盐碱环境养殖对鲤幼鱼生长性能和肠道健康的影响OA

Aquaculture in saline-alkaline water environments has increasingly emerged as a viable and productive approach to unlocking the potential of underutilized low-lying saline-alkaline water resources.The present study was designed to systematically assess how long-term rearing under saline,alkaline,and combined saline-alkaline conditions influences the growth performance and intestinal health status of juvenile common carp(Cyprinus carpio).A total of four experimental groups were established:a control group N maintained in aerated tap water(salinity 1.5,alkalinity 3.1 mmol/L),alongside three treatment groups—the salinity group S(salinity 3.5,alkalinity 3.1 mmol/L),the alkalinity group A(salinity 1.5,alkalinity 11.4 mmol/L),and the combined saline-alkaline group AS(salinity 3.5,alkalinity 11.4 mmol/L).Each group was set up with three biological replicates,containing 20 fish per replicate,and the entire culture trial was conducted over a 60-day period.The results indicated that after 30 days of rearing,the specific growth rate and weight gain rate in group S were significantly higher than those recorded in the control group N,whereas the feed conversion ratio was significantly lower than group N(P<0.05).By the end of the 60-day culture period,however,the final body weight,specific growth rate,and weight gain rate in groups A and AS were significantly lower than those of the control group N(P<0.05).Across all experimental groups,the intestinal tissue architecture of common carp remained largely intact.Notably,the thickness of the intestinal muscular layer in the AS group was significantly greater than that in group N(P<0.05),while no statistically significant differences were detected in intestinal villus length,villus width,or goblet cell count among all groups.For digestive enzyme activities,intestinal lipase activity in group S was significantly elevated compared to group A(P<0.05);intestinal trypsin activity in group S was significantly greater than in groups N and A(P<0.05);intestinal amylase activity in group A was markedly lower than in both groups N and S(P<0.05).Long-term exposure to saline-alkaline environments reshaped the overall intestinal microbial community structure of common carp.At the phylum level,the relative abundance of(Proteobacteria)in the AS group was significantly enriched(P<0.05),while the abundance of(Fusobacteriota)was significantly reduced in both S and AS groups(P<0.05).At the genus level,the relative abundance of(Cetobacterium)was significantly decreased in groups S and AS(P<0.05).Collectively,these experimental findings demonstrate that short-term(30-day)rearing of juvenile common carp under low-salinity conditions can significantly stimulate their growth.As the culture duration extends to 60 days,saline,alkaline and combined saline-alkaline treatments do not cause histological damage to intestinal tissue and elevate partial intestinal digestive enzyme activities,accompanied by increased intestinal microbial diversity;nevertheless,both alkaline and combined saline-alkaline rearing conditions ultimately exert significant growth-inhibiting effects on juvenile common carp.This study provides a valuable reference framework for evaluating the impacts of saline-alkaline aquaculture on the intestinal health and growth performance of fish,and offers critical scientific support for the development and utilization of saline-alkaline water resources in Western Inner Mongolia.