99.5% of each diet type. Nine plastic tanks (about 0.10 m2 bottom area), each with 45.0 L total volume capacity, filled with 30.0 L of water. Aeration in the tanks was maintained by the insertion of air stones. Monosex male O. niloticus with mean weight 22.8 ± 2.1 g were randomly divided into three groups of 4 fish (three treatments in triplicate) and stocked in the tanks. The fish were fed twice a day (0900 and 1500 hours) at a rate of 6% of their body weight with the various diets for 20 days. Faeces were collected for about two weeks. An indirect method of measuring digestibility was used to calculate the apparent digestibility coefficients (ADCs) of nutrients of the diets.   Results: There were significant differences (P < .05) in the ADCs of all the parameters in all the dietary treatments. The apparent nutrient digestibility coefficients were high (> 65%) in all the diets. The digestibility of crude protein, crude lipid and carbohydrate ranged from 77.49 to 87.02%, 81.46 to 93.90% and 65.28 to 85.94% respectively. Conclusion: All the diets can be well utilized by O. niloticus, hence they will be appropriate for commercial production of Nile tilapia.