Effects of dietary sunflower meal supplementation on productive performance, antioxidative capacity, lipid metabolism, and gut microbiota in laying ducks

Abstract

This study investigated the effects of increasing content of sunflower meal (SFM) in diets of laying ducks on laying performance, oxidative status, lipid metabolism and gut microbiota. In total, 720 Jingjiang females at 22-week-old with similar body weight were selected and randomly assigned to 6 treatments, each consisting of 6 replicates of 20 birds. The basal diet was a typical corn-soybean ration (SFM0) while the experimental diets were formulated by substituting soybean meal with 40 (SFM40), 80 (SFM80), 120 (SFM120), 160 (SFM160), and 200 (SFM200) g/kg of SFM, respectively. The feeding trial was lasted for 16 weeks. Average egg mass decreased linearly as the level of SFM inclusion increased (P < 0.001), while feed conversion ratio linearly increased (P < 0.05). Yolk color and yolk cholesterol content declined as a linear and quadratic response to SFM substitution (P < 0.001). Increasing of SFM substitution quadratically increased hepatic expression of glutathione peroxidase 1 (GPX1), heme oxygenase 1, nuclear factor, erythroid 2 like 2 and hepatic activities of GPX and total antioxidative capacity, whereas the hepatic content of malondialdehyde was decreased (P < 0.05). There was a linear increase (P < 0.001) in hepatic transcript abundance of cytochrome P450 7A1 along the increased portion of SFM substitution, and linear decrease (P < 0.001) in fatty acid synthase, acetyl-CoA carboxylase alpha, sterol regulatory element binding protein 1, and 3-hydroxy-3-methylglutaryl-CoA reductase. In addition, sequencing data of 16S rRNA indicated that a high level of SFM decreased the abundance of cecal Spirochaetes phylum and Megamonas genus, while increased that of Bacteroides (P < 0.05). In conclusion, the present results suggested that SFM can be used as an alternative to replace soybean meal, at levels up to 120 g/kg in the diets of laying ducks without affecting laying performance and egg quality. Moderate substitution of soybean meal with SFM also increased hepatic antioxidative capacity, suppressed de novo lipogenesis, and improved gut microbiota.