Effects of Stress on Poultry
Environmental stressors can make animals more vulnerable to infections, physiological changes, behavioral alterations, reduced egg and meat quality, tissue damage, and mortality. Key environmental stressors include heat and cold stress, feed restriction, stocking density, and pollutants.
Stress reduces feed intake and growth, and disrupts immune system responses and functions, thereby increasing the animal’s susceptibility to disease outbreaks.
One of the strategies to cope with environmental stress challenges is to modify housing conditions, such as reducing environmental contamination and managing lighting as a low-cost and safe approach.
Nutritional strategies also enhance bird immunity by improving the development of lymphoid tissues and stimulating beneficial modulators and immune responses.
Heat Stress
Heat stress (HS) occurs when the heat produced within the body exceeds its ability to dissipate it, and the body can no longer control the excess heat.
An increase in corticosterone in response to heat stress leads to the breakdown of muscle protein, and the resulting amino acids are used in the liver’s gluconeogenesis process to provide energy.
Cold Stress
Another environmental stressor is cold stress (CS), which occurs when ambient temperatures drop below 18°C.
Adult birds can tolerate cold stress better than chicks because they are capable of regulating their body temperature and generating energy.
The two main causes of mortality in cold environments are ascites and cardiomyopathy.
Cold stress leads to intensified oxidative stress and the generation of free radicals.
Ambient temperatures below 16°C result in various negative effects such as reduced meat quality, increased feed intake, decreased egg production and nutrient digestibility, and reduced body weight.
Feed Restriction Stress
Feed restriction, especially in young chicks, is recognized as one of the causes of physiological stress because they are in rapid growth phases and have high metabolic demands.
Significant changes in blood biochemical indices due to feed restriction indicate that it imposes serious stress on chicks during the growth period.
Stocking Density Stress
Increased stocking density can result in serious challenges in controlling environmental contamination.
With the rapid growth of broiler chickens, flock density rises, which may be associated with leg disorders such as footpad dermatitis, lameness, and abnormal gait.
In laying hens, high stocking density contributes to thinner eggshells, broken eggs, reduced laying rate, changes in shell color, strength, thickness, and relative weight.
Keeping poultry in overcrowded environments can also lead to changes in blood biochemical markers and potentially cause oxygen depletion, leading to hypoxia.
Effect of Environmental Pollutants
Environmental pollutants such as arsenic (As), ammonia (NH₃), and hydrogen sulfide (H₂S) can induce oxidative stress when inhaled by chicks.
These pollutants may inhibit antioxidant enzymes such as catalase and glutathione peroxidase and intensify lipid peroxidation.
Strategy for Counteracting the Adverse Effects of Environmental Stress
Adjusting feed formulation and incorporating dietary supplements such as amino acids, vitamins, minerals, polyphenols, phytogenics, and probiotics—due to their medicinal and nutritional properties, antioxidant activity, and immune-enhancing effects—play a significant role in mitigating the harmful effects of environmental stress in poultry.
To improve chick adaptability under stressful conditions, using a combination of active ingredients that reduce oxidative stress, along with appropriate dosing in the diet, can result in improved growth performance and reduced impact of environmental stressors.
Importance of Using Zerostress Product
The Zerostress anti-stress product, due to its effective biological and mineral components, improves physiology, intestinal morphology and structure, and immune system performance—ultimately enhancing the performance and health of poultry under environmental stress.
Composition of the Anti-Stress Supplement Phytogenic compounds containing anthocyanins, bioactive polyphenolic and flavonoid components, L-carnitine, essential vitamins such as C and E, and mineral and organic elements including chromium, selenium, manganese, magnesium, and zinc.
