Evaluation of three artificial diets in the culture of tropical edible frog Hoplobatrachus occipitalis (Günther, 1858) from tadpole stage to full metamorphosis

Abstract Background The consumption of edible frogs caught mainly from the wild is on the rise and their population declining. A challenge to frog farming is the acceptability of artificial diets by frogs. Three artificial diets for the culture of a tropical edible frog Hoplobatrachus occipitalis from tadpole stage to full metamorphosis were evaluated. One hundred eighty Hoplobatrachus occipitalis tadpoles (average length and weight of 5.8 cm ± 0.1 and 1.90+ g ± 0.1) were distributed into three experimental tanks with 60-L water capacity each, renewed through a flow-through system. The tadpoles were fed twice daily at 10% of body mass for 112 days with duckweed, pawpaw leaf, and Coppens fish feed. Water quality parameters and proximate composition of the feeds were determined. Results Tadpoles fed with duckweed produced the highest percentage weight gained, specific growth rate, feed intake, and efficient food conversion, with mortality of 10%, survival of 90%, and metamorphosis rate of 100%. This was followed by tadpoles fed with pawpaw leaf and those fed with fish feed. Mortality in these two groups was 15%, survival 85%, and metamorphosis rate 98%. Water quality in the tanks was within the ranges optimal for the growth and survival of the tadpoles. The highest growth percentage recorded in tadpoles fed duckweed was due to the high percentage of crude protein in the feed, which was highly digestible and absorbable by the tadpoles. The duckweed suits the herbivorous feeding of the tadpoles which converted the feed to high biomass. A similar trend was observed for pawpaw leaf, and its growth performance as compared to duckweed was due to its low protein content. The lowest growth performance showed in tadpoles fed with Coppens feed in spite of its very high crude protein was due to the lower intake of the feed resulting in high FCR, ineffective absorbance, and utilization of the protein in the feed on the account of herbivorous feeding of the tadpoles. Size, pellet form, floating time, and odor of the feed were other factors responsible for the lower growth performance. Conclusion Duckweed is a good artificial diet for the breeding of Hoplobatrachus occipitalis due to its high protein content and acceptability by the species.