Mixed organic acids improve nutrients digestibility, volatile fatty acids composition and intestinal microbiota in growing-finishing pigs fed high-fiber diet.

Objective: The objective of this study was to investigate effects of mixed organic acids (MOA) on nutrient digestibility, volatile fatty acids composition and intestinal microbiota in growing-finishing pigs fed high wheat bran diet.

Methods: Six crossbred barrows (Duroc × Landrace × Yorkshire), with an average body weight 78.8 ± 4.21 kg, fitted with T-cannulas at the distal ileum, were allotted to a double 3 × 3 Latin square design with 3 periods and 3 diets. Each period consisted of a 5-d adjustment period followed by a 2-d total collection of feces and then a 2-d collection of ileal digesta. The dietary treatments included a corn-soybean-wheat bran basal diet (CTR), mixed organic acid 1 diet (MOA1; CTR + 3,000 mg/kg OA1), mixed organic acid 2 diet (MOA2; CTR + 2,000 mg/kg OA2).

Results: Pigs fed MOA (MOA1 or MOA2) showed improved (p < 0.05) apparent total tract digestibility (ATTD) of gross energy, dry matter and organic matter, and pigs fed MOA2 had increased (p < 0.05) ATTD of neutral detergent fiber compared to CTR. Dietary MOA supplementation decreased (p < 0.05) pH value, and improved (p < 0.01) concentrations of lactic acid and total volatile fatty acids (TVFA) in ileum compared to CTR. Pigs fed MOA showed higher (p < 0.05) concentration of acetic acid, and lower (p < 0.05) content of formic acid in feces compared to CTR. Pigs fed MOA1 had increased (p < 0.05) concentration of TVFA and butyric acid in feces. Pigs fed MOA1 showed higher concentration of Lactobacillus and lower concentration of Escherichia in feces compared to CTR.

Conclusion: Dietary supplementation of mixed organic acid 1 or 2 could improve nutrients digestibility, total volatile fatty acids concentration and intestinal flora in growing-finishing pigs fed high fiber diet.