Multivariate analysis of hematological and immunological responses in Quarter horses supplemented with Amazonian tucumã oil (Astrocaryum vulgare) and probiotics

Abstract

This study aimed to evaluate the effects of dietary supplementation with Amazonian tucumã oil and probiotics on hematological and immunological parameters in Quarter Horses, using multivariate analysis. Seventeen Quarter Horses (9 males and 8 females) were randomly assigned to three treatments: (1) CON (no supplementation), (2) TUC (20 mL/day of tucumã oil), and (3) LAC (20 g/day of a Lactobacillus-based probiotic blend). All animals received a diet with a 50:50 forage-to-concentrate ratio, consisting of Cynodon spp. hay and a commercial concentrate (CP = 13%, DE = 3.2 Mcal/kg, DM = 89%, EE = 5%, Ca = 0.8%, P = 0.5%). Blood samples were collected from the jugular vein at 7:00 a.m., after supplement administration, for complete hemogram and leukogram analysis. Principal Component Analysis (PCA) was performed separately for red and white blood cell variables across three experimental time points (D0, D15, and D30), using SAS 9.2 (PROC PRINCOMP). For the red blood cell series, the first two principal components explained 91.3% of the total variance (PC1: 65.9%, PC2: 25.4%). PC1 was mainly influenced by red blood cell count, hemoglobin concentration, hematocrit, and mean corpuscular hemoglobin, with mean corpuscular volume showing negative loading—highlighting that erythrocyte concentration and morphology were key factors in group differentiation. For the white cell series, PC1 and PC2 explained 85.3% of the total variance (PC1: 60.7%, PC2: 24.6%). PC1 showed negative loadings for total leukocyte count, lymphocyte percentage, and intermediate mononuclear cells, and a positive loading for granulocyte percentage. These findings reveal distinct immunomodulatory profiles: probiotics induced a progressive immune activation, while tucumã oil promoted a transient response. PCA confirmed treatment- and time-related shifts, supporting the immunological relevance of both supplements in horses.