High Temperature-Induced Oxidative Stress Affects Systemic Zinc Homeostasis in Broilers by Regulating Zinc Transporters and Metallothionein in the Liver and Jejunum

Metal binding feature of copper‒induced metallothionein from freshwater crab Sinopotamon henanense reveals its Cu‒thionein character

Sinopotamon Henanense expresses two metal‒induced metallothioneins (MTs), Cd‒induced MT and Cu‒induced MT (ShCuMT). The Cd‒induced MT has been characterized as a Cd‒thiolate MT. However, it is unknown whether ShCuMT is a Cu‒thiolate MT. In the present study, ShCuMT was expressed heterologously in Escherichia coli and purified by Ni‒NTA column and superdex‒75 column. And its metal‒binding feature was evaluated by DTNB reaction, circular dichroism spectroscopy (CD), isothermal microtitration (ITC), electrospray flight mass spectrometry (ESI‒TOF‒MS), and matrix‒assisted laser desorption ionization flight mass spectrometry (MALDI‒TOF‒MS). Bioinformatics analysis demonstrated that ShCuMT possessed the cysteine‒triplet motif of a Cu‒specific MT. Expression and purification of ShCuMT illustrated that SUMO tag used as the production system for ShCuMT resulted in a high production yield. The stability order of ShCuMT binding metal ions were Cu (Ⅰ) > Cd (Ⅱ) > Zn (Ⅱ). The CD spectrum indicated that ShCuMT binding with Cu (I) exhibited a compact thiol metal clusters structure. Besides, there emerged no a visible nickel‒thiol absorption after Ni‒NTA column affinity chromatography. The ITC results implied that Cu‒ShCuMT possessed the optimal thermodynamic conformation and the highest stoichiometric number of Cu (Ⅰ). Overall, the results suggested that SUMO fusion system is a robust and inexpensive approach for ShCuMT expression and Ni‒NTA column had no influence on metal binding of ShCuMT and Cu(Ⅰ) was considered its cognate metal ion, and ShCuMT possessed canonical Cu‒thiolate characteristics. The metal binding feature of ShCuMT reported here contributes to elucidating the structure‒function relationship of ShCuMT in S. Henanense.

Benefits and costs: Understanding the influence of heavy metal pollution on environmental adaptability in Strauchbufo raddei tadpoles through an energy budget perspective

Understanding the impact of environmental pollution on organismal energy budgets is crucial for predicting adaptive responses and potential maladaptation to stressors. However, the regulatory mechanism governing the trade-off between energy intake and consumption remains largely unknown, particularly considering the diverse adaptations influenced by exposure history in realistic field conditions. In the present study, we conducted a simulated field reciprocal transplant experiment to compare the energy budget strategies of Strauchbufo raddei tadpoles exposed to heavy metal. The simulated heavy metal concentrations (0.29 mg/L Cu, 1.17 mg/L Zn, 0.47 mg/L Pb, 0.16 mg/L Cd) mirrored the actual environmental exposure concentrations observed in the field habitat. This allowed for a comparison between tadpoles with parental chronic exposure to heavy metal pollutants in their habitat and those without such exposure. Results revealed that under heavy metal exposure, tadpoles originating from unpolluted areas exhibited heightened vulnerability, characterized by reduced food intake, diminished nutrient absorption, increased metabolism cost, reduced energy reserves, and increased mortality rates. In contrast, tadpoles originating from areas with long-term heavy metal pollution demonstrated adaptive strategies, manifested through adjustments in liver and small intestine phenotypes, optimizing energy allocation, and reducing energy consumption to preserve energy, thus sustaining survival. However, tadpoles from polluted areas exhibited certain maladaptive such as growth inhibition, metabolic suppression, and immune compromise due to heavy metal exposure. In conclusion, while conserving energy consumption has proven to be an effective way to deal with long-term heavy metal stress, it poses a threat to individual survival and population development in the long run.

Zinc glycinate alleviates LPS-induced inflammation and intestinal barrier disruption in chicken embryos by regulating zinc homeostasis and TLR4/NF-κB pathway

The effect of an immune challenge induced by a lipopolysaccharide (LPS) exposure on systemic zinc homeostasis and the modulation of zinc glycinate (Zn-Gly) was investigated using a chicken embryo model. 160 Arbor Acres broiler fertilized eggs were randomly divided into 4 groups: CON (control group, injected with saline), LPS (LPS group, injected with 32 µg of LPS saline solution), Zn-Gly (zinc glycinate group, injected with 80 µg of zinc glycinate saline solution) and Zn-Gly+LPS (zinc glycinate and LPS group, injected with the same content of zinc glycinate and LPS saline solution). Each treatment consisted of eight replicates of five eggs each. An in ovo feeding procedure was performed at 17.5 embryonic day and samples were collected after 12 hours. The results showed that Zn-Gly attenuated the effects of LPS challenge-induced upregulation of pro-inflammatory factor interleukin 1β (IL-1β) level (P =0.003). The LPS challenge mediated zinc transporter proteins and metallothionein (MT) to regulate systemic zinc homeostasis, with increased expression of the jejunum zinc export gene zinc transporter protein 1 (ZnT-1) and elevated expression of the import genes divalent metal transporter 1 (DMT1), Zrt- and Irt-like protein 3 (Zip3), Zip8 and Zip14 (P < 0.05). A similar trend could be observed for the zinc transporter genes in the liver, which for ZnT-1 mitigated by Zn-Gly supplementation (P =0.01). Liver MT gene expression was downregulated in response to the LPS challenge (P =0.004). These alterations caused by LPS resulted in decreased serum and liver zinc levels and increased small intestinal, muscle and tibial zinc levels. Zn-Gly reversed the elevated expression of the liver zinc finger protein A20 induced by the LPS challenge (P =0.025), while Zn-Gly reduced the gene expression of the pro-inflammatory factors IL-1β and IL-6, decreased toll-like receptor 4 (TLR4) and nuclear factor kappa-B p65 (NF-κB p65) (P < 0.05). Zn-Gly also alleviated the LPS-induced downregulation of the intestinal barrier gene Claudin-1. Thus, LPS exposure prompted the mobilization of zinc transporter proteins and MT to perform the remodeling of systemic zinc homeostasis, Zn-Gly participated in the regulation of zinc homeostasis and inhibited the production of pro-inflammatory factors through the TLR4/NF-κB pathway, attenuating the inflammatory response and intestinal barrier damage caused by an immune challenge.

Elemental analysis of Fadogia ancylantha leaves used as a nutraceutical in Mashonaland West Province, Zimbabwe

In this study, the concentrations of the essential elements to the human body N, K, Mg, P, Ca, Fe, Mn, and Zn of the fermented and non-fermented Fadogia ancylantha leaf samples were analysed to assess their nutritional value in two different areas in Zimbabwe: Mhangura (Mashonaland West, Province) and Alaska (Mashonaland West Province). Atomic absorption spectroscopy and ultraviolet spectrophotometry techniques were used to measure the concentrations of the minerals. The concentrations of manganese were significantly high (p < 0.05) in non-fermented treatments, with Mhangura samples having 0.447 mg/g and Alaska samples having 0.453 mg/g. Iron was high in fermented samples with Mhangura samples having 0.245 mg/g and Alaska samples having 0.270 mg/g. The concentrations of manganese and iron in Fadogia ancylantha can be used to supplement the recommended daily doses in pregnant, menstruating, and lactating women. The study, therefore, recommends that Fadogia ancylantha be used as a nutraceutical for the supplementation of iron and manganese.

Dietary sodium butyrate improves female broiler breeder performance and offspring immune function by enhancing maternal intestinal barrier and microbiota

This study aimed to investigate the effects of dietary sodium butyrate (SB) supplementation on the reproductive performance of female broiler breeders under intensive rearing conditions and to analyze antioxidant capacity, immune function, and intestinal barrier function of the female breeders and their offspring. A total of 96,000 40-wk-old Ross308 female broiler breeders were divided into the control (CON) and SB groups, each with 6 replicates of 8,000 birds. Each house with similar production performance characteristics was considered a replicate. The experiment lasted for 20 wk, whereupon sampling took place. Results showed that SB improved the egg production performance, egg quality of broiler breeders, and hatchability (P < 0.05). Maternal supplementation with SB substantially increased serum immunoglobulin A levels in broiler breeders and offspring (both P = 0.04) and offspring immunoglobulin G (P < 0.001). The levels of interleukin-1β (P < 0.001) and interleukin-4 (P = 0.03) in the offspring were downregulated, while the total superoxide dismutase in the offspring and the eggs increased (P < 0.05). The serum biochemical components in breeders and offspring were altered by SB, as evidenced by the reduction in triglycerides, total cholesterol, and high- and low-density lipoproteins (P < 0.05). The intestinal morphology of broiler breeders and offspring also improved by the SB with the decreasing the jejunal crypt depth (P = 0.04) and increasing villus height in offspring (P = 0.03). Maternal jejunal and ileal intestinal barrier-related genes were also shown to be significantly affected by SB. Furthermore, SB altered the microbial diversity in maternal cecal contents, thus increasing the abundance of Lachnospiraceae (P = 0.004) and Ruminococcaceae (P = 0.03). Dietary SB enhanced the reproductive performance and egg quality of broiler breeders and improved the antioxidant capacity and immune function of broiler breeders and offspring, with the benefits potentially arising from the regulation of the maternal intestinal barrier and gut microbiota by SB.