To determine the effect of different doses of Salmonella enteritidis on immunocompetent cells, the thymus, bursa of Fabricius, and peripheral blood were examined. One-day-old chickens were orally infected with 2 × 102CFU/ml (low dose) and 2 × 108 CFU/ml(high dose) of S. enteritidis PT4. Subsets of T lymphocytes (CD3, CD4, and CD8), and BU1b cells using an indirect immunofluorescent method and flow cytometry were analysed on days 7, 10, 14, 21, and 27 postinoculation (dpi). The actual number of lymphocytes in the peripheral blood showed a significant increase in the low dose group (P < 0.05) on day 21 pi, and in the high dose group on day 27 pi (P< 0.001) compared to controls. The increase of CD3+, CD4+, and CD8+ T cells was observed in both infected groups compared to the controls from day 14 pi, significant on day 21 pi (P < 0.05) in the high dose group. The subpopulation of CD8+ was higher also on day 27 pi (P < 0.01) compared with the values of the control group. The subpopulation of BU1b+ B cells in both infected groups showed higher values, but without significant differences from controls. The thymus T lymphocytes showed a significant decline in CD3+ T cells on day 7 pi, whereas CD4+ T cells were significantly (P < 0.05) increased on day 7 pi in both infected groups. The bursal lymphocytes showed a decrease in BU1b+ B cells in both infected groups compared with the control group, significant in the high dose group on day 21 pi (P < 0.05). These results indicate that S. enteritidis infection induced the changes in immunocompetent cells, included cellular and humoral immune response. Salmonella infection accelerated the maturation and differentiation of thymus T cells in the first phase of infection, what was secondarily reflected by increased number of studied T lymphocyte subpopulations in the peripheral blood from day 14 to 27 after infection. Similarly, it appears that the activation of B cells in bursa of Fabricius caused the decrease number of bursal B lymphocytes and increased number of these cells in the peripheral blood from day 14 to 27 pi in both infected groups.
A. A. Asheg(3-2003)

Aim: The aim of this work was to isolate and molecularly identify enterohemorrhagic Escherichia coli (EHEC) O157 in milk and dairy products in Libya, in addition; to clear the accuracy of cultural and biochemical identification as compared with molecular identification by partial sequencing of 16S rDNA for the existing isolates. Materials and Methods: A total of 108 samples of raw milk (cow, she-camel, and goat) and locally made dairy products (fermented cow’s milk, Maasora, Ricotta and ice cream) were collected from some regions (Janzour, Tripoli, Kremiya, Tajoura and Tobruk) in Libya. Samples were subjected to microbiological analysis for isolation of E. coli that was detected by conventional cultural and molecular method using polymerase chain reaction and partial sequencing of 16S rDNA. Results: Out of 108 samples, only 27 isolates were found to be EHEC O157 based on their cultural characteristics (Tellurite- Cefixime-Sorbitol MacConkey) that include 3 isolates from cow’s milk (11%), 3 isolates from she-camel’s milk (11%), two isolates from goat’s milk (7.4%) and 7 isolates from fermented raw milk samples (26%), isolates from fresh locally made soft cheeses (Maasora and Ricotta) were 9 (33%) and 3 (11%), respectively, while none of the ice cream samples revealed any growth. However, out of these 27 isolates, only 11 were confirmed to be E. coli by partial sequencing of 16S rDNA and E. coli O157 Latex agglutination test. Phylogenetic analysis revealed that majority of local E. coli isolates were related to E. coli O157:H7 FRIK944 strain. Conclusion: These results can be used for further studies on EHEC O157 as an emerging foodborne pathogen and its role in human infection in Libya.
Hesham Taher Naas(11-2016)

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)