Effect of Vitamin A Supplementation on Growth Performance, Serum Biochemical Parameters, Intestinal Immunity Response and Gut Microbiota in American Mink (Neovison vison)

Abstract

This experiment investigated the effect of vitamin A supplementation on growth, serum biochemical parameters, jejunum morphology and the microbial community in male growing-furring mink. Thirty healthy male mink were randomly assigned to three treatment groups, with 10 mink per group. Each mink was housed in an individual cage. The mink in the three groups were fed diets supplemented with vitamin A acetate at dosages of 0 (CON), 20,000 (LVitA) and 1,280,000 IU/kg (HVitA) of basal diet. A 7-day pretest period preceded a formal test period of 45 days. The results show that 20,000 IU/kg vitamin A increased the ADG, serum T-AOC and GSH-Px activities, villus height and villus height/crypt depth ratio (p < 0.05). The mRNA expression levels of IL-22, Occludin and ZO-1 in the jejunum of mink were significantly higher in the LVitA group than those in the CON and HVitA groups (p < 0.05). Vitamin A supplementation increased the diversity of jejunum bacteria, decreased the ratio of Firmicutes to Bacteroidetes and increased the relative abundance of Akkermansia, uncultured bacterium f Muribaculaceae, Allobaculum, Lachnospiraceae NK4A136 group, Rummeliibacillus and Parasutterella. The comparison of potential functions also showed enrichment of glycan biosynthesis and metabolism, transport and catabolism pathways in the vitamin A supplementation groups compared with the CON group. In conclusion, these results indicate that dietary vitamin A supplementation could mediate host growth by improving intestinal development, immunity and the relative abundance of the intestinal microbiota.

Keywords: Akkermansia; IL-22; growth performance; mink; villus height; vitamin A.

Figure 1

Effect of vitamin A on serum antioxidant capacity (A) and immunological indices (B) of growing-furring male mink. CON group, vitamin A with 0 IU/kg of diet; LVitA group, vitamin A with 20,000 IU/kg of diet; HVitA group, vitamin A with 1,280,000 IU/kg of diet. MDA, malondialdehyde; T-AOC, total antioxidant capacity; GSH-Px, glutathione peroxidase; IgA, immunoglobulin A; IgM, immunoglobulin M; C3, complement C3; C4, complement C4.

Figure 2

Effect of vitamin A on the mRNA levels of IL-22 (A), Occludin (B) and ZO-1 (C) in the mink jejunum. CON group, vitamin A with 0 IU/kg of diet; LVitA group, vitamin A with 20,000 IU/kg of diet; HVitA group, vitamin A with 1,280,000 IU/kg of diet.

Figure 3

Comparisons of the alpha diversity indices of the mink gut microbiota among the three groups. CON group, vitamin A with 0 IU/kg of diet; LVitA group, vitamin A with 20,000 IU/kg of diet; HVitA group, vitamin A with 1,280,000 IU/kg of diet.

Figure 4

Composition and comparisons of the mink gut microbiota among the three groups. PCoA revealing the separation of the gut microbiota in the three groups based on the binary Jaccard distance (A), Bray–Curtis distance (B), unweighted UniFrac distance (C) and weighted UniFrac distance (D). Microbial compositions in the gut of mink from the CON, LVitA and HVitA groups at the phylum (E) and genus (F) levels. CON group, vitamin A with 0 IU/kg of diet; LVitA group, vitamin A with 20,000 IU/kg of diet; HVitA group, vitamin A with 1,280,000 IU/kg of diet.

Figure 5

Histogram of ANOVA among the CON, LVitA and HVitA groups at the phylum (A) and genus (B) levels. CON group, vitamin A with 0 IU/kg of diet; LVitA group, vitamin A with 20,000 IU/kg of diet; HVitA group, vitamin A with 1,280,000 IU/kg of diet.

Figure 6

Comparison of KEGG pathways predicted by PICRUSt according to diet. The differential analysis diagram of KEGG metabolic pathways between the CON and HVitA groups at levels 2 (A) and 3 (C) and the differential analysis diagram of KEGG metabolic pathways between the CON and LVitA groups at levels 2 (B) and 3 (D). CON group, vitamin A with 0 IU/kg of diet; LVitA group, vitamin A with 20,000 IU/kg of diet; HVitA group, vitamin A with 1,280,000 IU/kg of diet.