The mediation of the AHR/IL-22/STAT3/IL-6 axis by soft-shelled turtle (Pelodiscus sinensis) peptide and Chinese pond turtle (Chinemys reevesii) peptide contributed to their amelioration effects on intestinal mucosal immunity in immunosuppressed mice.

This study investigated the immunomodulatory effects of soft-shelled turtle (Pelodiscus sinensis) peptide (TP) and Chinese pond turtle (Chinemys reevesii) peptide (TMP) on the intestinal mucosal immune system (IMIS). The results demonstrated that TP and TMP improved holistic immunity by restoring the vital immune organ atrophy and proliferation capacity of spleen immune cells. Moreover, TP and TMP significantly increased the serum content of IgA and cytokines that are responsible for immune cell activation and antigen clearance. TP and TMP promoted intestinal B cell activation, class switching recombination, and antibody secreting processes in a T cell-independent manner to increase the SIgA content. Furthermore, TP and TMP enhanced the intestinal barrier by increasing the protein expression of tight junctions (TJs) and adhesion junctions (AJs) and ameliorating the intestinal morphology. Mechanistically, TP and TMP activated the AHR/IL-22/STAT3/IL-6 axis to enhance the IgA response and improve the intestinal barrier, indicating their potential in intestinal health modulation.

Sea cucumber (Acaudina leucoprocta) peptides extended the lifespan and enhanced antioxidant capacity via DAF-16/DAF-2/SOD-3/OLD-1/PEPT-1 in Caenorhabditis elegans.

The sea cucumber peptides (SCPs) from Acaudina leucoprocta were derived from the patented bio-enzyme digestion technology and the molecular weight of obtained SCPs was < 10 kDa. In this study, we investigated the possible anti-aging effects of SCPs on the model of Caenorhabditis elegans and the underlying mechanisms. SCPs extend the average lifespan of nematodes by 31.46%. SCPs enhance the anti-stress capacity of C. elegans by improving heat resistance and mobility, Also, the accumulated potential oxidative stress inducers like lipofuscin and reactive oxygen species (ROS) were reduced to 40.84 and 71.43%. In addition, SCPs can increase the antioxidant capacity in nematodes by enhancing the activity of SOD and CAT and reducing MDA accumulation in nematodes to 32.44%. Mechanistically, SCPs could mediate DAF-16/DAF-2/SOD-3/OLD-1/PEPT-1 axis to improve antioxidant capacity and extend lifespan in nematodes. Taken together, these findings provide a direction for the anti-aging effects of sea cucumber peptides and new insights into the further purifications of SCPs and future research on aging.

Enhancement in the metabolic profile of sea buckthorn juice via fermentation for its better efficacy on attenuating diet-induced metabolic syndrome by targeting gut microbiota.

To enhance physiological activity and probiotic availability of sea buckthorn juice, sea buckthorn juice pulp (BHJ) went through fermentation to the fermented (FHJ). In vitro, FHJ displayed better antioxidant and antidiabetic capacities. To further study effects of FHJ on diet-induced metabolic syndrome (MS) and possible mechanisms in vivo, C57BL/6 mice were fed on BHJ and FHJ under high fat diet (HFD). FHJ, rather BHJ, displayed better performance on ameliorating hyperlipidemia, insulin resistance, and oxidative stress in MS. Mechanistically, FHJ intervention significantly reversed the microorganism dysbiosis by restoring the microbial diversity, and modulating obesogenic bacteria abundance, like Oscillospira. Furthermore, fermentation altered FHJ's metabolomics, especially flavonoids, contributing to interactions between FHJ and probiotics, like Akkermansia and Lachnospiraceae. Furthermore, short-chain fatty acids, related to ameliorations of MS, were increased by FHJ. This study demonstrated that interactions between metabolomic alterations in FHJ and microorganisms were vital to attenuate MS.

Soft-Shelled Turtle Peptides Extend Lifespan and Healthspan in Drosophila.

In traditional Chinese medicine, soft-shelled turtle protein and peptides serve as a nutraceutical for prolonging the lifespan. However, their effects on anti-aging have not been clarified scientifically in vivo. This study aimed to determine whether soft-shelled turtle peptides (STP) could promote the lifespan and healthspan in Drosophila melanogaster and the underlying molecular mechanisms. Herein, STP supplementation prolonged the mean lifespan by 20.23% and 9.04% in males and females, respectively, delaying the aging accompanied by climbing ability decline, enhanced gut barrier integrity, and improved anti-oxidation, starvation, and heat stress abilities, while it did not change the daily food intake. Mechanistically, STP enhanced autophagy and decreased oxidative stress by downregulating the target of rapamycin (TOR) signaling pathway. In addition, 95.18% of peptides from the identified sequences in STP could exert potential inhibitory effects on TOR through hydrogen bonds, van der Walls, hydrophobic interactions, and electrostatic interactions. The current study could provide a theoretical basis for the full exploitation of soft-shelled turtle aging prevention.

Antiaging function of Chinese pond turtle (Chinemys reevesii) peptide through activation of the Nrf2/Keap1 signaling pathway and its structure-activity relationship.

Chinese pond turtle is a traditional nourishing food with high nutritional value and bioactivity and has been considered a dietary remedy for prolonging the lifespan since ancient times. However, only limited information about their effects on longevity is available. This study was performed to assess the antioxidant activities and antiaging potential of Chinese pond turtle peptide (CPTP) using Drosophila melanogaster model and uncover the possible mechanisms underlying the beneficial effects. CPTP exhibited excellent antioxidant capability in vitro with IC 50 values of 3.31, 1.93, and 9.52 mg/ml for 1,1-diphenyl-2-pycryl-hydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazo-line-6-sulfonic acid) diammonium salt (ABTS), and hydroxyl radical scavenging, respectively. In vivo, 0.8% of CPTP significantly extended the mean and median lifespan of female flies by 7.66 and 7.85%, followed by enhanced resistance to oxidative and heat stress. Besides, CPTP remarkably increased the antioxidant enzyme activities and diminished the peroxide product accumulation. Furthermore, CPTP upregulated the relative mRNA expression of antioxidant-related genes, including nuclear factor-erythroid-2-like 2 (Nrf2) and its downstream target genes, while downregulated the expression of Kelch-like ECH-associated protein 1 (Keap1). Taken together, CPTP displayed promising potential in both antioxidant and antiaging effects on flies by targeting the Nrf2/Keap1 pathway. Further peptide sequence determination revealed that 89.23% of peptides from the identified sequences in CPTP could exert potential inhibitory effects on Keap1. Among these peptides, ten representative peptide sequences could actively interact with the binding sites of Keap1-Nrf2 interaction through hydrogen bonds, van der Walls, hydrophobic interactions, and electrostatic interactions. Conclusively, CPTP could be utilized as health-promoting bioactive peptide with antioxidant and antiaging capacities.

Evaluating dynamic effects of dietary glycerol monolaurate on the productive performance and flesh quality of large yellow croaker (Larimichthys crocea).

The effects of GML (Glycerol monolaurate) supplementation with two level (0.5 and 1.0 g kg-1) on the productive performance and flesh quality of large yellow croaker (360 per group) were investigated during feeding (23,50-days) and fasting stage (23,70-days). The GML supplementation significantly increased body weight after 23-days and crude protein, inosinic acid, and yellowness after 50-days. Moreover, it increased hardness, springiness, and chewiness by increasing the collagen content, myofiber density, and decreasing myofiber diameter. The high GML supplementation increased the total free amino acids, delicate amino acids, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (n-3 PUFA), and EPA + DHA, whereas it decreased the content of saturated fatty acids/unsaturated fatty acids (SFA/UFA). During fasting, better body shape and color were shown were shown at high GML supplementation. Conclusively, high dose GML supplementation exerted promising effects on the productive performance and flesh quality of large yellow croaker.

Integrated metabolomic and gene expression analyses to study the effects of glycerol monolaurate on flesh quality in large yellow croaker (Larimichthys crocea).

To improve the quality of cultured large yellow croaker (Larimichthys crocea), this study was performed to study the impacts of glycerol monolaurate (GML) on the nutritional value, growth performance, muscle texture, and taste intensity of L. crocea. The results showed that GML as a feed additive significantly increased the crude lipid content and reduced the diameters of muscle fibers, which in turn markedly altered the flesh texture in terms of cohesiveness. Moreover, the taste indicators (umami and richness) and flavor-related amino acid (glutamic acid, glycine, and proline) contents of L. crocea muscle were significantly higher in the GML group. Metabolomic and gene expression analyses showed that GML supplementation could significantly improve amino acid biosynthesis and metabolism, promote protein and lipid synthesis, and activate myogenic-related signaling pathways of L. crocea. Consequently, adding an appropriate amount of GML to fish feed would be conducive to providing healthy, nutrient-rich and acceptably flavored aquatic-products.