RESUMO
There are large areas of saline-alkaline waters worldwide, the utilization of which would greatly enhance the development of aquaculture productivity. To elucidate the regulatory mechanisms underlying the adaptation of large yellow croaker (Larimichthys crocea) to saline-alkaline water, this study analyzed the growth performance, tissue histology, and gills transcriptome profiles of L. crocea in both seawater (CK) and saline-alkaline water (EX) groups. Growth indices statistics revealed that L. crocea can adapt to saline-alkaline water, with growth performance comparable to that of the CK group. Histological examination revealed partial cellular detachment and structural relaxation in the gills tissue of the EX group, while liver and kidney tissues appeared normal. Transcriptome analysis revealed 3821 differentially expressed genes (DEGs), with 1541 DEGs up-regulated and 2280 DEGs down-regulated. GO enrichment analysis indicated that up-regulated DEGs were enriched in terms related to metabolite production during biological activities, while down-regulated DEGs were associated with terms related to maintaining cellular activities. KEGG enrichment analysis revealed that up-regulated DEGs were enriched in pathways related to the synthesis and metabolism of amino acids and lipids, such as the PPAR signaling pathway and glutathione metabolism. The down-regulated DEGs were predominantly enriched in immune-related signaling pathways, including the Toll-like receptor signaling pathway and NOD-like receptor signaling pathway. Further analysis revealed that genes such as lipoprotein lipase A (lpla), branched-chain amino acid aminotransferase 2 (bcat2), interleukin 8 (il8), interleukin 10 (il10), and interferon regulatory factor 7 (irf7) were involved in the adaptation of L. crocea to saline-alkaline water culture conditions. This study provides a basis for understanding the adaptability of large yellow croaker to saline-alkaline water and lays the foundation for the rational utilization of fishery water resources.
RESUMO
To solve the problem of soil salination and to desalinate saline−alkaline water in arid areas, this study involved the design and testing of a separation and desalination device for farmland saline−alkaline water that is suitable for arid areas. The results of this study indicate that after the pretreatment of farmland saline−alkaline water, the water yielded by the pretreatment device had a mean turbidity of <1 and a mean silt density index (SDI) of <3, which met the working conditions of nanofiltration (NF) and reverse osmosis (RO) membranes. When used to filter saline−alkaline water, the composite NF−RO membrane system achieved a desalination rate of 97.06%, a total hardness removal rate of 97.83%, and a Cl− removal rate of 99.65%, which satisfied the standard for irrigation water quality. Some indicators of the yielded water reached the hygienic standard for drinking water, thus successfully reutilizing water resources. The circulating solar collector tube of the device was designed with a collection area of 6 m2, which could basically satisfy the heat demand of the flash tank for distillation. The design of the flash tank and the shell-and-tube circulating condenser met the requirements for vapor condensation. The crystals in the solar salt box precipitated under solar action. X-ray diffraction was used to identify the primary compound of the crystals as NaCl, suggesting that the precipitates have potential value as industrial salts. This study offers new technical references and helpful engineering guidance for arid saline−alkaline enrichment areas facing the problem of saline farmland irrigation water.