Evaluation of an Organic Acid Blend on Gut Morphology and Nitrogen Retention in Nursery Pig

The present experiment was conducted to determine the effect of an organic acid blend (OA) on growth performance, nitrogen retention, and gut morphology in nursery pigs. Dietary treatments were: 1) basal diet [CON] and 2) basal + 0.10% OA (Biotronic Top3® a blend of formic, propionic, and acetic acids combined with cinnamaldehyde and Permeabilizing Complex^TM; BIOMIN Holding GmbH). Diets were corn-soybean meal based and formulated to contain 4.42 and 3.85 g SID lysine/Mcal ME for phase 1 (d 0 – 14) and 2 (d 14 – 28), respectively. Pigs (n = 8/trt, BW = 7.71 ± 0.91 kg) were individually penned and fed ad libitum until d 21, then pigs were fed daily three times of maintenance in metabolism crates for 7 d. Body weight and feed disappearance were measured on d 7, 14, 21, and 28. Total feces and urine were collected from d 23 to 26, and along with feed were analyzed for N content. Thereafter, whole body nitrogen balance was calculated. On d 28, pigs were euthanized and ileum sections were collected approximately 1.2 m proximal from the ileocecal junction for assessment of intestinal villus and crypt morphology. Supplementation of OA increased villi height (263 vs. 310 µm, SEM=9.67, P<0.001) and crypt depth (180 vs. 203 µm, SEM=6.50, P<0.001), and did not affect villi:crypt ratio (1.38 vs. 1.45, SEM=0.06, P=0.252). Supplementation of OA increased N intake (15.76 vs. 21.83 g/d, SEM=1.49, P=0.011), fecal N excreted (3.78 vs. 5.44 g/d, SEM=0.53, P=0.044), and did not affect urine N excreted (3.11 vs. 3.07 g/d, SEM=0.32, P=0.926). As a result, compared to the CON, N retained in the pigs was significantly improved by OA supplementation (8.87 vs. 13.32 g/d, SEM=1.15, P=0.015). Supplementation of OA also increased serum IGF-1 concentrations (123 vs. 149 ng/mL, SEM=4.9, P=0.002). For the 21-d growth period post weaning, supplementation of OA did not alter final BW (11.68 vs. 12.03 kg, SEM=0.52, P=0.638), ADG (0.183 vs. 0.213 kg/d, SEM=0.020, P=0.294), ADFI (0.266 vs. 0.299 kg/d, SEM=0.021, P=0.280), and G:F (0.671 vs. 0.709 kg/kg, SEM=0.032, P=0.424). Overall, the supplementation of an organic acid blend to nursery pigs caused an improvement in gut morphology, N retention, and serum IGF-1. Further research is needed to evaluate growth performance of nursery pigs with more replications under commercial conditions.