Study of the characteristics of intestinal bacteria of little yellow croaker (Larimichthys polyactis) and big head croaker (Collichthys lucidus) from the Lyusi fishing ground

Abstract

ABSTRACT Little yellow croaker (Larimichthys polyactis) and big head croaker (Collichthys lucidus) are economically important fishes of the Lyusi fishing ground. The intestinal bacterial communities of L. polyactis and C. lucidus were examined using 16S rRNA high-throughput sequencing technology. The Shannon and Chao-1 indices of the small body length group were significantly larger than those of the large body length group, and the Simpson index was the opposite (P < 0.05). Pseudomonas and Photobacterium of L. polyactis were significantly less abundant than those of C. lucidus (P < 0.05), and Clostridium sensu stricto and Acinetobacter were significantly more abundant than those of C. lucidus (P < 0.05). The abundance of Pseudomonas in L. polyactis increased significantly with increasing body length (P < 0.05), and the abundances of Psychrobacter and Acinetobacter decreased significantly with increasing body length (P < 0.05). The abundance of Clostridium sensu stricto in the large body length group was significantly increased compared with that in the small body length group (P < 0.05). The abundance of Vibrio first increased significantly and then decreased significantly (P < 0.05) with increasing body length. The abundances of Pseudomonas and Photobacterium of C. lucidus increased significantly with increasing body length (P < 0.05). The abundance of Psychrobacter in the large body length group was significantly lower than that in the other groups (P < 0.05). Clostridium sensu stricto was significantly more abundant in the small body length group than in the other groups (P < 0.05). Vibrio was significantly more abundant in the small body length group than in the other groups (P < 0.05). Studies have shown that the feeding range of L. polyactis is wider than that of C. lucidus. Compared with C. lucidus, L. polyactis is less carnivorous and more herbivorous. The carnivorous habit of the two fish became more and more obvious with the increase of body length. The Clostridium sensu stricto related to herbivory of the two fishes may be related to the need to degrade indirectly ingested plants. The larval stages of the two fishes had a higher proportion of Vibrio.