Environmental Stress in Chickens and the Potential Effectiveness of Dietary Vitamin Supplementation

Abstract

Environmental stressors can promote the vulnerability of animals to infections; it is therefore, essential to understand how stressors affect the immune system, the adaptive capacity of animals to respond, and effective techniques in managing stress. This review highlights scientific evidence regarding environmental stress challenge models and the potential effectiveness of vitamin supplementation. The major environmental stressors discussed are heat and cold stress, feed restriction, stocking density, and pollutants. Much work has been done to identify the effects of environmental stress in broilers and layers, while few involved other types of poultry. Studies indicated that chickens' performance, health, and welfare are compromised when challenged with environmental stress. These stressors result in physiological alterations, behavioral changes, decreased egg and meat quality, tissue and intestinal damage, and high mortalities. The application of vitamins with other nutritional approaches can help in combating these environmental stressors in chickens. Poultry birds do not synthesize sufficient vitamins during stressful periods. It is therefore suggested that chicken diets are supplemented with vitamins when subjected to environmental stress. Combination of vitamins are considered more efficient than the use of individual vitamins in alleviating environmental stress in chickens.

Evaluation of Phytogenic Feed Additive on Egg Production, Egg Quality and Feed Intake in Layer Chicken

“…Stress is a factor affecting the biology of the bird from both internal (homeostasis) and external factors (nutritional, environmental) affecting equilibrium and decreasing the production and reproduction performances [2]. Poultry suffer from various environmental stressors such as heat stress [3], cold stress [4], feed restriction [5], stocking density, pollutants, and many more [6].…”

Effects of protected complex of biofactors and antioxidants on growth performance, serum biochemistry, meat quality, and intestinal antioxidant and immunomodulatory-related gene expressions of broiler chickens

“…In addition, they suggested an increase of dietary vitamin levels by 0.6 to 1.0% yearly is required to maintain constant vitamin intake per unit of output. Recently, it has been suggested that combination of multivitamins is more efficient than the use of individual vitamins ( Akinyemi and Adewole, 2021 ). In addition, dietary vitamins play an important role in poultry feed and could be used as an effective nutritional strategy for immunity and antioxidant modulation ( Shojadoost et al, 2021 ).…”

A critical assessment of the cellular defences of the avian respiratory system: are birds in general and poultry in particular relatively more susceptible to pulmonary infections/afflictions?

“…Although environmental conditions alone do not directly cause illnesses in poultry, they weaken the general health and thus compromise immunity in birds, making them vulnerable to infections (Quarles & Kling, 1974; Butler & Egan, 1974; Reece & Lott, 1980; Sterling et al ., 2003; Kocaman et al ., 2006; Talukder et al ., 2010). In animals, stress under abnormal environmental conditions reduces humoral immune capacity and weakens cellular body defences (Bridle et al ., 2006; Dhabhar, 2014; Akinyemi & Adewole, 2021). By altering the Type 1–Type 2 cytokine equilibrium, long‐term stress reduces or causes imbalances in innate and adaptive immune responses, triggering low‐grade chronic inflammation and limiting numbers, movement and function of immunoprotective cells (Dhabhar, 2014).…”