Dietary vitamin C and E supplementation and reproduction of milkfish Chanos chanos Forsskal

Milkfish Chanos chanos Forsskal broodstock (11 years old, average body weig ht 5.23-5.73 kg) reared in 10-m-diameter by 3-m-deep floating net cages (31 -36 fish per cage) at SEAFDEC AQD's Igang Marine Substation in Guimaras Isl and, central Philippines, were fed daily at 3% of total body weight formula ted diets (36% protein, 7-8% lipid) supplemented with 0.1% vitamin C, 0.05% vitamin E, both vitamin C and E or no vitamin supplementation (control) fo r 3 years. Reproductive performance was assessed in an attempt to determine the optimum nutrition for successful spawning of milkfish. The total egg p roduction, mean number of eggs per spawning, number of spawns and mean egg diameter were not affected by dietary vitamin C and E supplementation. Howe ver, broodstock given dietary supplementation of vitamin C alone or in comb ination with vitamin E had a higher percentage of spawns with higher (> 90% ) percentage egg viability, hatching and cumulative survival rate than thos e of the control. Broodstock. given dietary vitamin E supplementation alone had few spawns, which made the results difficult to analyse. The results c onfirm the essentiality of vitamin C supplementation in producing more spaw ns with good egg and larval quality. The production of an adequate volume o f good quality eggs and larvae to support hatchery operation is necessary t o offset the huge investment in broodstock development, as it takes at leas t 5 years for milkfish to attain sexual maturation and spawning.