Phytogenic affects performance, egg quality, and expression of intestinal cytoprotective and inflammatory responses in laying hens

      

This study was conducted to investigate the inclusion level effects of a natural phytogenic blend (PB) on production performance, egg quality, and underlying detoxification (aryl hydrocarbon receptor; AhR), antioxidant (nuclear factor erythroid 2-related factor 2; Nrf2) and inflammatory (nuclear factor-kappa B; NFκB) responses in layers’ duodena and ceca. Depending on PB inclusion level (0, 250, 750, 1,000, or 1,500 mg/kg) in the basal diet, 21-wk-old Hy-Line Brown laying hens (n = 385) were assigned into 5 treatments: CON, PB250, PB750, PB1000, or PB1500, with 7 replicates of 11 hens each. The PB consisted of selected Mediterranean plants having olive oil polyphenols, carvacrol, and thymol among its main bioactive components (NuPhoria®; Nuevo SA, Greece). Performance and egg quality parameters were determined weekly for a 12-wk period (i.e., wk 33 of layers’ age) and reported as overall. Intestinal samples from the duodena and ceca of 33-wk-old layers were collected for qPCR analysis. Data were analyzed by ANOVA, and statistical significance was determined at P < 0.05. Linear and quadratic patterns of biological responses to PB inclusion levels were studied via polynomial contrast analysis. Inclusion of PB improved (P < 0.05) laying rate, egg mass, and feed conversion ratio, compared with CON, and peaked at PB750. Incremental levels of PB quadratically increased (P ≤ 0.01) albumen height and Haugh unit. Increasing dietary PB inclusion level downregulated (P < 0.05) the AhR pathway related genes in both intestinal segments. Additionally, most of the genes related to the NF-κB pathway were downregulated (P < 0.05) with increasing PB inclusion level, in both the duodenum and the cecum, respectively. However, most of the antioxidant genes implicated in Nrf2 pathway were upregulated (P < 0.05) with increasing PB inclusion level in both intestinal sites. Overall, phytogenic inclusion upregulated cytoprotective genes, downregulated inflammation related ones, and documented further production and egg quality improvements in layers, with PB750 displaying the optimal benefits.

Key Words: Phytogenic, nutrigenomic, laying hen, performance, gut cytoprotection.