Recently, researchers from the Institute of Feed Research of Chinese Academy of Agricultural Science and Wageningen University found the physical properties of extruded feed could affect fish gastrointestinal emptying and feed utilization. That means future research on fish nutrition should also focus on the impact of physical quality of feed. Relevant results were published in Aquaculture.

The physical quality of aquafeed is crucial for transportation, feeding, as well as the physiological response and feed utilization of fish. In this study, contrasting physical qualities of extruded feed were produced (hardness: 79 N and 112 N, hydration time: 20 min and 53 min) by adjusting the conditioning water content (22% and 28%). These feeds were fed to spotted seabass for 48 days.

The results showed that the extruded feed with high hardness and long hydration time significantly reduced the stomach water flux and chyme emptying rate, without affecting the stomach digestion kinetic of fish. However, it did increase the feed conversion ratio. This study provides insights into the effects of feed with high hardness and long hydration time on the physiological response and feed utilization of seabass. These findings lay the foundation for further research and development of specialized feed for recirculating aquaculture system (RAS) and deep-sea cage aquaculture.

This study was supported by National Key Research and Development Program of China (2021YFD1300300), National Natural Science Foundation of China (32202954, 31902382) and the WUR-CAAS joint Ph.D. Programme.

Original link: https://doi.org/10.1016/j.aquaculture.2023.739442

By Shujuan Xing (shujuanxing@wur.nl)