Tilapia Feed Bulletin...WorldFish Centre played a crucial role in tilapia breeding with the development of the Genetically Improved Farmed Tilapia (GIFT). It It demonstrated that a

Tilapia Feed Bulletin

Introduction

Nowadays you can find tilapia all over the world for eating and for farming, but where is it coming from?

Tilapia is an ancient fish, known to mankind and depicted in Egyptian paintings dating 5000 years ago. From biblical times it is known as Saint Peter’s fish.

Tilapia is endemic to Africa with more than 70 species identified in the family Cichlidae. Three genera are distinguished on the basis of breeding behavior:- Tilapia Males guard eggs and fry in nests on bottom of water bodies.- Oreochromis Females incubate eggs & fry in their mouth- Sarotherodon Primarily, males as mouth-brooders

Most species important for aquaculture today belong to the genus Oreochromis. Number one species is the Nile tilapia (O. niloticus). Others are Mozambique tilapia (O. mossambicus), blue tilapia (O. aureus) and various hybrids such as red tilapia (hybrid O. mossambicus x O. hornonum and others).

Tilapia is by many described as an ideal species for aquaculture: it is both hardy, fast-growing and prolific. Maybe too prolific! As a tropical fish it requires water tem-peratures of 24-30 C for maximum growth. It can not tolerate (winter) temperatures below 10-12 C. It can be reared in ponds, cages and tanks in freshwater and even brackish water.

Global production of farmed tilapia has reached about 4 million tonnes in 2013 and is growing at the annual rate of 3-5%. China is the largest producer followed by Egypt and Indonesia; Not far behind are Thailand, The Philippines, Brazil, Vietnam and Bangladesh.

Tilapia is a wonderful source of lean meat, healthy minerals and it is low in fat. In Africa tilapia has great potential to become a major source of animal protein and to contribute to food security. Egypt produces more than 600.000 t of tilapia already and is still growing. Production is mostly in ponds. All tilapia is consumed locally. Egypt is leading the way, but other countries like Uganda and Ghana and many more are following.

WorldFish Centre played a crucial role in tilapia breeding with the development of the Genetically Improved Farmed Tilapia (GIFT). It demonstrated that a dedicated breeding program using proper selection and quantitative genetics can produce within a few genera-tions a tilapia that will grow 50% better, using less feed while better adapted to farming conditions. The impact of the GIFT-project is evident from the fact that 10 out of 17 Nile tilapia breeding programs reported in a global study by Neira (2010) confirm that their base population originated from WorldFish Centre.

With the exception of the two World Fish Centre Nile tilapia breeding programs (GIFT) in Malaysia and Egypt, breeding programs are quite young. Most of them started as recently as 2005. Most tilapia breeding programs are part of fully integrated farm operations. Some examples of globally operating fry / broodstock producers are Aquaculture Production Technologies (APT, Israel), Til-Aqua (Netherlands) and FishGen (UK-based with satellites).

Tilapia was one of the first commercial aquaculture species to have its complete genome sequenced by a group of English and American scientists. This will most certainly speed up the process of genetically improvements for farmed tilapia.

There is an increasing variety of tilapia breeds available for aquaculture around the world. Some varieties are coloured (red, black, sil-very), others are salt-tolerant. When you choose a tilapia fry producer, try to get information on the tilapia breed and the type of breed-ing program used. Ask what kind of (growth) performance you can expect. Be aware of national legislation with regard to the import of non-native tilapia breeds.

Genetic Breeds

FreshwaterRed tilapia (NMT Til-Aqua)

Wild-typeNile tilapia

For tilapia it is often mentioned that it is a hardy fish tolerating poor water quality and low oxy-gen levels and while this may be true in that ti-lapia may survive those conditions for a short period, it will certainly not thrive and grow well.

Therefore, the tilapia farmer must assure that there is sufficient water and that water qual-ity does not deteriorate. A number of important water quality parameters for closed systems are given in the table.

Water temperature should be measured daily. Optimal temperature is 24 - 30 C. Temperatures below 20 C should be avoided. Small fingerlings

are more susceptible to low temperatures than large fish.

Oxygen should be measured at least weekly ear-ly in the morning in ponds when levels are reach-ing a minimum. Aeration may be needed in grow out ponds when levels fall below 5 ppm; other-wise tilapia will not grow optimally anymore. Big tilapia are more sensitive to suboptimal oxygen levels than small fish.

In ponds proper management of algae and zoo-plankton may be important for natural food and may require the use of fertilisers to balance nitro-gen, phosphorous (and potassium).

In recirculating aquaculture systems one has to focus on biofilter functioning to minimise levels of ammonia, nitrite, and CO2.

SalinityTilapia is a freshwater fish but can tolerate brack-ish waters and sometimes even salinity levels close to seawater. Tolerance is affected by genet-ics, but also temperature, method of acclimatisa-tion, age and body size. Florida red and Mozam-bique tilapia can tolerate full seawater strength whereas Nile tilapia does better at lower salini-ties (0 - 10 ppt).

Water quality Parameter Unit Value or rangeTemperature C 24-30Oxygen mg / L 4-6pH 6-8CO2 mg / L < 20Total suspended solids mg / L < 20Total ammonia - N mg / L < 3NH3 - N mg / L < 0.06Nitrite - N mg / L < 1Nitrate - N mg / L < 100

Mostly from : Timmons & Ebeling (2007)

Tilapia is more resistant to cold water tempera-

tures in a saline environment. Hence, overwinter-

ing of tilapia will be more successful in brackish

water. When transferring tilapia to saline waters

it is advisable to gradually increase salinity ( max.

5 part per thousand per day. In addition, feeding

dietary salt (10%, 2-4 weeks) can also improve sa-

linity tolerance.

Breeding of tilapia is, however, suppressed in

higher salinity waters.

Ammonia is very toxic for tilapia and union-

izedammonia-nitrogen should be kept below

0.1 mg/L. Nitrite is also toxic to tilapia and should

be maintained below 1 mg/L.

Water quality parameters

for Tilapia

Parameter Unit Value or rangeTemperature C 24-30Oxygen mg / L 4-6pH 6-8CO2 mg / L < 20Total suspended solids mg / L < 20Total ammonia - N mg / L < 3NH3 - N mg / L < 0.06Nitrite - N mg / L < 1Nitrate - N mg / L < 100

Mostly from : Timmons & Ebeling (2007)

What sets tilapia apart as an omnivorous, herbivorous fish species is its long and

efficient intestinal tract. First of all, it has a well-defined stomach with a low pH (<

2). This allows for a high protein digestibility. Next, its long intestinal tract often 5-6x its

body length is unique in farmed fish. It allows a thorough digestion process of all nutri-

ents including complex carbohydrates. Tilapia can digest even raw uncooked starch very

Tilapia Nutrition

Tilapia is a versatile, opportunistic feeder, eating anything from algae and bacteria up to water plants, fish eggs and insect larvae.

well. It has a high tolerance for dietary

fibers. In the lower part of the intestinal

tract microbial activity is considerable and

contributes to carbohydrate fermentation

(production of healthy volatile fatty acids)

and modest vitamin synthesis (vitamin

B12, biotin).

As a consequence tilapia can utilize a wide

variety of feedstuffs and byproducts.

Therefore, with the right nutritional know-how

tilapia feed production can take advantage of

local feedstuffs and byproducts and reduce de-

pendency on import of more expensive feed-

stuffs.

Intestinal tract of tilapia

Characteristics:

o Low pH in stomach is a barrier for pathogens

o Ratio gut length/body length > 6

o High digestive capacity

o High tolerance for fibers

o Microbial fermentation in hindgut

o Volatile fatty acids produced o Intestinal synthesis of vitamins

Wageningen University (2012)

Tilapia Nutrition

Certified Quality & Food Safety

Ingredient and Supplier Assessment & Management

Monitoring & Control

Risk Management

Tracking & Tracing

Certified Quality & Food Safety

Skretting tilapia feed is produced according to internal and ex-

ternal certified quality standards (ISO 9000).

Ingredient and Supplier Assessment & Management

Our suppliers underwent an assessment and approval process

before we purchase their feed ingredients

Monitoring & Control

We have a globally managed program to analyze tilapia feeds

& ingredients for food safety risks using approved laboratories

and methods. For example, mycotoxins.

Risk Management

We are prepared for potential issues, accidents and calamities in

the production process of tilapia feed.

Tracking & Tracing

Skretting can recall tilapia feed immediately if required using

state-of-the-art tracking & tracing solutions.

Nutrace

Nutrace® is our quality standard, ensuring safety and quality from feed ingredients to feed and food products. What does it mean for you as a tilapia farmer?

What are mycotoxins?

In many areas of the world mycotoxins may present a feed safety challenge. The term ‘my-cotoxin’ is usually reserved for a toxic chemi-cal produced by certain molds that readily colonize agriculture crops. Aflatoxins are a well known type of mycotoxin produced by Asper-gillus species of fungi. Aflatoxin B1, the most toxic, is a potent carcinogen and has been di-rectly correlated to adverse health effects, such as liver cancer, in humans as well as animals. Aflatoxins are largely associated with commod-ities produced in the tropics and subtropics, such as cotton, peanuts, spices, pistachios and maize. Byproducts of these crops may often be utilised in tilapia feed.

Aflatoxin contamination of tilapia feeds are therefore a real threat in the tropics. Exposure to aflatoxin can reduce the growth of tilapia and induce liver disorders.

What are mycotoxins? It should be mentioned that aflatoxin is normally deposited in the liver of fish. Consuming only tilapia fillet would not pose a risk of exposure to aflatoxin for hu-man consumers.

It is obvious that all measures have to be taken by a feed producer to assure that the risk of mycotoxins in tilapia feed is controlled. This includes regular testing of raw materials for mycotoxins. Our qual-ity system Nutrace has been implemented with that target in mind.

Furthermore, in-feed solutions have been developed to protect fish against a broad spectrum of mycotoxins.

Production cycle

From: FAO

Hatchery phase (4 weeks)

Tilapia can spawn as early as 4 months old. Their ability to spawn

naturally in captivity makes tilapia suitable for mass production. Breed-ing takes place in saucer-shaped nests built by the male on the pond bottom. Eggs are taken up in the mouth by the female. Eggs hatch after 4-5 days. Eggs or yolksac fry can be collected from the females and transfered to incubators. Swim-up fry are generally <9 mm.

Fry collected from breeding facil-ities need to be graded through

3.2 mm mesh material to remove fish that are >14 mm, which are too old for successful sex reversal. Males grow faster than females.

To create all-male populations, me-thyl testosterone (MT ) is added

to a powdered commercial feed, containing >40 percent protein, by dissolving it in 95-100 percent ethanol, which is mixed with the feed to create a concentration of 60 mg MT/kg feed after the alcohol has evaporated. The alcohol car-rier is usually added at 200 ml/kg feed and mixed thoroughly until all the feed is moist. The moist feed is air dried out of direct sunlight, or stirred in a mixer until dried, and then stored under dark, dry conditions. MT breaks down when exposed to sunlight or high tem-peratures.

You need 250-400g MT in treat-ed feed per 1000 fry.

Fry are stocked at 2.000 to 4.000/m2 in hapas or tanks with water exchange. Stocking densities as high as 20 000/m2 have been used if good water quality can be maintained. An initial feed-ing rate of 20-30 percent body weight per day is gradually de-creased to 10-20 percent by the end of a 3 to 4 week sex-reversal period. Rations are adjusted dai-ly, and feed is administered four or more times per day. If sex-reversal is conducted in hapas, the feed must be slow-sinking or floating. Otherwise a consid-

erable amount of feed would be lost as it settles through the bot-tom of the hapa.

Sex-reversed fry reach an aver-age of 0.25-0.5 g after 3 weeks and 0.5-1.0 g after 4 weeks. The average efficacy of sex-reversal ranges from 95 to 100 percent depending on the intensity of management.

Good hatcheries using high quality starter feeds can reach more than 75% survival and FCR < 0.8. In practice, however, sur-vival varies between 25-75%.

Tilapia are often offered a fine pow-dered diet in the hatchery phase, but it is preferred to offer a series of crumbles and mini-pellets. The latter are more easily eaten and less sus-ceptible to nutrient leaching.

For larval tilapia it is recommended to formulate high protein diets (> 40-50% protein) coming from a mix of fish, animal and/or vegetable ori-gin for easy uptake and digestibil-ity. The high protein level ensures growth rates of > 30% per day after yolksac absorption.

Hatchery Diets

Energy is supplied by both lipids, phospholipids and starch. Lipids have to be balanced to provide both n-3 and n-6 fatty acids.

For proper growth and high survival hatchery

diets must contain copi-ous amounts of vitamins, minerals & trace ele-ments. Antoxidants may provide health support in this phase in combination with immuno-stimulants.

Hatchery Feeding Guidelines

Week after hatch

Feed size (mm)

Fry size (mg) Water 20 C

Temp 30 C

1 0.2 - 0.5 10 - 100 20 - 30 30 - 402 0.2 - 0.5 100 - 200 15 - 20 20 - 303 0.5 - 0.7 200 - 500 10 - 15 15 - 20

Feeding rates as % of body weight per day are indica-tive only and must be ad-justed depending on water quality, oxygen availability and feeding response. Feeding frequency: 5-10x per day.

The genital papilla is located right behind the anus of the fish. If the genital papilla

has one single opening you are looking at a male tilapia. Males have only one open-

ing and both urine and milt will pass through this hole. If the genital papilla has two

openings you are looking at a female tilapia, because tilapia eggs do not pass through

the same hole as urine. If you find it hard to examine the genital papilla of fingerlings,

Sex differentiation

When a tilapia fingerling has reached a weight of 25 grams it can normally be sexed by looking at the genital papilla.

try placing a drop of dye, such as food col-

ouring or methylene blue, on the genital

region. The colour will normally make it

easier to distinguish the openings. Manual

sexing for single sex populations of tilapia

is not very common anymore.

For achieving all-male populations,

there is a new breeding technology us-

ing ‘supermales’ that only produce males

as offspring. Til-Aqua (www.til-aqua.com)

and FishGen are two commercial compa-

nies that currently provide super males as

an alternative to hormonal sex reversal in-

corporated in the breeding programs.

Broodstock

Tilapia breeders should not be fed a standard grower diet but deserve a dedicated brood-

stock diet. Tilapia are continuous spawners and as a consequence have a high turnover rate of pro-tein and other nutrients in the body.

Therefore, a tilapia broodstock diet is charac-terised by a higher protein level and protein/

energy ratio to maximise fecundity. Balance of n-3 and n-6 fatty acids is essential for egg and sperm quality. Furthermore, phospholipids are an eas-ily digestible form of fatty acids and energy for proper larval development. Minerals especially,

calcium-to-phosphorus ratio are contributing to proper bone development. A number of micro-nutrients and vitamins are implicated in protect-ing gametes against oxidation and improving egg hatchability. Finally, the use of immuno-stimulants can be recommended for breeders.

A good broodstock diet is fed 2-3 months before planned spawning and can improve breeder

survival, egg and sperm production as well as fry survival. Also, use the broodstock diet between multiple spawnings.

Broodstock diet improves fry survival

After introduction of a broodstock diet (Vitalis) at a large Tilapia Breeding Station, survival of hatched fry after one week increased from 50% to 65%.

Broodstock feeds have to be used for at least 2-3 months to measure the impact.

These trials illustrate the importance of complete broodstock nutrition on hatchery output and econom-ics

28,000 broodfish were divided over 6 ponds; 3 ponds were fed a broodstock diet (Vitalis), 3 ponds continued on a control diet at a large Tilapia breeding company.

After 10 weeks, ponds fed Vitalis had 26% more eggs (and fry) production. Broodfish survival was also im-proved by 1.5%.

Hatched fry survival after 1st wk was good at 63% for both groups.

0

10

20

30

40

50

60

70

Control Vitalis

Fry survival 1st week post-hatch%

Broodstock diet improves fry survival Broodstock diet improves fecundity

28,000 broodfish were divided over 6 ponds; 3 ponds were fed a broodstock diet (Vitalis), 3 ponds continued on a control diet at a large Tilapia breeding company.

After 10 weeks, ponds fed Vitalis had 26% more eggs (and fry) production. Broodfish survival was also im-proved by 1.5%.

Hatched fry survival after 1st wk was good at 63% for both groups.

020406080

100120140

Control Vitalis

Fry survival 1st week post-hatch Egg production% %

Nursery phase

o When tilapia fry have reached 1

grams, they are still too small for

stocking in grow-out holding units

and they are kept in nursery facilities

until they reach 10-50 grams finger-

lings.

o Nursery facilities can consist of

tanks, small ponds, hapas in big-

ger ponds, or small cages with fine-

mashed nets.

o During this phase tilapia have still

a relative high protein requirement

for maximum growth. There seems to

be an optimum protein level; lower

than in the hatchery phase, but still

significantly higher than the grow-

out phase. Moreover, tilapia finger-

lings also respond to digestible en-

ergy; this means that fingerling diets

should not be too low in digestible

energy.

o In this nursery phase feed conver-

sion (FCR) is typically still close to 1.

o Stocking rates in ponds can range

from 10-110 fish/m2 depending on

the level of intensity.

o Survival ranges typically from 60-

95%

Response to protein and energy

in fingerlings

In these university research trials tilapia was growing from 2 to 10 grams.Growth was high with SGR > 8.

Tilapia fingerlings responded to a mini-mum of digestible protein. Not meeting that requirement will reduce growth.

Tilapia fingerlings responded also to a minimum of digestible energy. Not meeting that requirement will reduce growth.

Both trials illustrate that juveniles held under optimized conditions for fast growth require high density nursery di-ets.

Nursery feeding guidelines

Week after hatch

Feed size (mm)

Fry size (g) Water 24 C

Temp 30 C

4 - 6 0.7 - 1.0 1 - 10 6 - 8 8 - 106 - 8 1.0 - 1.8 10 - 25 4 - 5 5 - 6

8 - 12 1.8 - 2.5 25 - 50 3 - 4 4 - 5

Feeding rates as % of body weight per day are indica-tive only and must be ad-justed depending on water quality, oxygen availability and feeding response. Feeding frequency: 3 - 5x per day.

In pond systems natural food consisting of phytoplankton, and zooplankton will contribute to the

total ration consumed by tilapia. This will be a function of the level of farming intensity:o Extensive:

Stocking 1-2 fish per m2; fertilization schemes; no or little water exchangeo Semi-intensive:

Stocking 3-4 fish per m2; night time aeration in summer; water exchange 10%o Intensive:

Stocking > 5 fish per m2, continuous aeration; water exchange 100%

Grow-out & Harvesting

Grow out of tilapia can take place in a variety of systems from ponds, raceways, cages, aquaria and tanks up to advanced closed recirculating water systems. The farming system often dictates stocking densities , input efforts and choice of feed.

Depending on the farming intensity one could adjust certain nutrient limits in the tilapia feed under the assumption that part of the nutrient (energy) requirement is met by the natural food.

In cage systems the diet must be complete as natural food will be absent or limited. Moreover, diets should be floating or slow-sinking for tila-pia. Density of fish depends on water flow, but 50-100 fish per cubic or 25 kg of fish/m3 is safe.

In recirculating aquaculture systems (RAS) also no natural food is available; in addition diet adaptations may be needed to reduce organic loading of the mechanical and bio filters of RAS. Fish densities of 50-150 kg/m3 can be reached safely.

Protein and amino acid requirements gradu-ally reduce in tilapia with increasing body

size. While protein levels of 40% are still rec-ommended in the nursery phase, in the grow out protein levels can be reduced significantly. On the contrary energy requirements per kg of growth will increase slightly with body size as the amount of energy used for maintenance processes will increase as well.

Complete harvests are necessary in ponds and are accomplished by seining in combi-

nation with draining. A complete harvest is not

possible by seining alone as tilapia are adept at

Fish size (grams) Crude Protein (%)< 20 40

20 - 200 34

200 - 600 30600 - 1500 28

> 1500 26

According to National Research Council (2011)

escaping seine nets. The pond should be dried between production cycles to avoid carryover to the next production cycle. Partial harvests of tanks, raceways and recirculation systems, which maximize production, are accomplished with grader bars to remove the largest fish.

Extruded floating feeds are becoming the general standard. Extrusion offers advantages in pellet durability and water stability. Furthermore, nutrient availability and density can be improved. Floating feeds allow for better feed management as appropiate feeding rates can be

estimated more accurately.

Fish size (grams) Crude Protein (%)< 20 40

20 - 200 34

200 - 600 30600 - 1500 28

> 1500 26

According to National Research Council (2011)

Feed size (mm) Fry size (g) Water 24C Temp 30C2 - 3 50 - 200 3 - 4 3.5 - 4.54 - 5 200 - 500 1.5 - 2.5 2 - 36 - 8 > 500 0.8 - 1.8 1 - 2

Grow-out feeding guidelines

Feeding rates as % of body weight per day are

indicative only and must be adjusted depending

on water quality, oxygen availability and feeding

response.

Feeding frequency:2-3x per day.

During the grow-out phase

the tilapia grow and consume

increasing amounts of feed.

Hence, the capital invested

in the fish rapidly increase

and survival rate becomes an

important economical factor

for the tilapia farmer. Proper

health management includes

disinfection procedures of

ponds and equipment, hy-

giene procedures for farm

workers and visitors, quaran-

tine periods for breeders and

fingerlings, disease preven-

tion by maintaining good wa-

ter quality and reducing han-

dling stress.

Basic nutrition can contribute

to general health manage-

ment of tilapia. In addition,

nutritional supplements have

been identified that con-

tribute to stress resistance,

immune-support and disease

prevention. Skretting has de-

veloped a health diet Protec.

Protec shields the natural

barriers (skin, gut and gills)

of fish, supports the immune-

systems, and seeks a good

balance between hostile mi-

crobes and fish.

A major tilapia farming group

in Indonesia tested the effect

of Protec elements in a large

scale commercial trial. In total

more than 60 batches, each

consisting of 8000 fingerlings,

were used in the experiment

equally divided over the treat-

ments: feed with or without

Protec. Fingerlings were fed

with the test feeds for a period

of 3 weeks prior to their trans-

fer to the grow-out cages.

Feeding rates applied were 1 –

3 % per day. Fingerlings grew

from 12 to 20 g. The transfer

of fingerlings to net cages

involved the handling, a 4

hour journey by truck and in-

troduction to a new environ-

ment with lower salinity and

lower temperature. Mortality

after transfer was significantly

reduced by 2% points in the

Protec fed batches (Figure).

This demonstrated that Protec

elements also work in practice

in tilapia and give a positive

return on investment.

Health management

Post-transfer mortality of tilapia finger-

lings moved to grow-out cages is re-

duced when feeding Protec elements

10%

5%

15%

20%

0%

0 40302010

Control group

Protec

15,38%

13,46%Cumulative Mortality

Post-transfer period (days)

Survival

Streptococcus is a serious bacterial disease in tilapia farming. The

disease is often breaking out when temperatures are high and wa-

ter quality is hampered by organic pollution.

We studied the survival of 100 grams tilapia fed a basal diet or

a special health diet 2 weeks after a challenge with Streptococcus

aglactiae. Survival was significantly improved (almost doubled)

with the health diet.

Nutrition can contribute to a holistic health management plan for

your operation.

As a tilapia farmer you have to keep good records of your farm activities:

o Number and size of ponds, cages and rearing unitso Stocking rates and origin of fry or fingerlingso Water temperature and quality parameterso Daily feeding rates and feed sourceo Use of fertilizers, pesticides and veterinary drugso Harvesting date and quantitieso Fish purchaser or processing plant

Records will help you to define good practice, plan your production better the next time, how to improve step-by-step and avoid mistakes. Records are also important for trace-ability and mandatory when you seek certifi-cation.

0102030405060708090

Basal diet Health diet

% Survival

Survival Record-keeping

As a tilapia farmer you have to keep good records of your farm activities:

o Number and size of ponds, cages and rearing unitso Stocking rates and origin of fry or fingerlingso Water temperature and quality parameterso Daily feeding rates and feed sourceo Use of fertilizers, pesticides and veterinary drugso Harvesting date and quantitieso Fish purchaser or processing plant

Records will help you to define good practice, plan your production better the next time, how to improve step-by-step and avoid mistakes. Records are also important for trace-ability and mandatory when you seek certifi-cation.

The economic feed conversion ratio is calculated to by dividing kg feed by biomass gain. For bio-

logical feed conversion ratio it would be more correct to include biomass that is lost due to mortali-

ties or other causes.

Growth and FCR calculations

biomassinitialkgbiomassfinalkgusedfeedkg

FCREconomic−

=

Growth in fish is most commonly expressed by

calculating the specific growth rate (SGR). How-

ever, any growth measure in fish is influenced

to a certain extent by water temperature and

initial body weight. It is easiest to put these

equations in a spreadsheet.

10011

×

−

=

days

weightstartweightendSGR

Or more simple

( ) 100*/ dayswtstartLnwtendLnSGR −=

Feed requirement

How can you calculate how much feed you need for your rearing unit or for your farm? This is a typical question that we get from tilapia farmers.

This can be calculated by hand, but also using a spreadsheet software like Microsoft Excel:

What is the end weight of a tilapia on a feed type? Take, for example 500 gram.

What is the start weight of the same tilapia? Suppose 250 gram

Next, you calculate that the fish will grow 500 – 250 = 250 gram gain

Divide this gain by the expected feed conversion factor. For big tilapia 1.3 is good.

That means that you need 250 grams gain/ 1.3 = 325 grams or 0.325 kg of feed

Suppose you have 5000 fish

The feed requirement would be 0.325 kg * 5000 = 1625 kg feed

Feed calculation for TilapiaSize feed type start weight end weight Estm. Feed amount Number of Feedmm g g FCR per fish Fingerlings * 1000 kg

0,3 Crumble starter 0,3 crumble 0 0,3 0,5 0,15 5 0,750,5 Crumble starter 0,5 crumble 0,3 1 0,5 0,35 5 1,750,7 Crumble starter 0,7 crumble 1 3 0,6 1,2 5 6,00

1,0 Crumble Nursery 1 crumble 3 10 0,7 4,9 5 24,501.7 Nursery 1.7 mini pellet 10 25 0,8 12 5 60,002,0 Nursery 2 floating 25 60 1,1 38,5 5 192,50

Tilapia Grower 3,0 3,2 floating 60 250 1,2 228 5 1140,00Tilapia Grower 4,5 5 floating 250 500 1,3 325 5 1625,00

Total 3050,50

Skretting invests in research and development of its tilapia feeds. This is organised

in a dedicated company Skretting Aquaculture Research Centre based in Stavanger,

Norway, with satellite research stations in China, Italy and Japan. More than 40 interna-

tional scientists focus on fish nutrition, health and feed technology to bring innovations

to our customers.

Nutritional research defines optimal nutrient requirements, for example digestible pro-

Skretting ARC

tein and energy, of the different life stages

of tilapia. Estimating apparent digestibil-

ity coefficients of typical feedstuffs used

in tilapia feed. Differentiating nutrient

requirements for rearing tilapia in ponds,

cages and recirculating aquaculture sys-

tems.

Health research studies interactions be-

tween nutrition, environment (water qual-

ity) and tilapia health. Particularly, the

influence of feed ingredients on intestinal

health (barrier function, microbiota com-

position) is important in tilapia to prevent

pathogens from entering the host.

Feed technology assures that tilapia feed

factories are efficient in producing both

floating or sinking feeds with the correct

pellet quality including hardness and du-

rability.

Tilapia research is carried out at the re-

search station in China, but also in collab-

oration with Wageningen University (The

Netherlands) and Humboldt University

(Germany).

Skretting AfricaVeerstraat 38

P.O. Box 2345830AE, BoxmeerThe Netherlands

Tel: +31 485 589 988

www.skretting.comFor more information: [email protected]