Evaluation of Growth Performance and Body Proximate Composition of Three Strains of Oreochromis Niloticus L., (1758) Under Greenhouse Condition
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Date
2018-02-04
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Addis Ababa University
Abstract
Growth performance and proximate body composition of fingerling Oreochromis niloticus strains
from different lakes (Chamo, Babogaya and Hashengie) were compared in tank culture system
under greenhouse condition between April and October, 2017. Fingerlings of average weight 4.4
g were stocked at stocking density of 20 fish/m3 in tanks (1.2 m3 each) in three treatments with
four replicate each. The treatment groups were fed formulated feed with 30% crude protein at a
rate of 5% body weight per day. Fish samples were taken monthly from each tank for body length
and weight measurement. Nutrient content of fish fillet was chemically determined following
standard methods of Association of Official Analytical Chemists at the end of the experiment.
Growth performance parameters (final weight, daily weight gain and specific growth rate), feed
conversion ratio, body proximate composition (except carbohydrate) and survival rate were not
significantly different (p>0.05) among the strains tested. However, the wellbeing of the fish,
expressed as Fulton’s condition factor was significantly higher (p<0.05) for the strain from Lake
Hashengie compared with those from Lakes Chamo and Babogaya. Body proximate composition
of the strains were well in the range reported for tilapia except for the lower crude fat content of
strain from Lake Hashengie, which was reported to have the highest compared with O. niloticus
strains from other lakes in the natural system. The reason for no variation in the growth
performances of the three strains could be due to the culture system where culturing tanks were
under greenhouse which brought the culture water temperature in the optimum range for O.
niloticus growth. Despite the optimum culture water temperature, the daily growth rates of the
three strains were low which might be due to breeding, and poor nutritional quality and low
digestibility of feed. The feed quality also explains why strain from Lake Hashengie had lower
crude fat content while has the highest crude fat in the natural system. Generally, based on the
current finding, strains of O. niloticus either from lakes Chamo, Babogaya or Hashengie can be
used for further experiment and stoking activities with feed supplementation. However, we
strongly recommend further research to be conducted in this regard with standard fish feed and
more strain included since this is the only study reported under greenhouse condition.
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Keywords
Diversity of Nile Tilapia Strain in Africa, Aquaculture, World Aquaculture