Bacdterial and mechanical damages of Oreochromics niloticus eggs during the inculation period [Sudan]
1997
Suliman, E.M. (University of Juba. College of Natural Resources, Khartoum (Sudan))
The development of a successful incubation system is highly needed for Oreochromis niloticus (Linnaeus, 1758) eggs to meet the high demands of seed for culture systems. Oreochromis niloticus eggs were incubated at various flow regimes (500 m1/min, 440 m1/min, and 380 m1/min) in ultra violet (U.V) treated and untreated systems. Hatchability success in all incubators was investigated. The medium flow regime (440 m1/min) was found to give the best hatchability result (85+under mins 4.4 and 54+ under mins 4.8). The high flow regime (500 m1/min) was found to give the lowest result (47.8+ mins 6.9 and 42 +under mins 9.1). The hatchability of the low flow regime (380 m1/min) was found to be 62+under mins 18.3, and 42+under mins 7.7 of the U.V treated and untreated systems respectively. Investigation of the eggs under the scanning electron microscope (SEM) showed an association of bacterial and mechanical damages with high flow regimes (500 m1/min) and the statistical analysis showed significant differences (p0.05) between the various incubators and the two systems used. By optimizing flow condition high hatching success can be obtained from non U.V. sterile systems. This may have important implications for large scale hatcheries in field conditions
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