Implication of Dietary Acidifiers for Growth Performance and Intestinal Morphometry in Nursery Piglets

This study was conducted to assess the use of dietary acidifiers and their effects on the growth performance and intestinal morphometry of challenged and non-challenged nursery piglets. A total of 18,597 piglets distributed across 1,300 experimental groups from 128 papers published between 1984 and 2020 were included in the meta-analysis. All treatments were categorized as negative control (CON), organic acid (OAC), salts of organic acids (SAL), and blends of acidifiers (BLE). The presence (+) or absence (-) of health challenges in each study was also considered. The meta-analysis was conducted sequentially via graphical, correlation, and variance-covariance analyses. Piglets weighed between 8.4 and 15.8 kg and were assessed at 29.4-48.3 - 48.3 days of age. The addition of OAC, BLE, and SAL to the diets improved the feed conversion ratio (FCR) of piglets (P<0.001) by 5.3%, 3.6%, and 3.6%, respectively, compared to CON. Challenged piglets consumed 7.7% less feed (P<0.05) than the non-challenged piglets. Addition of OAC to diets reduced stomach pH by 8.6% (P<0.05) compared to CON piglets. The OAC and BLE diets reduced jejunum pH by 2.7% and 2.1% (P<0.05), respectively, compared to CON piglets. Challenged piglets had a 14.8% lower (P<0.01) villus height in the ileum compared non-challenged piglets. Acidifiers reduced the crypt depth in the jejunum of piglets by 17.4% (P<0.05) compared to the CON group. Acidifiers in the diet of nursery piglets improve performance by reducing pH in the gastrointestinal tract and indirectly improving intestinal integrity. Blends improved the performance of nursery piglets.