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To investigate the effects of luteolin (LUT) on the growth, antioxidant capacity, non−specific immunity and intestinal microbiota of red swamp crayfish (Procambarus clarkii), 300 individual crayfish (4.17 ± 0.50 g average body weight and 50.19 ± 1.40 mm average body length) were randomly divided into five groups and fed with LUT doses of 0 mg/kg (CG), 50 mg/kg (LG50), 100 mg/kg (LG100), 300 mg/kg (LG300), and 500 mg/kg (LG500) for 8 weeks, respectively. Firstly, the results demonstrated that the survival and growth performance were significantly improved in all LUT added groups compared to the control (CG group), with no significant differences in hepatosomatic index, feed coefficient and muscle components, and the crayfish in LG100 group showed the maximal survival rate (SR) and specific growth rate (SGR) (P < 0.05). Secondly, histological observations displayed that the hepatopancreas and intestine tissues were not impacted in the LUT−supplemented groups, and the length of intestinal folds was significantly increased in LG100 and LG300 groups. Thirdly, LG50, LG100, and LG300 groups produced significantly increased hepatopancreatic antioxidant enzyme activities and hemolymph immune indicators compared with the control. In all experimental groups, malondialdehyde (MDA) contents were significantly reduced, as were aspartate aminotransferase and alanine aminotransferase activities. Lastly, dietary LUT specifically improved the structure and optimized the function of the gut microbiota. Compared to the control, the LG100 group displayed a significant increase in the index of Chao1 and Observed species, an increase in the relative abundance of Proteobacteria and Actinobacteria, a decrease in the ratio of Bacteroidetes to Firmicutes, and an increase in the abundance of Thermomonas , Turicibacter , Bdellovibrio and Enterococcus. PICRUSt analysis demonstrated a significant improvement in the KEGG pathway associated with isoflavone biosynthesis in the LG group. In conclusion, the present study confirms that dietary supplementation with 50−300 mg/kg LUT favors growth, non−specific immunity and antioxidant function in P. clarkii , with optimal additions ranging from 102−165 mg/kg. Furthermore, it optimized gut microbiota function, suggesting that LUT can be used as a potential feed additive for P. clarkii. These findings provide new insights for crayfish's healthy culture. • The optimal level of LUT addition to P. clarkii diet was 102−165 mg/kg. • Dietary addition of LUT improved the survival and growth performance of P. clarkii. • Dietary addition of LUT enhanced the antioxidant and immune capacity of P. clarkii. • Dietary addition of LUT improved intestinal microbiota structure of P. clarkii. [ABSTRACT FROM AUTHOR]

This study investigated the effects of water-soluble polysaccharide extracted from the sporoderm-removed spores of Ganoderma lucidum (GLP) against AOM/DSS-induced inflammation, tumorigenesis, and gut microbiota modification, which has never been reported before. Our data revealed that GLP (200 and 300 mg/kg) decreased AOM/DSS-induced colitis and tumorigenesis, manifested by significantly reduced disease activity index score, and total number and size of tumors. Furthermore, GLP ameliorated AOM/DSS-induced microbiota dysbiosis, increased short-chain fatty acid production, and alleviated endotoxemia by inhibiting TLR4/MyD88/NF-κB signaling. Besides, GLP profoundly improved gut barrier function as evidenced by increased numbers of goblet cells, MUC2 secretion, and tight junction protein expressions. GLP treatment inhibited macrophage infiltration and downregulated IL-1β, iNOS, and COX-2 expressions. Additionally, GLP inhibited lipopolysaccharides (LPS)-induced inflammation markers and MAPK (JNK and ERK) activation in macrophage RAW264.7, intestinal HT-29, and NCM460 cells. In conclusion, these results indicate that GLP is a promising prebiotic for the treatment of colorectal cancer. • GLP inhibits AOM/DSS-induced colitis, inflammation, and tumorigenesis in mice. • GLP improves microbiota dysbiosis and endotoxemia, increases SCFAs production. • GLP improves intestinal barrier function, inhibits immune cell infiltration in mice. • GLP inhibits LPS-induced inflammation in RAW264.7 and intestinal cells. • GLP inhibits TLR4/MyD88/NF-κB and MAPK pathways in vivo and in vitro. [ABSTRACT FROM AUTHOR]

The red swamp crayfish (Procambarus clarkii) is an important farming species in China and there is a high degree of overlap between the main crayfish production areas and areas contaminated with the heavy metal lead (Pb), thus putting crayfish farming at potential risk of Pb contamination. To assess the toxic effects of Pb on crayfish, in this study they were exposed to different concentrations of Pb (0, 0.1, 1, 10, 50 mg/L) for 72 h, and 0.1 mg/L represents the level of Pb in the contaminated water. Histomorphology and activities of antioxidant or immune-related enzymes suggest that the damage of Pb to the hepatopancreas and intestine was dose- and time-dependent, with the intestine being more sensitive to Pb than the hepatopancreas. Notably, after a short period (24 h) of stress at low concentrations (0.1 mg/L) of Pb, the malondialdehyde (MDA) content and antioxidant enzymes such as catalase (CAT) and glutathione peroxidase (GSH-Px) in the intestine of crayfish showed significant changes, indicating that low concentrations of Pb were also highly detrimental to crayfish. High-throughput sequencing of the intestinal microbial community indicated that Pb exposure led to a disturbance in the relative abundance of intestinal bacteria, increasing the abundance of pathogenic bacteria (Bosea, Cloacibacterium, Legionella spp.) and decreasing the abundance of potentially beneficial bacteria (Chitinibacter, Chitinilyticum, Paracoccus, Microbacterium, Demequina , and Acinetobacter spp.). In conclusion, Pb damages the hepatopancreas and intestinal barrier of crayfish, leading to the destruction of their anti-stress ability and immune response, and at the same time disrupts the homeostasis of intestinal microbes, resulting in adverse effects on the gut. This study contributed to the assessment of the ecotoxicity of the heavy metal Pb to the crustacean aquatic animals. [ABSTRACT FROM AUTHOR]

Thermal stress is a common experience suffered in rice-crayfish integrated systems (RCIS) by the red swamp crayfish, Procambarus clarkii. Based on our previous studies, the adaptability of this crayfish to non-hyperthermal stress over a specified period was explored within a short term by investigating the antioxidant capacity, immune function, HSP70 expression and intestinal microbial changes. Under the non-hyperthermal stress temperature (30 °C) determined by cumulative survivals, the malondialdehyde (MDA) content, total antioxidant capacity (T-AOC), total super oxide dismutase (T-SOD) and catalase (CAT) activities in hepatopancreas significantly increased to the peak values during at 12 h or 24 h (P < 0.05), respectively, and then gradually recovered to the levels of the controls (24 °C) (P > 0.05); the immune-related enzymatic activities (alkaline phosphatase, AKP; acid phosphatase, ACP; lysozyme, LZM) and gene expressions (TNFAIP , TNF and Toll) rapidly increased and reach the peaks at 12 h and 48 h, respectively, and maintained subsequently the higher levels compared with the controls (P < 0.05) except for TNFAIP. The relative expressions of HSP70 in the hepatopancreas, intestine and gill all increased sharply and reached the peak at 6 h (P < 0.05), then decreased fast and roughly returned to the levels of the controls at 96 h (P > 0.05), while, there was still a relatively high expression during the later stages in the gill. High-throughput sequencing of 16S ribosomal DNA revealed the thermal stress altered the diversity and composition of intestinal microbiota. The increased abundance of Proteobacteria and decreased abundance of Bacteroidetes (mainly Bacteroides) and Firmicutes might be indicative of the elevated microbial instability and the unnecessity for high level of nutrient metabolism in the host. The abundance increase of relevant metabolic pathways (e.g., the biosynthesis and degradation of amino acids and lipids) predicted by MetaCyc might be caused by the abundance increase of Proteobacteria. The decreased abundance of two phyla (Actinobacteria and Fusobacteria) and genus Anaerorhabdus could adversely affect the crayfish's intestinal health status. While, the obvious abundance decrease of putatively opportunistic genera (Shewanella and Acinetobacter), combined with the abundance increase of beneficial phylum Tenericutes and genus Rhodobacter , suggested that there concurrently existed some adaptability to the non-thermal stress, which did not resulted in apparent risks of intestinal disorder. This study provides insights into the underling adaptive mechanisms associated with the anti-oxidation, immunity, intestinal microflora and nutrient metabolism of P. clarkii in response to the short-term non-hyperthermal stress. • Non-hyperthermal stress caused oxidant damage and induced the instability of intestinal microbiota. • The increased indices of oxidant damage, anti-oxidation and HSP70 gene expression could be gradually recovered in the short-term non-hyperthermal stress. • High levels of immune-related enzymatic activities and gene expression were sustained for the adaption to short-term non-hyperthermal stress. • The modulated gut microflora and decreased metabolic level could be beneficial to the adaption to short-term non-hyperthermal stress. [ABSTRACT FROM AUTHOR]

Gastrointestinal probiotics are important members of intestinal microflora in both healthy animals and human beings, and these bacteria may reduce the risk of infection caused by certain opportunistic pathogens through exclusive inhibition, competition, and displacement. The lp_1643 protein on the cell surface of Lactobacillus plantarum WCFSI was assumed to possess a mucus-binding capability. This study aimed to determine if purified His-N2 protein exclusively inhibits pathogen adhesion to porcine mucus. The interaction of the His-N2 protein with porcine mucus was determined by indirect enzyme-linked immunosorbent assay (ELISA), and the adhesion was assessed by a traditional plating method to count the bacteria adhered to the porcine mucus. Indirect ELISA showed that His-N2 protein adhered to porcine mucus, and its interacting molecules existed. The His-N2 protein effectively inhibited the adhesion of Escherichia coli DH5α, Listeria monocytogenes CMCC54004, Salmonella Typhimurium ATCC 14028, and Shigella flexneri CMCC(B)51572 to porcine mucus. Results showed that inhibition of pathogen adhesion to porcine mucus depended on dose and strain. The adhesion of L. monocytogenes CMCC54004, Salmonella Typhimurium ATCC 14028, and S. flexneri CMCC(B)51572 was reduced by 95.7, 97.0, and 95.7%, respectively, by pre-adding 100 µl of 3.92 mg/ml of His-N2 protein, whereas that of E. coli DH5α was only 50.4%. The inhibition of adhesion of some pathogens by His-N2 was different at pH 6.6 and 7.5. The inhibition of E. coli DH5α, L. monocytogenes CMCC54004, and Salmonella Typhimurium ATCC 14028 at pH 6.6 was significantly higher than that at pH 7.5, whereas no statistically significant difference was observed in S. flexneri CMCC(B)51572. These results suggest that various types of inhibition mechanisms of His-N2 were involved in different pathogens. [ABSTRACT FROM AUTHOR]

Abstract: Plant protein sources have been identified to have the greatest potential to replace fish meal protein in aquafeeds. However, plant ingredients contain significant quantities of carbohydrates, and the ability of fish to utilize dietary carbohydrates as energy sources for growth is limited. Included in the carbohydrate group, cellulose is not tolerated by most fish. In the present study, the grass carp, a typical herbivorous fish, fed with duckweed was selected to study the effect of exogenous cellulase on the growth. The results of 2-month feeding experiment showed that the cellulase promoted the growth of grass carp. In addition, the cellulase increased various digestive enzyme activities, such as cellulase, amylase and protease but not the lipase activity. Meanwhile, the polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) analysis indicated that the intestinal microbiota of fish fed with the supplemental cellulase changed in bacteria species and density. Band patterns derived from control and cellulase samples showed a low degree of similarity when analyzed by cluster analysis. Some bands were unique to control samples, whereas other bands were obtained only with samples of the cellulase group. The 16S rRNA gene sequencing identified that Proteobacteria and Firmicutes were the two dominant groups, and the emergence of certain bacterial strains including Bacilli and Sphingomonas may contribute to the digestion of cellulose. The former researches and this paper results suggest that the endogenous cellulase is far from sufficient to fully digest the ingested fiber, so cellulase should be developed as a kind of aquatic additive. [Copyright &y& Elsevier]

• BSGLP inhibits HFD-induced obesity and hyperlipidemia. • BSGLP inhibits inflammation and macrophage infiltration. • BSGLP improves gut microbiota dysbiosis. • BSGLP improves intestinal barrier function. • BSGLP inhibits TLR4/Myd88/NF-κB signaling pathway. Ganoderma lucidum has been shown to have anti-obesity effects. However, polysaccharide extracted from the sporoderm-broken spores of Ganoderma lucidum (BSGLP) against obesity and its underlying mechanisms have never been reported. In the current study, we showed that BSGLP inhibited high-fat diet (HFD)-induced obesity, hyperlipidemia, inflammation, and fat accumulation in C57BL/6 J mice. BSGLP improved HFD-induced gut microbiota dysbiosis, maintained intestinal barrier function, increased short-chain fatty acids production and GPR43 expression, ameliorated endotoxemia, manifested by reduced serum lipopolysaccharide level, and increased ileum expression of tight junction proteins and antimicrobial peptides. Fecal microbiota transplantation study confirmed that BSGLP-induced microbiota change is responsible, at least in part, for obesity inhibition. Besides, BSGLP notably alleviated HFD-induced upregulation of TLR4/Myd88/NF-κB signaling pathway in adipose tissue. Collectively, our study showed for the first time that BSGLP might be used as a prebiotic agent to inhibit obesity and hyperlipidemia through modulating inflammation, gut microbiota, and gut barrier function. [ABSTRACT FROM AUTHOR]