Chlorogenic acid improves common carp (Cyprinus carpio) liver and intestinal health through Keap-1/Nrf2 and NF-κB signaling pathways: Growth performance, immune response and antioxidant capacity.

In this experiment, we investigated the effects of adding chlorogenic acid (CGA) to the diet on growth performance, immune function, inflammation response, antioxidant capacity and its related mechanisms of common carp (Cyprinus carpio). A total of 600 fish were selected and randomly divided into five treatment groups and fed with CGA containing 0 mg/kg (CK), 100 mg/kg (L100), 200 mg/kg (L200), 400 mg/kg (L400) and 800 mg/kg (L800) for 56 days. The results of the experiment were as follows: addition of CGA significantly increased the WGR, SGR, FER, and PER of common carp (P < 0.05). The addition of 400-800 mg/kg of CGA significantly increased the serum levels of LZM, AKP activity, C3 and C4 concentration, and increased immune function of common carp (P < 0.05). Regarding antioxidant enzyme activities, adding CGA significantly increased SOD, CAT, and GsH-Px activities, while decreasing MDA content (P < 0.05). Compared with the CK group, the mRNA expression levels of NF-κB, TNF-α, and IL-1ß were decreased. The IL-10 and TGF-ß were increased in the liver and intestines of the CGA supplemented group. Meanwhile, the addition of CGA also significantly up-regulated the mRNA expression levels of Nrf2, HO-1, SOD, CAT, and GPX (P < 0.05). CGA also positively contributed to the development of the carp intestinal tract, as demonstrated by decreased serum levels of DAO, D-LA, and ET-1. And the mucosal fold height was increased significantly with increasing levels of CGA. In conclusion, the addition of CGA in the feed can enhance the growth performance, immune function and antioxidant capacity of common carp, and improve the health of the intestine and liver. According to the results of this experiment, the optimal addition amount in common carp diets was 400 mg/kg.

Unlocking the potential of N-acetylcysteine: Improving hepatopancreas inflammation, antioxidant capacity and health in common carp (Cyprinus carpio) via the MAPK/NF-κB/Nrf2 signalling pathway.

N-acetylcysteine (NAC) positively contributes to enhancing animal health, regulating inflammation and reducing stress by participating in the synthesis of cysteine, glutathione, and taurine in the body. The present study aims to investigate the effects of dietary different levels of NAC on the morphology, function and physiological state of hepatopancreas in juvenile common carp (Cyprinus carpio). 450 common carps were randomly divided into 5 groups: N1 (basal diet), N2 (1.5 g/kg NAC diet), N3 (3.0 g/kg NAC diet), N4 (4.5 g/kg NAC diet) and N5 (6.0 g/kg NAC diet), and fed for 8 weeks. The results indicated that dietary 3.0-6.0 g/kg NAC reduced hepatopancreas lipid vacuoles and nuclear translocation, and inhibited apoptosis in common carp. Simultaneously, the activities of hepatopancreas alanine aminotransferase and aspartate aminotransferase progressively increased with rising dietary NAC levels. Dietary NAC enhanced the non-specific immune function of common carp, and exerted anti-inflammatory effects by inhibiting the MAPK/NF-κB signaling pathway. Additionally, dietary 3.0-6.0 g/kg NAC significantly improved the antioxidant capacity of common carp, which was associated with enhanced glutathione metabolism, clearance of ROS and the activation of Nrf2 signaling pathway. In summary, NAC has the potential to alleviate inflammation, mitigate oxidative stress and inhibit apoptosis via the MAPK/NF-κB/Nrf2 signaling pathway, thereby improving hepatopancreas function and health of common carp. The current findings provide a theoretical basis for promoting the application of NAC in aquaculture and ecological cultivation of aquatic animals.

Social Presence, Negative Emotions, and Self-Protective Behavioral Intentions of Nonsmokers in Response to Secondhand Smoking in Virtual Reality: Quasi-Experimental Design.

BACKGROUND: The application of virtual reality (VR) in health care has grown rapidly in China, where approximately half of the population is directly exposed to secondhand smoke (SHS). As VR headsets have become increasingly popular and short video platforms have incorporated 360° videos in China, new formats and opportunities for health campaigns about SHS have emerged. OBJECTIVE: In a simulated environment of exposure to SHS, this study aims to explore the emotional and behavioral responses to enhanced social presence brought about by VR in contrast to flat-screen videos. It also aims to examine whether and to what extent video modality (360° video vs flat-screen video) and contextual cues (high threat vs low threat) influence psychometric and intentional variables among viewers. METHODS: A total of 245 undergraduate and graduate students who were nonsmokers and from a large university in China participated in this study between October 2020 and January 2021. This study created 4 different versions of a SHS experience in a café with a 2 (360° video on a head-mounted display vs flat-screen display) × 2 (high threat vs low threat) experimental design. It developed and tested a path model examining the effects of experience modality and threat levels on social presence, emotions (anger and disgust), and eventually behavioral intentions (staying away and asking for help). RESULTS: We found that both video modality (P<.001) and threat level (P=.005) significantly influenced social presence, whereas the interaction of video modality and threat level did not have a statistically significant effect on social presence (P=.55). Negative emotions mediated the relationships between social presence and SHS-related self-protective behaviors. Specifically, anger positively predicted the intention to ask smokers to stop smoking through the waitress (P<.001). Disgust and fear both positively predicted the intention to stay away from the SHS environment (P<.001 for disgust; P=.002 for fear). CONCLUSIONS: This study explored the potential mediating mechanisms that influence individuals' responses to the risks of SHS in public areas. The results demonstrated that social presence and negative emotions are 2 important mediators that underlie the relationship between video modality and behavioral intention regarding SHS in a VR setting. These findings suggest that an immersive environment could be a better stimulator of anti-SHS emotions and behaviors than flat-screen videos.

Enhanced lincomycin production by co-overexpression of metK1 and metK2 in Streptomyces lincolnensis.

Streptomyces lincolnensis is generally utilized for the production of lincomycin A (Lin-A), a clinically useful antibiotic to treat Gram-positive bacterial infections. Three methylation steps, catalyzed by three different S-adenosylmethionine (SAM)-dependent methyltransferases, are required in the biosynthesis of Lin-A, and thus highlight the significance of methyl group supply in lincomycin production. In this study, we demonstrate that externally supplemented SAM cannot be taken in by cells and therefore does not enhance Lin-A production. Furthermore, bioinformatics and in vitro enzymatic assays revealed there exist two SAM synthetase homologs, MetK1 (SLCG_1651) and MetK2 (SLCG_3830) in S. lincolnensis that could convert L-methionine into SAM in the presence of ATP. Even though we attempted to inactivate metK1 and metK2, only metK2 was deleted in S. lincolnensis LCGL, named as ΔmetK2. Following a reduction of the intracellular SAM concentration, ΔmetK2 mutant exhibited a significant decrease of Lin-A in comparison to its parental strain. Individual overexpression of metK1 or metK2 in S. lincolnensis LCGL either elevated the amount of intracellular SAM, concomitant with 15% and 22% increase in Lin-A production, respectively. qRT-PCR assays showed that overexpression of either metK1 or metK2 increased the transcription of lincomycin biosynthetic genes lmbA and lmbR, and regulatory gene lmbU, indicating SAM may also function as a transcriptional activator. When metK1 and metK2 were co-expressed, Lin-A production was increased by 27% in LCGL, while by 17% in a high-yield strain LA219X.