Tilapias are becoming increasingly popular culture fish because of their superior culture adaptability. In recent years, there has been a great interest in the use of probiotics in fish aquaculture. The objectives of the present study were to evaluate the effect of dietary graded levels (0, 5, 10, and 15 g/kg commercial diet, referred to treatments numbers T1, T2, T3, and T4, for males and T5, T6, T7, and T8 treatments for females) of a new probiotic Hydroyeast Aquaculture(®) on hematological and biochemical parameters, serum sex hormones, and the reproductive efficiency parameters of the adult Nile tilapia Oreochromis niloticus for 8 weeks. Results revealed that high levels of probiotics diet, 15 g (T4, ♂) and 10 g (T7, ♀) probiotic/kg diet, significantly (P ≤ 0.05) enhanced the physiological responses (hematological as well as serum biochemical parameters) together with, reproductive performances (sex hormones, testes and sperm quality parameters, absolute and relative fecundity, and ovarian measurements). Therefore, it could be conclude that Hydroyeast Aquaculture(®) is useful at levels of 15 g (T4) and 10 g (T7)/kg diet in improving the reproductive efficiency of adult O. niloticus males and females, respectively. Thus, the use of Hydroyeast Aquaculture(®) may be economically important for fish hatcheries.

The objective of the present study was to determine the effects of dietary inclusion of different levels of pawpaw seeds powder (PSP) at different periods on the growth performance, survival rate, feed utilization and carcass composition of fry and fingerlings of Nile tilapia (Oreochromis niloticus). The experiment was divided into two periods; the first was feeding period of Nile tilapia fry with PSP for 71 days; and, the second was rearing period where the Nile tilapia fingerlings fed control diet (0 g/kg diet from PSP) for 84 days. Apparently-healthy 1200 Nile tilapia fry of one day old with an average initial body weight 0.012 g/fry were randomly distributed to 20 treatments. Each treatment was referred to three aquaria. The PSP was added to the basal diet at levels of 0, 2, 4, 6 and 8 g/kg diet for 15, 30, 45 and 60 days, different periods. The results of the first period showed no significant (P ≥ 0.05) differences in all growth performance parameters and feed conversion ratio (FCR) during all periods (15, 30, 45 and 60 day); however, different levels of PSP showed significant (P ≤ 0.01) improvement in all growth performance, survival (intervals SR and final SR) and feed utilization (FI and FCR) by increasing level of PSP till 6 g PSP/ kg diet, then significantly decrease (P ≤ 0.01) till 8 g PSP / kg diet. In case of the second period, all growth performance parameters and feed utilization (FI and FCR) gradually (P ≤ 0.01) improved with increasing feeding periods until 45 day, and then decreased with increasing feeding period (60 day). The interaction between levels of PSP and different periods of treatment indicated that 6 g PSP/kg diet for 45 day had the best (P ≤ 0.01) values of FW, TWG and ADG compared with other treatments. Thus, the results of this study lead to useful and safety recommended use of 6 g PSP /kg diet for 45 day, to be economic and efficient for fish farms.

The objectives of the present study were to evaluate the effects of graded levels of a new commercial probiotic Hydroyeast Aquaculture ® (0, 5, 10 and 15 g/Kg diet) on both sexes of adult Nile tilapia Oreochromis niloticus, referred to treatments No. T1, T2, T3 and T4, respectively, for males and T5, T6, T7 and T8 treatments for females, on their growth performance, feed and nutrients utilization and carcass composition for 8 weeks. The obtained results showed that tested probiotic at level of 15 g /kg diet (T4) and 10 g /kg diet (T7) for adult males and females O. niloticus respectively, significantly (P ≤ 0.05) enhancing fish growth, feed intake and nutrients utilization, as well as realized slight improving of fish carcass composition. Hence, it could be concluded that Hydroyeast Aquaculture ® probiotic is useful at levels of 15 g /kg diet (T4) and 10 g /kg diet (T7) for enhancing production performance of adult males and females Nile tilapia (O. niloticus) respectively, so may be using of this probiotic led to economic efficiency especially, for fish farming and hatcheries.

Medicinal herbs have curative powers and are used in making medicines because of their healing properties. The present study aimed to evaluate the effect of dietary graded levels (0, 1, 2 and 3% kgG 1 diet) of both Dried Rocket (Eruca sativa) Leaves (DRL) or Seeds (DRS) on the growth performance, feed utilization, chemical composition of body and physiological parameters of all male monosex Nile tilapia, Oreochromis niloticus fingerlings for 8 weeks in indoor feeding experiment. A total of 168 fish with average initial body weight 17.14±0.35 g were randomly distributed into eight treatments referred No. T 1 , T 2 , T 3 and T 4 for DRL and T 5 , T 6 , T 7 and T 8 treatments for DRS. Results revealed that T 4 and T 7 were the best treatments which were responsible for the significantly (p#0.05) increased growth performance, feed utilization, chemical composition of the whole fish body, blood hematological and biochemical parameters among all treatments. Dietary DRS gave the best results compared with DRL. Thus, it is recommended that the inclusion of 3% DRL (T 4 ) or 2% DRS (T 7 ) as feed additives of all male monosex O. niloticus are more useful for improving their growth performance, feed utilization, chemical composition of the whole fish body and physiological responses. Dietary treatments:A Basal Diet (BD) was formulated from the local commercial ingredients namely, 22% fish meal, 27% soybean meal, 21% yellow corn, 20% wheat bran, 3% corn oil, 5% molasses and 2% vit. and min premix (each 1 kg premix contains; Vit. A, 12000,000 IU; Vit. D 3 , 3000,000 IU; Vit. E, 10,000 mg; Vit. K 3 , 3000 mg; Vit. B 1 200 mg; Vit. B 2 , 5000 mg; Vit. B 6 , 3000 mg; Vit. B 12 , 15 mg; Biotin, 50 mg; Folic acid 1000 mg; Nicotinic acid 35000 mg; Pantothenic acid 10,000 mg; Mn 80 g; Cu 8.8 g; Zn 70 g; Fe 35 g; I 1 g; Co 0.15 g and Se 0.3 g). However, the BD proximate chemical analysis (% on dry matter basis) was 89.89% Dry Matter (DM), 30.13% Crude Protein (CP), 4.42% ether extract, 11.91% ash, 53.54% total carbohydrate, 426.2 kcal 100/g DM Gross Energy (GE) and 70.69 mg CP kcalG 1 GE, P/E ratio.The ingredients and additives (leaves and seeds of E. sativa), were bought from the local market. The leaves and seeds of E. sativa were cleaned and shade-dried in a drying oven at 50°C for 72 h. DRL and DRS were milled into fine particle size (<250 μm) and kept in a dry, air-tight transparent plastic container. Feed ingredients were ground and the different ingredients mixed manually, then the experimental diets were pressed by manufacturing machine (pellets size 1 mm). Fish fed the diets at a rate of 3% of their live body weight daily, six days a week. Experimental diets were introduced manually twice daily, at 8.00 am and 14.00 pm. The amount of food was adjusted bi-weekly based on the actual body weight changes.

The present study was carried out to evaluate the ability of using Pawpaw (Carica papaya) seeds powder (PSP) as natural reproductive inhibitor for Nile tilapia (Oreochromis niloticus) to control their propagation. The experiment was divided into two periods; the first was the treating period (1 st) during which the Nile tilapia fry were treated with PSP for 71 days and the second was the rearing period whereas the Nile tilapia fingerlings (2 nd) obtained from the first period until sexual maturation stage for 84 days. The PSP was added to the basal diet at levels of 0, 2, 4, 6 and 8 g/kg diet for 15, 30, 45 and 60 days, different periods (1 st). Results of the 2 nd period showed that there were no significant (P ≥ 0.05) effects on total cholesterol, testosterone and progesterone hormones among all periods; however the testosterone and progesterone hormones were decreased (P ≤ 0.0 1) by increasing levels of PSP. Also, the high levels of PSP (4, 6 and 8 g / kg diet) and increasing exposure periods (30, 45 and 60 day) caused obvious histological alternations of testes and ovaries of O. niloticus which reduce the fertility of both males and females. Consequently, it could be recommended that the effectiveness use of PSP as a natural reproductive inhibitor for O. niloticus.

Background and Objective: Fish intensification had led to the outbreaks of stress effects and inflicting major problems in the fish farming industry. Hence, the objective of the present study was to evaluate the effects of dietary probiotic Pro-Grow® contrary to the stocking density stress (SD) on adult Oreochromis niloticus (O. niloticus ) for 15 weeks. Methods: The present study was designed to evaluate the effects of graded levels of Pro-Grow® (0, 10 and 20 g kgG 1 diet) against SD (40 and 80 fish mG 3 ) stress on water quality parameters, growth performance, physiological, immune responses, besides the economic efficiency parameters of adult O. niloticus. Data was analyzed using SAS. Results: The results revealed that increasing SD (80 fish mG 3 ) significantly (p<0.05) decreased the water dissolved oxygen, while water NH 3 -N was significantly increased. Also, high SD had drastically effects on all growth and feed efficiency parameters, body composition (ash and crude protein), hematological parameters (hemoglobin, red blood cells and white blood cells) and the economic efficiency compared to O. niloticus reared at low SD (40 fish mG 3 ). No significant (p>0.05) effects of all tested immune responses parameters of fish reared at both SDs rates. However, addition of 10 and 20 g Pro-Grow® kgG 1 diet alleviated the severely effects of both SDs stress 40 and 80 fish mG 3 , respectively on all above tested parameters. Conclusion: Thus, it could be concluded that the Pro-Grow® probiotic was successfully using at these levels into O. niloticus intensive production systems. Regarding its predicted high fish production, improving physiological responses, besides the high economic efficiency or the environmental friendly effects.

A field study was conducted to assess the effect of mono-and polyculture systems in net Hapas of monosex Nile tilapia (Oreochromis niloticus), striped mullet (Mugil cephalus) and /or thin-lipped mullet (M. capito) at different stocking ratios on growth performance, feed efficiency, chemical composition of the whole body, and economic efficiency parameters of experimental fish for 107 days rearing period. Five experimental treatments were represented as 100% Nile tilapia (T 1 , monoculture); 75% Nile tilapia: 25% striped mullet (T 2 , polyculture); 75% Nile tilapia: 13% striped mullet: 12% thin-lipped mullet (T 3 , polyculture); 50% Nile tilapia: 50% striped mullet (T 4 , polyculture) and 100% striped mullet (T 5 , monoculture). Fish of T 2 showed the highest significant of all growth performance, feed utilization, and economic efficiency parameters followed by the same fish species reared in polyculture system (T 4) at stocking ratio (50%: 50%) compared to other experimental fish-culture systems. Generally, it could be recommended that rearing monosex O. niloticus in polyculture system with M. cephalus at stocking ratio 75%: 25%, respectively (T 2) is more effective than other aquaculture systems under the experimental conditions of the present study.

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