DIETARY COENZYME Q10 ON GROWTH PERFORMANCE, BODY COMPOSITION, ANTIOXIDANT CAPACITY, AND DIGESTIVE SYSTEM MORPHOLOGY OF JUVENILE JIAN CARP (CYPRINUS CARPIO VAR. JIAN)

To evaluate the effect of dietary coenzyme Q10 (CoQ10) on the growth performance, body composition, antioxidant capacity, and digestive system histology of juvenile Jian carp (<italic>Cyprinus carpio</italic> var. Jian), fish with an initial body weight of (11.01±0.05) g were fed four diets containing 0, 40, 80, and 160 mg/kg CoQ10 for 84 days, respectively. The results indicated that dietary CoQ10 supplementation did not significantly affect final body weight (FBW), survival rate (SR), feeding rate (FR), weight gain rate (WG) or specific growth rate (SGR) among all experimental groups (<italic>P</italic>&gt;0.05), while 160 mg/kg CoQ10 group had the highest FBW and SGR. Compared with the control group, feed efficiency (FE), apparent digestibility coefficient of dry matter (ADCDM), and protein efficiency ratio (PER) were significantly increased at the 160 mg/kg CoQ10 level (<italic>P</italic>&lt;0.05). In contrast, no significant differences were observed in condition factor (CF), hepatosomatic index (HSI), or viscerosomatic index (VSI) among the groups (<italic>P</italic>&gt;0.05). Dietary CoQ10 supplementation did not significantly affect the moisture, crude protein, or ash content of juvenile carp across all experimental groups (<italic>P</italic>&gt;0.05). However, significantly lower crude lipid content was found in the 160 mg/kg CoQ10 group (<italic>P</italic>&lt;0.05). The activity of trypsin (TRY) in intestine of 160 mg/kg CoQ10 group was significantly higher than that in the control (<italic>P</italic>&lt;0.05). Serum activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), catalase (CAT), glutathione S-transferase (GST), and albumin (ALB) content remained unchanged across groups (<italic>P</italic>&gt;0.05). Nevertheless, compared with the control group, 80 and 160 mg/kg CoQ10 supplementation significantly decreased triglyceride (TG) and total cholesterol (TC) contents in serum (<italic>P</italic>&lt;0.05), while increasing glutathione peroxidase (GPX) and total superoxide dismutase (SOD) activities in both serum and hepatopancreas (<italic>P</italic>&lt;0.05). The malondialdehyde (MDA) content in the 80 and 160 mg/kg CoQ10 groups was significantly lower than that in the control group (<italic>P</italic>&lt;0.05). No significant structural changes were found in the liver histology of all the experimental groups (<italic>P</italic>&gt;0.05). In comparison to the control group, fish fed a diet supplemented with 160 mg/kg CoQ10 exhibited significantly increased intestinal villus length and muscular layer thickness (<italic>P</italic>&lt;0.05). In conclusion, dietary coenzyme Q10 supplementation can enhance the digestibility, antioxidant capacity, and intestinal structure of juvenile Jian carp, while effectively reducing systemic and whole-body lipid levels.