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A factorial trial was conducted to detect the effect of different feeding strategies of supplementation of effective microorganisms (EM) liquid on the growth performance, feed utilization, body chemical composition and economic efficiency of monosex Nile tilapia (Oreochromis niloticus) juveniles. Three experimental treatments were formulated a basal diet without any addition of EM (control; A), a diet supplemented with 2% EM (B), and a diet supplemented with 4% EM (C). All treatments were offered to fish through two different strategies of feeding the meal: 2/3 in the morning and 1/3 in the afternoon or 1/3 in the morning and 2/3 in the afternoon. Each treatment was replicated three times. Juveniles Nile tilapia with an average initial body weight of 3.85 ± 0.22 g (± SE) were randomly stocked at a rate of 90 juveniles per 1.5 m3 tank. Fish growth performance and feed utilization significantly (P ≤ 0.05) increased with increasing EM supplementation and were positively affected by different feeding strategies. Moreover, the economic evaluation showed that there were more benefits by when using the 4% EM diet and feeding 2/3 of daily meal in the morning.

The current study was carried out to investigate the effect of water salinity (5, 15, 25 and 35‰) on growth performance, survival, feed utilization and body chemical composition of the Pacific white shrimp, Litopenaeus vannamei, juvenile in the water environment of Qaroun Lake. Juveniles of L. vannamei with an initial body weight (2.77 ±0.12g) were acclimated to laboratory conditions for 14days before being randomly distributed into in eight circular fiberglass tanks with a volume of 1.5m3 for 80-days at stocking density of 40 juveniles/tank. All tanks were provided with continuous aeration. Results revealed that survival (%) was within the range of 90–98.75%, recording insignificant differences. Results of growth performance parameters were the highest with shrimp reared in water salinity (5‰) compared to the other salinity percentages. The best FCR (lowest values) was recorded with shrimp reared in water salinity of 5‰. While, shrimp reared in water salinity (35‰) showed the worst FCR. The lowest body protein content was recorded with shrimp reared in water salinity of both 5 and 15 ‰. The opposite trend was recorded for body ether extract. Based on the obtained results, the optimum growth rate of L. vannamei was obtained when reared in water salinity of 5‰ under experimental conditions which makes it suitable for cultivation in water environment of Lake Qarun. [ABSTRACT FROM AUTHOR]