LISTERIA MONOCYTOGENESIN RAW MILK AND DAIRY PRODUCTS;OCCURRENCE AND TRIALS FOR THEREDUCTION OF THEIR RESISTANCE TO ANTIBIOTICS.

Listeria monocytogenes is a facultative intracellular pathogen responsible for severe infection in animals and humans. This study aimed to determine the occurrence of Listeriamonocytogenes in 200 samples of raw milk and dairy products marketed in Egypt, with detection the antimicrobial resistance profiles of the isolates for different antimicrobial agents. The synergistic effects of three plant extracts in combination with the used antimicrobials to control resistant L. monocytogenes isolates were assessed, with evaluation of relationship between the antibacterial activity and composition of plant extracts. A total of 5 (2.5%) L. monocytogenes isolates were identified (3 isolates from raw milk and two isolates from kariesh cheese and ice cream, one each). The isolates were sensitive to ciprofloxacin and sulphadimidine, while for amoxicillin and oxytetracycline, were resistant. The higher antimicrobial effects of basil and cinnamon extracts were detected, in addition, low concentrations of them were enough to show synergistic effect with the amoxicillin and oxytetracycline to control resistant isolates, these might be attributable to their chemical compositions. In conclusion, there is need for effectively pasteurized raw milk consumption or usage in the production of dairy products. In addition, the chemical composition of these plant extracts might help in its use to control resistant isolates with appropriate antibiotics without the need for increasing the used dosage doses

Physiological and Biochemical Mechanisms of Exogenously Applied Selenium for Alleviating Destructive Impacts Induced by Salinity Stress in Bread Wheat

Salinity is a major abiotic stress that poses great obstacles to wheat production, especially in arid regions. The application of exogenous substances can enhance plant salt tolerance and increase its productivity under salinity stress. This work aimed to assess the mechanisms of selenium (Se) at different concentrations (2, 4 and 8 μM SeCl2) to mitigate hazardous impacts of salt toxicity at physiological, biochemical and agronomic levels in bread wheat. The results displayed that Se foliar application increased chlorophyll content, net photosynthetic rate, transpiration rate, stomatal conductance, relative water content, membrane stability index, excised leaf water retention, proline, total soluble sugars, Ca content, K content, antioxidant enzyme activities and non-enzymatic antioxidant compounds compared to untreated plants. On the other hand, Se application decreased the content of Na, hydrogen peroxide and superoxide contents. Accordingly, our findings recommend exogenous Se application (in particular 8 μM) to alleviate the deleterious effects induced by salinity stress and improve wheat yield attributes through enhancing antioxidant defense systems and photosynthetic capacity

Long-Term Feeding with Curcumin Affects the Growth, Antioxidant Capacity, Immune Status, Tissue Histoarchitecture, Immune Expression of Proinflammatory Cytokines, and Apoptosis Indicators in Nile Tilapia, <i>Oreochromis niloticus</i>

The impact of dietary curcumin (CUR) on the growth, antioxidant activity, histomorphology of certain organs, proinflammatory cytokine production, and immune status of Oreochromis niloticus was evaluated. The fingerlings (n = 225, 41.60 ± 0.09 g/fish) were randomly allotted into five experimental groups in triplicate. Fish were fed basal diets complemented with 0, 200, 400, 600, or 800 mg curcumin/kg diet (CUR0, CUR200, CUR400, CUR600, and CUR800, respectively) for 10 weeks. An increase in fish growth was reported in the CUR200 and CUR400 groups. The feed conversion ratio was enhanced by 15% in the CUR400 group. Fish body protein content was increased in the CUR600 group (p ≤ 0.01). Body fat was decreased, and ash content was increased by CUR supplementation in a level-related way (p O. niloticus challenged with Aeromonas hydrophila was highest in the CUR200-CUR600 groups (100%) and decreased in the CUR800 group (80%). This study concluded that CUR could be added to Nile tilapia diets up to 400 mg·kg−1 to achieve better growth, antioxidant capacity, immune response, and intestinal histology. Long feeding periods on high levels of CUR (600 and 800 mg·kg−1) stimulate inflammatory reactions in fish tissues

Foliar Supplementation of Clove Fruit Extract and Salicylic Acid Maintains the Performance and Antioxidant Defense System of Solanum tuberosum L. under Deficient Irrigation Regimes

A field trial was conducted twice (in 2020 and 2021) to evaluate the effect of clove fruit extract (CFE) and/or salicylic acid (SA), which were used as a foliar nourishment, on growth and yield traits, as well as physiological and biochemical indices utilizing potato (Solanum tuberosum L.) plants irrigated with deficient regimes in an arid environment. Three drip irrigation regimes [e.g., well watering (7400 m3 ha−1), moderate drought (6200 m3 ha−1), and severe drought (5000 m3 ha−1)] were designed for this study. The tested growth, yield, and photosynthetic traits, along with the relative water content, were negatively affected, whereas markers of oxidative stress (hydrogen peroxide and superoxide), electrolyte leakage, and peroxidation of membrane lipids (assessed as malondialdehyde level) were augmented along with increased antioxidative defense activities under drought stress. These effects were gradually increased with the gradual reduction in the irrigation regime. However, under drought stress, CFE and/or SA significantly enhanced growth characteristics (fresh and dry weight of plant shoot and plant leaf area) and yield components (average tuber weight, number of plant tubers, and total tuber yield). In addition, photosynthetic attributes (chlorophylls and carotenoids contents, net photosynthetic and transpiration rates, and stomatal conductance) were also improved, and defensive antioxidant components (glutathione, free proline, ascorbate, soluble sugars, and α-tocopherol levels, and activities of glutathione reductase, peroxidase, superoxide dismutase, catalase, and ascorbate peroxidase) were further enhanced. The study findings advocate the idea of using a CFE+SA combined treatment, which was largely efficient in ameliorating potato plant growth and productivity by attenuating the limiting influences of drought stress in dry environments