Use of microworm on nursing danio (Brachydanio rerio Hamiton-Buchanan, 1822)

Concentration of crude protein, crude fat, crude fiber and ash in these organisms was determined by proximate analysis. The concentration of essential amino acids and essential fatty acids also analyzed via the HPLC procedures. Six experimental feeds were comprised either exclusively of microworm, moina and rotifer or 50 percent count each of rotifer plus moina, rotifer plus microworm, and moina plus microworm. One hundred freshly hatched danio larvae each were placed in 28*60*36 cm aquarium and raised on these feeds to 15 days of age. The larvae fed microworm alone had significantly higher final weight and specific growth rate compared to larvae fed rotifer alone but were not different from other treatments for the same parameters of performance. Final body weight and the specific growth rate obtained with the combination of microworm and moina was significantly greater than obtained with the combination of microworm and rotifer but not different from combination of moina and rotifer. In line with body weight, final length of larvae fed microworm alone was significantly higher than those fed rotifer alone but not different from other treatments. There was no significant (p GT 0.05) difference among treatments in terms of survival of the danio larvae. These results show that microworm when fed as the sole dietary source can provide an adequate nutrition for zebra danio yielding performance similar to that provided by moina but significantly superior than rotifer. Despite a relatively low crude protein content of microworm (43.9 percent on dry weight basis) compared with moina (70.7 percent) and rotifer (70.6 percent), an adequate performance with microworm can be attributed to a better digestibility compared with the crustaceans where chitin digestibility may be a limiting factor. Poor performance with rotifer could be due to its high fiber content (14.15 percent on dry weight basis) compared with microworm (1.47 percent) and moina (7.47 percent). A high crude fat content in microworm (14.84 percent on dry weight basis) relative to moina (3.25 percent) and rotifer (5.13 percent) could also provide the energy superiority to this live food explaining the cause of an adequate performance with this organism.