Administration of botanicals with the diet regulates gene expression in peripheral blood cells of Sarda sheep during ACTH challenge

The aim of the present research was to investigate the regulation of gene expression in ovine blood leukocytes during ACTH-induced cortisol release and the effect of dietary administration of botanicals to counteract the evoked response in polymorphonucleate cells (PMNCs). Thirty-six homogeneous Sarda sheep (age, 18 +- 4.1 mo; BW, 38.7 +- 1.3 kg) were allotted to six groups of six sheep each. One group was used as a negative control (Saline) and five groups were treated, every 12 h for 48 h, with 0.5 mL of ACTH agonist (250 mg/mL of tetracosactrin). Before ACTH treatment, four of the five ACTH-treated groups were separated and fed for 22 d with a basal diet supplemented with extracts from Echinacea angustifolia roots (PO + ACTH), Echinacea angustifolia flowers (EA + ACTH), Andrographis paniculata (AP + ACTH), and the bark of Larix decidua milled (LB + ACTH). Control groups (Saline and ACTH) were fed with the same basal diet without botanicals. Total RNA was extracted from blood samples collected before (T0) and after 3 h (T3) and 51 h (T51) from the first ACTH injection, and transcriptome analysis was performed using a custom oligoarray, designed from 12,194 Ovis aries UniGenes on a CombiMatrix platform. At T3, treatment with ACTH caused down-regulation of transcripts (P<0.001) involved in “response to stress” (GADD45A, GADD45B, WRNIP1, and XRCC6) and in “innate immune response” (MAPK3 and NFkBIB). At T51, treatment with ACTH caused down-regulation (P<0.001) of genes involved in “immune response” (IFNG and IL2) and up-regulation (P<0.001) of NF-kB1 and TP53. Each botanical produced a different (P<0.001) molecular signature for these genes at T3 and T51. The most active botanical in modulating transcriptome modifications in PMNCs after ACTH-induced cortisol release was Larix decidua Mill bark followed by Polinacea roots. These botanicals can be viewed as promising feed supplements in ruminants to cope with conditions associated with increased concentrations of plasma cortisol.