Effect of Dietary Protected Organic Acids on Growth Performance, Fecal Microflora in Weanling Pigs

Among a variety of candidates for the replacement of antibiotics, organic acids (OA) have been broadly applied worldwide with reasonable success. The present study was to evaluate the effect of dietary inclusion of protected organic acids (POA) on growth performance and fecal microflora in weanling pigs compared with unprotected organic acids (UOA). A total of 112 weanling pigs with an average BW of 6.70 ± 1.31 kg were used in a 6-week feeding trial and allotted to one of four experimental diets as basal diet supplemented with (1) Control, basal diet (CON); (2) CON + 0.2% UOA (UOA); (3) CON + 0.1% POA (POA1); (4) CON + 0.2% POA (POA2). Feed intake was recorded on a daily basis, accordingly, the ADG, ADFI and G: F were calculated. For microbial analysis, fecal samples were collected directly by massaging the rectum of 2 pigs randomly selected from each pen (1 gilt, and 1 barrow) at week 6, and pooled, and placed on ice for transportation to the laboratory. Microbial analysis was immediately carried out. All results were analyzed with SAS in a randomized complete block design using pen as experimental unit. Before conducting statistical analysis of the microbial counts, the value was logarithmically transformed. Duncan’s multiple range tests were used to determine differences between treatments. Statistical significance was considered at p < 0.05. The pigs fed POA2 diet showed greater (p < 0.05) average daily gain (ADG), gain: feed ratio (G: F) and nutrient digestibility of dry matter and nitrogen than other dietary treatments without effects on average daily feed intake and energy digestibility (p >0.05). Increased fecal Lactobacillus and decreased E. coli and Salmonella counts were observed with diets of POA fed to weanling pigs (p < 0.05). In conclusion, dietary inclusion of POA has potential to improve growth performance, while balancing microbial counts in weanling pigs without any adverse effects on pig’s health.