Comparative assessment of sodium selenite, selenised yeast and nanosized elemental selenium on performance response, immunity and antioxidative function of broiler chickens
ITALIAN JOURNAL OF ANIMAL SCIENCE
Authors: Pardechi, Amirarsalan; Tabeidian, Sayed Ali; Habibian, Mahmood
Although selenium (Se) supplementation is a common practice in poultry, the best source and level has not been established yet. Thus, a 42-day experiment involving diets with three levels (0.1, 0.2 and 0.5 mg/kg) of supplemental Se from sodium selenite (SS), selenised yeast (SY) and nanoelemental Se (SN) was conducted to evaluate the possible differential responses of broiler chickens to inorganic, organic and nano Se sources relative to a control diet. Throughout the experiment, broilers receiving Se supplements had higher feed intake, body weight gain (BWG) and survival rate than the control. Broilers fed dietary SY or SN had improved BWG compared with those fed the SS-supplemented diets. Broilers treated with Se supplementation had increased serum glutathione peroxidase (GPx) and thioredoxin reductase (TrxR) activities and produced higher antibody responses to avian influenza virus (AIV) and sheep red blood cell (SRBC) versus the control. These effects were enhanced with increasing Se addition, except for GPx that responded equally to all supplemental Se levels. Also, broilers receiving supplementary SY or SN exhibited higher anti-AIV and anti-SRBC titres along with more elevated serum Se, TrxR activity and total antioxidant capacity compared with those receiving SS. At the same time, SN had the most increasing effect on anti-SRBC titre. To conclude, diet supplementation with 0.5 mg/kg of Se in the form of SY or SN was capable of meeting the Se demands of broiler chickens for optimum growth and antioxidant capability, while SN seemed to be the most effective Se source in enhancing immunity.
A novel aptasensor based on HCR and G-quadruplex DNAzyme for fluorescence detection of Carcinoembryonic Antigen
Authors: Bai, Yunfeng; Zhang, Huilin; Zhao, Lu; Wang, Yuzhen; Chen, Xiaoliang; Zhai, Hong; Tian, Maozhong; Zhao, Ruirui; Wang, Tao; Xu, Hui; Feng, Feng
In this paper, a rationally designed aptasensing platform based on Hybridization Chain Reaction (HCR) and G-quadruplex DNAzyme for the fluorescence detection of Carcinoembryonic Antigen (CEA) has been developed. In the presence of target CEA, the aptamer sequence in Aptamer Probe (AP) specifically bound to CEA, resulting in the AP conformation change and thus releasing initiator, which triggered the autonomous cross-opening of Hairpin 1 (H1) and Hairpin 2 (H2) that yielded extended nicked double-stranded DNA via HCR. Upon the addition of hemin, G-rich segments at the end of H1 and H2 self-assembled into the peroxidase-mimicking hemin/G-quadruplex DNAzymes, which catalyzed the hydrogen peroxide-mediated oxidation of thiamine to achieve fluorescence detection of CEA. The HCR product, and the formation and catalytic performance of DNAzyme were characterized by agarose gel electrophoresis, UV-vis spectroscopy and fluorescence spectroscopy, respectively. Under optimal conditions, the fluorescent aptasensor showed a linear relationship ranging from 0.25 to 1.5 nM toward CEA with a detection limit of 0.2 nM. In addition, this aptasensor exhibited high selectivity for CEA without being affected by other interfering proteins, such as IgG, AFP and PSA. Furthermore, this proposed aptasensor was successfully applied to CEA analysis in diluted human serum samples. It is believed that this strategy has a promising potential in biochemical analysis and clinic application.