Feeding dihydroquercetin and vitamin E to broiler chickens reared at standard and high ambient temperatures

ABSTRACT

The use of natural antioxidants, in particular polyphenols such as dihydroquercetin (DHQ), in animal nutrition has recently increased in popularity. This may partly be due to the risk of increased incidences of heat stress associated with raising livestock in warmer ambient temperatures, facilitated by global warming, reducing antioxidant capacity. The current research demonstrates the effect of dietary DHQ, vitaminEand standard or high ambient temperatures on growth performance, energy and nutrient metabolism, gastrointestinal tract (GIT) development, jejunal villus morphometry and antioxidant status in broiler chickens. Each of the four experimental diets was fed to 16 pens of five birds, which were allocated to four rooms (four pens in each room). The temperature in two rooms was maintained at aconstant 35°C (high temperature; HT), and the temperature in the other two rooms was gradually reduced from 27°C at 7 dof age to 22°C at 20 dof age (standard temperature; ST). Rearing birds at HT reduced feed intake, weight gain, weight of small intestine, total GIT, liver, spleen, heart, villus height, villus surface area and lowered blood glutationperoxidase (GSH-Px). Dietary DHQ increased blood GSH-Px and total antioxidant status, increased heart weight and reduced caecal size. When fed separately, DHQ and vitamin E improved hepatic vitamin E concentration. Feeding vitamin Eincreased spleen and liver weights. When fed together, DHQ and vitamin Ereduced villus height, villus height to crypt depth ratio and villus surface area. Temperature and antioxidants did not affect energy and nutrient metabolism. There were no effects of dietary antioxidants on growth performance of broiler chickens and there were no mortalities. At present, it is unclear if feeding antioxidants (in particular DHQ) at different levels, using different dietary formulations, and rearing birds under arange of environmental conditions may be effective at enhancing production performance and bird health in hot ambient climates.

KEYWORDS:

• Broilers
• dihydroquercetin
• environmental temperature
• glutathione peroxidase
• growth
• performance
• vitamin E

Acknowledgments

Special thanks to Richard James and Rose Crocker of the National Institute of Poultry Husbandry (Harper Adams University) for their technical support in conducting the study.

Disclosure statement

The authors report no potential conflicts of interest. This work was not sponsored by any funding agency or commercial company.

Ethics statement

The authors confirm that they have followed all appropriate EU and UK standards and regulations for the protection of animals used for scientific purposes. All mandatory laboratory health and safety procedures have been complied within the course of conducting this experimental work. This manuscript complies with the ARRIVE guidelines (Kilkenny et al. 2010).

Data availability statement

The data that support the findings of this study are available from the corresponding author, upon reasonable request, subject to restrictions and conditions.