Dietary Supplementation of Crossbred Pigs with Glycerol, Vitamin C, and Niacinamide Alters the Composition of Gut Flora and Gut Flora-Derived Metabolites.

The addition of glycerin, vitamin C, and niacinamide to pig diets increased the redness of longissimus dorsi; however, it remains unclear how these supplements affect gut microbiota and metabolites. A total of 84 piglets (20.35 ± 2.14 kg) were randomly allotted to groups A (control), B (glycerin-supplemented), C (vitamin C and niacinamide-supplemented), and D (glycerin, vitamin C and niacinamide-supplemented) during a feeding experiment. Metagenomic and metabolomic technologies were used to analyze the fecal compositions of bile acids, metabolites, and microbiota. The results showed that compared to pigs in group A, pigs in group D had lower virulence factor expressions of lipopolysaccharide (p < 0.05), fatty acid resistance system (p < 0.05), and capsule (p < 0.01); higher fecal levels of ferric ion (p < 0.05), allolithocholic acid (p < 0.01), deoxycholic acid (p < 0.05), tauroursodeoxycholic acid dihydrate (p < 0.01), glycodeoxycholic acid (p < 0.05), L-proline (p < 0.01) and calcitriol (p < 0.01); and higher (p < 0.05) abundances of iron-acquiring microbiota (Methanobrevibacter, Clostridium, Clostridiaceae, Clostridium_sp_CAG_1000, Faecalibacterium_sp_CAG_74_58_120, Eubacteriales_Family_XIII_Incertae_Sedis, Alistipes_sp_CAG_435, Alistipes_sp_CAG_514 and Methanobrevibacter_sp_YE315). Supplementation with glycerin, vitamin C, and niacinamide to pigs significantly promoted the growth of iron-acquiring microbiota in feces, reduced the expression of some virulence factor genes of fecal pathogens, and increased the fecal levels of ferric ion, L-proline, and some secondary bile acids. The administration of glycerol, vitamin C, and niacinamide to pigs may serve as an effective measure for muscle redness improvement by altering the compositions of fecal microbiota and metabolites.

Effects of Supplementing Growing-Finishing Crossbred Pigs with Glycerin, Vitamin C and Niacinamide on Carcass Characteristics and Meat Quality.

The objective of this study was to determine the influence of supplementing the diet of growing-finishing pigs with glycerin and/or a mixture of vitamin C and niacinamide on carcass traits and pork quality. Eighty-four weaned piglets with an initial average body weight of 20.35 ± 2.14 kg were assigned, at random, to four groups for a 103-day feeding experiment: control; glycerin-supplemented group; vitamin C and niacinamide-supplemented group; and glycerin, vitamin C and niacinamide-supplemented group. At the end of the experiment, three pigs/group were randomly selected and slaughtered, and samples were collected for analysis. The results indicated that supplementing crossbred pigs with glycerin, vitamin C and niacinamide simultaneously increased the redness (a*) value (p < 0.05), glycerol content (p < 0.01) and myristoleic acid content (p < 0.01) in the longissimus dorsi and tended to increase the level of flavor amino acids, linoleic acid, linolenic acid and erucic acid, as well as the percentage and density of type I myofibers in the longissimus dorsi and the semimembranosus muscle. Glycerin had an influence (p < 0.01) on the erucic acid content in the longissimus dorsi and the semimembranosus muscle, and vitamin C and niacinamide had an interaction effect (p < 0.05) on the redness (a*) value of the longissimus dorsi. Glycerin, vitamin C and niacinamide supplementation in the diet of crossbred pigs improved the color, flavor and nutritional value of pork, which contributed to an increased intent to purchase this product.