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Strategic approach to combat heat stress in poultry
1. Strategic approaches to combat
Heat Stress
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
2. Heat Stress? The Consequence of occurrence
LCT
(Low Critical Temperature)
25
0
C
18
0
C
Thermoneutral Zone
Regulate heat loss
Normal Temperature
No Sign of stress
Cold
Stress
UCT
(Upper Critical Temperature)
Slow panting Fast Panting
Maximum heat loss
Failure in thermoregulation
Heat Loss > Heat Production Heat Loss = Heat Production Heat Loss < Heat Production
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
3. The ways of heat loss in excess into the body
Radiation Distance Objects
Electromagnetic waves transfer body heat
through the air towards cooler objects. The
higher the difference in temperature, the
more heat is lost from the surface of the body.
Convection Surrounding air
Heat from body parts such as the comb,
wattles and wings is naturally lost to cooler
surrounding air.
Conduction In direct contact
Heat is transferred from the body to a cooler
surface when both are in direct contact. Birds
can for example sit on litter or lean against
cage wire to lose body heat.
Evaporation Breathing
Panting is shallow open-
mouth breathing which allows
heat loss via evaporation of
water from the mouth &
respiratory tract.
Excretion Faces
Heat also losses with water in faces.
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
5. Heat Index, Temperature & Humidity relationship
Heat Index < 70
Bird’s comfort zone
No action is required
Right time for preparation
Heat Index 70-75
Start taking action
Increase Ventilation
Increase fan speed
Can use misters
Be sure drinking & ventilation is working
Heat Index 76-81
Danger time, birds are in stress
Maximize air speed @ 1.8-2 meter/second
Adjust nutrition to compensate
Provide cool water
Closely monitor the bird behavior.
Heat Index >81
Emergency Situation
Birds are in extreme stress
Avoid bird handling
Avoid vaccination
Don’t feed at hot time
Comfort Zone
Alert Zone
Danger Zone
Emergency
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
6. BLOOD
BLOOD
SHELL GLAND
KIDNEY
Bird’s effort to cope with heat stress
1 Panting (Evaporative cooling)
Laborious work- Energy Loss
Respiratory alkalosis- Electrolyte imbalance, affect egg shell 25
breaths/minute
250
breaths/minute
LUNG
CO2 + H2O H2CO3 H+ + HCO3
-
HCO3
-
Ca+
Na+
K+ CO3
- + H+CaCO3
Carbonic anhydrase activity
pH
Ca2+
Ca2+
Ca2+
Electrolyte Imbalance
Lower the Egg Shell Quality
Reduce bone density
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
8. Bird’s effort to cope with heat stress
3 Shifting of visceral blood flow towards
peripheral circulation
4 Avoid crowding & Find cool
surfaces
Expend more time for comfort- get
less feed & suffer from psychological
stress.
Ischemia & Hypoxia
in enterocytes
Limiting Gut motility
Less Nutrient Uptake
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
9. Bird’s Effort to cope with heat stress
5 Endocrine Response
Fight or flight response, increase heat rate,
BP, increase muscle activity, decrease
digestion & immune function
Adrenaline & Noradrenaline
Activation of adrenal
medulla & peripheral SNS
Activation of anterior
Pituitary Glands
CRF
Stimulation of adrenal
cortex
ACTH
Hyperglycemia, immunosuppressive,
Anti-inflammatory activity
Corticosteroid
Heat Stress
Sympathetic portion of
Autonomic Nervous system
Hypothalamus
SAM
Axis
HPA
Axis
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
10. Bird’s Effort to cope with heat stress
5 Endocrine Response
Adrenaline: fight or flight response
Blood Pressure ↑
Heart rate ↑
Muscle activity ↑
Respiration ↑
Digestion ↓
Immune Function ↓
Chronic Stress: Major production loss occurred
Cell damage by ROS
Increase Pathogen susceptibility
Decrease production performance
Hamper egg shell quality
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
11. Oxidative Stress, a consequence of heat stress
Reactive Oxygen Species (ROS)
[peroxides, superoxide, hydroxyl radical, singlet oxygen & alpha-oxygen]
O2 + e− → •O−
2
Normal
Physiological
Response
Redox State
[ROS Production+ Detoxification=0]
Superoxide (•O−
2 ) produces hydrogen peroxide (H2O2)
2 H+ + •O−
2 + •O−
2 → H2O2 + O2
H2O2 in turn may be partially reduced, thus forming hydroxide
ion & hydroxyl radical, or fully reduced to H2O.
Environmental
Stress Condition
Oxidative Stress
[Increase ROS]
Damage of DNA or RNA
Lipid peroxidation
Oxidations of amino acids
Deactivation of enzymes
Cellular Damage (Mitochondria)
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
12. Gut Health: The enterocyte is most vulnerable to ROS
2 Alteration of intestinal
Morphology
1 Alteration of intestinal
Tight Junction
Lower total & relative weight of SI
Shorter jejunum & duodenum
Shorter villi
Reduced absorption areas
3 Change in the intestinal
Microbiota
Leaky gut favors pathogens
Dysbacteriosis
Leaky Gut
Syndrome
Intestinal cell death by
Ischemia & Hypoxia
ROS effects on intestinal
tight junction
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
13. Immune function falls on heat stress
Heat Stress
Suppress
Immune Function
Lower levels if total circulation
antibodies, as well as lower specific
IgM & IgG level
Cortisol & Catecholamines
An increase in
Heterophils: Lymphosite ratio
Affect cellular trafficking,
proliferation, cytokine secretion,
Antibody production & cytolytic
activity
Lipid peroxidation of cell membrane
mainly T-lymphocytes
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
15. Ultimate Effects of Heat Stress
Acid base imbalance
Leaky gut syndrome
Gut Health disturbances
Impaired immunity
Electrolyte imbalances
Reduce Egg shell integrity
Target allthe
Effects to Mitigate
Reduce bone integrity
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
17. Keep House Cool
as much as possible
Proper ventilation
Misters/Spraying
Humidity monitoring
Use of fan & exhauster
Lighting schedule
100%
80%
60%
40%
20%
10%
The
Comfort
Zone
Death Zone
Fan & misters is not effective
Only Air conditioning is Effective
Death Zone
Risk increase with the increase of Rh
Fan can to minimize death
Evaporative cooling
Use of Fan & Misters are useful
Bird can
control the own
temperature.
But your help
is required.
Set house in a proper direction
to facilitate ventilation
Implantation around the farm
can reduce hot air entrance into the farm
Rh>80%
Rh<80%
19. Help birds
to comfort & ease
Cool water & with easy access
Provide more space
Avoid feeding at hot time
Manage Feed sets
Create wind chill effects
Stock Density
Keep proper uniformity in flock
Increasing floor space helps bird to loss heat
Age (Days)
Floor Space
(Sq.ft)/Bird
Floor Space
(Sq.ft)/1000 Birds
1-4 0.3 300
5-7 0.4 400
8-10 0.5 500
11-15 0.8 800
>16 1.2 1200
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
22. Pay attention on
Nutrition
Energy balance in feed
Use amino acid profile
Electrolyte Balance
DEB Balance
Energy balance
The concentration of energy can be increased
by 10% during heat stress.
Need to select the raw material which have
digestive coefficient more then 85%.
Fat should be increased by 2 to 3% (<5% ) at
the cost of CHO without changing ME.
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
28. Keep cellular water content by
Use of Osmolytes
Betaine (Osmolyte)
Heat Stress
In order to maintain the water balance in the cells, increase
the Na+/K+ pump across the cell membranes.
Water loss
in respiration
Water loss due to
Leaky gut syndrome
Loss energy
Dehydration
Osmolyte/Betaine
Increase osmotic function
Cell less rely on
Na+/K+ pump
Prevent Dehydration
Less energy production
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
29. Looks on the
Opportunistic
Necrotic Enteritis
Coccidiosis
Mycotoxin
Other Infections
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress
https://www.heatstress.info/heatstressinfo/Heatstressincattlepoultryandswine/BiochemistryofdietaryelectrolytebalanceinPou/tabid/2214/Default.aspx
The end products of
metabolism within the cells are usually acids, which means there is an increase
in hydrogen ions [H+] these are neutralised by bicarbonate [HCO3].
An increase in the ambient housing temperature from 21.1 to 32.2°C caused a drop in feed intake of about 9.5% per bird/day from the first week to the sixth week of age. When ambient temperature rose from 32.2 to 37.8°C, it caused a further drop in feed intake of 9.9% per bird/day, as compared to 21.1°C (North and Bell, 1990)
Body weight of broilers at six weeks of age was decreased by about 14.3% and 21.2% at 32.2°C and 37.8°C, respectively (North and Bell, 1990) and even up to 34% at 32.2°C as compared to 21.1°C (Cheng et al., 1997).
H+ + HCO3 ---> H2CO3 ---> H2O+ CO2
Lactic Acid+NaHCO3 --->H2CO3 ---> H2O+ CO2
High ambient temperature also reduces thyroid activity in poultry. Plasma T3 and T4, important growth promoter in animals and are reduced at high temperature. In addition, heat stress stimulates the release of corticosterone and catecolamines and initiates lipid peroxidation in cell. During heat stress, plasma protein is reduced and markedly increased blood glucose concentrations. Such high ambient temperature results in decreases in serum vitamin and mineral concentrations in poultry as well as in human.
Corticosterone can affect protein synthesis in the muscles.
Intestinal Tight Junction: Ensure a plague by 3 Transmembrane proteins (Ocludine, Claudin & Junction addition Protein). Some few peripheral protein are supportive here.