Tilapia: From the Nile to the world.

This study addressed the potential of tilapia aquaculture as a major contributor to food production and poverty alleviation all over the world. To encompass this subject, tilapia history, origin, aquaculture potential, constraints, current and future production levels were reviewed. Tilapias are native to the River Nile and Africa in general then they were introduced and disseminated worldwide. Positive aquacultural characteristics of tilapia made tilapias the most cultured species worldwide now and in the near future. Tilapia world production is expected to reach 3 million tons this year 2010. Thus, tilapias could make a significant contribution to the livelihoods support especially in the tropical and subtropical countries

Study on the effect of wormseed plants; artemisia cina L. and chamomile; matricaria chamomilla L. on Growth Parameters and Immune Response of African Catfish, Clarias gariepinus

A number of 420 fingerlings of catfish were used to examine the effect of wormseed plants and chamomile on the growth parameters and on non-specific immune response of the African catfish; Clarias gariepinus. Both types of herbs were used in rates of 1, 3 and 5% with 3 replicates per each of the 6 treatments. The 7th treatment was kept as a control group. The experimented catfish were fed with the 7 examined diets in the rate of 3% of fish biomass for 1 month. Different growth parameters as well as blood parameters were estimated to evaluate the growth performance and immune response of the experimented catfish. Results revealed that wormseed plants Artemisia cina L. in the rate of 3 and 5% and chamomile Matricaria chamomilla. L. in the rate of 1% showed the best figures of growth parameters as well as immune response parameters of the examined catfish

Herbal sensitivity of Pseudomonas bacteria isolated from cultured tilapia with useful applications in vaccine preparation.

The antibacterial activity of certain commercial antibiotics and common herbs was evaluated against pathogenic Pseudomonas fluorescens, Pseudomonas putida and Pseudomonas aeruginosa isolated from Malaysian and Egyptian cultured fish, mainly tilapia. A suspension of freshly cultured isolates was prepared (with 0.5 OD) and 100 μL of this suspension was spread over the Muller’s Hinton agar plates. The antibiotic discs were inoculated on each cultured plate while the herbal extracts were soaked on Whatman filter paper (20 μL each) that have been cut into discs and later inserted on to bacteria-cultured plates to screen their sensitivity to both antibiotics and herbs. Double-fold dilution was used to determine the Minimal Inhibitory Concentration (MIC) for the effective herbs at 100, 50, 25, 12.5 and 6.25%. Results revealed high resistance of the tested bacteria against most of the screened antibiotics except Ciprofloxacin. With regard to herbal sensitivity, only Origanum vulgare showed effectiveness and inhibition zone against all isolates. The MIC ranged from 15-40% for both Egyptian and Malaysian isolates. Thus, Origanum vulgare is recommended as a feed additive for cultured fish and can also be applied for inactivated and live-attenuated Pseudomonas vaccines’ preparation

Indoor study on the immunization of red tilapia: Oreochromis niloticus x O. mossambicus against Aeromonad and Pseudomonad septicemias

Monovalent, killed and live attenuated vaccines of Aeromonas hydrophila and Pseudomonas putida were used in the immunization of red tilapia against Motile Aeromonad and Pseudomonad septicemias. There were 4 treatments and a 5th control group with 3 replicates per each. A 4th replicate was kept for replacement of natural mortality among the experimented fish. The 4 treatments included, Heat-killed vaccine of A. hydrophila, Live-attenuated vaccine of A. hydrophila (using herbs), Heat-killed vaccine of P. putida and Live-attenuated vaccine of P. putida. A total of 160 brood stocks of O. niloticus with 250 g average body weight were used for all treatments (8 fish per each glass aquarium). Vaccination was conducted via the Intra Peritoneal route (I/P) as an initial dose followed by 2 booster doses every 2 weeks. The last dose was applied via the immersion route. The evaluation of vaccination was carried out through periodical antibody titration of the serum of the examined fish (every 2 weeks) using direct agglutination method as well as by the experimental challenge 3 months after the initial immunization. Results revealed that there were a significant difference between the vaccinated and non vaccinated fish of the control group regarding antibody titers and Relative Percent Survival (RPS) of the challenge test. Differences in immunity levels within the vaccinated groups themselves were demonstrated

Herbal and antibiotic resistance of Aeromonas bacteria isolated from cultured fish in Egypt and Malaysia.

Motile Aeromonad septicemia is the main devastating disease in cultured fish and caused mainly by Aeromonas hydrophila. Development of pathogenic bacterial resistance caused by the excessive use of chemotherapeutics is the main disadvantage of antibiotic application. Thus, the sensitivity of certain commercial antibiotics and common herbs was evaluated against pathogenic A. hydrophila, A. sobria and A. caviae, isolated from Malaysian and Egyptian cultured fish, mainly tilapia. A suspension of freshly cultured isolates was prepared and spread over the Muller’s Hinton agar plates to study their sensitivity to both antibiotics and herbs. Double-fold dilution was used to determine the Minimal Inhibitory Concentration (MIC) for the effective herbs at 100, 50, 25, 12.5 and 6.25%. Results revealed high resistance of the 6 tested Aeromonas isolates against most of the screened antibiotics except Ciprofloxacin and Gentamicin. Regarding herbal sensitivity, only Origanum vulgare showed an efficacy and inhibition zone against all isolates except A. hydrophila isolated from cultured tilapia in Egypt which exhibited resistance to that herb. The MIC ranged from 25-55% for the Egyptian isolates (25% for A. caviae and 55% for A. sobria) and 24-30% for the Malaysian isolates (24% for A. hydrophila, 25% for A. caviae and 30% for A. sobria). This study recommends the mandate of effective vaccine development against A. hydrophila to protect cultured fish from that pathogen due to its high resistance for both herbs and antibiotics

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Tilapia: From the Nile to the world.

This study addressed the potential of tilapia aquaculture as a major contributor to food production and poverty alleviation all over the world. To encompass this subject, tilapia history, origin, aquaculture potential, constraints, current and future production levels were reviewed. Tilapias are native to the River Nile and Africa in general then they were introduced and disseminated worldwide. Positive aquacultural characteristics of tilapia made tilapias the most cultured species worldwide now and in the near future. Tilapia world production is expected to reach 3 million tons this year 2010. Thus, tilapias could make a significant contribution to the livelihoods support especially in the tropical and subtropical countries

Antibacterial ability and molecular characterization of probionts isolated from gut microflora of cultured red tilapia

Four bacterial isolates, which proved to have the potential to be used as probiotics, were used to study their genotypic characterization using analysis of 16S rRNA gene sequence, antagonistic ability and safety when applied on tilapia via immersion. Gram staining showed that all 4 probionts were Gram positive bacteria. Three probionts were rod in shape and the fourth was cocci in shape and arranged in grape-like cluster. These 4 probionts were also identified using 16S rRNA gene sequencing and their identities were Paenibacillus barcinonensis strain D12, Paenibacillus sp. strain D14, Staphylococcus cohnii strain Bll and Bacillus megaterium strain E28, respectively. All of the probionts were examined for their antagonistic ability against pathogenic bacteria (Vibrio alginolyticus ATCC 33839, Aeromonas salmonicida and Aeromonas hydrophila ATCC 35654) under in vitro conditions by using cross-streaking method. P. barcinonensis strain D12 and Paenibacillus sp. strain D14 have shown stronger antagonistic ability than S. cohnii strain Bll and B. megaterium strain E28 in the antagonism test. P. barcinonensis strain D12 and Paenibacillus sp. strain D14 were chosen to test their safety on tilapia due to their better performance in antagonism test. Both probionts, P. barcinonensis strain D12 and Paenibacillus sp. strain D14, were safe for tilapia

Bacillus cereus; JAQ04 strain as a potential probiotic for red tilapia; Oreochromis species

The present study evaluated the inhibitory effect of Bacillus cereus strain JAQ04 against several pathogenic bacteria for tilapia under in vitro conditions. B. cereus strain JAQ04 was tested against Vibrio alginolyticus, Aeromonas hydrophila and Pseudomonas putida in a cross streaking assay, where B. cereus showed a strong antagonistic effect against the three tested bacterial fish pathogens. In the following test, B. cereus strain JAQ04 at 103, 105 and 107 CFU mL-1 was then tested against V. alginolyticus at 103 CFU mL-1 for 6 days in co-culture assay. The results revealed that higher concentrations (105 and 107 CFU mL-1) of B. cereus strain JAQ04 had higher inhibitory effect against pathogenic V. alginolyticus. Bacillus cereus strain JAQ04 was administered to juvenile tilapia to determine its safety for tilapia. The results showed that the Relative Percent Survival (RPS, %) was 70.83+18.2 which was not significantly different from the RPS of fish in the control group (78.50+3.5%)