A 60-day culture in brackish water (0, 3, 5, 7, 9, and 11 ppt) was conducted to study the effects of salinity on muscle nutrition, fatty acid composition, and anabolic metabolism of blue tilapia Oreochromis aureus. Current research showed that WGR, SGR, and FCR indicators of tilapia were better improved in brackish water. In addition, the physical properties of O. aureus muscle demonstrated a positive correlation with salinity levels. The content of amino acids and fatty acids in O. aureus muscles grown under salinity was higher than that in freshwater ( ). Venn analysis showed that 2343 common differentially expressed genes (DEGs) were identified in the four groups (0, 3, 7, and 11 ppt), of which 767 were up-regulated and 1576 were down-regulated. GO and KEGG analysis revealed 39 significant pathways, mainly including unsaturated fatty acid biosynthesis, fatty acid elongation, and α-linolenic acid metabolism. The heat map and trend analysis showed that the expression levels of key genes involved in the physiological processes of ELOVL, SPLA2, and FADS2 in the test group were significantly higher than those in the control group ( ). The above results suggested that O. aureus can not only adapt to the saline habitat but also improve muscle quality by regulating the body’s metabolic pathways.

Flavonoid n-butanol (FNB) possess diverse pharmacological properties. This study aimed to explore the mechanism of FNB in regulating oxidative response in PCV2-infected RAW264.7 cells. PCV2-infected macrophages were treated with FNB, and oxidative stress markers, antioxidant enzyme activities, as well as related gene and protein expression were assessed to evaluate FNB's regulatory effects. Specifically, the level of Nitric Oxide (NO), Total antioxidant capacity (T-AOC), anti-hydroxyl radical capacity, anti-superoxide anion capacity, L-Glutathione (GSH) level, Super Oxide Dismutase (SOD) and Catalase (CAT) were detected. The expression of key oxidative stress-related and signaling pathway genes and proteins was determined by qPCR and western blotting, respectively. The results indicated that FNB reduced intracellular ROS, increased SOD and CAT activities, improved antioxidant capacity, upregulated the mRNA expression levels of HO-1, NQO1, Nrf2, Pi3kca, SOD, and HDAC1, downregulated AKT, Keap1, and HAT1, enhanced HDAC1 activity, and inhibited HAT activity. In conclusion, FNB protects against PCV2-induced oxidative damage by activating the PI3K/AKT pathway and inhibiting Keap1, which collectively enhance the Nrf2/HO-1 antioxidant response.

Bellamya purificata is an important medicinal value and economically farmed species in China. However, because little is known about the genetic characteristics of this species, the utilization of high-quality germplasm resources is hindered. The study examined the genetic differentiation between, and the structure of 12 B. purificata populations in Guangxi using 7 microsatellite DNA markers. High genetic diversity occurred in each population, with mean observed heterozygosity 0.655 and a mean expected heterozygosity 0.832. Analysis of molecular variance reveals genetic diversity to be greater within (95.2%) than among populations (4.8%). Genetic differentiation between populations is weak (Fst = 0.048, P < 0.001), with mixing of genetic clusters prevalent at the level of the individual. Genetic flow exists between populations (Nm = 3.084–11.778), with Longshui and Guilin populations exchanging frequently. A Mantel test reveals a low correlation between geographic and genetic distances (r = 0.2482, P < 0.071), suggesting that dispersal between neighboring populations facilitates population exchange. No significant heterozygosity excess was observed for any population (P > 0.05), indicating a lack of recent genetic bottlenecks. The results provide important genetic information for B. purificata, and data for potential germplasm discovery and aquaculture development.

Cipangopaludina chinensis, as a financially significant species in China, represents a gastropod in nature which frequently encounters starvation stress owing to its limited prey options. However, the underlying response mechanisms to combat starvation have not been investigated in depth. We collected C. chinensis under several times of starvation stress (0, 7, 30, and 60 days) for nutrient, biochemical characteristics and transcriptome analyses. The results showed that prolonged starvation stress (> 30 days) caused obvious fluctuations in the nutrient composition of snails, with dramatic reductions in body weight, survival and digestive enzyme activity (amylase, protease, and lipase), and markedly enhanced the antioxidant enzyme activities of the snails. Comparative transcriptome analyses revealed 3538 differentially expressed genes (DEGs), which were significantly associated with specific starvation stress-responsive pathways, including oxidative phosphorylation and alanine, aspartate, and glutamate metabolism. Then, we identified 40 candidate genes (e.g., HACD2, Cp1, CYP1A2, and GPX1) response to starvation stress through STEM and WGCNA analyses. RT-qPCR verified the accuracy and reliability of the high-throughput sequencing results. This study provides insights into snail overwintering survival and the potential regulatory mechanisms of snail adaptation to starvation stress.