Effects of Diet and Phytogenic Inclusion on the Antioxidant Capacity of the Broiler Chicken Gut

Abstract

The reduction in energy and protein dietary levels, whilst preserving the gut health of broilers, is warranted in modern poultry production. Phytogenic feed additives (PFAs) are purported to enhance performance and antioxidant capacity in broilers. However, few studies have assessed PFA effects on a molecular level related to antioxidant response. The aim of this study was to investigate the effects of administering two dietary types differing in energy and protein levels (L: 95% and H: 100% of hybrid optimal recommendations) supplemented with or without PFA (−, +) on gene expressions relevant for antioxidant response along the broiler gut. Interactions of diet type with PFA (i.e., treatments L−, L+, H−, H+) were determined for critical antioxidant and cyto-protective genes (i.e., nuclear factor erythroid 2-like 2 (Nrf2) pathway) and for the total antioxidant capacity (TAC) in the proximal gut. In particular, the overall antioxidant response along the broiler gut was increased upon reduced dietary energy and protein intake (diet type L) and consistently up-regulated by PFA addition. The study results provide a new mechanistic insight of diet and PFA functions with respect to the overall broiler gut antioxidant capacity.

Dietary and phytogenic inclusion effects on the broiler chicken cecal ecosystem

“…It has been shown that dietary metabolizable energy (ME) and crude protein (CP) reduction negatively affected broiler performance and that phytogenics inclusion tended to ameliorate this effect (Paraskeuas et al, 2016;Griela et al, 2021). Several mechanisms for the growth enhancement of phytogenics have been proposed, some of which include antioxidant activity, antimicrobial and anti-quorum-sensing activity, and anti-inflammatory and transcription-modulating effects on gut health biomarkers (Pandey et al, 2019;Kikusato, 2021).…”

“…In the case of healthy broilers, downregulation of HDPs could point to phytogenics' potential to contribute towards an improved intestinal environment via an antiinflammatory mechanism. Downregulation of AvBD6 and LEAP2 will have to be considered in context, considering overall zootechnical performance, which has been shown to tend to be improved by phytogenic addition (Griela et al, 2021).…”

“…This study forms part of our previous research work (Griela et al, 2021). To avoid excessive repetition, a brief description of the experimental treatments is given below.…”

“…In particular, for each growth phase, two diets were formulated to meet 95% and 100% of optimal Cobb 500 metabolizable energy (ME) and protein (CP) specifications. The phytogenic used was a commercial product; a blend of bioactive compounds such as carvacrol, thymol, carvone, methyl salicylate, and menthol (Digestarom ® Biomin Phytogenics GmbH, Germany), as previously described (Griela et al, 2021).…”

Effects of Deoxynivalenol and Fumonisins on Broiler Gut Cytoprotective Capacity

“…The cellular cytoprotection against oxidative stress is regulated by the aryl hydrocarbon receptor (AhR) and nuclear factor erythroid-derived 2-like 2 (Nrf2) signaling pathways [ 9 ]. The AhR pathway is related to the detoxification of xenobiotic compounds, such as mycotoxins, and the Nrf2 pathway is the main modulator of the antioxidant response [ 10 ], responsible for the transcription of phase II antioxidant and cytoprotective genes [ 11 , 12 , 13 ].…”