BACKGROUND:The tiger frog (Hoplobatrachus rugulosus) is an economically important species extensively farmed in southern China. However, high-density farming is frequently challenged by infectious diseases such as ascites disease, red leg syndrome, and hepatomegaly disease.
OBJECTIVE:This study aims to develop and evaluate a compounded herbal medicine (CHM, composed of Taraxacum mongolicum Hand-Mazz., Canarium album (Lour.) Raeusch, Thlaspi arvense Linn., Metaplexis japonica (Thunb.) Makino, and seed of Vitis vinifera L.) for disease prevention in frog aquaculture.
METHODS:UPLC-MS/MS was performed to identify and analyze the pharmaceutical constituents of the CHM. Frogs were fed with diets containing 0 % (Control) or graded levels of CHM (0.25 %, 0.5 %, 0.75 %, 1 %) under high-density farming conditions for 80 days. Growth performance, physiology, histopathology and immune parameters were assessed. Subsequently, hepatic protein alterations were explored via iTRAQ-based proteomics, and gut microbial composition was evaluated using 16S rDNA sequencing.
RESULTS:A total of 64 bioactive compounds were identified in the CHM. Supplementation of CHM significantly improved growth performance and survival rate, and reduced feed conversion rate. CHM enhanced gut amylase and lipase activities, serum SOD and CAT activities, and decrease serum ASL, ALT, T-CHO, TG levels. Additionally, CHM increased serum immune indicators (IgG, IgM, LZM, ACP, and AKP) and levels of pro-inflammatory factors (IL-6, IL-8, and TNF-α). Proteomic analysis revealed 89 differentially abundant proteins between the CHM1 and Control, primarily associated with pathways related to immune system and infectious diseases: bacterial. Although no significant differences were detected in OTU richness and α-diversity among groups, 1 % CHM supplementation markedly altered gut microbial composition, characterized by increased abundances of Firmicutes and Turicibacter, as well as higher Firmicutes/Bacteroidetes ratio. Functional predictions based on KEGG and COG analyses revealed the alterations of amino acid, lipid, and carbohydrate metabolism, particularly in the CHM1 group.
CONCLUSION:Dietary supplementation with 1 % CHM regulates gut microbiota and hepatic protein expression, promoting growth and enhancing immune function in H. rugulosus. These findings suggest that CHM is a promising feed additive and alternative immunopotentiator for sustainable frog aquaculture.