Effects of dietary glycerol, vitamin C and niacinamide supplementation on liver of growing-finishing pigs

The influence of supplementing glycerol, vitamin C and niacinamide on the liver of growing-finishing pigs has not yet been examined. This study investigated the effect of 10% glycerol, 0.06% vitamin C and 0.05% niacinamide supplementation at single or combination on liver of growing-finishing pigs. Compared with pigs supplemented with 0% glycerol, 0% vitamin C and 0% niacinamide, pigs supplemented only with 10% glycerol had higher (<i>p</i> < 0.05) TNF-<i>α</i> concentration, partially hepatic steatosis, higher (<i>p</i> < 0.05) relative abundances of <i>Escherichia_shigella</i>, <i>Prevotellaceae_UCG_003</i>, <i>Lachnospiraceae_XPB1014_group</i>, <i>Coprococcus</i>, <i>Lactococcus</i> and <i>Megamonas</i>, lower (<i>p</i> < 0.05) solute carrier family 7 member 11 (<i>SLC7A11</i>) expression in liver tissue. However, pigs offered the diet with a mixture of 0.06% vitamin C and 0.05% niacinamide had higher (<i>p</i> < 0.05) relative abundance of <i>Faecalibaculum</i> and expression of <i>SLC7A11</i>, lower (<i>p</i> < 0.05) relative abundances of <i>Staphylococcus</i> and <i>Clostridium_sensu_stricto_1</i> in liver tissue. Supplementation of 10% glycerol, 0.06% vitamin C and 0.05% niacinamide simultaneously to pigs increased (<i>p</i> < 0.05) the ferrous ion level, the relative abundances of <i>Escherichia_Shigella</i>, <i>Lactococcus</i> and <i>Desulfobacterota</i>, the expressions of gene Cryptochrome-1(<i>CRY1</i>) and <i>SLC7A11</i>, but decreased (<i>p</i> < 0.05) the expressions of gene C-reactive protein (<i>CRP</i>) and galactokinase 1 (<i>GALK1</i>) in liver tissue. Supplementation with 0.06% vitamin C and 0.05% niacinamide can alleviate the damage in liver of pigs fed a diet containing 10% glycerol.