Frequently asked questions (FAQs)

1. What is a typical, suitable nutrient composition for the diet of tiger prawn?

2. What is a typical feed formulation for giant tiger prawn diets?

Some examples of feed formulations are provided in the following table:

3. What types of soybean by-products could be used in giant tiger prawn feeding?

The following types could be used: heat processed full-fat soybean (38 percent protein, 18 percent fat), mechanically extracted (expeller) soybean cake (42 percent protein, 3.5–5 percent fat), solvent extracted soybean meal (44 percent protein, 0.5–1 percent fat), dehulled solvent extracted soybean meal (47.5–49 percent protein, 0.5–1 percent fat) and soy protein concentrate (SPC) (65–67 percent protein). Of these, the solvent extracted forms are usually used in shrimp feeds. As the percentage inclusion increases, SPC will become increasingly useful for feed formulation.

4. What are the main nutrient limitations of the use of soybean for shrimp nutrition as an alternative protein source?

Methionine and cysteine are usually the amino acids that first become limiting (total sulphur amino acids). Highly unsaturated fatty acids, cholesterol and phosphorus also limit the maximum inclusion of soybean meal in shrimp feeds.

5. I am formulating my diet using commercial software and find that I cannot attain the necessary nutritional balance. How can I improve this?

Most feed formulators and mill manufacturers select a reasonable level of high protein ingredients to allow “room” in formulations for additives. The main high protein sources usually used are fishmeal, soybean meal and wheat gluten (binder).

6. I saw a formula for shrimp that had nearly 20 percent “milo”. What is this included for?

Milo is grain sorghum, a grass similar to corn in vegetative appearance and used as a carbohydrate source to replace the traditional wheat usage in the shrimp feed.

7. I am trying to improve my pellet water stability. What pelletizer parameters should I check?

Most starches completely gelatinize at high moisture levels (moisture above 63 percent), and temperatures of 55–85 ⁰C. Moisture and cooking time for shrimp feed production is limited, so the following should be targeted to improve pellet stability: a moisture level of 15–18 percent before pelletizing; a temperature attained in the pre-conditioner of 85–95 ⁰C for as long a period as practically possible; a pressure of 1 atmosphere (atm); thicker pelleting dies to provide higher compression ratios; post pellet conditioning and drying.

8. If I am using an extruder machine to produce shrimp feeds, what parameters should I check to maximize pellet water stability?

Target a moisture level of 25 to 33 percent before pelletizing, a temperature attained of 120 to 140⁰C and a pressure of 5 to 8 atm (1 atm = 1.01 bar and 1.03 kg/cm²).

9. Why is wheat flour so commonly used in shrimp feed?

Pellet water stability is important for shrimp feed. Shrimp feed manufacturers improve water stability through the use of wheat flour as a binder and as carbohydrate source. Wheat starch has a lower gelatinization temperature than corn, rice, sorghum, and other grains and so is suited to the pelletizer used for shrimp feeds. The gluten content and fine particle size of wheat flour also aids in the binding process.

10. What oils are suitable for inclusion for Penaeus monodon diets as well as for other crustaceans as energy sources?

Sunflower oil, peanut oil, soybean oil, palm oil and marine fish oil (sardine, cod liver) are all suitable in terms of their dietary value for juvenile crustaceans as long as soy lecithin is included in the diet.

11. I want to include lupins in my Penaeus monodon diet. Which type of lupin should I use?

Blue lupine (Lupinus angustifolius) seed meal is better utilized by P. monodon than that of white lupin (L. albus). Results of a feeding preference test have indicated that a diet containing blue lupin was more attractive for juvenile P. monodon than a diet containing white lupin.

12. What protein level and key amino acid levels should I use for Penaeus monodon diets as well as for other crustaceans?

Most Penaeus monodon diets have a feed protein level of over 35 percent, with higher levels for post-larvae and juveniles. At a 38 percent crude protein level, arginine should be at least 2.2 percent (as fed basis) and preferably over 2.5 percent, methionine at least 0.72 percent and preferably over 0.91 percent and lysine at least 2 percent and preferably over 2.1 percent or the diet.

13. What size of feed do I need for the different sizes of shrimp from post-larvae onwards?

A good commercial feed manufacturer/supplier will include this information on the feed bag. Start with the feed supplier’s guideline until you develop your experience with the feed and shrimp species.

A typical specification is as follows:

14. When should I start using feeding trays in the pond?

Begin using feed trays as early as possible. At first, use the feeding tray to look at the condition and quality of the post-larvae and get an idea of the survival and growth. After stocking, you need to keep only one or two trays in the pond for this purpose. Trays should be placed at least 30 centimetres deep in the water. From about 5 g shrimp weight, feed trays become effective indicators of feed consumption, so four or more trays per hectare should then be used.

15. How many times should I feed my shrimp per day?

Initially, when the shrimp are small and the feed quantity is minimal; two feeds per day will suffice. After about 30 days of stocking, this should be increased to about 4 or 5 feeds per day. Feeding frequency should be increased to the highest practical number. The feeding ration should be more during night than day.  Use at least 2 trays per ha of pond water surface for semi-intensive ponds and six trays per hectare for intensive ponds.

Feeding schemes for shrimp production are provided in detailed in the following table:

MWB= mean body weight