Strategic approach to combat heat stress in poultry

Strategic approaches to combat
Heat Stress
Dr. Md. Aminul Islam
Saturday, April 10, 2021
Heat Stress

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
Heat Stress

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.
Heat Stress

Heat Index, Temperature & Humidity relationship
Relative Humidity (Rh) %
o
F o
C 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Temperature
68 20 63 63 63 64 64 64 64 65 65 65 66 66 66 66 67 67 67 67 68 68
72 22 64 65 65 66 66 66 67 67 67 68 68 69 69 69 70 70 70 71 71 72
75 24 66 67 67 68 68 69 69 70 70 70 71 71 72 72 73 73 74 74 75 75
79 26 68 69 69 70 70 71 71 72 73 73 74 74 75 75 76 77 77 78 78 79
82 28 70 70 71 72 72 73 74 74 75 76 76 77 78 78 79 80 80 81 82 82
86 30 71 72 73 74 74 75 76 77 78 78 79 80 81 81 82 83 84 84 85 86
90 32 73 74 75 76 77 77 78 79 80 81 82 83 84 84 85 86 87 88 89 90
93 34 75 76 77 78 79 80 81 82 83 84 84 85 86 87 88 89 90 91 92 93
97 36 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 93 94 95 96 97
100 38 78 79 81 82 83 84 85 86 88 89 90 91 92 93 95 96 97 98 99 100
Heat Stress

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
Heat Stress

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
Heat Stress

2 Reduce Eating & Drinking more
 Nutritional deficiency- accounts for
90% of the weight loss.
 Increase Urination- Triger ion loss,
increase humidity from wet litter
Water-Feed intake ration
2:1
at 21 oC
8:1
at 38 oC
Broiler:
1% rise in the zone of comfort leads to a
1.6% decline in feed intake.
Layer:
A daily feed intake reduction of 28.58 g/bird,
resulting the reduction of-
• 28.8% decrease in egg production
• 3.41% in egg weight
• 1.2% egg shell thickness
• 9.93% eggshell weight
© Byrd el al. Poult. Sci. 2012)
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
Heat Stress

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
Heat Stress

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
Heat Stress

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)
Heat Stress

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
Heat Stress

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
Heat Stress

Carcass quality deteriorated on heat stress
Heat Stress

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
Heat Stress

Strategies
to cope up
the impacts

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%

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
Effect of water temperature on intake
© Ross Note – Broiler Management in Hot Weather, July 2016
 Increase waterer number (1/30 birds)
 Water tank can be paint with white color
 Cover tank with wet gunny bags
 Keep tank filled in 80% at least
 Give ice in water tank if possible
Heat Stress

Help birds
to comfort & ease
 Manage Feed sets
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
Heat Stress

Help birds
to comfort & ease
 Manage feed sets
Feeding pattern of chicks on mash & pellet diets
Chinks 21-28 day Mash Pellet
Meals/day, no. 35 27
Eating Time, min 103 34
Time/meal, min 2.9 1.3
Feed Consumed, g 38 37
© Jensen et al.
 Increase feeder number (1/25 birds)
 Increase the frequency of feeding
 Allow feed at cooler part of the day
 Feed can be mixed with water (20 L /100 kg)
Heat Stress

Help birds
to comfort & ease
 Cool water supply
 Increase number of drinker
 Manage feed sets
Fast moving air over birds creates a wind-chill effect.
© Ross Note – Broiler Management in Hot Weather, July 2016
Heat Stress

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.
Heat Stress

Pay attention on
Nutrition
 DEB Balance
Amino Acids Ratio with Lysine
Lysine 100
Methionine + Cystine 75-76
Threonine 66-70
Valine 76-80
Arginine 110
Histidine 30
Isoleucine 67-70
Leusine 100
Tryptophan 20-24
Phenylalanine+Tyrosine 105
Serine+Glysine 100-105
Supplemental electrolytes in drinking water
Supplement Dose Reference
NH4Cl 0.2% Teeter et al., 1986
KCl 0.15% Ait Boulashem et al., 1995
NaHCO3 0.2% Hayat et al., 1999
© Lin et al., 2006
Heat Stress

Pay attention on
Nutrition
 DEB Balance
DEB balance
©
+250
-250
0
Cl- + S- Na-+K-
DEB
balance in feed +280
In heat
stress time
Thumb Rule of Inclusion
 Na=Cl or Na is 10% more than Cl
 K is 3-4 time of Na

Prevent Cellular Damage
by formulating diet
 Trace mineral
 Antioxidants
Trace Mineral
©
Metals such as iron, copper, chromium & cobalt are
capable of redox cycling in which a single electron may be
accepted or donated by the metal.
M(n+1)+ − SOD + O−
2 → Mn+ − SOD + O2
M-Metal, N-electron number of metal, SOD-Superoxide dismutase
Heat Stress

Prevent Cellular Damage
by formulating diet
 Trace mineral
 Antioxidants
Antioxidant
©
Vitamin-A
 Decrease Corticosteroids secretion
 Helps to reduce oxidative damage
Vitamin-C
 Prevent oxidative damage
 Improve immunity
Vitamin-E
 Ensure cell membrane integrity
 Protect cell from ROS actions
Heat Stress

Keep cellular water content by
Use of Osmolytes
 Betaine (Osmolyte)

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
Heat Stress

Looks on the
Opportunistic
 Necrotic Enteritis
 Coccidiosis
 Mycotoxin
 Other Infections
Heat Stress

Thank
You
aminul.vet@gmail.com
+8801743444560

Strategic approach to combat heat stress in poultry

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