Thermal stress challenge in broiler chickens and the mitigative effects of phytogenic and multivitamin additives.

Abstract

As the quest for enhanced production performance in poultry persists, maintenance of a stress-free environment should be paramount. Four experiments were conducted to study the efficacy of various bioactive substances: brown seaweed meal (SWM), brown seaweed extract (SWE), red osier dogwood extract (ROD), grape pomace (GP), and encapsulated multivitamins (EMV) in mitigating thermal challenges in broiler chickens. In experiment 1 (heat stress; HS), dietary supplementation of 2% SWM improved the growth performance of birds independent of HS, and ameliorated HS-induced intestinal impairment by promoting the abundance of beneficial microbes and improving the gut morphology of heat-stressed broiler chickens. SWE mitigated the negative effects of HS by improving the plasma enzyme activities of heat-stressed birds. In experiment 2 (HS), ROD and GP promoted the intestinal health of chickens challenged with HS while the ROD improved the growth performance parameters of birds (all effects in a similar capacity to antibiotics). In experiment 3 (cold stress; CS), EMV improved broiler chickens’ growth performance parameters and enhanced the total antioxidant capacity of birds at the early stage of growth. In experiment 4 (combined heat and cold stress; CHS), EMV enhanced gut health by reducing the growth of pathogenic microbes, improving gut morphological characteristics, and enriching essential metabolic pathways of thermal challenged birds. In conclusion, SWM, SWE, ROD, GP and EMV could potentially mitigate thermal stress by exerting regulatory and protective mechanisms on the gut health of chickens challenged with cold and heat stress.