Dietary ascorbic acid needs of milkfish (Chanos chanos
Forsskal) larvae
I.G.
Borlongan
A
30-day feeding experiment was conducted with first-feeding milkfish larvae
to determine its minimum dietary vitamin C requirements for optimal growth
and normal development. Seven diets were formulated to contain graded levels
(0, 50, 100, 200, 300, 400 and 500 mg/kg) of ascorbic acid equivalent
supplied as L-ascorbyl-2-monophosphate calcium salt. The experimental diets
were prepared as microbound/flakes larval diets. Triplicate groups of 6,000
larvae each were fed one of the experimental diets. Growth (measured as body
length and weight increments) and survival were recorded. At the end of the
feeding trial, whole body ascorbate and hydroxyproline content of vertebrae
were analyzed. The results suggest that the minimum dietary requirements for
optimal growth and normal development is in the range of 50-100 mg ascorbic
acid equivalent/kg dry diet. Maximal whole body ascorbate concentration was
observed in larvae fed 200 mg ascorbic acid equivalent/kg or more.
(Aquaculture
Department, Southeast Asian Fisheries Development Center, Tigbauan, Iloilo,
Philippines, 5021)