RAPESEED MEAL REPLACEMENT FOR FISHMEAL ON GROWTH PERFORMANCE, ANTIOXIDANT CAPACITY, AND INTESTINAL MORPHOLOGY OF PARAMISGURNUS DABRYANUS

The purpose of this study was to determine the optimal proportion of rapeseed meal to replace fishmeal in the feed formula of Paramisgurnus dabryanus. Rapeseed meal was used to replace different proportions of 0 (P0), 10% (P10), 20% (P20), 30% (P30), 40% (P40), and 50% (P50), resulting in six experimental diets with equal nitrogen and energy. These diets with rapeseed meal content of 6.00%, 8.50%, 11.00%, 13.50%, 16.00%, and 18.50% were fed to Paramisgurnus dabryanus with an average initial weight of (5.09±0.01) g for 8 weeks. The effects of different alternative proportions of rapeseed meal on the growth performance, antioxidant capacity, and intestinal morphology of Paramisgurnus dabryanus were analyzed. The weight gain rate and specific growth rate of the replacement group (P10—P40) were not significantly different from the control group (P>0.05), while the P50 group showed a significantly decline (P<0.05). No significant differences were observed in the activity of intestinal CAT, SOD, and T-AOC among the groups (P>0.05). Compared with P10 group, the MDA content in P50 group was the highest and significantly increased (P<0.05), and the AKP activity was significantly higher in P40 and P10 groups (P<0.05). The activities of TP, CAT, and SOD in liver did not change significantly with the increase of rapeseed meal replacement ratio (P>0.05). Compared with P0 group, the MDA content in P20, P30, and P50 groups were not significantly different (P>0.05), but was significantly different from that in P10 and P40 groups (P<0.05), with the P40 group showing the lowest MDA content. With the increase of replacement ratio in rapeseed meal, the intestine morphological structure was damaged, the villus height and crypt depth gradually decreased, reaching their lowest values in the P50 group (P<0.05), while the thickness of the muscular layer gradually increased. In conclusion, replacing up to 40% of fishmeal with rapeseed meal did not affect the weight gain rate and specific growth rate of Paramisgurnus dabryanus, however, higher replacement ratios had a negative impact on the antioxidant capacity and intestinal morphological structure.