This study examined the differences in intestinal health between fast- and slow-growing bullfrogs (Lithobates catesbeianus) fed a soybean meal (SM)-based diet. A total of 108 froglets (26.14 ± 0.21 g) were randomly distributed into three tanks at a density of 36 froglets per tank and fed a SM-based diet for 8 weeks. At the end of the feeding period, four heaviest and four lightest bullfrogs from each tank were captured and considered as fast-growing (FG) and slow-growing (SG) groups. The FG group had significantly higher weight gain than the SG group (p < 0.05). A basic intestinal tissue structure integrity with higher values of jejunal diameter, villus numbers, villus thickness and muscular thickness was observed in the FG group compared with the SG group (p < 0.05). Moreover, lower activity of serum diamine oxidase was detected in FG group than the SG group, which indicated better gut barrier function of froglets in FG group (p < 0.05). However, no significant differences were found in the mRNA expression level of tight junction proteins including occludin and zo-1 in the jejunum, and serum D-lactate concentration between the two groups (p > 0.05). Significantly lower pH values in corpora ventriculi and ileum and higher jejunal protease and amylase activities were found in the FG group than SG group (p < 0.05). Relatively higher expression of anti-inflammatory genes and lower expression of pro-inflammatory genes were found in the FG group; however, the differences were not significant. The abundances of potential probiotics including Akkermansia, Lactobacillus and Prevotellaceae_UCG_001 were higher in the intestinal microflora of FG group compared with the SG group. In conclusion, these findings suggested that higher growth of FG bullfrogs fed the SM-based diet could be attributed to their better intestinal morphological structure and barrier function compared with the SG bullfrogs.

中文翻译：

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与生长缓慢的牛蛙相比，饲喂以豆粕为基础的饮食的快速生长的牛蛙（Lithobates catesbeianus）的肠道健康状况更好

这项研究检查了以豆粕 (SM) 为基础的饮食喂养的快速和缓慢生长的牛蛙 ( Lithobates catesbeianus )在肠道健康方面的差异。将总共​​ 108 只小蛙 (26.14 ± 0.21 g) 随机分配到三个水箱中，每缸 36 只小蛙的密度，并以 SM 为基础的饮食喂养 8 周。在喂养期结束时，从每个水箱中捕获四只最重和四只最轻的牛蛙，并将其视为快速生长 (FG) 和缓慢生长 (SG) 组。FG 组的体重增加明显高于 SG 组（p  < 0.05）。与 SG 组相比，FG 组观察到基本的肠组织结构完整性，空肠直径、绒毛数量、绒毛厚度和肌肉厚度值更高（p < 0.05)。此外，FG组血清二胺氧化酶活性低于SG组，说明FG组幼蛙的肠道屏障功能更好（p  < 0.05）。但两组间空肠中occludin、zo-1等紧密连接蛋白mRNA表达水平及血清D-乳酸浓度差异无统计学意义（p  >0.05）。与 SG 组相比，FG 组脑室和回肠的 pH 值显着降低，空肠蛋白酶和淀粉酶活性更高（p < 0.05)。FG组抗炎基因表达相对较高，促炎基因表达较低；但是，差异并不显着。FG组肠道菌群中Akkermansia、Lactobacillus和Prevotellaceae_UCG_001等潜在益生菌的丰度高于SG组。总之，这些研究结果表明，与 SG 牛蛙相比，饲喂以 SM 为基础的饮食的 FG 牛蛙的更高生长可归因于它们更好的肠道形态结构和屏障功能。