miRNA-seq analysis of liver tissue from largemouth bass (Micropterus salmoides) in response to oxytetracycline and enzyme-treated soy protein

The specific miRNA regulation triggered by enzyme-treated soybean protein in response to well-known stressors, such as the prophylactic use of the antimicrobial oxytetracycline, remains unknown. Hence, this study aimed to evaluate the regulatory changes of hepatic miRNAs induced by oxytetracycline and enzyme-treated soybean protein in largemouth bass dietary formulations. The experiment was designed with three groups: the normal control (NC), the oxytetracycline exposure treatment group (OTC), and the pre-treatment with enzyme-treated soybean protein before oxytetracycline exposure group (ETSP). miRNA sequencing was employed to characterize the differences between these groups. In conclusion, the NC group exhibited up-regulation of 13 host miRNAs and down-regulation of 1 miRNA compared to the OTC group, whereas the ETSP group showed an increasing trend of 36 host miRNAs and a decreasing trend of 13 host miRNAs compared to the OTC group. Nine miRNAs were identified as prudential targets for enzyme-treated soy protein, protecting the largemouth bass liver from oxytetracycline. Furthermore, gene ontology analysis revealed nine key miRNAs that mediate signaling pathways with significant differences. The cellular lipid metabolic process was identified as the most important biological process, and the propanoate metabolism pathway was highlighted as significant. These results will facilitate further exploration of the mechanism by which enzyme-treated soy protein alleviates the effects of oxytetracycline on largemouth bass in water environments.

Effect of Antarctic krill phospholipid (KOPL) on high fat diet-induced obesity in mice

Phospholipids are the main lipid components in Antarctic krill oil, and the combination of n-3 polyunsaturated fatty acids (n-3 PUFAs) shows multiple nutritional advantages. At present, the research about Antarctic krill phospholipid (KOPL) mainly focuses on the purification, and there are few reports on the anti-obesity effect. Thus, this study aimed at evaluating the effect of KOPL on the high-fat diet (HFD)-induced obesity mice. All the mice were divided into five groups, which were fed chow diet, HFD, and different doses of KOPL + HFD, respectively. The results showed that KOPL treatment could reduce the weight gain, fat accumulation, and liver tissue damage in HFD-induced mice. KOPL treatment could reduce the levels of serum lipid (TC, TG, L-LDL) and fasting blood glucose in HFD-induced mice, and the inflammatory cytokines (IL-1β and TNF-α) in serum. Further analysis showed that KOPL could promote the normal expression of lipid-synthesis-related genes and proteins, including sterol regulatory element-binding protein-1c (SREBP-1c), fatty acid synthetase (FAS), and peroxisome proliferator-activated receptor alpha (PPAR-α) in liver tissue. Besides, it inhibited the overexpression of inflammatory cytokine genes (IL-1β and TNF-α), but increased the expression of tight junction genes (ZO-1 and Occludin) in the colon tissue. Additionally, KOPL improved the decrease of diversity and imbalance of intestinal microbiota, which could contribute to its beneficial effects. In summary, the KOPL treatment improves the effects of HFD-induced obese mice by maintaining normal lipid levels, protecting the liver tissue, reducing inflammation response and intestinal damage, and regulating intestinal microbiota abnormalities. It refer to KOPL could be a promising dietary strategy for treating obesity and improving its related metabolic diseases.

Effect of okra fruit powder supplementation on metabolic syndrome and gut microbiota diversity in high fat diet-induced obese mice

This study aimed to explore a novel strategy for dietary okra fruit powder (OFP) consumption on attenuation of non-alcohol fatty liver damage, lipid metabolic disorder and gut microbiota dysbiosis and associated mechanisms in high-fat diet (HFD)-induced obese mice. C57BL/6J mice were fed a normal diet and HFD feeds supplemented with or without OFP (2.5%, 5% and 10%, n = 10) for 12 weeks. The results showed that supplementation of OFP caused strong inhibition on HFD-caused high blood glucose, body weight gain and liver fat accumulation, as well as dyslipidemia involved in a dose-dependent modulation of hepatic FAS and CD36 expressions of obese mice. The hepatic LXR-α energy metabolism and PPAR-α pathway were also doubly activated by OFP to alleviate lipogenesis, obesity and metabolic syndrome. Malonaldehyde production was effectively antagonized, and glutathione peroxidase and superoxide dismutase activities were elevated by OFP supplementation in HFD-fed mice. OFP also significantly improved colonic SCFAs (acetic acid, propionic acid and butyrate acid) formation, especially for butyrate production via increasing the proportion of selected butyrate-producing bacteria. OFP also dramatically modified the gut microbial species at the family level with suppressing an increase in Proteobacteria, Actinobacteria and F/B ratio, and the decrease in Bacteroidetes caused by HFD. These findings support that dietary OFP consumption is a novel strategy to prevent obesity, metabolic syndrome and gut microbiota imbalance.

Liver transcriptome analysis and de novo annotation of the orange-spotted groupers (Epinephelus coioides) under cold stress

Cold stress has caused great economic loss in fish culture worldwide. Orange-spotted grouper (Epinephelus coioides) is one of the most serious lost aquatic animals in 2016 cold fronts in South China. However, the molecular mechanism of grouper's cold resistance has remained largely unknown. In the present study, HiSeq™2000 (Illumina) was used to analyze the transcriptomic profiles of the liver from grouper under control temperature (CT, 28 °C) and low temperature (LT, 13 °C). Two normalized liver cDNA libraries of CT and LT groups were created. We obtained 51,944,970 and 51,905,036 clean reads from CT and LT groups, respectively. Comparing the LT group to the CT group, a total of 5905 significantly differentially expressed genes (DEGs) were identified, including 2093 up-regulated unigenes and 3812 down-regulated unigenes. GO annotation and functional enrichment analysis indicated that all of the DEGs were classified into three categories: biological process (23 subclasses), cellular component (18 subclasses) and molecular function (13 subclasses). KEGG analysis of the DEGs showed that 2732 DEGs were annotated to 253 signaling pathways. The most highly enriched pathways were cell adhesion molecules, Staphylococcus aureus infection, PPAR signaling pathway, Vibrio cholerae infection, primary immunodeficiency, fatty acid elongation, and we found cold stress mainly affects immunity, metabolic and signal transduction. Thirteen of the DEGs were further validated by qRT-PCR. Our results provide valuable information for further analysis of the mechanisms of groupers response under cold stress.