Frequently asked questions (FAQs)
1. What is a typical and suitable proximate composition for a milkfish diet?
The diet of the milkfish varies with fish size. Typical dietary proximate compositions are as follows:
| Proximate composition | Larvae & fry | Starter/fingerling grower | Juvenile grower | Finisher | Broodstock |
| Fish size (g) | 0.01–2 to 5 | 2 to 5–70 | 70–170 | >150 | 1–11 kg |
| Moisture (% max) | 12 | 12 | 12 | 12 | 12 |
| Crude protein (% max.) | 31–40 | 30–36 | 27–34 | 29 | 36 |
| Crude lipid (% max.) | 6–12 | 5–9 | 5–8 | 8 | 6–8 |
| Ash (% max.) | 16 | 16 | 16 | 16 | 16 |
| Crude fibre (% max.) | 6 | 8 | 7 | 7 | 7 |
| Carbohydrate/NFE*(% max.) | 30 | 44 | 45 | 45 | 36 |
| Gross energy (kJ/g feed) | <20 | 17–19 | 17–19 | >17 | >18 |
*Nitrogen free extract
2. What is a typical feed formulation for milkfish diets?
The following ingredients and percentages are frequently used in milkfish diets:
| Ingredient composition (% dry matter) | Larvae and fry | Starter/fingerling grower | Juvenile grower | Finisher | Broodstock |
| Fishmeal | <33 | <33 | 4–25 | 4–25 | 20–25 |
| Soybean meal (defatted) | <20 | <20 | 20–35 | 30–35 | <43 |
| Rice bran | 16–49 | 16–49 | 16–49 | 16–49 | 20–27 |
| Copra meal | <13 | 13–33 | 13–33 | 13–33 | 13–33 |
| Wheat pollard | <15 | <15 | <15 | <15 | <15 |
| Meat and bone meal | <8 | <8 | <8 | <8 | <8 |
| Molasses | <4 | <4 | <4 | <4 | <4 |
| Squid meal | <15 | | | | |
| Shrimp meal (Acetes sp.) | <24 | | | | |
| Soybean oil | 1.5–2 | 0–2 | 0–2 | 0–2 | 0–2 |
| Fish oil /cod liver oil | <8 | 2–4 | 2–4 | 2–4 | 2–4 |
| Vitamin premix | <1 | <1 | <1 | <1 | <1 |
| Vitamin C | | | | | 0.1 |
| Mineral premix | <0.5 | <0.5 | <0.5 | <0.5 | <0.5 |
| Dicalcium phosphate | <3 | <3 | 1–4 | 1–4 | 1 |
| Bread flour (binder) | 7.0 | | | | |
| Wheat flour | <25 | 5 | 5 | 5 | 4 |
| κ-carageenan (binder) | 5.0 | | | | |
| Lecithin | 1.0 | | | | |
| Preservative (BHT*) | 0.05–0.1 | | | | |
| β-carotene | 0.3 | | | | |
**BHT = butylated hydroxyanisole
Examples of practical diets for fry, juveniles, growers and broodstock:
| Ingredient composition (% as fed basis) | Fry | Grower | Broodstock |
| Fishmeal | 30 | 10 | 25 |
| Soybean meal | 20 | 34–35 | 34 |
| Squid or shrimp meal | 15 | | 15 |
| Wheat flour | 25–26 | | 21 |
| Fish oil | 8 | 2 | 2.5 |
| Grains or grain by-products | | 48 | |
| Dicalcium phosphate | | 1.5 | 1 |
| Vitamin premix | 1 | 0.5 | 1 |
| Trace mineral premix | 0.5 | 0.5 | 0.5 |
| Binder (lignin sulphonate or hemicellulose) | | 3 | 3 |
| Antioxidant (BHA* or BHT) | 0.05 | | |
*BHA: butylated hydroxyanisole; BHT: butylated hydroxytoluene
3. What protein level should I use for milkfish diets?
A suitable milkfish diet will have the following crude protein levels under semi-intensive and intensive farming conditions: fry 40-46 percent, fingerling 25-40 percent, juvenile 25-40 percent and broodstock 36 percent.
4. What plant protein sources and typical inclusion rates can I consider for milkfish feeds?
Copra meal (<33 percent), soybean oil cake (<35 percent), corn gluten meal (<20 percent), wheat gluten meal (<5 percent), cow pea (<15 percent), pea (Pisum sativum) (<26 percent), full fat soya (<30 percent) and ipil-ipil (Leucaena glauca) are plant protein sources used in milkfish diets.
Wheat flour (<26 percent), wheat pollard and wheat bran (<20 percent), palm kernel (<10 percent), corn (maize), corn starch (<35 percent), rice and rice bran (<35 percent), rice hulls (<5 percent) and cassava meal are low protein plant ingredients used in milkfish diets.
5. What typical animal by-product meals can I use in milkfish feeds?
Fishmeal (<25 percent), shrimp meal (<15 percent), squid meal (<15 percent), meat and bone meal (<15 percent), mussel meal (<5 percent), poultry by-product meal (<35 percent), feather meal (<10 percent) and blood meal (<10 percent) can all be included in milkfish diets.
6. What alternative energy sources are suitable for inclusion in normal diets?
The listed ingredients could be included at no more than a 50 percent ratio:
| Ingredients | Moisture/ DM (%) | Gross energy (kJ/g) | Inclusion (% max) | Main nutritional interest | |
|
| Corn grain | 30 | 18 | 35 | Energy | |
| Corn meal | 8 | 18 | | Energy, vitamin A in yellow corn | |
| Wheat grain | 11 | 18 | 10–15 | Energy, B vitamins, phosphorus | |
| Rice bran | 9 | 18 | 35 | Energy, B-vitamins | |
| Corn starch | 12 | 17 | 35 | Energy, binder | |
| Wheat pollard | 10 | 16 | 10–20 | Energy, B vitamins, phosphorus | |
| Wheat flour | 13 | 18 | 10–15 | Energy, B vitamins, phosphorus, binder | |
| Cassava tuber | 56 | 16 | | Energy | |
| Molasses | 19 | 16 | | Energy | |
DM = dry matter
7. What vitamin and mineral mixture can I use in my pelleted feed for milkfish?
Vitamin requirements of juvenile milkfish are not so well known with a scientifically based approach. However, vitamin and mineral premixes are incorporated into the feeds, especially in complete diet formulation or feeds formulated for intensive systems. Amount of vitamin and mineral premixes in a compound pelleted feed varies between 0.5 and 1.0 percent.
8. What size of feed do I need for the different sizes of milkfish from first-feeding fry onwards and how frequently should I feed?
A typical feed in relation to fish size is provided in the table below. Grow-out feeds are typically broadcasted 3 times a day at 08:00, 12:00 and 16:00 at fixed areas of the pond. Automatic and demand feeders are also used. 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. In intensive ponds, pens and cages, milkfish are fed ad libitum throughout the day.
| Life stage | Fish size (g) | Feed type | Feed size (mm) | Feeding rate (% body weight) in intensive systems |
| Fingerling | 5–20 | Crumble | 1.5 x 2.0 | 10.0 |
| Grower | 20–60 | Sinking pellet | 2.2–2.3 x 2–5 | 10.0 |
| 60–100 | Sinking pellet | 2.2–2.3 x 2–5 | 7.0–10.0 |
| 101–200 | Sinking pellet | 2.5–3.2 x 4–6 | 6.0–7.0 |
| 201–400 | Sinking pellet | 2.5–3.2 x 4–6 | 4.0–5.5 |
| 401–500 | Sinking pellet | 2.8–4.0 x 5–8 | 3.5 |
| >500 | Sinking pellet | 2.8–4.0 x 5–8 | 3.0 |
9. Is my farming intensity considered extensive, semi-intensive or intensive?
Intensive milkfish systems usually stock at 20 000 fish per hectare or even higher. Semi-intensive systems normally stock over 8 000 fish per hectare. Production in intensive ponds is typically over 3 000 kg/ha and semi-intensive ponds over 1 300 kg/ha. Natural food produced through fertilization in extensive systems can support around 1 500 to 3 000 fish per hectare.
10. What yields could I get if I only apply fertilizers and do not use any type of supplemental feeds?
Extensive milkfish ponds typically produce a gross yield of 500-750 kg/ha/crop. Some farms may attain gross yields approaching 1 000kg/ha/crop.
11. How much dry feed should I use daily?
Supplemental feeding of milkfish in fertilized ponds would typically be as in the table below.
| Life stage | Fish size (g) | Feeding rate (% of fish biomass per day) | Feeding frequency (no./day) |
| Fry | <10 | 3 | 3 |
| Juvenile | >150 | 3 | 3 |
| Juvenile | >50 | 4 | 3 |
12. What organic fertilizers can I use in my pond?
Organic fertilizers, such as chicken manure are typically applied at a rate of 450-500 kg/ha/crop. Good results have been achieved with chicken manure applied on the pond bottom at a rate of 1 000 kg/ha/crop at the start of pond-filling, and then, inorganic fertilizers are applied at a rate 100-140 kg of urea and 70-100 kg of TSP (16-20-0) per hectare per crop. Organic fertilizer is first applied on the moist pond bottom, prior to flooding, and inorganic fertilizers are then broadcasted a few days later, when the natural food starts to grow.
Another method is to mix urea with cow dung or compost at a ratio of 3:100 by weight. The mixture is then spread into the soil. A second application of urea and triple-superphosphate at 45 kg/ha each and about 60 kg of molasses is added to the filled pond to promote lab-lab growth
