Supplementation with organic acids showing different effects on growth performance, gut morphology and microbiota of weaned pigs fed with highly or less digestible diets

Abstract

Two studies were conducted to evaluate the effects of organic acid (OA) supplementation in a highly digestible (Exp. 1) or a less digestible diet (Exp. 2) on the growth performance and intestinal health of weaned pigs. In Exp. 1, a total of 240 pigs weaned at day 21 were assigned to one of five dietary treatments: negative control (NC) (basal diet, 3,000 ppm zinc oxide (ZnO) in the first 2 wk only); positive control (PC) (NC plus 10 mg/kg zinc bacitracin, 5 mg/kg colistin sulfate, and 5 mg/kg olaquindox); OA1 (NC plus a 0.2% blend of encapsulated butyrate, medium-chain fatty acids [MCFA], OA, and phenolics); OA2 (NC plus 0.3% blend of free and buffered short-chain fatty acids [SCFA] combined with MCFA); and OA1 plus OA2 (NC plus 0.2% OA1 plus 0.3% OA2) for 49 d. All treatments in Exp. 1 used the same highly digestible basal diet. At day 28, eight pigs from each group were sacrificed, to collect intestinal and digesta samples for biochemical analysis. Growth performance and intestinal morphology were not affected by the treatments. However, pigs subjected to the OA2 treatment had lower levels of Escherichia coli (P < 0.05) in the colon. In addition, the OA1 and OA2 treatments, and their combination resulted in higher concentrations of acetate and propionic acid in the cecum and colon (P < 0.01) in comparison to the NC. A less digestible diet without high levels of ZnO was used in Exp. 2. A similar design was used with the exception of the replacement of OA2 with another OA blend (OA3, a blend of free and buffered OA). In comparison to the NC, supplementation with OA1 and OA3 in a less digestible diet improved the ADG and the F:G ratio in the seventh week post-weaning (P < 0.01); reduced the diarrhea index of pigs during the first 3 wk post-weaning (P < 0.05); increased the ileal villus height (P < 0.05), and acetic and propionic acid concentrations in colon contents (P < 0.05). Moreover, the genus Prevotella was increased in the colon and the microbial community structure was significantly altered in the OA1 + OA3 treatment. The present research indicated that dietary supplementation with OA improved intestinal health. The OA blends showed a similar growth-promoting effect as antibiotics in the less digestible diet, to which high levels of ZnO had not been added.

From Acidifiers to Intestinal Health Enhancers: How Organic Acids Can Improve Growth Efficiency of Pigs

“…Regarding MCFA, caprylic acid, and to a lesser extent capric acid at 0.3%, allowed to reduce E. coli counts both in jejunum and cecum digesta of weaning pigs [69]. Blends of organic acids and MCFA showed variable results either reducing E. coli and increasing microbial diversity in the colon or not affecting at all large intestine or fecal microflora [40,41,70].…”

“…In a meta-analysis collecting data from 22 studies using individual organic acids at high doses (1% to 2%), stomach pH was lower in 55% of the cases, higher in 36% and equal in 9% of the cases for acidified diets compared to control [2]. More recently, no relevant effects on gastric pH were reported for different combinations of organic acids, mainly fumaric acid-based blends, MCFA, or mixtures of organic acids and MCFA fed to weaning pigs [38][39][40][41]. In a study conducted by Zentek and coworkers, a fumaric and lactic acid mixture did not have any effect, whereas a blend of caprylic and capric acid reduced pH in pylorus, but not in cardia and fundus of the stomach [42] These inconsistencies among different studies may be due to the fact that gastric contents are heterogeneous, and that there are different pH values in different stomach regions.…”

“…Nevertheless, in the colon digesta an interesting reduction of some E. coli pathogenicity factors was observed particularly for organic acids that may be relevant to support intestinal health at weaning [42]. More recently, different commercial blends of organic acids including SCFA, MCFA, and acids salts were shown to increase the levels of acetic, propionic, and butyric acid produced by microbial fermentation of carbohydrates in the large intestine, while reducing E. coli counts [41]. In addition, other mixtures of organic acids (including MCFA) fed to growing pigs increased VFA content in the ileum and fiber fecal digestibility, indicating a positive stimulation on microflora that can utilize carbohydrates in the large intestine and produce SCFA [51].…”

Eucommia Ulmoides Flavones as Antibiotic Alternatives in a Low-protein Diet Improve Growth Performance and Intestinal Health in Weaning Piglets

“…Bacteria counting were performed according to the previous studies [5,19]. 0.2 g of ileal and colonic contents were collected and immediately diluted with 9 mL of 0.9% sterilizing saline and homogenized.…”

“…acids, microecologics, antimicrobial peptides, could promote the animal development and enhance the intestinal health [3][4][5][6].…”