Feed costs account for approximately 70% of aquaculture production costs. Developing new aquaculture varieties that combine rapid growth with high feed conversion efficiency (FCE) has long been a major goal of genetic breeding scientists, as it can reduce farming costs, improve production efficiency, and decrease waste discharge from aquaculture systems. However, the key regulatory genes underlying FCE in aquatic animals, as well as the molecular mechanisms coupling rapid growth with high FCE, remain poorly understood.

Recently, a research group led by Prof. MEI Jie from the Institute of Hydrobiology (IHB) of the Chinese Academy Sciences found that miR-200a/200b deficiency enhances growth and FCE in yellow catfish (Pelteobagrus fulvidraco) through upregulating Stat5b expression. This study was published in SCIENCE CHINA Life Sciences.

The researchers first established a yellow catfish breeding population combining rapid growth and high FCE traits. Genome-wide association analysis mapped a key locus near the miR-200 cluster on chromosome 23 and revealed that miR-200a and miR-200b were significantly downregulated in fast-growth, high-FCE individuals.

Further analyses showed that knockout of miR-200a/200b significantly improved growth and FCE without significantly increasing average feed intake. By integrating TargetScan prediction, miRNA-RNA pulldown, and sequencing analyses, the team identified several key target genes related to growth and metabolism, including stat5b and fasn. Among them, stat5b was confirmed as a core target of miR-200a/200b, and stat5b-transgenic yellow catfish also showed significantly improved growth and FCE.

These findings indicate that miR-200a/200b enhances nutrient utilization mainly by regulating energy metabolism-related target genes and signaling pathways, providing important theoretical support and technical guidance for dissecting the coupling mechanism of high yield and feed-saving traits and for the precise genetic improvement of these traits.

The molecular mechanism by which miR-200a/200b deficiency promotes growth and feed conversion efficiency. (Image by IHB)

(Editor: MA Yun)