Enhanced intestinal microflora composition and phosphorus-transportation efficiency in fast-growing spotted seabass (Lateolabrax maculatus) fed a low-phosphorus diet

This study examined differences in the intestinal microflora composition and phosphorus-transportation effi-ciency between fast-and slow-growing spotted seabass (Lateolabrax maculatus) fed a low-phosphorus diet. A total of 60 spotted seabass (9.48 & PLUSMN; 0.19 g) were randomly distributed into three tanks at a density of 20 fish per tank and fed a low-phosphorus diet for eight weeks. At the end of the experiment, the four heaviest and four lightest individuals from each tank were sampled as the fast-growing spotted seabass (FGS) and slow-growing spotted seabass (SGS), respectively. FGS had significantly higher weight gain (WG) than those in SGS. Higher whole-body phosphorus deposition, serum phosphorus content and the mRNA expression of genes associated with phos-phorus transportation (NaPIiib, PiT1, and PiT2) were observed in FGS compared to SGS. Moreover, lower serum alkaline phosphatase (AKP) activity was found in FGS compared to SGS. However, no significant differences were found in liver phosphorus deposition or serum parathyroid hormone (PTH) levels between FGS and SGS. Compared to SGS, higher relative abundances of operational taxonomic units (OTUs) and potential probiotics, including Lactobacillus and Cetobacterium, and lower relative abundances of potentially pathogenic bacteria, including Enhydrobacter and Chryseobacterium, were observed in the intestinal microflora of FGS. Overall, these findings suggested that higher growth rates in spotted seabass fed a low-phosphorus diet were associated with enhanced phosphorus-transportation efficiency and intestinal microflora composition.