Blue Resources for Aquaculture, Environment and Society DevelopmentEgyptian Journal for Aquaculture2090-787710120200301Nitrogen and Phosphorus budget for Nile tilapia hatchery1227918410.21608/eja.2020.21286.1012ENYaser T. A.MoustafaLimnology department, Central Laboratory for Aquaculture Research, Agricultural Research Center, Egypt0000-0002-8449-4559AhmedAliFish physiology and hatchery department, Central laboratory for aquaculture research - Agriculture research center,
EgyptSafwat A. A.GomhaAquaculture department, Central Laboratory for Aquaculture Research,
Agricultural Research Center, EgyptEnas MohamedMansourLiminology Department, Central laboratory for aquaculture Rsearch, Agricultural Research Center, EgyptJournal Article20191223Tilapia hatcheries if not well managed, it can cause environmental damage. The present study was designed to quantify the impacts generated by Nile tilapia hatcheries, through applying environmental indicators, which is necessary for tilapia hatcheries sustainable development. Three culture trials, each of 15 days, have been carried out to determine environmental indicators: the nitrogen and phosphorus flux and nutrient mass balance based on inputs from feed and losses in fish harvest, nutrients load in the effluent water, and fish bio-solid wastes (sludge). In each, three cement ponds were assigned to determine the nutrients input and loss for 15 days intervals, fry production cycle. The results showed that every 1 Kg feed of 35% protein produce 420 g sludge, of which 262 gm fish excretion. Uneaten feed was found to represent 15.8-20% of the introduced feed and produce 37.6 - 43.2 % of sludge. Fish retained at least 25.8 ± 3.91 % and 2.74 ± 0.37 % of the input feed nitrogen and phosphorus, respectively. While the sludge contained 11.3 ± 0.78 % and 32.62 ± 14.46 of the feed nitrogen and phosphorus, respectively. Effluent water contained 43.64 ± 6.45 % and 50.22 ± 16.63 % of feed nitrogen and phosphorus, respectively, distributed in three main fractions: particulate form; dissolved organic and dissolved inorganic forms. The feed nitrogen recovery in the present study was 80. 57%, while the phosphorus recovery reached 85.58% of the feed phosphorus content. Fry production is discussed in response to the feed protein content and feeding rate.https://eja.journals.ekb.eg/article_79184_3820e710655014ff0a57d88884a1f8ef.pdfBlue Resources for Aquaculture, Environment and Society DevelopmentEgyptian Journal for Aquaculture2090-787710120200301Prevalence and Antibiotic Susceptibility of Bacterial Pathogens Implicating the Mortality of Cultured Nile Tilapia, Oreochromis niloticus23437918810.21608/eja.2020.25437.1017ENSaadHassanBotany and microbiology department, faculty of science , Al-Azhar UniversityMohamedAbdel-RahmanFaculty of science, Al-Azhar UniversityEl SayedMansourBacteriology Department, Animal Health Research Institute, Zagazig Branch, EgyptWalidMonirBotany and Microbiology Faculty of Science, Al-Azhar University, Cairo, EgyptJournal Article20191230Nile-Tilapia (<em>Oreochromis niloticus</em>) aquaculture represents one of the most important cultivation species in Egypt. However, Tilapia fish farming is challenged by some problems. Of those, the presence of bacterial pathogens resulting in high fish mortalities and huge economic losses. Thus, the current investigation aimed to isolate, identify, and characterize the pathogenic bacteria from Nile tilapia fish farm in El-Abassa village, Egypt and to investigate their antibiotic susceptibility as a primary step for controlling diseases. 182 bacterial isolates were obtained from one hundred Tilapia fish samples. The microbiological and biochemical analysis of the examined fish indicated the presence of only 5 bacterial genera. Three of them are Gram-negative bacteria (representing 86.26% of total isolates) including <em>Aeromonas</em> spp. (46.70 %), <em>Pseudomonas </em>spp. (23.08 %), and <em>Vibrio </em>spp. (16.48 %). While two genera are Gram-positive bacteria (representing 13.74% of the total isolates) including <em>Streptococcus </em>spp. (8.79 %) and <em>Staphylococcus </em>spp. (4.95 %). This indicates that Gram-negative bacteria are the main cause of high fish mortalities in the studied area while <em>Aeromonas hydrophila</em> exhibited the highest prevalence in infected tilapia. Antibiogram test revealed high levels of resistance expressed by all isolates to ampicillin, amoxicillin, and erythromycin. On the other hand, norfloxacin was effective against all isolated bacteria followed by ciprofloxacin; therefore, norfloxacin should be recommended as a supplement in fish fed-diets to control the bacterial infection. Establishing effective control methods for pathogenic isolates would greatly enhance fish production.https://eja.journals.ekb.eg/article_79188_405196cf4a2516524266284486cd9370.pdfBlue Resources for Aquaculture, Environment and Society DevelopmentEgyptian Journal for Aquaculture2090-787710120200301Evaluating the influence of different water sources on water quality, survival and growth rates of Nile tilapia (Oreochomis niloticus) larvae in tilapia hatcheries45647953410.21608/eja.2020.25601.1018ENAhmedAliFish physiology and hatchery department, Central laboratory for aquaculture research, Agriculture research center, EgyptYaser T. A.MoustafaLimnology department, Central Laboratory for Aquaculture Research, Agricultural Research Center, Egypt0000-0002-8449-4559Soha M. A.El-SaidLiminology Department, Central Laboratory for Aquaculture Research, Agriculture Research Center ARC, EgyptJournal Article20200311This study was conducted to evaluate the effect of different water sources on survival rate and growth performance of Nile tilapia (<em>O. niloticus</em>) larvae during nursing period. Larvae (post yolk sac stage) were stocked at 50000 / pond and fed 48 % crude protein diet 6 times daily at rates of 35, 26 and 18% of their weight in the successive three weeks, respectively. Nine concrete ponds assigned for 3 treatments, triplicates in each. The ground water and agricultural drainage water were the water sources in the first and third treatments, respectively, while the second treatment received a 1: 1 mixture of the two water sources. Water samples, for some physico-chemical analysis, were monitored before pumping water into the ponds and within the ponds at each fry harvest. The experiment lasted for 21 days and replicated four times. At the end of each rearing period, fry number was estimated in each pond; the survival and growth rates were calculated.
The results showed that the significantly highest survival and growth rates were obtained in the mixed water treatment. Mixing agricultural drainage water with ground water results the most suitable water quality for Nile tilapia performance than each of these sources separately. Generally, water quality parameters for the studied sources at the end of each rearing period were within the acceptable range for fish culture.https://eja.journals.ekb.eg/article_79534_8f1578f10327be19c1465a6b1801c047.pdfBlue Resources for Aquaculture, Environment and Society DevelopmentEgyptian Journal for Aquaculture2090-787710120200301Effect of Digestrom® on growth performance and feed utilization of red tilapia ( O. niloticus × O. mossambicus)65838030410.21608/eja.2020.23919.1016ENAhmedAboelwardby-product Research Department, Animal Production Research Institute, ARC, Dokki Giza Egypt.AbdelhamidEidFish nutrition debartment, Agriculture faculty,Suiz Canal UniversityBadiaA.Department of Animal Production and Fish Resources, Faculty of Agriculture, Suez Canal University- Ismailia- Egypt.MohamedK. A.Department of Animal Production and Fish Resources, Faculty of Agriculture, Suez Canal University- Ismailia- Egypt.Hayam D.Tonsyby-product Research Department, Animal Production Research Institute, ARC, Dokki Giza Egypt.Ahmed NabilAyyatFish nutrition- central laboratory of aquacultureJournal Article20200212Our investigation is to study the effect of the effect of protein levels (25 and 30%) within each protein levels four levels of Digestarom® P.E.P. (0.00, 0.01, 0.02 and 0.03%) on growth performance, feed utilization and economical evaluation of red tilapia fingerlings. Red tilapia fingerlings were fed on eight experimental diets composed of two protein levels a 25 % and 30% crude protein within each protein levels supplemented with Digestarom® P.E.P. at four levels (0.00, 0.01, 0.02 and 0.03%). The results indicated that protein levels 30% and Digestarom® at 0.02% had positive effect on the final weight, weight gain, specific growth rate, feed conversion ratio and feed efficiency ratio. The interaction of Digestarom® and protein levels have a significantly higher in growth performance, feed utilization, survival rate and economical evaluation. <br />It could be concluded that the best Digestrom® levels was 0.02% Digestrom® in each protein levels 25 and 30 % in terms of growth performance, feed utilization, survival rate and economic evaluation.https://eja.journals.ekb.eg/article_80304_458a5c32ec1427fc692eaad2ebbd6de1.pdf