Feeding methods/methods of feed presentation
Earlier methods of larviculture involved feeding of Chlorella-reared rotifers to larvae for the first 15 days followed by feeding brine shrimp nauplii until harvest at 21 days post hatch (Table 12). Chlorella and rotifer (Brachionus) densities are maintained at 5–10 individual/ml in rearing tanks during the first 15 days. From day 15–19 post hatch the larvae are provided with HUFA and Vit C enriched brine shrimp at a density of 0.5 individual/ml, increasing to 1 individual/ml from day 19–22 and to 1.5 individual/ml from day 22–25 and then ad libitum until harvest.
Improved larviculture techniques involves the use of formulated diets in combination with Brachionus at 2–8 days post hatch and solely on artificial diet from day 15. Feeding rates range from 2 g/m3/day in semi-intensive hatchery systems to 8–12 mg/m3/day in intensive systems. Larvae are fed natural food once daily while formulated diets are dispensed 4 times daily at 08:00, 11:00, 14:00 and 17:00.
Grow-out feeds are generally broadcast 3 times a day at 08:00, 12:00 and 16:00 at fixed areas of the pond. Automatic and demand feeders are loaded with feed two times a day (09:00 and 14:00). Supplemental feed is fed to fry and juveniles in modified extensive systems at 3 percent of biomass/day. A feeding rate of 4 percent of biomass/day is recommended when the fish reach 50 g in semi-intensive ponds (Table 13). In intensive ponds, pens and cages milkfish are fed ad libitum throughout the day.
Aside from the generally recommended feeding guide for farm-made feeds (see Table 13), commercial feed manufacturers also distribute feeding guides for semi-intensive and intensive systems in brackishwater ponds. Table 14 shows some feeding guides for grow-out culture in ponds, marine pens and cages, and for broodstock maintenance in marine cages.
