الفهرس 
World AquacultureOnly 14 pages are availabe for public view
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Abstract
Food is one of the most important issues for humanity, not only at the present time, but
also in the near future and for the long term. Hence, the increase in food gap represents the
biggest problem faced by Egypt and the developing countries, so they rely on the outside
countries to fill the gap (Abul-Enin, 2010).
Egypt is facing a lot of risks, one of which is a DROP in food imports with the necessity
of taking into consideration the growing crisis in the provision of animal protein in Egypt
against the annual accretion in the population. Therefore, the water resources sector,
especially aquaculture, is a shelter and savior of this crisis, especially with the planning and
management of integrated scientific vocabulary of possibilities and capabilities of Egyptian
(Essa, 2014).
Aquaculture is currently the largest single source of fish supply in Egypt accounting for
almost 74.2 percent of the total fish production of the country, 1.4 million tons in 2012 and
by species, tilapia was the most cultivated species (66% of total aquaculture production, 980
thousand ton) (GAFRD, 2012).
Fish culture activates in Egypt as in many parts of the world, the necessity of depended
able supply of Nile Tilapia, (Oreochromis niloticus), fry is therefore imperative, but the
problem of high quality mass production is still remain. There are many possible reasons for
the lack of access to high-quality tilapia fry. These include too low density of brood stock,
inappropriate sex ratios, inadequate spawning techniques and brood stock nutrition (Refaey,
2013).
During the last decade, there has been a marked increase to produce a high quality
tilapia fry by using some of the modern techniques that will produce larvae of high quality in
terms of growth, feed efficiency and survival rates such as: the use of extruded diets for
feeding fish. These diets have superior water stability, better floating properties and a higher
energy than pelleted diets (Ammar, 2008) and appropriate density. Also, stocking density is
a major factor affects fish growth under farmed conditions (Maragoudaki et al., 1999).
Recently, several efforts have been done to replace chemical drugs by herbal medicine
and plant extracts in aquaculture industry in many countries to stimulate the immune system
in fish (Obaroh and Achionye-Nzeh, 2011 and Sarkar et al., 2011). However, few data are
available concerning the effect of green water on larval tilapia rearing (Refaey, 2013).
Consequently, the main objective of this work is to produce high quality mono sex
Nile Tilapia fingerlings within four separated experiments as the following:
Study the effect of using the green algae in feeding the mono sex Nile tilapia larvae.
Study the influence of feeding frequency and two feed forms (pressed and extruded) diets
on the performance of monosex Nile tilapia fry during nursing period.
2
Study the effect of the stocking density and temperature on the performance of monosex
Nile tilapia fry.
Study the effect of some additives like watercress seed and oil on Nile tilapia fry growth
performance, survival and feed utilization parameters