Haisu Liu,Kun Qian,Sanshan Zhang,Qianxun Yu,Yudong Du,Shengli Fu
Lead (Pb) is one of the most common trace metals in water, and its high concentration in the environment can cause harm to aquatic animals and humans. In the present study, the effects of Pb exposure (3.84 mg/kg) on the morphology, digestive enzyme activity, immune function and microbiota structure of silver carp ( Hypophthalmichthys molitrix ) intestines within 96 h were detected. Moreover, the correlation between them was analyzed. The results showed that Pb exposure on the one hand severely impaired the intestinal morphology, including significantly shortening the intestinal villi's length, increasing the goblet cells' number, causing the intestinal leukocyte infiltration , and thickening the intestinal wall abnormally, on the other hand, increasing the activity of intestinal digestive enzyme (trypsin and lipase). In addition, the mRNA expressions of structure-related genes ( Claudin-7 and villin-1 ) were down-regulated, and the immune factors genes ( IL-8 , IL-10 and TNF-α ) were up-regulated after Pb exposure. Furthermore, data of the MiSeq sequencing showed that the abundance of membrane transport , immune system function and digestive system of silver carp intestinal microbiota all decreased, while cellular antigens increased. Finally, the canonical correlation analysis (CCA) showed that there were correlations between silver carp's intestinal microbiota and intestinal morphology and immune factors. In conclusion, it is speculated that the entry of Pb into the intestine leads the microbiota dysbiosis , affects the intestinal immunity and digestive function , and further damages the intestinal barrier of silver carp.
Yongjie Zhou,Jiamin Liang,Yan Zhang,Huijuan Zhang,Sam K.C. Chang,Hui Hong,Yongkang Luo,Yuqing Tan
Deep eutectic solvents (DESs) are renowned in chemical and food industries for their eco-friendly extraction efficacy. Silver carp swim bladders, a collagen-rich byproduct of surimi production, are underutilized, resulting in considerable protein waste. Traditionally, collagen extraction has relied on harsh acids, contributing to environmental pollution and producing collagens with limited solubility, thus constraining their applications. This study evaluated DESs compared to conventional acids in extracting collagen, focusing on structural and solubility variations. Notably, urea-based DESs (urea-lactic acid: U-LA, 1:10, w/v) achieved the highest hydroxyproline recovery rates (∼ 94 %), comparable to acetic acid (AA, 1:20, w/v), but with half the solid-liquid ratio. Unlike acid-extracted collagen, which preserved the triple-helical structure, urea-based DESs partially disrupted this configuration by reducing intramolecular hydrogen bonding within collagen. However, these solvents simultaneously increased intermolecular hydrogen bonding. This alteration significantly enhanced collagen's solubility, maintaining over 60 % across a broad pH range (1−10) and various NaCl concentrations (0–6 %, w/v). Furthermore, urea-acetic acid (U-AA) extracted collagen exhibited the highest maximum transition temperature (solid state, T max = 101.94 °C) and gel strength (165 g). The findings suggest that urea-based DESs not only enhance collagen recovery rates but also its solubility and gelation properties, broadening its potential applications in cosmetics, food products, and biomaterials.
危险品化学品经营许可证（带存储）