Medium-chain fatty acid triglycerides (MCTs) possess antibacterial, antiviral, nutritional, and other biological activities and have demonstrated significant application potential in humans and terrestrial animals. In recent years, with the development of the green aquaculture industry, MCTs have been gradually applied to aquaculture animals, which can enhance growth performance, improve flesh quality, regulate lipid metabolism, boost immune activity, and modulate the intestinal flora, thereby improving the production efficiency of aquaculture. This paper elaborates in detail on the biological activities of MCTs and their applications in aquatic animals, providing a theoretical and practical basis for the application of MCTs in aquaculture.

The excessive use of chemical fertilizers causes many problems for which solutions are being sought in a variety of agricultural production systems. From the perspective of paying attention to the health requirements of aquatic animals in terms of water quality, this study investigated the impact of chemical fertilizer application on water quality in a rice (Oryza sativa L.; Cultivar Qingxiangruangeng, accession number: 2014004)eel (Monopterus albus) coculture system in Shanghai, China. Chemical fertilizer was applied four timesas base fertilizer, rejuvenated fertilizer, tiller fertilizer, and ear granule fertilizerduring the production process of a riceeel coculture system (June to October 2020). Changes in the water quality parameters of rice fields surface water and ring ditch water in the regular chemical fertilizer group (RF) and no chemical fertilizer group (NF, the control) were compared before and at 24h, 48h, and 72h after the chemical fertilizer application. The results for the analyzed physical and chemical indexes of each water area before and after four fertilizations revealed several consistent trends. First, the pH, dissolved oxygen (DO), water temperature (T), and chemical oxygen demand (COD) of either water area were similar between the NF and RF groups, whereas their total nitrogen (TN), total ammonia nitrogen (TAN), and total phosphorus (TP) levels differed significantly. After adding the above fertilizer containing nitrogen and phosphorus, 24h later, the TN, TAN, and TP content had already increased significantly in comparison with the control. The maximum average content of TAN and nitrite nitrogen (NO₂⁻-N) in the ring ditch water reached 12.30mg/L and 0.37mg/L, respectively, at 24h after the chemical fertilizer application. Nonlinear regression analysis results showed that there was a significant positive relationship TN (δTN) and TAN (δTAN) vis--vis the nitrogen content of the fertilizer. The results of this study provide a timely empirical reference and data support for improving fertilizer management in riceeel coculture systems.

This study investigated the dose-dependent effects of dietary glycerol monolaurate (GML) supplementation on the growth performance, bile acid metabolism, and intestinal health of Asian swamp eel (Monopterus albus). A total of 225 healthy eels with an initial body weight of 25.0 ± 2.0 g were randomly divided into three groups and fed a basal diet (control), 0.5 g/kg GML, or 1.0 g/kg GML for 60 days, respectively. The results showed that dietary GML supplementation increased the weight gain rate by 8.75% and decreased the feed conversion ratio by 8.16% in the GML1 group compared with the control. Dietary GML significantly reduced the contents of TP and ALB (p < 0.05). Meanwhile, the MDA content in the GML0.5 and GML1 groups decreased significantly by 24.80% and 38.15%, respectively. The contents of total bile acids and secondary bile acids were significantly elevated in the GML1 group (p < 0.05). In addition, GML supplementation optimized the intestinal microbial community and significantly reduced the relative abundance of potentially harmful bacteria such as Nocardia and Stenotrophomonas (p < 0.05). In conclusion, under the conditions of this study, dietary GML could effectively the improve growth performance, bile acid metabolism, antioxidant capacity, and intestinal health of M. albus. Among the tested concentrations, 1.0 g/kg GML showed the optimal beneficial effects.