Salvia miltiorrhiza polysaccharides enhance the antioxidant capacity and immune resistance of hybrid sturgeon (Acipenser baerii♀ x Acipenser schrenckii♂) against Streptococcus iniae infection

A large number of studies have indicated that Chinese herbaceous polysaccharides possessed immune-promoting effects in animal husbandry. However, the function of Salvia miltiorrhiza polysaccharides (SMP) in fish remains poorly understood. In the present study, juvenile hybrid sturgeons (Acipenser baerii female x Acipenser schrenckii male) were studied to assess the effects of SMP on growth performance, antioxidant capacity, non-specific immunity, and resistance to Streptococcus iniae. The results showed that weight gain rate, specific growth rate, and daily growth coefficient had no difference from those of the control group, but 0.1% SMP significantly increased the thickness of muscle layer and height and number of intestinal villus (P < 0.05). 0.5% and 0.7% SMP could significantly increase the T-AOC activity in the liver and valvular intestine, along with 0.5% SMP that significantly decreased the MDA content in the liver (P < 0.05). Moreover, all experimental groups could significantly increase serum TP and GLO contents. After infection with S. iniae, the survival rate of the experimental groups was higher than that of the control group, especially in 0.5% SMP group. In conclusion, dietary supplementation of SMP could enhance the antioxidant and non-specific immune capacity of hybrid sturgeon, thus improving disease resistance and promoting the healthy breeding of juvenile hybrid sturgeon. Our findings provide novel recommendations for the application of SMP supplementation in farmed fish.

Automated summary

The study found that Salvia miltiorrhiza polysaccharides (SMP) have positive effects on the growth performance, antioxidant capacity, non-specific immunity, and resistance to Streptococcus iniae in hybrid sturgeon. The dietary supplementation of SMP can enhance the antioxidant and non-specific immune capacity of hybrid sturgeon, improve disease resistance, and promote healthy breeding. These findings provide novel recommendations for the application of SMP supplementation in farmed fish.