Evaluation of different protections of butyric acid aiming for release in the last part of the gastrointestinal tract of piglets

Three tests, 2 in vivo and 1 in vitro, were conducted to compare how 2 forms of protection of butyric acid (BA) affect its liberation along the gastrointestinal tract (GIT) of piglets. The 2 forms of BA were vegetable fat-encapsulated sodium butyrate (SBE) and monoglyceride of butyric acid (MB). In the first trial, 528 piglets were weaned at 21 d of age and assigned to 3 diets in 8 replicate pens of 22 piglets per pen for 39 d. The 3 diets were (i) prestarter and starters I and II (Con), (ii) C + SBE (6 kg/t in both prestarter and starter feeds), and (iii) C + MB (2.5 kg/t in the prestarter feed, 2 kg/t in the starter feed I, and 0 kg/t in the starter feed II). Piglets receiving C and SBE feeds tended to show higher BW (18.74, 18.66, and 17.82 kg; P < 0.1) and ADG (331.2, 330.5, and 308.9 g/d; P < 0.1) than MB piglets; no significant differences were observed in feed intake or FCR. In the second trial, 8 pens of 4 piglets each (4 pens per treatment), weaned at 21 d, were given either a standard postweaning program with SBE (2 kg/t) or with MB (2 kg/t) and received the same amount of BA. Body weight, feed intake, and FCR were evaluated at days 14 and 28 of trial. At the end of the trial, 1 animal per pen was euthanized and the concentration of BA and VFA in duodenum, jejunum, ileum, colon, and cecum were quantified with HPLC. There were no statistical differences in growth, feed intake, or FCR. However, SBE-fed animals had higher concentration of VFA in colon than MB-fed animals. There were relevant numerical differences in the rest of the GIT sections but they were not statistically significant. The in vitro digestion of the products confirmed that BA can be released more easily from SBE (157.2 g of BA/kg of product after 7 h) than from MB (56.4 g of BA/kg of product after 7 h). It is concluded that the addition of SBE allows more BA to reach the distal sections of the GIT than MB.