18 research outputs found

    Utilization of prickly pear waste for baker's yeast production

    Get PDF
    The feasibility of baker's yeast production using fruits and peels of Opuntia ficus indica (OFI) as carbohydrate feedstock was investigated. Two response surface methodologies involving central composite face centered design (CCFD) were successfully applied. The effects of four independent variables on baker's yeast production from OFI fruit juice was evaluated using the first CCFD. The best results were obtained with 24 H of inoculum age, 30 degrees C temperature, 200 rpm of agitation, and 10% inoculum size. At the maximum point, the biomass concentration reached 9.29 g/L. A second CCFD was performed to optimize the sugar extraction from OFI fruit peels. The potential of these latter as a fermentation substrate was determined. From the experimental results, the OFI fruit peel is an appropriate carbon source for the production of baker's yeast. The maximum biomass concentration was 12.51 g/L. Different nitrogen supplements were added to promote the yields of baker's yeast. Corn steep liquor was found to be the best alternative nutrient source of casein hydrolysate and yeast extract for baker's yeast production.info:eu-repo/semantics/publishedVersio

    Reactive oxygen species and male reproductive hormones

    Get PDF
    Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous and endogenous factors that are able to induce excessive production of reactive oxygen species (ROS) beyond that of cellular antioxidant capacity, thus causing oxidative stress. In turn, oxidative stress negatively affects male reproductive functions and may induce infertility either directly or indirectly by affecting the hypothalamus-pituitary-gonadal (HPG) axis and/or disrupting its crosstalk with other hormonal axes. This review discusses the important exogenous and endogenous factors leading to the generation of ROS in different parts of the male reproductive tract. It also highlights the negative impact of oxidative stress on the regulation and cross-talk between the reproductive hormones. It further describes the mechanism of ROS-induced derangement of male reproductive hormonal profiles that could ultimately lead to male infertility. An understanding of the disruptive effects of ROS on male reproductive hormones would encourage further investigations directed towards the prevention of ROS-mediated hormonal imbalances, which in turn could help in the management of male infertility

    The effect of vitamin E treatment on selected immune and oxidative parameters in Kivircik ewes suffering from transport stress

    No full text
    The study aimed to investigate the effects of vitamin E injection for the prevention of transport stress on ewes. Kivircik ewes (2-3 years old, n = 24) were randomly separated into three groups; G1 (Control) and G2 treated with 14 ml. saline as the placebo, G3 treated with 2100 IU/ind. DL-alpha-tocopherol acetate prior to transport. G2 and G3 were transported at 80 km/h for 4 h on a truck. Serum samples were obtained before (T0) and after (T1) transport. Serum cortisol, catalase, IgG, ceruloplasmin, C-reactive protein, complement component 4, interleukin-1 beta, tumour necrosis factor-alpha, glutathione peroxidase (GPx), superoxide dismutase, malondialdehyde analyses performed by ELISA, and serum alpha-tocopherol concentrations were evaluated by HPLC-UV. Wilcoxon and Kruskal-Wallis tests were used for statistical assessments (p < 0.05). Alpha-tocopherol concentrations were founded 1.22 +/- 0.82, 0.27 +/- 0.14 and 0.14 +/- 0.07 mu mol/L, respectively, in G1, G2 and G3 at T1. Alpha-tocopherol concentration decreased significantly in G2 between T0 and T1. GPx concentrations were increased twofold in G2 and G3 between T0 and T1 (p < 0.01). As a result, G2 alpha-tocopherol concentrations decreased but, the stress and oxidative parameters tested in this study were not affected by treating 2100 IU/ind. DL-alpha-tocopherol acetate before transport

    Heat stress effects on sheep: Are hair sheep more heat resistant?

    No full text
    corecore