Effects of arsenic supplementation in feed on laying performance, arsenic retention of eggs and organs, biochemical indices and endocrine hormones

Highly Luminescent MOF and Its In Situ Fabricated Sustainable Corn Starch Gel Composite as a Fluoro-Switchable Reversible Sensor Triggered by Antibiotics and Oxo-Anions

Frequent use of antibiotics and the growth of industry lead to the pollution of several natural resources which is one of the major consequences for fatality to human health. Exploration of smart sensing materials is highly anticipated for ultrasensitive detection of those hazardous organics. The robust porous hydrogen bonded network encompassing a free-NH₂ moiety, Zn(II)-based metal-organic framework (MOF) (1), is used for the selective detection of antibiotics and toxic oxo-anions at the ppb level. The framework is able to detect the electronically dissimilar antibiotic sulfadiazine and nitrofurazone via fluorescence "turn-on" and "turn-off" processes, respectively. The antibiotic-triggered reversible fluoro-switching phenomena (fluorescence "on-off-on") are also observed by using the fluorimetric method. An extensive theoretical investigation was performed to establish the fluoro-switching response of 1, triggered by a class of antibiotics and also the sensing of oxo-anions. This investigation reveals that the interchange of the HOMO-LUMO energy levels of fluorophore and analytes is responsible for such a fluoro-switchable sensing activity. Sensor 1 showed the versatile detection ability which is reflected by the detection of a carcinogenic nitro-group-containing drug "roxarsone". In view of the sustainable environment along with quick-responsive merit of 1, an in situ MOF gel composite (1@CS; CS = corn starch) is prepared using 1 and CS due to its useful potential features such as biocompatibility, toxicologically innocuous, good flexibility, and low commercial price. The MOF composite exhibited visual detection of the above analytes as well as antibiotic-triggered reversible fluoro-switchable colorimetric "on-off-on" response. Therefore, 1@CS represents a promising smart sensing material for monitoring of the antibiotics and oxo-anions, particularly appropriate for the real-field analysis of carcinogenic drug molecule "roxarsone" in food specimens.

Highly regenerative, fast colorimetric response for organo-toxin and oxo-anions in an aqueous medium using a discrete luminescent Cd(II) complex in a heterogeneous manner with theoretical revelation

The highly luminescent complex [CdQ₂(H₂O)₂] (1) shows ultra-selectivity and high sensitivity to the explosive organo-toxin trinitrophenol (TNP). This detection is extremely fast with a high quenching constant (5.3 × 10⁴ M^-1) and a very low limit of detection (LOD) of 137 nM/59 ppb. This motivated us to detect the lethal carcinogenic arsenical drug roxarsone (ROX), which is reported here for the first time. The quenching constant and LOD for ROX using 1 were found to be 4.9 × 10⁴ M^-1 and 86 nM (or 37 ppb), respectively. Moreover, the probe also recognizes three lethal toxic oxo-anions (MnO₄^-, Cr₂O₇^2- and CrO₄^2-) with outstanding quenching constant (2.2 × 10⁴ M^-1, 1.4 × 10⁴ M^-1 and 1.1 × 10⁴ M^-1) and very low LODs (141 nM/61 ppb, 178 nM/78 ppb and 219 nM/95 ppb). Compared to the previously reported homogeneous sensing nature of the discrete complexes, our complex showed the detection of toxic pollutants in a heterogeneous manner, which results in high recyclability and hence multi-cycle sensing capability. Interestingly, 1 shows the possibility for real-time monitoring through naked eye detection by visible colorimetric changes in solid, solution and strip paper methods, i.e., triphasic detection ability. In addition, the sensor also exhibited the cross-sensing ability for these pollutants. The experimental sensing mechanism is strongly supported by the exhaustive theoretical investigation. Based on the fluorescence signal shown by each analyte, an integrated AND-OR logic gate is constructed. Furthermore, the sensing ability of 1 remains intact towards the detection of versatile real field samples including lethal carcinogenic arsenical drug roxarsone in the real food sample.

Dietary arsenic supplementation induces oxidative stress by suppressing nuclear factor erythroid 2-related factor 2 in the livers and kidneys of laying hens

This study investigated the effects of dietary arsenic supplementation on laying performance, egg quality, hepatic and renal histopathology, and oxidative stress in the livers and kidneys of laying hens. Furthermore, the nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway was explored to reveal the molecular mechanism of the stress. Five hundred and twelve 40-week-old Hyline White laying hens were randomly allocated to 4 groups with 8 pens per group and 16 hens per pen. The doses of arsenic administered to the 4 groups were 0.95, 20.78, 40.67, and 60.25 mg/kg. The results revealed that dietary arsenic supplementation significantly reduced hen-day egg production (P < 0.05), average egg weight (P < 0.05), Haugh units (P < 0.05), albumen height (P < 0.05), and eggshell strength (P < 0.05). Dietary arsenic supplementation also induced the accumulation of arsenic and histopathological damages in the liver and kidney. In accordance, dietary arsenic supplementation significantly enhanced serum alanine aminotransferase (P < 0.05), aspartate aminotransferase (P < 0.05), blood urea nitrogen (P < 0.05), and uric acid (P < 0.05) levels. After arsenic exposure, the activities of superoxide dismutase (SOD) (P < 0.05), catalase (P < 0.01), glutathione reductase (P < 0.05), and glutathione peroxidase (P < 0.05), and glutathione content (P < 0.05) were significantly decreased, while the malondialdehyde level was significantly increased (P < 0.05) in the liver and kidney. Positive correlations occurred between antioxidant enzyme activities and antioxidant enzyme gene expressions in the liver and kidney, except for renal manganese superoxide dismutase gene expression and SOD activity. Additionally, hepatic and renal Nrf2 mRNA expression was positively correlated with antioxidant gene expressions and negatively correlated with Keap1 mRNA expression. In summary, dietary arsenic supplementation induced oxidative stress by suppressing the Nrf2-Keap1 pathway in the livers and kidneys of laying hens.

Resistance to Metals Used in Agricultural Production

Metals and metalloids have been used alongside antibiotics in livestock production for a long time. The potential and acute negative impact on the environment and human health of these livestock feed supplements has prompted lawmakers to ban or discourage the use of some or all of these supplements. This article provides an overview of current use in the European Union and the United States, detected metal resistance determinants, and the proteins and mechanisms responsible for conferring copper and zinc resistance in bacteria. A detailed description of the most common copper and zinc metal resistance determinants is given to illustrate not only the potential danger of coselecting antibiotic resistance genes but also the potential to generate bacterial strains with an increased potential to be pathogenic to humans. For example, the presence of a 20-gene copper pathogenicity island is highlighted since bacteria containing this gene cluster could be readily isolated from copper-fed pigs, and many pathogenic strains, including Escherichia coli O104:H4, contain this potential virulence factor, suggesting a potential link between copper supplements in livestock and the evolution of pathogens.