This study was conducted to develop a short-term immersion procedure for masculinisation of Nile Tilapia (Oreochromis niloticus) by using 17α-methyltestosterone at 100, 200 or 400 µg l-1 for 3, 6 or 12 h. Fry were immersed two successive times with 3 days interval period. The highest percentage of male Oreochromis niloticus (96±4 %) and the lowest gonado-somatic index of female Oreochromis niloticus (1.89±0.02) were obtained by immersion of fry in 17α-methyltestosterone at the level of 400 µg l -1 for 6 h. However, survival rate of Oreochromis niloticus Fry during hormone treatment period did not differ significantly from survival rate in the control group. Tilapia culture is widespread all over the world. The problem of overpopulation in fish ponds caused by uncontrolled reproduction is a major constraint to the further development of the Tilapia culture industry. This problem could be overcamed by culturing all-male populations of Tilapia. One of the most common techniques for producing all-male populations of Tilapia is androgen-induced-sex-reversal by using androgen-treated feed. However, the immersion of fry is not fully developed for practical usage. Feeding androgen carries some potential disadvantages as in efficiency in masculinisation. Immersion of Tilapia fry in androgen solutions may be an alternative to oral administration of androgen, this technique is well developed in salmonid culture; however it remains largely experimental in Tilapia culture. The objective of this research was to develop short-term immersion procedure for the masculinisation of Nile Tilapia by using 17α-methyltestosterone and evaluating the most proper dose concentration and hormone treatment period.
ABDUSSALAM ABUMHARA(10-2009)

In this study, antibacterial, antioxidant and phenolic compounds of raisin extracts was evaluated. Different solvent extraction methods were utilized to extract phenolic compounds from raisin. The phenolic compounds of raisin extracts was determined using HPLC and three compounds were found, catechin, quercetin and rutin. The antibacterial activity of the acetonic extract was tested against four bacterial pathogens viz. Staphylococcus aureus, Pseudomonas aeroginosa, Salmonella typhimurium and Escherichia coli using both disk diffusion and minimum inhibitory concentration (MIC) methods. The acetonic extract exhibited the highest activity against Staphylococcus aureus with zone of inhibition of 14mm and the MIC of 25 mg/ml. However, there was a little activity against E. coli and S. typhimurium. The methanolic extract showed good antioxidant activity as indicated by 2,2-diphenyl-1-picrylhydrazyl free radical assay (DPPH). In conclusion, raisin contains potent phenolic compounds and their application might function as promising natural preservative and antimicrobial agents in food industry and also good antioxidant food that helps to minimize the risk of degenerative diseases. arabic 11 English 86
Abdulgader Dhawi Alfitouri Dhawi(1-2021)

Marine macroalgae are considered as an excellent source of bioactive compounds which has a broad range of biological activities including antibacterial and antioxidant. Crude methanolic and water extracts of 19 marine algal species (6 Chlorophyta, 8 Phaeophyta and 5 Rhodophyta) collected from the western coast of Libya were evaluated for antibacterial activity against pathogenic bacteria (4 Gram-positive, 4 Gram-nega- tive). The extracts showed a significant antibacterial activity against Gram positive (Staphylococcus aureus, Bacillus subtilis, Bacillus spp., and Staphylococcus epidermidis) as well as Gram negative bacteria (Escherichia coli, Salmonella typhi, Klebsiella spp., and Pseudomonas aerugi- nosa). The algal aqueous and methanolic extracts displayed different degrees of antimicrobial activities against different bacteria, in some cases methanolic extracts showed higher antibacterial activity than aqueous extracts. Among tested algae, Brown algae namely Cystoseira crinite exhibited the highest antibacterial activity among tested algal species.
Salah M. Azwai(1-2013)