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.

Potential protective effects of sodium butyrate on glycinin-induced oxidative stress, inflammatory response, and growth inhibition in Cyprinus carpio.

Investigated mitigating effects of sodium butyrate (SB) on the inflammatory response, oxidative stress, and growth inhibition of common carp (Cyprinus carpio) (2.94 ± 0.2 g) are caused by glycinin. Six isonitrogenous and isoenergetic diets were prepared, in which the basal diet was the control diet and the Gly group diet contained 80 g/kg glycinin, while the remaining 4 diets were supplemented with 0.75, 1.50, 2.25, and 3.00 g/kg SB, respectively. The feeding trial lasted for 8 weeks, and the results indicated that supplementing the diet with 1.50-2.25 g/kg of SB significantly improved feed efficiency and alleviated the growth inhibition induced by glycinin. Hepatopancreas and intestinal protease activities and the content of muscle crude protein were significantly decreased by dietary glycinin, but supplement 1.50-2.25 g/kg SB partially reversed this result. SB (1.50-2.25 g/kg) increased the activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the hepatopancreas and reduced the activities of AST and ALT in the serum. Glycinin significantly reduced immune and antioxidant enzyme activities, whereas 1.50-2.25 g/kg SB reversed these adverse effects. Furthermore, compared with the Gly group, supplement 1.50-2.25 g/kg SB eminently up-regulated the TGF-ß and IL-10 mRNA, and down-regulated the IL-1ß, TNF-α, and NF-κB mRNA in hepatopancreas, mid-intestine (MI), and distal intestine (DI). Meanwhile, supplement 1.50-2.25 g/kg SB activated the Keap1-Nrf2-ARE signaling pathway and upregulate CAT, SOD, and HO-1 mRNA expression in hepatopancreas, MI, and DI. Summarily, glycinin induced inflammatory response, and oxidative stress of common carp ultimately decreased the digestive function and growth performance. SB partially mitigated these adverse effects by activating the Keap1-Nrf2-ARE signaling pathway and inhibiting the NF-κB signaling pathway.

Degradation potential and pathways of methylcyclohexane by bacteria derived from Antarctic surface water.

Cycloalkanes pose a tremendous environmental risk due to their high concentration in petroleum hydrocarbons and hazardous effects to organisms. Numerous studies have documented the biodegradation of acyclic alkanes and aromatic hydrocarbons. However, insufficient attention has been paid to studies on the microbial degradation of cycloalkanes, which might be closely linked to psychrophilic microbes derived from low-temperature habitats. Here we show that endemic methylcyclohexane (MCH, an abundant cycloalkane species in oil) consumers proliferated in seawater samples derived from the Antarctic surface water (AASW). The MCH-consuming bacterial communities derived from AASW exhibited a distinct species composition compared with their counterparts derived from other cold-water habitats. We also probed Colwellia and Roseovarius as the key active players in cycloalkane degradation by dilution-to-extinction-based incubation with MCH as sole source of carbon and energy. Furthermore, we propose two nearly complete MCH degradation pathways, lactone formation and aromatization, concurrently in the high-quality metagenome-assembled genomes of key MCH consumer Roseovarius. Overall, we revealed that these Antarctic microbes might have strong interactions that enhance the decomposition of more refractory hydrocarbons through complementary degradation pathways.

Protective effect of vitamin C and lycopene on the in vitro fertilization capacity of sex-sorted bull sperm by inhibiting the oxidative stress.

The fertilization capacity of sex-sorted sperms is seriously decreased, which inhibits its wide application. However, little information is still available about the effect of vitamin C (VC) and lycopene (Lyc) on the fertilization capacity of sex-sorted bull sperm. In this study, the washing medium and fertilization medium of sex-sorted sperm from three bull individuals were supplemented with different concentrations of VC (0, 1 × 10-3 , 1 × 10-4 , 1 × 10-5 , 1 × 10-6  M) or Lyc (0, 1 × 10-4 , 1 × 10-5 , 1 × 10-6 , 1 × 10-7 ). After washing twice and incubation for 1.5 hr, the malondialdehyde (MDA) level, phosphatidylserine (PS) translocation, membrane potential (Δψm) and IVF (in vitro fertilization) ability of sex-sorted sperm were investigated. For the sex-sorted sperm of bulls A, B and C, 1 × 10-3  M VC or 1 × 10-4  M Lyc treatment significantly decreased their MDA levels and PS translocation and increased their Δψm levels and cleavage rates after IVF. When blastocysts were concerned, 1 × 10-4  M Lyc significantly improved the blastocyst rates and their IFN-tau expression of bulls A and C. In conclusion, supplementation of 1 × 10-3  M VC or 1 × 10-4  M Lyc in washing and fertilization medium contributed greatly to improving the fertilization capacity of sex-sorted bull sperm during IVF procedure.

Melatonin Improves the Fertilization Capacity of Sex-Sorted Bull Sperm by Inhibiting Apoptosis and Increasing Fertilization Capacitation via MT1.

Little information is available regarding the effect of melatonin on the quality and fertilization capability of sex-sorted bull sperm, and even less about the associated mechanism. Sex-sorted sperm from three individual bulls were washed twice in wash medium and incubated in a fertilization medium for 1.5 h, and each was supplemented with melatonin (0, 10-3 M, 10-5 M, 10-7 M, and 10-9 M). The reactive oxygen species (ROS) and endogenous antioxidant activity (glutathione peroxidase (GPx); superoxide dismutase (SOD); catalase (CAT)), apoptosis (phosphatidylserine [PS] externalization; mitochondrial membrane potential (Δψm)), acrosomal integrity events (malondialdehyde (MDA) level; acrosomal integrity), capacitation (calcium ion [Ca2+]i level; cyclic adenosine monophosphate (cAMP); capacitation level), and fertilization ability of the sperm were assessed. Melatonin receptor 1 (MT1) and 2 (MT2) expression were examined to investigate the involvement of melatonin receptors on sex-sorted bull sperm capacitation. Our results show that treatment with 10-5 M melatonin significantly decreased the ROS level and increased the GPx, SOD, and CAT activities of sex-sorted bull sperm, which inhibited PS externalization and MDA levels, and improved Δψm, acrosomal integrity, and fertilization ability. Further experiments showed that melatonin regulates sperm capacitation via MT1. These findings contribute to improving the fertilization capacity of sex-sorted bull sperm and exploring the associated mechanism.