The Interactive Effects of a Matrix Coated Organic Acids Blend and Antibiotic Supplementation in Growing Pigs

Dietary addition of organic acids can promote nutrient digestibility, growth performance, and gut health outcomes in pigs. Thus, we investigated the effect of supplementing a matrix coated organic acids blend (MCOA) without or with antimicrobial growth promoters (AGP) in growing pig diets on growth performance, hematological profiles, diarrhea score, and in-vitro fecal noxious gas emission. Ninety six growing pigs [(Yorkshire × Landrace) × Duroc] with an average BW of 47.71 ± 1.15 kg (mean ± SD) were used in a 6-wk experiment. Based on initial BW and gender, pigs were randomly blocked and allocated to 1 of 4 experimental treatments each with 12 replicates and 2 pigs per pen. Pigs were allotted to diets containing 0 or 0.2% MCOA, and 0, or 0.25% AGP (aureomycin, Aureo S-P 250 G) according to a 2 × 2 factorial arrangement of treatments. For hematology and serum urea N (SUN) measurements, 1 pig from each pen was randomly selected, and blood samples (10 mL per pig) were collected via jugular vein puncture on d 41. The occurrence and severity of diarrhea was monitored and assessed during the whole experiment. All data were statistically analyzed using the PROC MIXED procedure of SAS. Pigs fed the diet supplemented with MCOA had higher feed efficiency (G:F) than those fed the diets without MCOA (0.38 vs. 0.36; P = 0.030). Moreover, AGP × MCOA supplementation tended to have higher G:F (P = 0.083). However, pigs fed AGP × MCOA diet had reduced SUN (P = 0.024). Diarrhea score was not affected (P > 0.10) by dietary AGP or MCOA. Pigs fed diet supplemented with AGP had reduced fecal ammonia (NH₃) gas emission compared to those fed without AGP (8.49 vs. 8.80 ppm; P = 0.037). Moreover, pigs fed diet supplemented with MCOA had reduced fecal NH₃ and acetic acid gas emission compared to those fed without MCOA (8.36 vs. 8.93 ppm, and 1.73 vs. 2.79 ppm; P < 0.001, and P = 0.048, respectively). In conclusion, growing pigs fed diets supplemented with MCOA had improved G:F and similar beneficial responses as those fed diets with AGP in terms of reducing serum urea N, and in-vitro noxious gas emission. This suggests that supplementation of MOCA can promote G:F of growing pigs in antibiotic-free-feeding regimens.