The poultry industry invests significant resources into genetics, hatching and breeding to ensure high-quality birds enter the supply chain. How do you preserve that value through catching, transport, lairage, and processing – without compromising welfare, quality, or operational efficiency? Live bird handling has become one of the most critical control points in modern poultry processing. It directly influences product quality, compliance, yield, and overall plant performance.

Efficient, low-stress live bird handling is essential for the performance and success of any poultry processing operation.

The Challenge Behind Live Bird Handling
In today’s poultry industry, processors operate under increasing pressure from multiple directions.
Higher processing speeds demand more from every part of the system. At the same time, labour challenges make manual handling more difficult to sustain. Stricter animal welfare regulations continue to raise expectations, while sustainability targets require reductions in energy use, emissions, and waste. On top of this, biosecurity risks must be tightly controlled to protect both product and plant integrity.

These external pressures translate into very real operational challenges:
– Avoiding dead-on-arrivals and bird injuries
– Ensuring high standards of animal welfare throughout catching, transport, lairage, and reception
– Maintaining consistent product quality
– Ensuring steady line feeding without disruption
– Reducing reliance on manual labour
– Managing variability in farm and transport conditions

Even small inefficiencies in live bird handling can cascade through the entire production process, affecting both cost and output.

Automation in the reception area ensures smooth, efficient handling while reducing reliance on manual labour.

Why It Matters More Than Ever
Live birds represent a high-value input that has already required significant investment before they reach the plant. Any loss in quality during handling translates directly into lost yield and reduced profitability.

Poor handling conditions during catching, transport, or reception can lead to stress, injury, and inconsistent product quality. These issues do not remain isolated – they impact downstream efficiency, outcome quality, and customer expectations.

In contrast, well-designed handling systems help maintain control over a process that has traditionally been variable and labour-intensive.

Transport equipment should be robust and allow for a safe journey from farm to plant.

The Role of Modern Live Bird Handling Systems
To address the above-mentioned challenges, the industry is increasingly moving toward integrated, automated, and welfare-focused handling systems.
Modern solutions are designed to manage the full journey from farm to shackling in a controlled and consistent way, reducing variability and improving outcomes across multiple dimensions.

Key capabilities include:
Gentle and Controlled Handling
Reducing stress and physical impact during catching, transport, and unloading helps preserve both welfare and product quality.

Automated Processes Where It Counts
Automation in key areas such as catching, unloading, stacking, or equipment washing reduces labour dependency while improving consistency and throughput.

Stable Line Feeding
Reception systems are designed to ensure a continuous and controlled flow of birds to the shackling area, even at high processing speeds.

Environmental Control
Proper airflow during transport and lairage helps prevent heat stress and supports animal welfare under varying climate conditions.

Hygiene and Biosecurity
Washable and disinfection-ready systems help reduce pathogen risks and maintain strict hygiene standards between flocks.

Scalability and Flexibility
Modular system designs allow processors to expand capacity or adapt layouts as production needs evolve, without major operational disruption.

Highly effective washing equipment eliminates the risk of inconsistencies associated with manual cleaning, ensuring reliable and repeatable hygiene standards.

Key Factors in System Design
Selecting the right live bird handling approach depends heavily on operational context. Farm layout, infrastructure, and access conditions all influence system design.
Large-scale operations require high-capacity systems capable of handling volume efficiently, while maintaining gentle handling principles. In contrast, labour availability may determine the level of automation required.

Climate conditions also play an important role. Systems must support adequate airflow and temperature control to prevent heat stress during transport and lairage.
Finally, biosecurity requirements and cleaning protocols are increasingly important, requiring equipment designed for effective washing and contamination control.

A well-designed live bird handling system takes conditions across the farm, transport, and reception areas into account to ensure best performance

A System-Level Approach to Performance
The most effective live bird handling strategies treat the entire process as one integrated system rather than isolated steps.
From farm loading to plant reception, every stage must work together to maintain flow, protect bird welfare, and support consistent processing.
When this is achieved, processors benefit from:
– Improved animal welfare outcomes
– Higher and more consistent product quality
– Reduced dead-on-arrivals and injuries
– Better operational efficiency and throughput stability
– Lower labour dependency
– Stronger compliance with regulatory standards
–   Greater long-term scalability

Choosing the Right Provider
To meet these diverse needs of a global market, BAADER offers crate handling and module/drawer solutions in a variety of modular layout options. These solutions are designed to adapt to specific operational requirements, ensuring flexibility and efficiency in handling processes.

Our live bird handling specialists provide processing audits to effectively analyse current and future challenges, helping processors design reception layouts that meet market demands. With over 80 years of proven expertise in handling live birds, we offer solutions supported by both global and local services to ensure equipment operates smoothly and efficiently.

Visit: https://poultry.baader.com/live-bird-handling to learn more about the BAADER live bird handling solutions

Every day, a broiler’s intestine processes several times its body weight in feed and water, encounters billions of microorganisms, responds to environmental stress, and continuously decides what enters the body and what remains outside.

In many ways, the gut functions as a customs checkpoint, security system, digestive factory, and immune headquarters—all at the same time.

In fact, nearly 70% of the bird’s immune cells are associated with the gastrointestinal tract, making it a key player in both health and performance. The remarkable aspect is that when the gut is functioning well, nobody notices it. When it begins to fail, everybody notices the consequences.

The Modern Poultry Bird: Built for Speed
Today’s broiler is a biological marvel. Through decades of genetic selection, modern birds reach market weight faster and more efficiently than ever before.
However, this achievement comes with a hidden challenge.

The digestive tract has become one of the most critical performance-limiting organs in poultry production. Every gram of feed must be digested, absorbed, and converted into muscle within an increasingly compressed production cycle.

Twenty years ago, a small reduction in nutrient absorption might have gone unnoticed. Today, even minor intestinal inefficiencies can translate into measurable losses in body weight gain, feed conversion ratio, and profitability. Modern birds can no longer afford a lazy gut.

The Gut Is Constantly Making Decisions
Traditionally, we think of the intestine as a nutrient absorption organ.
In reality, the gut is making thousands of biological decisions every second.

– Should nutrients support growth or immunity?
– Should a microorganism be tolerated or eliminated?
– Should energy be invested in production or defense?
– Should the intestinal barrier remain open for absorption or tighten to prevent invasion?

These microscopic decisions ultimately determine flock performance.
In many ways, poultry production is not simply about feeding birds—it is about influencing the decisions being made within the gut.

The Hidden Cost of Inflammation
One of the most important concepts emerging in poultry science is that inflammation carries a nutritional cost.
Whenever the intestine encounters stress from pathogens, mycotoxins, heat, poor litter quality, or microbial imbalance, the immune system becomes activated.
The immune response is essential for survival, but it is expensive.
Energy that could support growth is redirected toward immune activity.
Amino acids that could build muscle are utilized to produce immune proteins and inflammatory mediators.
Vitamins and minerals become involved in tissue repair and antioxidant defense.
The bird continues eating, yet a significant proportion of nutrients may no longer be contributing to production.
This phenomenon is often referred to as the “hidden feed cost” of inflammation.

The Silent Performance Thief
One of the greatest misconceptions in poultry production is that intestinal problems always produce visible symptoms.
– Not necessarily.
– Many flocks show normal feed intake, acceptable mortality, and no obvious disease outbreaks. Yet they consistently fail to achieve target performance.
– A slight reduction in nutrient absorption.
– A minor microbial imbalance.
– A low level of intestinal inflammation.
– A subtle increase in intestinal permeability.
Individually these changes may appear insignificant. Collectively they can result in substantial economic losses. This is why gut health is increasingly viewed not as a disease issue but as a performance issue.

The Microbial Workforce Inside Every Bird
Perhaps the most fascinating discovery in recent years is the realization that birds are never truly alone.
The digestive tract contains trillions of microorganisms collectively known as the gut microbiome.
These microbes help digest feed ingredients, produce beneficial metabolites, support intestinal development, influence immune responses, and compete with harmful bacteria.
Some scientists now describe the microbiome as an additional organ because of its profound influence on bird health.
This raises an interesting question:
Are we feeding the bird, or are we feeding its microbiome?
The answer is both.
The future of poultry nutrition may depend as much on managing microbial populations as on balancing nutrients.

Heat Stress: The Gut’s Greatest Enemy
In many poultry-producing regions, heat stress has become one of the most significant challenges affecting gut health.
High environmental temperatures reduce blood flow to the intestine, increase oxidative stress, and compromise intestinal barrier integrity.
As a result, harmful bacterial toxins can cross the intestinal wall and trigger inflammation.
Often the first casualty of heat stress is not growth—it is gut integrity.
This may explain why heat-stressed flocks frequently show poorer FCR, increased wet litter, reduced nutrient utilization, and greater disease susceptibility.
As global temperatures continue to rise, protecting gut health during periods of heat stress will become increasingly important.

The Gut in the Antibiotic-Free Era
The poultry industry is rapidly transitioning toward antibiotic-free and reduced-antibiotic production systems.
While this shift addresses consumer concerns and regulatory requirements, it has also increased attention on intestinal health.
Without routine antibiotic growth promoters, producers must rely on alternative strategies to maintain gut stability.
Probiotics, prebiotics, β-glucans, mannan oligosaccharides (MOS), organic acids, phytogenic compounds, and postbiotics are increasingly being used to support intestinal resilience and microbial balance.
The focus is shifting from killing pathogens to creating an intestinal environment where beneficial microbes and the host can thrive together.

More Birds or More Protein?
The global poultry industry is not being asked to produce more birds.
It is being asked to produce more protein.
As the world’s population grows and consumers increasingly seek affordable animal protein, poultry production continues to expand. Industry projections estimate the sector will grow at a CAGR of approximately 5–7% over the coming years.

But growth alone is not enough.
Producers are expected to deliver more meat with fewer resources, lower feed costs, and a smaller environmental footprint.
This means that every gram of feed matters more than ever before.
And that brings us back to the gut.
Because the difference between feed consumed and protein produced is ultimately determined by the efficiency of the digestive system.

The Future Begins in the Gut
For decades, poultry production focused on genetics, nutrition, and disease control.
The next frontier may be intestinal resilience.
Future improvements in productivity will likely come from better management of inflammation, enhanced barrier integrity, optimized microbiomes, and improved nutrient efficiency within the gastrointestinal tract.
The question may no longer be:

“How much feed did the bird consume?”

Instead, the more important question may be:
“How much of that feed actually became growth?”
The answer lies within the gut.
Not because it is merely another organ, but because it is the organ that determines how effectively all the others perform.
In an era of narrow margins, rising feed costs, heat stress, and antibiotic-free production, the healthiest gut may ultimately become the most valuable asset in the poultry house.

What is Stress?
• Stress is a state of worry caused by a difficult situation, a natural response to address challenges & threats in life. Stress is a situation just opposite to Comfort
• Chicken has a limited amount of stored up resources to help adapt to unstable conditions, a challenge or a threat. As long as the challenges are within tolerable limits, chicken manages through its reserves, adjust to the situation & come out with little/no damage
• Stress is the situation when these challenges are more intense or greater numbers, resulting a serious chemical, physical & psychological changes in chicken with harmful consequence

Picture 1
Development stages of Stress in Chicken
– The 3 stages of Stress are ALARM, ADAPTATION & EXHAUSTION
– The first stage is Alarm, a short neurological stage. It is the ‘fright or flight’ reaction based on adrenalin release which triggers the release of glucose into the blood & helps the bird prepare to power to escape
– Adaption is next, where hormones are released to control the long-term effects of stress as they adjust to the new changes in their environment. There may be elevated cortisone levels in the blood, which arrange release of glucose from the body’s reserves of carbohydrates, proteins & fats to help the bird to adjust to the stressor. Diseases associated with long term stress, like diseases of heart, digestive system, metabolic imbalances and susceptibility to disease, are all attributed to high corticosteroid production in managing long term stress.
– The third stage, Exhaustion occurs when chicken does not recover from the stressor, its body reserves depleted, and the normal metabolic function fails with death of the bird.

Once chicken is exposed to stress, it results in immunological or metabolic consequences as below:
– Regression of immune organs/systems leads to Suppressed immune function & increased disease susceptibility
– Reduction of the oxidative metabolic capacity of mitochondria
– Deficit of antioxidant reserves
– Changes in the activity of antioxidant enzymes

Types of Stress in Chicken
– Noticeable Stress
– Disease
– Environment; Heat Stress, Winter Chilling, High Speed Wind (Cyclone), Poor Ventilation
– Starvation or Drinking Water shortage
– Debeaking

– Non-Noticeable Stress
• High performance; rapid growth and peak egg production
• Overcrowding
• Mycotoxin
• Endotoxin
• Wet Litter
• Litter Ammonia
• Poor Quality Feed
• Change of Feed
• Handling
• Transportation
• Vaccination
• Transfer/Mixing/Isolation

Factors responsible for Stress in Chicken:
A. Physiological
1. High Body Weight Gain in Broiler
2. Egg Laying, especially Peak period in Layer & Breeder

B. Nutritional
1. Feed Starvation due to poor supply or inefficient feeding system
2. Drinking Water scarcity
3. Deficiency of Protein, Carbohydrate, fats, Minerals, & Vitamins.
4. Poor quality like Dusty, too Hard or too Big Particle size or old damage feed

C. Environmental
1. Heat Stress
2. Winter Chilling
3. High Humidity
4. Cyclonic Wind
5. Lightening
6. Splash of Rain water
7. Earthquake

D. Operational
1. Debeaking or Beak Trimming
2. House/Cage Transfer, Mixing & Isolation
3. Transportation from one farm to another (Chick to Grower and to Laying farm)
4. Vaccination
5. Handling for Insemination, medication & vaccination
6. Management issues like poor Space (overcrowding), Ventilation, Wet litter, Litter Ammonia
7. Change in Feed
8. Change of attendant

E. Pathological
1. Infections; bacterial, viral, fungal, protozoan, etc
2. Metabolic Disorder like gout, ascites, etc.
3. Endotoxins
4. Mycotoxins
Out of all above, the important & dreaded stresses are all Pathological stress like Infections, Mycotoxins, Endotoxins, Metabolic disorders and 2 environmental stresss, viz. Heat Stress & Cold Stress or Chilling. Please remember when one stress comes after another, then 1 + 1 is not 2 but become 11, means combined stresses are dreaded to chicken.

Heat Stress:
– Heat Stress is a situation when chicken faces difficulty in achieving balance between body heat production & body heat loss
– Chickens lack sweat glands to facilitate latent heat loss by evaporation (perspiration), and have limited un-feathered body surface areas for loss of sensible heat through conduction, radiation, & convection
– Genetics, Feather cover, Age, Body Weight, Egg Production stage & flock maintenance all affect a chicken’s heat tolerance
– Chickens are homeotherms & regulate their body Temperature across a wide range of external Temperature.
– But continuous high climate Temp overwhelm the thermoregulatory mechanisms, resulting imbalance between the amount of metabolic heat produced & their capacity to dissipate body heat in the environment

Picture 2

Picture 3

Physiological response of Chicken to elevated temperature and the Loss in Poultry?
– With Increase in Climate Temp, the Thermal gradient between the Body surface & the surrounding environment lessens with Dissipation of Heat decreasing, resulting Chicken suffering from environment-induced Hyperthermia.
– This increases Respiratory rate (Thermal Polypnea or Panting) to increase Latent Heat Loss via Evaporation of water from the Respiratory tract
– Dehydration is the most harmful effect of panting, which causes Respiratory Alkalosis, acid base imbalance leading to permanent physiological damages
– Alkalosis reduces blood ionized Calcium and ultimately Eggshell mineralization resulting Reduced Egg production, Pale Egg, Soft Shell Eggs, Thin Shell Egg, Increased Broken egg % in Layer & Breeder
– Panting causes Oxidative Stress leading to Immunosuppression, damage of Gut mucosa leading to poor digestion, Dysbacteriosis, Enteritis and increase incidence of secondary infections (Viral like LPAI & ND, Mycoplasma & Bacterial) because of immunosuppression & leaky gut situation.
– Heat Stress reduces feed consumption resulting Poor Body Weight gain in Broiler and reduced Egg production in layer & breeder.
– Heat Stress has Permanent damaging effect; damages the muscles affecting Meat Quality and Lowering Breast Muscle Yield
– Reduces Protein content of the muscles, reduction of muscle pH & Water Holding Capacity and ultimately affecting Juiciness of Chicken Meat
– Disturbs Lipid metabolism by affecting enzyme function in lipid breakdown causing Excess Fat deposition instead of converting to meat
– Heat Stress reduces Male fertility in breeder and affects hatchability severely.
– Heat Stress impact the Expression of Gene related to Growth, Production Performance & Resistance to disease
– Heat stress impairs chicken’s immune system, leading to a reduced response to vaccines, suppressing the production of antibodies and affecting the function of immune cells, particularly lymphocytes, due to the atrophy of immune organs like thymus under high temperatures; heat stress makes it harder for chicken to fight against infections after vaccination and increases their vulnerability to disease
– Heat stress lowers the level of circulating antibodies (IgM & IgG) produced after vaccination, resulting in a weaker immune response against pathogens
– High Temp cause atrophy of thymus, leading to decreased T-cell production and impaired cell-mediated immunity
– Heat stress increases release of corticosteroid and further suppress the immune system.
– Heat stress disrupts the function of immune cells; macrophages & lymphocytes, affecting their ability to recognize and fight pathogens.
– Heat stress damage the intestinal lining, allowing entry of harmful & resident microorganisms into the body system to produce infections.

How to reduce the effect of heat stress in Chicken?
– Poultry House Environment need to made near comfort zone in terms of Temperature, Humidity & Ventilation. Closed Environment Control poultry house is the perfect answer.
– Plantation of Tress on both side of each shed
– Farm construction near forest or under Coconut or Mango Garden
– Reduce Stocking Density in summer to provide more space & more ventilation
– In open house system action must be taken to REDUCE TEMPERATURE at Birds level through

I) Elevated Roof, higher centre height
ii) Coated Roofing materials
iii) Extended side roof overhang to prevent entry of direct Sunlight
iv) Thatching of Roof by Agricultural waste (Paddy & wheat straw, Jute stick, Mustard/seasame harvested dry plant) and Ceiling by Thermostat Aluminium foil
v) Constructing Side Pandals (Leaned Roof Over-hang 1 meter)
vi) Hanging of Gunny with Dipper on both side (2 layers is best)
vii) Ceiling fans in case of Broiler and Circulatory fans in Layer or breeder to improve ventilation
viii) Springler on Rooftop to cool the roof
ix) Fogger inside the shed to reduce inside temperature

Disease Stress:
– Dis ease (Not fine) or Disease is No 1 stress factor in chicken like all other living being. Even unnoticed infection cause stress to force chicken to sit without movement and stay away from feed & water.
– Stress due to Diseases is the most neglected chapter in poultry farming, especially the subclinical or asymptomatic diseases.
– Global Animal Productivity loss due to clinical & subclinical diseases is 20%. Hence, we need to understand the disease stress on chicken and must act to minimize the same.
– Every disease has some specific symptoms but there are some common manifestations to every disease as below:
1. Anorexia or off-feed
2. Dullness, lack of movement or inactive
3. Poor eye reflection
4. Huddling
5. Poor body Weight Growth and poor Egg production
6. Death

Picture 4

Picture 5

Disease Stress produces:
– Uneasy physical status beyond comfort level
– Many physiological changes in the body resulting different symptoms
– Loss of appetite, poor growth & poor production
– Direct or indirect Immunosuppression inviting many other diseases
– Death due to system failure or lack of food for long time anorexia

Mitigation of Disease:
– Practical & 100% Biosecurity to avoid disease entry in to the poultry area.
– Welfare of chicken with respect to space, ventilation, temperature, drinking water & nutrition
– Daily Health monitoring
– Monitoring of Bird’s activity & Feed Intake everyday
– Immediate identification of any deviation in health & production parameter
– Immediate diagnosis at farm & confirmatory from laboratory
– Immediate treatment or necessary action to protect the health & life of chicken

How to Recognize Stress in Chicken
– Vocalization: Chickens have alarm sounds to alert other chickens, like repetitive chirps or screaming.
– Loss of Appetite; poor feed consumption, eating little sometime & stay away from feed in almost all stresses including Heat or Cold stress and disease stress.
– Abnormal Posture: In Heat Stress Birds sits on its belly & breast touching the floor and wings spread apart to lose heat through conduction, convection & radiation. In case of Disease Stress, birds are usually inactive & huddle together near to corner or at areas of Sunlight in open shed.
– Abnormal Behavior: In Heat Stress, there will be too much Panting to lose body heat through evaporation. During disease stress, the birds remain inactive and lying with head down & beak inside litter. Deep breathing is seen in respiratory diseases.
– Water Intake: Heavy increase in case of Heat Stress but reduced in Cold stress and in most diseases.
– Repetitive Behavior: include packing, constant rocking back & forth, head swinging or toe-taping

Effect of Stress in Chicken
– Uneasy state of life, abnormal posture & abnormal activity
– Stressed chickens usually extremely anxious, pick feather & self-mutilate, may cause permanent damage of feather follicles and scar develop on their skin
– Reduced Feed intake & reduced water (except Heat Stress) intake
– Immuno-suppression leading to many diseases from already existing microorganism in the house environment or in the intestine as commensal
– Oxidative stress leading to damage of gut mucosa, poor digestion, dysbacteriosis and enteritis
– Panting & Dehydration
– Excess release of Stress hormone (corticosteroid) leading to further immunosuppression & loss of body condition
– Poor commercial performance like, poor body weight gain & high FCR in broiler and reduced egg production with poor egg shell quality in layer & breeder
– Mortality

Mitigation of Stress in Chicken
– Maintain clean, calm & disease-free poultry house environment
– Noise-free environment; chicken don’t like unusual circumstances
– Avoid environmental stress like winter chilling, summer heat stress, monsoon high humidity inside poultry house through modification of infrastructure & husbandry practice.
– Need conceptual, infrastructural & operational changes to avoid environmental stress with climate change induced global worming situation.
– Avoid compromised ventilation, especially during winter & rainy days in open system farming. Avoid poor ventilation during high humid monsoon & chilly winter months in EC shed especially with compromised structure
– Avoid overcrowding; welfare is most unattended issue creating stress in poultry
– Avoid litter ammonia, wet litter & dust in poultry house
– Follow SOP & behave gently while handling, transfer, mixing, transportation, vaccination and insemination.
– Implement 100% Biosecurity, arrange regular health monitoring & health management. Educate your team about importance of biosecurity in poultry.
– Making sure your flocks have access to safe drinking water and regular supply of recommended fresh nutritious feed during the whole production cycle.

Author:
DEEP CHAND VASHISHTHA -M.Sc , MBA
NSM- Bioncia International Pvt Ltd

Stress comes in many forms and seems to affect the performance of birds. The term “stress” is used to describe the detrimental effect of variety of factors on the health and performance of poultry (Rosales, 1994) Or “Stress is the nonspecific response of the body to any demand”, whereas stressor can be defined as “an agent that produces stress at any time”. Therefore, stress represents the reaction of the animal organism (i.e., a biological response) to stimuli that disturb its normal physiological equilibrium or homeostasis (Selye, 1976). The commercial high yielding breeds are more susceptible to stress and diseases. Stress represents the reaction of the animal organism (i.e., a biological response) to stimuli that disturb its normal physiological equilibrium or homeostasis. The importance of animal responses to environmental challenges applies to all species. However, poultry seems to be particularly sensitive to temperature-associated environmental challenges, especially heat stress. Understanding and controlling environmental conditions is crucial to successful poultry production and welfare. Heat Stress not only causes suffering and death in the birds, but also results in reduced or lost production that adversely affects the profit from the enterprise.

Heat stress or any type of Stress have side effect on Vital organs heart, brain, kidneys, liver, and lungs.
Heat Stress adverse effects on liver
The liver is pivotal organ of metabolic activity, which performs essential cellular functions containing the balance of energy metabolism, biosynthesis of vitamins and minerals, and ammonia detoxification (Schliess et al., 2014). Elevated blood flow transfers from the hepato-splanchnic region to respiratory muscles and superficial body tissues to accelerate heat dissipation and decrease body temperature under heat stress, therefore, liver is more sensitive to heat stress (Hai et al., 2006; Crandall et al., 2008). It has been reported that heat stress caused liver fat accumulation and inflammation, and impaired liver function in broiler.

Heat stress adverse effects on respiratory system
Heat stress can cause damage to the lung tissue of broiler chickens by disrupting the integrity of the blood-air barrier and increasing permeability diseases can cause different degrees of lung damage Mammals mainly rely on sweat glands to dissipate heat and maintain body temperature balance (Yahav, 2015), but poultry lack sweat glands, so they primarily dissipate heat through respiration when the temperature is too high (Bell et al., 2001). High-frequency breathing leads to increased susceptibility of lung tissue damage in a heat stress environment. Damage to the blood-air barrier can lead to increased lung permeability, impaired oxygen and carbon dioxide exchange function, and induce respiratory difficulties (Wang et al., 2020), further leading to various lung diseases such as tuberculosis and pulmonary inflammation (Research has shown that heat stress causes lung injury and results in the upregulation of various proinflammatory cytokines, including tumor necrosis factor.

Conclusion
High ambient temperature has emerged as a major constraint for the future development of the poultry industry, especially in the tropics and subtropics. The scarcity of resources coupled with harsh environmental conditions is the most crucial predicaments in the way to rationalize optimum production of broiler. Heat stress disturbs the physiological biochemistry of the broiler which ultimately reduces feed intake and feed efficiency which ultimately results in reduced performance and productivity. Under hot environmental conditions, feed utilization is disturbed by the deposition of fat and oxidative stress. In addition, changes in blood cells, acid-base balance, immune response, liver health, and antioxidant status are some of the major dynamics altered by heat stress.

Alleviating the Adverse Effects of Heat Stress is mandatory to achieve Production & performance poultry Business.

Dr.Partha P. Biswas
M.Sc.,Ph.D.,F.Z.S.,F.Z.S.I.
Former Asso. Professor & H.O.D.,
Dept. of Zoology, R.K.Mission V.C.College,
Kolkata ,W.Bengal.
Senior Consultant, Aqua-Vet inputs,
Fin-O-Wing Formulations, Kolkata-700084

The chicken industry is becoming more vulnerable to environmental shifts, particularly high temperatures. Open-sided poultry species are susceptible to heat stress, negatively impacting growth and productivity. Factors determining heat stress include temperature radiation, humidity, metabolic rate, age, and duration. Modern commercial broilers are more sensitive to heat stress, making understanding and controlling environmental conditions crucial for poultry production and health. High temperatures in birds reduce antioxidant capacity, requiring food handling and expensive cooling. Understanding and controlling environmental conditions is crucial for poultry production and health.

Thermoregulatory Device in Chicken
Unlike mammals, birds do not have sweat glands, but they have developed a number of behavioral adaptations to cope with heat, including increased breathing rate, panting and raised wings. Commercial poultry prioritize high production, making broilers more sensitive to environmental stresses, and affecting meat quality and immune problems. Under conditions of heat stress, metabolic heat increases, and the animal succumbs to hyperthermia. In summary, it can be concluded that high ambient temperature outside the thermoneutral region during the production phase has a bad effect on meat production, meat quality and causes serious immune problems in broilers.

Heat Shock Proteins of Poultry Birds During Heat Stress
Heat shock proteins (HSPs) are stress proteins found in all living organisms that are activated by high environmental temperatures to protect cells from stressors such as heat. The 70 kDa heat shock proteins (HSP70) are a family of proteins known for their potential role in thermotolerance and widely regarded as cellular thermometers. Over expression of HSP70 has been observed under oxidative stress, leading to mitochondrial reactive oxygen species scavenging and pulmonary endothelial protection against bacterial toxins. They keep cells in order by synthesizing other proteins, attract immune cells and participate in protein assembly and degradation. Higher HSP expression is associated with better heat tolerance and is produced by all living organisms in high temperature environments.

Effects of Heat Stress in Poultry Birds
Reduced voluntary feed intake which affects the functionality of the entire digestive system High environmental temperatures activate the hypothalamus–pituitary axis, brain-gut axis and elevate plasma corticosterone concentrations, affecting the digestive system’s functionality.

This leads to changes in motility, flux patterns, secretory activity, content viscosity and pH Generation of ROS (reactive oxygen species) and the efficacy of the antioxidant defense system deteriorate. Overproduction of ROS in mitochondria can damage proteins, lipids, and DNA Heat stress can impair the feeding process, nutrient absorption and utilization, although water intake increases rapidly Upregulation of adipokines secretion (leptin and adiponectin) and the expression of their receptors can negatively regulate feed intake and calorie consumption thus resulting in decreased metabolic heat production The decline in trypsin, chymotrypsin and amylase (intestinal secretion) due to reduced feed intake often results in impairment of digestive functionality, nutrient digestibility Hypoperfusion and an increase in blood flow to the skin surface occur as an adaptive response of the circulatory system to stabilize blood pressure and promote heat loss It is known that heat challenge has an immune-suppressive effect.

Use of Dietary Phytochemicals to Reduce Heat Stress
Experimental studies on poultry birds suggest phytochemical ingestion may reduce heat stress effects. These phytochemicals can directly or indirectly influence genes and metabolic pathways, with stress reduction linked to antioxidant qualities.

Fig.3: The chicken’s response to being overheated. Chickens raised in high temperatures produce more reactive oxygen species and show signs of immunological inflammation in addition to consuming less food.

Mitigating Heat Stress Using Epigallocatechin-3-Gallate (EGCG), A Secondary Metabolite in Green Tea

Green tea’s most prevalent catechin, EGCG, is thought to be its most bioactive ingredient and possesses potent antioxidant properties. The primary cause of heat stress-induced oxidative stress in poultry is damage to tissues and cells, which is mostly manifested in an increase in MDA (malondialdehyde) concentration in such tissues and cells. It has been demonstrated that adding the polyphenol EGCG to broilers housed in thermoneutral environments may increase their antioxidant capacity. Acutely heat-stressed broilers may have greater antioxidant capacity and less oxidative damage in their muscles because EGCG may activate the Nrf2 signaling pathway.

Reducing Heat Stress in Broiler Chickens With Additional Ginger (Zingiber Officinale) and Onion (Allium Cepa)

Onion and its derivatives including saponins, aglycones, quercetin, cepaenes, flavonoids, organosulfurs, and phenolic compounds showed various pharmacological properties and therapeutic effects.When broilers are heat stressed, the combination of onion and ginger supplements increases the nutrition of the groups more than no supplementation.

According to research results, growth performance, carcass quality, antioxidant levels and immune system response of broilers are improved when fed 10 g of ginger and and 2.5 g of onion during heat stress. Ginger contains substances with powerful antibacterial and antioxidant properties, including chagaol, ginger diol and ginger diol. Ginger (2%) added to broilers suffering from heat stress significantly improved blood biochemical parameters and growth indicators compared to the control group.

Seeds of Black Cumin (Nigella Sativa) improve Bird’s Ability to Live in Heat-stressed Conditions

Black cumin seeds have been shown to have pharmacological and antibacterial properties and also contain drug-like compounds. The volatile oil (0.4-0.45%) contains saturated fatty acids, which include: nigellone, which is the only component of the carbonyl fraction. oil, thymoquinone (TQ), thymohydroquinone (THQ), dithymoquinone, thymol, carvacrol, α and β-pinene, d-limonene, d-citronellol, carvacrol, t-anethole, 4-terpineol and longifolin etc. Thymoquinone improves hatchability, pos-thatching performance and antioxidant activity of thermally stressed broiler embryos. Black cumin extract has been shown in trials to reduce serum MDA levels and protect against oxidative stress.

Hot Red Pepper (HRP) Reduces Heat Exhaustion in Birds

Ascorbic acid, or vitamin C, is abundant in capsaicin, a terpenoid found in HRP that helps prevent heat exhaustion in birds. Carotenoids, which are rich in vitamins E, C, and provitamin A (beta carotene), are known to have powerful antioxidant qualities that help prevent the damaging effects of free radicals and, in certain situations, oxidative stress, which can lead to cell death in broilers. Furthermore, it has been found that adding capsaicin, an active ingredient in red pepper that is present in grill feed at a dose of 50 mg/kg, can lessen the harmful effects of heat stress.

Moringa (Moringa Oleifera)helps to Survive Birds Under Heat Stress

Moringa leaves contain high levels of total polyphenols (260mg/100g), b-carotene (34mg/100g), kaempferol (34mg/100g), quercetin (100mg/100g), as well as a total antioxidant capacity of 260mg/100g. Kaempferol and quercetin are the flavonoids present in moringa leaves and possess strong antioxidants. It has been found that 0.3% incorporation of M. oleifera leaf meal improves the performance and physiological parameters of broilers and also helped the birds survive under heat stress.

THYME (THYMUS VULGAIS) Protects Chicks Against Heat Stress

The two most important bioactive compounds in this plant are carvacrol and thymol, which may be the primary source of thyme’s pharmacological actions. Thus research has identified linalool, thymol, carvacrol, gamma-terpineol, and geraniol as the primary components of thyme. Dietary thyme essential oil (150–200 mg/kg) is more effective at shielding chicks from the harmful effects of heat stress while also enhancing immunological function and development performance. One material that may be able to improve growth in broilers located in hot climates is thyme oil.

Coriander (Coriandrum Sativum) Seed in Ameliorating the Impact of Thermal Challenges

According to research, broilers under heat stress that are fed 2% coriander seed have higher feed intake, weight gain, reduced panting, and higher levels of corticosterone. The broilers’ poor intestinal absorptive capacity and shape may be connected to the rise in corticosterone levels during stress. Furthermore, according to a different study, adding 2% coriander to the diet helps broiler birds by lessening the effects of heat shock. The supplement, according to the author, benefitted broilers that were experiencing heat stress and enhanced their blood parameters, immunity, and overall performance.

Cinnamon (Cinnamomum Zeylanicum) Powder as Antioxidant in Thermally Challenged Birds

The common herbal plant, cinnamon contains different active phenolic compounds, which include flavones, catechin, isoflavones, flavonoids and other phenolics. The main bioactive constituent of cinnamon is cinnamaldehyde. The phenolic components function as antioxidants and can effectively scavenge ROS. Cinnamon supplements help in homeostasis due to the reduced pH caused by heat stress. It has also been reported that an increase in the activity of CAT, total antioxidant capacity and SOD and a decrease in the MDA when birds were placed in a thermally challenged environment during their finishing phase.

Turmeric (Curcuma Longa) for Heat-stressed Broilers

The yellowish pigments of turmeric, namely demethoxycurcumin, curcumin, and bisdemethoxycurcumin, are commonly referred to as curcumoids. Curcuminoids are an antioxidative compound found in turmeric. Researchers have shown the effects of turmeric powder supplement at 0.3 and 0.6 g/kg when administered to birds under heat stress. The superoxide radicals are neutralized, and there is an increase in the activity of SOD and CAT (ROS-removing enzymes or antioxidant enzymes ) and a decrease in MDA in broilers. The increased level in MDA indicates oxidative damage in liver of heat stressed broilers.

Conclusion
Heat stress can hurt poultry birds by making them grow slower, weakening their immune system, causing intestinal inflammation, and causing other health problems. It can also trigger oxidative process. But using natural substances called phytogenic compounds can help chickens who are raised in hot conditions.But more research is needed to understand the molecular changes made by medicinal herbs and the interactions between their active components, gut microbiota, and gut barriers. By using these approaches, we can improve chicken welfare and make poultry production more sustainable and efficient.

It was first discovered in the juice of sugar beets. Naturally accumulated in plants as osmolyte to protect against salt and temperature stress. Derivative of glycine (amino acid). Neutral molecule with bipolar structure (zwitterion) as shown in Fig. 1 contains three methyl groups.

Fig.1: Chemical Structure of Betaine

2. Betaine functions as (mode of action):
A. Methyl donor – methyl groups used for protein synthesis and other metabolic processes. Methyl groups play a pivotal role in several cellular processes, including DNA methylation, synthesis of phosphatidylcholine, and protein synthesis. Choline and betaine are both capable of donating methyl groups. However, for choline to do so, it must first be converted into betaine as shown in Fig. 2. In poultry, the capacity to synthesize betaine from choline is limited, thus making dietary supplementation the primary source.

Fig. 2: Role of betaine in the methionine cycle in liver

Betaine can substitute for choline in performing the following functions:
1) Regulating fat metabolism in the liver to prevent abnormal fat accumulation in hepatocytes.
2) Serving as a methyl donor for the formation of methionine and creatine, through its involvement in the transmethylation pathway.
Betaine cannot replace choline in the function of maintaining cell membrane and structure as an emulsifier to transport lipids, since choline is a constituent of phospholipids. Similarly, betaine cannot replace choline as a precursor of acetylcholine in the transmission of nerve impulses.

B. Osmo-regulator: – ability to bind and retain water in a reversible manner.
Osmolytes are compounds that aid in the regulation of osmotic pressure within cells and tissues, playing a crucial role in preserving cellular integrity.
Dehydration, disease, heat stress, and other factors can cause alterations in the water content of cells. Osmolytes can be either inorganic ions such as Na+, K+, Cl-, or organic compounds such as amino acids, certain sugars, and betaine. Betaine plays a crucial role in stabilizing cellular metabolic function during periods of stress, preserving the cell’s capacity to uptake nutrients, unlike osmolytes such as Na+, K+, and Cl-. Moreover, it offers protection to intracellular enzymes against osmotic inactivation.

3. Heat stress
Heat stress is a major challenge in poultry production, especially during the hot summer months. It occurs when birds face difficulty in achieving a balance between body heat produced and heat loss. This imbalance can lead to several health issues and production losses.

4. The Role of Betaine in Enhancing Poultry Health During Heat Stress.
a) Betaine aids in preserving intestinal integrity by facilitating water retention, increasing cell volume, promoting anabolic activity, and maintaining cellular integrity as shown in fig. 4. which are Representative photomicrographs of the ileum after 10 days of the experiment from broilers fed a control diet (CON, A and C) and betaine (BET, B and D) on villous height under thermoneutral (TN, A and B) or after 10 days being exposed to heat stress (HS, C and D).

Fig. 3 – Intestinal barrier damage in HS (Soheil Varasteh, et al. Nutrients, 2020)

Fig. 4 – Impact of betaine on intestinal integrity of broiler birds in Heat stress conditions (Shakeri et al, Animals 2020)

b) Betaine has three methyl groups in its structure and donates them in various metabolic reactions, which can spare compounds like methionine, choline, and folic acid. Therefore, supplementing with betaine may reduce the need for these nutrients.

c) The growth rate of poultry birds is enhanced by betaine, which conserves energy that would otherwise be expended on the Na+/K+ pump and Calcium pump in high temperatures. This conserved energy can then be directed towards growth.

d) Betaine enhances the concentration of beneficial short-chain fatty acids, such as acetic and propionic acid, which are vital to host bacteria like Lactobacillus and Bifidobacterium in poultry. This improvement enables these bacteria to effectively inhabit the caecum and inhibit the colonization of harmful bacteria in the intestinal tract.

e) Betaine supplementation in laying hens leads to an increase in daily egg mass production, reduces thin eggshell issues which are related to heat stress, and helps to enhance serum concentrations of estradiol and melatonin.

f) Trouw Nutrition’s Betaine is proven to elevate production performance even under heat stress conditions, notably increasing breast meat percentage through the provision of essential methyl groups, as depicted in Fig. 5. Recognizing that high-performing animals demand superior nutrition for sustained health and optimal growth, Selko Feed Additives introduces TNIbetain. This meticulously tested supplement supports animal performance across multiple metabolic pathways. TNIbetain adheres strictly to the stringent quality standards upheld by Trouw Nutrition Feed Additives.

Fig. 5: Effect of Trouw Nutrition betaine on broiler performance
Contrasting the Attributes of Trouw Nutrition’s Natural Betaine with Synthetic Betaine

Recommended Dosage:
For broiler, layer, and breeder birds: 0.5 to 1 kg per ton of feed. However, in challenging conditions such as heat stress, the Betaine dosage can be increased to up to 2 kg per ton of feed.
g) Betaine has been found to significantly enhance hematological parameters, including RBC and platelet count, while reducing the number of heterophils and increasing the number of lymphocytes. The reduction in lymphocyte count during heat stress is attributed to the rise in inflammatory cytokines, which stimulate hypothalamic production of corticotrophin releasing hormones.
h) Betaine aids in the expansion of intestinal mucosa, thereby enhancing the absorption and utilization of nutrients, which results in improved digestibility of crude protein, crude fiber, ether extract.
i) Studies have demonstrated that betaine interacts with lipid metabolism by promoting the oxidative catabolism of fatty acids through its involvement in carnitine synthesis. Therefore, betaine can be utilized to increase the proportion of lean meat and reduce fat in poultry carcasses.
j) Betaine acts as an osmoregulatory in the intestine, optimizing water and salt balance within cells for efficient nutrient absorption and reducing litter moisture. It increases villus height, protecting enterocytes during challenges like coccidiosis, and strengthens the gut, reducing damage during infections as shown in Fig. A, B and C.
The various effects described above are either directly or indirectly linked to betaine’s osmoregulatory function and its role in methionine biosynthesis.
Betaine emerges as a pivotal component in poultry health management, particularly in the face of heat stress challenges. Originating from sugar beets, its molecular structure rich in methyl groups facilitates its dual function as a methyl donor and osmoregulator, essential for maintaining cellular integrity and supporting metabolic processes. Amidst heat stress conditions, Betaine supplementation showcases remarkable efficacy, preserving intestinal integrity, conserving energy expenditure, and enhancing production performance. Its multifaceted benefits extend to improvements in hematological parameters, nutrient absorption, and lipid metabolism. With its proven effectiveness and adherence to stringent quality standards, Betaine stands as a crucial asset in optimizing poultry health and performance under challenging environmental conditions, exemplifying the potential of innovative nutritional strategies in safeguarding livestock welfare and productivity.

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