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Impact of Dietary Lactobacillus plantarum Postbiotics on the Performance of Layer Hens under Heat Stress Conditions

Open Journal of Veterinary Medicine 2024年第3期14卷 39-55页

作者： Mohamad Farran Bouchra El Masry Zeinab Kaouk houssam shaib Department of Agriculture Faculty of Agricultural and Food Sciences American University of Beirut Beirut Lebanon

This experiment was conducted to determine the performance of heat-stressed layers fed a diet containing the probiotic Lactobacillus plantarum RS5 or its products of fermentation (postbiotics). Twenty-week-old Isa White layers, were subdivided into six treatments of 32 individually caged birds. Half of the birds were reared under regular temperature conditions, while the other half was subjected to cyclic daily heat stress. Layers were offered one of three diets: 1) Control;2) Control + Lactobacillus plantarum RS5 probiotic;3) Control + Lactobacillus plantarum RS5 postbiotics. Birds were tested for performance and visceral organ development for 5 months. Heat stress negatively affected the birds’ feed intake, egg weight, shell weight percentage, Haugh unit, shell thickness, yolk color, body weight and spleen weight percentage. Postbiotics significantly increased egg production (p < 0.05) in comparison to the control and the probiotic fed group (94.8% vs 92.6% vs 93.1%, respectively). Birds under probiotic or postbiotic diet showed a significantly higher (p < 0.05) feed intake and egg weight, although the probiotic had a more pronounced and gradual effect. Specific gravity, yolk weight percentage and shell thickness didn’t show differences among dietary groups. The Haugh Unit was significantly higher (p < 0.05) in probiotic group which also showed a significantly lower yolk color index (p < 0.05). The different feed treatments did not impact the bird’s viscera weight percentage, except for the ileum that was significantly lower (p < 0.05) under postbiotic supplementation. Both probiotics and postbiotics could be used as a potential growth promoters and might alleviate heat stress impact in poultry industry.

关键词： Lactobacillus plantarum Layers Heat Stress Postbiotic Probiotics Performance

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Development and Validation of an Indirect Whole-Virus ELISA Using a Predominant Genotype VI Velogenic NewCastle Disease Virus Isolated from Lebanese Poultry

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Open Journal of Veterinary Medicine 2023年第6期13卷 82-95页

作者： houssam shaib Hasan Hussaini Roni Sleiman Youmna Iskandarani Youssef Obeid Faculty of Agricultural and Food Sciences American University of Beirut Beirut Lebanon

Commercial ELISA kits are commonly used to assess the levels of chicken antibodies against NewCastle Disease Virus (NDV) and trace a field strain infection. Nevertheless, the specificity of these kits vis-à-vis endemic strains in Lebanon remains in question. This study developed an in-house indirect ELISA system to evaluate the level of chicken antibodies against a predominant velogenic NDV strain belonging to Genotype VI. A checkerboard analysis comprised a five-factorial multivariate experiment to optimize the protocol: coating antigen concentration, blocking buffer utilization, serum and conjugate dilution levels, and OD reading wavelength. The developed test was optimized and then validated through parallel testing of the sera of 20 broilers and 5 layers using standard serological assays. There was a strong correlation between the developed ELISA results and those obtained with the Hemagglutination Inhibition test (P < 0.01), and a commercial NDV ELISA kit (P < 0.05). The specificity, sensitivity, and reproducibility of the developed ELISA suggest that it can be used as the test of choice for the assessment of chicken antibody titers against locally circulating velogenic NDV strains, specifically those belonging to Genotype VI. It also offers better help in the serological detection of birds’ exposure to the said strains.

关键词： ELISA Development Genotype VI NewCastle Disease Poultry Lebanon

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Pathogenicity and amino acid sequences of hemagglutinin cleavage site and neuraminidase stalk of differently passaged H9N2-avian influenza virus in broilers

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Advances in Bioscience and Biotechnology 2011年第4期2卷 198-206页

作者： houssam A. shaib Nelly Cochet Thierry Ribeiro Afif M. Abdel Nour Georges Nemer Maya F. Saade Elie K. Barbour Department of Animal and Veterinary Sciences Faculty of Agricultural and Food Sciences American University of Beirut (AUB) P.O. Box 11-0236 Beirut Lebanon

Low pathogenic Avian Influenza (AI) virus has the ability to evolve to high pathogenic viruses resulting in significant economic losses in the poultry sector. This study aims at assessing the impact of H9N2 viral passaging in broilers and its relatedness to pathogenicity and amino acid (a.a) sequences of the hemagglutinin (HA) cleavage site and neuraminidase (NA) stalk. The original H9N2 AI virus (P0) was used to challenge ten-21 days old broilers. Individual recovery of H9N2 virus from homogenates of trachea, lungs and airsacs was attempted in 9 days old chicken embryos, as a conclusion of the first passage (P1). Tracheal isolates of H9N2 were passaged for a second (P2) and a third (P3) time in broilers, followed by a similar embryonic recovery procedure. The a.a. sequence of a part of HA1 cleavage site and Neuraminidase stalk were compared among the differently passaged viruses;an assessement of the relatedness of the determined a.a. sequences to the pathogenicity in broilers, based on frequency of mortality, morbidity signs, gross and microscopic lesions at 3 days post challenge with the P1, P2, and P3-H9N2, is concluded. An increase in certain morbidity signs and specific lesions was observed in P2- and P3-H9N2 challenged broilers compared to birds challenged with P1-H9N2. A conserved R-S-S-R amino acid sequence at the HA1 cleavage site was observed in the differently passaged H9N2, associated with a variability in the NA stalk-a.a sequences. The passaging of the low pathogenic H9N2 virus in broilers leads to a trend of increase in pathogenicity, manifested in higher frequency of morbidity signs, and of specific gross and microscopic lesions of the examined organs. This passaging was associated with a conserved a.a. sequence of the hemaglutinin cleavage site and a variability in the sequence of the neuraminidase stalk. A detailed study of the potential of the detected variability in the neuraminidase stalk of H9N2 in induction of a higher pathogenicity in broile

关键词： H9N2 Avian Influenza Pathogenicity Passaging Broilers Amino Acid Sequences Hemagglutinin (HA) Neuraminidase (NA) Stalk

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Development and Validation of an Indirect Whole-Virus ELISA Using a Predominant Genotype VI Velogenic NewCastle Disease Virus Isolated from Lebanese Poultry

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Open Journal of Veterinary Medicine（兽医学） 2023年第6期

作者： houssam shaib Hasan Hussaini Roni Sleiman Youmna Iskandarani Youssef Obeid

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