Dietary Zn Deficiency Inhibits Cell Proliferation via the GPR39-Mediated Suppression of the PI3K/AKT/mTOR Signaling Pathway in the Jejunum of Broilers.

A prior investigation revealed that a lack of Zinc (Zn) could hinder intestinal cell proliferation in broiler chickens; however, the mechanisms responsible for this effect remain unclear. We aimed to investigate the possible mechanisms of dietary Zn deficiency in inhibiting the jejunal cell proliferation of broilers. For this study, a total of 112 chickens (21 days old) were randomly divided into two treatments (seven replicate cages per treatment, eight chickens per replicate cage): the control group (CON) and the Zn deficiency group. The duration of feeding was 21 d. Chickens in the control group were provided with a basal diet containing an extra addition of 40 mg Zn/kg in the form of Zn sulfate, whereas chickens in the Zn deficiency group were given the basal diet with no Zn supplementation. The results indicated that, in comparison to the CON, Zn deficiency increased (p < 0.05) the duodenal and jejunal crypt depth (CD) of broilers on d 28 and jejunal and ileal CD on d 35, and decreased (p < 0.05) the duodenal, jejunal, and ileal villus height/crypt depth (VH/CD) on d 28 and the jejunal VH, jejunal and ileal villus surface area, and VH/CD on d 35. Furthermore, Zn deficiency decreased (p < 0.0001) the number of proliferating cell nuclear antigen-positive cells and downregulated (p < 0.01) the mRNA or protein expression levels of phosphatidylinositol 3-kinase (PI3K), phosphorylated PI3K, phosphorylated serine-threonine kinase (AKT), phosphorylated mechanistic target of rapamycin (mTOR), G protein-coupled receptor 39 (GPR39), and extracellular-regulated protein kinase, but upregulated (p < 0.05) the mRNA or protein expression levels of P38 mitogen-activated protein kinase, c-jun N-terminal kinase (JNK) 1 and JNK2, and phosphorylated protein kinase C in the jejunum of the broilers on d 42. It was concluded that dietary Zn deficiency inhibited cell proliferation possibly via the GPR39-mediated suppression of the PI3K/AKT/mTOR signaling pathway in the jejunum of broilers.

Correction: Jin et al. Effects of Zinc Source and Level on the Intestinal Immunity of Xueshan Chickens under Heat Stress. Animals 2023, 13, 3025.

There were some errors in the original publication [...].

Effects of Zinc Source and Level on the Intestinal Immunity of Xueshan Chickens under Heat Stress.

Heat stress can cause intestinal inflammation, impaired barrier integrity, and decreased immunity in poultry. While zinc is known to mitigate the adverse effects of heat stress, how the dietary supplementation of different sources and levels of it can improve the heat stress capacity of Chinese landraces remains unclear. This study investigated Xueshan chickens, which are an important local breed in China. The effects of different levels of ZnS and Zn-Prot M on their intestinal immune function under heat stress were compared. We found that different levels of ZnS and Zn-Prot M could effectively reduce the secretion level of IL-6 in the serum, and 60 mg/kg was optimal. Compared with ZnS, Zn-Prot M significantly increased duodenal villus height and VH/CD ratio, thus Zn-Prot M was more effective than ZnS. Both ZnS and Zn-Prot M significantly down-regulated TNF-α, IL-1ß, and MyD88 in 102-day-old duodenum, and IL-1ß, IL-6, and NFKBIA in jejunum and ileum at 74, 88, and 102 days old, with 60 mg/kg Zn-Prot M determined as optimal. In conclusion, our study demonstrates that Zn-Prot M is superior to ZnS in improving intestinal immunity in Xueshan chickens, and 60 mg/kg is the optimal addition dose.

Impact of COVID-19 Risk Perception on Emotional Exhaustion among Chinese Hospitality Employees: The Mediating Effect of Job Insecurity.

This study aims to investigate the levels of COVID-19 risk perception (CVRP), job insecurity (JI), and emotional exhaustion (EE) among Chinese hospitality employees to examine the mediating effect of JI on the relationship between CVRP and EE. The moderating role of employee mindfulness (MF) and perceived employability (PE) have also be examined. Data were collected from 652 hospitality employees in Shandong and Jiangsu Province, China. We used structural equation modeling (SEM) to test the hypothesized relationship among the variables. Significant relationships were found between hospitality employees' CVRP and EE (ß = 0.103, p < 0.01), CVRP and JI (ß = 0.168, p < 0.001), and JI and EE (ß = 0.378, p < 0.001). According to the results, the higher level of the CVRP of hospitality employees, the higher level of the EE. In addition, results showed mediating effects of JI on the relationship between CVRP and EE. This study also found that MF buffered the positive relationship between CVRP and EE. Therefore, in the era of COVID-19, an effective support system at the organizational level is necessary to reduce JI and EE of hospitality employees.

Role of Reputation in Sustainable Performance of Online Crowdsourcing Vendors: An Explanation From Transaction Cost Theory.

This study reveals a new finding on the impact of reputation growth on crowdsourcing vendors' sustainable performance in different modes of markets using fixed-effect panel data regression models. To this end, we extract data from a large Chinese crowdsourcing platform named zbj.com for the period of 2012-2014, which was a key stage for the establishment of market diversification. Based on different transaction modes, the study divides the markets on the crowdsourcing platform into task-based market (TBM) and employment market (EPM). By applying the multiple framework, the empirical results exhibit a negative and significant effect of vendors' reputation on participation rate (PR) in TBM and EPM. At the same time, reputation also has a consistent effect on vendors' revenue share (RS) of each market. Moreover, this study shows that the significant reputation impact on PR and RS of EPM will be, respectively, weakened and strengthened in fixed-price mode and customized mode when vendors participate more in large-scale projects. The findings suggest that the growth of reputation will promote market transfer of vendors, that is, showing different sustainability in different markets, which will lead to uneven development of the crowdsourcing markets. By adopting the perspective of transaction cost theory (TCT), this study elaborates and analyses these phenomena and derives corresponding policy implications.