Meta-analytical approaches to assess citric and ascorbic acid use in nursery piglets

: This study evaluated different meta-analytical approaches tousing citric and ascorbic acids in the performance of nursery piglets. The study included 24 publications between 1985 and 2018 (mode 1998), totaling 4215 nursery piglets. The Higgins index indicated high heterogeneity (98.5%) among the studies concerning citric acid (96.9%) and ascorbic acid (91.4%). In variances and forest plot analysis, using citric and ascorbic acids and their analogs was no significant effect (P > 0.05) on piglet weight gain. In the meta-analysis approach proposed by LOVATTO et al. (2007) and SAUVANT et al. (2008), there was no significant effect (P > 0.05) of the addition of citric and ascorbic acids on piglet performance. Numerically, was observed an increased ADG (Δ > 0) related to acids (supplemented over control treatments) in 59.7% (ascorbic acid) and 46.6% (citric acid) of the ADG comparisons. The effect of ascorbic supplementation on the respective control treatment of the overall nursery period was on average 0.98%, 1.07%, and -1.3% for ADFI, ADG, and FCR, respectively. Citric acid supplementation to the respective control treatment of the overall nursery period was on average 1.67%, 4.40%, and -2.29% for ADFI, ADG, and FCR. Adding citric and ascorbic acids in diets for nursery piglets does not alter performance regardless of the meta-analysis method used.