Tilapia rendalli feed predominantly on aquatic
plants found around the margins of lakes
and dams. They are well adapted to feeding
on these larger plant forms and have robust
pharyngeal teeth for triturating or grinding up
these food items. The type of aquatic plants
eaten by this species varies considerably
but includes almost all true submerged
hydrophytes, many floating hydrophytes and
even terrestrial grasses which are flooded
during the rainy season.
Nutrient Requirements of Tilapia:
As the tilapia sector expands and technology
development continues, traditional extensive
culture is being replaced by semi-intensive
and intensive production systems. In semi-
intensive farming systems, supplemental feeds
that consist of locally available, low-cost single
feedstuffs such as rice bran, corn meal, copra
meal, coffee pulp, brewery by-products and/
or their combination are generally used as
supplements to natural food. These feeds are
high in energy, low in protein and deficient in
micronutrients such as vitamins and minerals.
It is assumed that the deficient nutrients will
be provided by natural food organisms. As
stocking rate increases, the contribution of
natural food decreases and more nutritionally
complete feeds are needed. In intensive
culture systems such as in ponds, raceways,
cages, and tanks, feed is the most expensive
item, often ranging from 30 to 60 percent of
the total variable expenses, depending on
the intensity of the culture operation. Thus,
the availability of least-cost, nutritionally well-
balanced feeds is one of the most important
requisites for successful and sustainable
tilapia production. Data on nutrient
requirements, among other information, are
needed for least-cost feed formulation.
Nile tilapia requires the same ten essential
amino acids as other finfishes. Protein
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requirements for optimum growth are
dependent on dietary protein quality/source,
fish size or age and the energy contents of the
diets and have been reported to vary from as
high as 45-50 percent for first feeding larvae,
35-40 percent for fry and fingerlings (0.02-10
g), 30-35 percent for juveniles (10.0-25.0 g) to
28-30 percent for on-growing (>25.0 g). The
best protein digestibility occurs at 25 °C and
the optimum dietary protein to energy ratio
was estimated in the region of 110 to 120
mg per kcal digestible energy respectively for
fry and fingerling. Tilapia brood fish require
about 40-45 percent protein for optimum
reproduction, spawning efficiency and for
larval growth and survival.
The lipid nutrition requirement of farmed
tilapia has been reviewed by various
researchers. The minimum requirement of
dietary lipids in tilapia diets is 5 percent but
improved growth and protein utilization
efficiency has been reported for diets with
10-15 percent lipids. Both n-3 and n-6
polyunsaturated fatty acids (PUFA) have been
shown to be essential for maximal growth of
hybrid tilapia (O. niloticus x O. aureus). For
Nile tilapia the quantitative requirement for
n-6 PUFA is around 0.5-1.0 percent. Unlike
marine fish species, tilapia appear not to have
a requirement for n-3 highly unsaturated fatty
acids (HUFAs) such as EPA (20:5n-3) and DHA
(22:6n-3) and its n-3 fatty acid requirement can
be met with linolenic acid (18:3n-3).
The exact carbohydrate requirements of
tilapia species are not known. Carbohydrates
are included in tilapia feeds to provide a
cheap source of energy and for improving
pellet binding properties. Tilapia can
efficiently utilize as much as 35-40 percent
digestible carbohydrate. Carbohydrate
utilization by tilapia is affected by several
factors, including carbohydrate source, other
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