Data Sheet 1_Effects of dietary supplementation with grape seed powders on growth performance and muscle nutrition of grass carp (Ctenopharyngodon idella) by gut microbiota mediation.docx

ObjectiveTo investigate whether grape seed powders (GSP) contribute to growth-promoting in aquaculture, a comprehensive analysis of the effects of GSP on grass carp (Ctenopharyngodon idella) was performed.
MethodsSix hundred grass carp were divided into four groups, including the control and the low (100 mg/kg), middle (500 mg/kg), and high (1000 mg/kg) GSP-supplemented groups. The material composition, growth parameters, physiological/biochemical indexes, and muscle nutrition were analyzed.
ResultsAfter feeding of 60 days, the weight gain rate, specific growth rate, and condition factor of grass carp significantly increased with GSP supplementation at low and middle levels in comparison to the blank control (P < 0.05). Additionally, the catalase activities in the gill and gut significantly elevated as dietary supplementation with GSP at the low and middle levels in comparison to the blank control (P < 0.05), while the interleukins’ (IL-1β, IL-4, IL-6, IL-10, and IL-12) contents in the spleen significantly decreased (P < 0.05), suggesting an enhancement in antioxidant capacity activities and a reduction in inflammation levels after supplemental feeding with GSP. The total amino acids and total fatty acids in the blank control were equivalent to these in the low GSP-supplemented group, which were inconsistent with the upregulation of total amino acids and downregulation of total fatty acids in the middle and high GSP-supplemented groups. Furthermore, pathogenic bacteria in the gut (e.g., Enterobacter hormaechei and Enterobacter cloacae) were effectively inhibited in the GSP-supplemented groups, with significant correlations to the increased amino acid (Pro) and the decreased fatty acids (e.g., C16:1n7, C18:1n9c, C20:2n6, and C22:6n3) (P < 0.05).
ConclusionBased on the results, we confirmed that dietary supplementation with procyanidin-rich GSP at a relative low level (100 mg/kg) was beneficial for the healthy aquaculture of grass carp.