Dietary Haematococcus pluvialis promotes growth of red swamp crayfish Procambarus clarkii (Girard, 1852) via positive regulation of the gut microbial co-occurrence network

Plant protein served as an alternative protein source to fish meal is widely used in the feed of Procambarus clarkii, but its excessive use has adverse impacts on aquatic animals. Haematococcus pluvialis has great potential for food applications due to its abundant astaxanthin. This experiment investigated the effects of dietary H. pluvialis on growth performance and gut microbiota of P. clarkii. That dietary H. pluvialis significantly increased weight gain rate (WGR), specific growth rate (SGR), and haemolymph immune-related enzyme activities was presented (P < 0.05), accompanied by a decrease in malondialdehyde (MDA) content. Moreover, dietary H. pluvialis reversed microbial dysbiosis and gut immune damage due to the decreased abundance of operational taxonomic unit (OTU) (s__Bacteroidaceae_bacterium_MS4), where interactions within the co-occurrence network restored gut villus development and microbial community stability. Thus, 0.6% H. pluvialis powder was recommended to be included in the feed. It was initially revealed that dietary H. pluvialis helped to stabilize microbial homeostasis, providing a scientific basis for the development of a functional feed.

Automated summary

The inclusion of H. pluvialis in the feed of P. clarkii significantly improved growth performance and gut microbiota, while also exerting antioxidant effects. The recommended inclusion level of H. pluvialis powder was 0.6%.