16 Sep Tilapia Feed Formulation and Feeding Technique
I. Nutrient Requirements for Tilapia
There are different species of Tilapia in different growth periods, so their demands for feed nutrients will be slightly different. The suitable protein content for Nile Tilapia fingerlings is around 35%-40%, and for Tialpia of above 50g, the protein required is about 20%-25%. For Blue Tilapia fingerlings, the suitable protein content is 36% and 26%-36% for adult fish. Generally speaking, the crude protein in Tilapia feed need to be above 25%. In intensive aquaculture, there are more nutrient requirements for Tilapia in the following chart.
Notice:the proportion of animal protein and plant protein should be 1: 2.8-3.4
For fish farming in pond, natural bait makings resources can satisfy Tilapia’s demand for Vitamin. In intensive farming, the amount of Vitamin addition in Tilapia farming is half of that of Carp farming.
II. Various Types of Fish Feed
1. Bran chaff feed
It would be Ok to use rice bran or wheat bran as feed.
2. Oil cake feed
Oil cake is regarded as good feed for fish farming, including soybean meal, rape seed meal, cotton seed meal and so on. These oil cakes contain high content of protein, but anti-nutrients in them are bad for fish growth. Due to urease, antitrypsin and etc. in soybean meal, it would be better to use soybean meal in cooked condition. Because of toxic free gossypol in cotton seed meal, it is often used mixing with bran chaff. Please notice that above 50% cotton seed meal in fish feed formulation will influence Tilapia reproduction.
3. Amphibious plant feed
The amphibious plants are the favorite food of Tilapia fingerlings and adult Tilapia, like lemna minor, soirodela polyrhiza, wolffia arrhiza. Some aquatic plants like water lettuce, water hyacinth or alligator are also good feed for Tilapia. Making feed by them, farmers just need to directly cut them into pieces or mix them into compound feed after cutting. Microcystis and Cyanophyceae are easy to digest to both Tilapia fingerlings and adult Tilapia.
4. Pomace feed and Cereal feed
Pomace feed can be treated as Tilapia feed. Cereal feed refers to malt, rice sprout as feed.
5. Animal feed
Animal feed are mainly used as the raw materials of compound feed, not appropriate to use them alone as feed.
These animal feed including fish meal, blood meal, meat and bone meal, are generally featured with higher protein content than oil cake. They are easy to digest, and rich in lysine that plant feed lacks.
6. Compound feed
Compound feed is widely applied in Tilapia farming in the world. Compound fish feed can be made depending on the following factors: feed sources, Tilapia nutrient requirements and raw material nutrient content. Whether in pond farming or in intensive farming, the addition of mineral salts is of importance for making fish feed.
III. Compound Feed of Tilapia
Generally the compound feed of Tilapia are in two types: pelleted feed and extruded feed.
To produce pelleted feed, the conditioning temperature should be controlled between 80-95℃. With sufficient conditioning period, good gelatinization can be achieved. And then pelleted feed produced are characterized with long term stability in water and smooth appearance.
To produce extruded feed, super micro-grinding equipment with above 80% 80 mesh need to be employed to produce perfect extruded feed. Furthermore, there are less wear on the extruder in feed production procedure to prolong its service life.
Whether pelleted feed or extruded feed, the pellet diameter is basically around 1.5-5.0mm. Being used in different growth periods, fish feeds are usually named fingerling feed, adult fish feed and etc.. In general, the price of extruded feed is higher than that of pelleted feed, but the breeding efficiency of extruded feed is prior to that of pelleted feed.
IV. Tilapia Feeding Skills
The key period is the first 15 days after putting in fingerlings. To improve the fingerling quality, premium feed should be applied and feeding way is: feeding frequently and little feed once.
The fingerlings can be fed on the second day after putting. Protein content in feed is around 32%-36%. Food quantity to feed is 6%-8% of total fish weight. In the beginning, powder feed is the major feed to spread around the pond.
Adjust the pellet size based on fish growth rate and fish size. Notice that do not prematurely adjust fish feed avoiding growing in non-uniform sizes. With fish growing, food to feed will be gradually reduced to around 250g. When their weights reach to about 500g, Tilapia enter fastest growth period. So feed quantity should be 1%-2% of that of total fish and protein content should be above 25%. Feeding way will be the following: feeding twice in one day and two periods: 8am-9am and 3pm-4pm.
Every 15-20 days, catching 30-50 fish to calculate the average weight for analyzing Tilapia growth, which contributes to adjusting feeding rate for helping fish grow healthily. Feeding rate also depends on fish eating. If feed can not be eaten up in 30mins, stop the next feeding until fish begin to eat normally again.
Fish health and climate change are decisive factors affecting fish feeding. When one factor becomes badly, farmers should immediately reduce feeding rate and even stop feeding until all goes well. When the water temperature is below 15℃ or above 32℃, farmers also need to reduce feeding or stop feeding, which contributes to fish digestion, good water quality and feed cost controlling.
In high temperature season, feed with high protein content is disadvantageous to fish digestion, resulting in fish disease. Furthermore, feeding quantity should be strictly controlled avoiding feeding too much.
From the above, fish feeding is obligated to keep the rules: fixed time, fixed place, fixed quality and fixed quantity, and also consider these four factors: season, weather, water quality and feed eating situation. With these rules and considerations, farmers can make good estimates about fish farming situation.