In the tropical climate like India, the high ambient temperature along with high humidity is the major stressor (abiotic), thus resulting in the HEAT STRESS a major concern of poultry production. 55°F – 75°F Thermoneutral zone 65°F – 75°F Ideal temperature zone 75°F – 85°F A slight reduction in feed consumption 85°F – 90°F Feed consumption falls further, cooling should be started before this temp is reached. 90°F - 95°F Feed consumption continues to drop, danger of heat prostration among layers, cooling . 95°F-100°F Heat prostration, water consumption is high. >100°F Emergency measures must be taken, survival is concern at these temperatures. CONCEPTS AND STRATEGIES TO AMELIORATE THE HEAT STRESS 1. Environmental strategies Intermittent Photoschedule(light). 2. Housing management Sites election, design and construction, ventilation, internal and roof cooling, Density of birds. 3. Nutritional strategies Increasing energy density Dietary Protein level and Amino acid composition Vitamins – A,C,E. Minerals. Non nutrient feed additives. Water and electrolyte balance. 4. Feeding strategies Early feeding Intermittent feeding Sex separate feeding Fasting or feed with drawl. 5. Genetic strategies Selection for heat tolerance. Selection for disease resistance. Use of major genes – Naked neck(Na), Frizzle(F), Dwarf(dw), Silky (h), Slow feathering (K). ENVIRONMENT STRATEGIES: A). Intermittent Photo schedule An intermittent light regime can improve the feed efficiency and thus the broiler production efficiency, by decreasing the fat deposition associated with increased incidence of leg abnormalities, metabolic and cardiovascular diseases, ascites. The favourable effect is related to the lower heat production during both light and dark period, although fluctuations in heat production are following closely the light-dark alternation. This photo schedule contains more than one scotophase and one darkphase which recur at 24 hr intervals. This regime increases the feed consumption during cooler part of the day. Symmetric - when scotophase and dark phase are of equal length. Asymmetric - when they are not in equal length. 3weeks age of broiler raised under 2L:4D intermittent light regime were significantly lighter than broilers raised in continuous light schedule but at 7 weeks it is reverse.(Proudfoot, 1975). The initial reduction in body weight gain of birds under intermittent schedule is followed by compensatory growth, but the compensatory growth depends on genotype and sex. Boschouwers and Nicaise (1992) observed that physical activity in broilers were lowest under 100Hz fluoroscent light and highest under incandescent. HOUSING MANAGEMENT  Orientation : east west to reduce direct solar radiation  Shade of trees and green crops around the houses will prevent direct heating, .vegetation should be mowed frequently so that it doesnot obstruct air flow Houses should be oriented perpendicular to wind direction for max

1. Credit seminar
stress in poultry - concepts and strategies to ameliorate
PRESENTED BY
ALAPATI HARSHINI
M- 6102
M.V.Sc PSC

2. What is Stress ?...
Latin word Stringene draw tight
Eustress (Greek word) - good Selye 1976
Distress( Latin word) - bad
Current Status of Stress
Deviation from normal or
Deterimental effects of variety of factors on
Health
Performance of birds

3. • Stress is an animal’s inability to cope up with its environment,
a phenomenon which is often reflected in a failure to achieve
genetic potential and occurs as a response to any stimuli that
disturb its homeostasis.
(Dobson and Smith, 2000)
• The term “STRESS” is used to describe the detrimental effects
of variety of factors on the health and performance of poultry.

4. • The stress response is a multidimensional complex mechanism
involving a series of behavioral, physiological, metabolic, and
immunological reactions that the body uses to redistribute the
demands placed on it for survival.
(Shini et al., 2010).

5.  Limited Resources (Energy) of body for:
Growth
Reproduction
Response to environmental change
Defense mechanism
 Under stress condition, redistribution of Body Resources at the Cost of
Above Aspect :
 Long term Stress Or repeated Stress
 Bird fatigue and week
 Prone to disease DIE

6.  Any stimulus that evokes this response is referred to as a
STRESSOR.
• Temperature
• Solar radiation
• Humidity,
• Wind, toxins
ABIOTIC
• Bacteria
• virus
• Fungi
• Parasites
BIOTIC

7. TYPES OF STRESS
There are common sources of stress which can be grouped under one or more
of the following categories (Freeman, 1987).
CLIMATIC
Extreme Heat & Cold,
High Humidity
ENVIRONMENTAL
Bright Light, Wet Litter,
Poor Ventilation
NUTRITIONAL
Shortages of nutrients,
Feed intake problems
PHYSICAL
Catching, Immobilization,
Injections, Transport
PHYSIOLOGICAL
Rapid growth, Process of
maturing sexually
SOCIAL
Overcrowding, Poor body
weight uniformity
PSYCHOLOGICAL
Fear, harsh care takers
PATHOLOGICAL
Bacteria, Virus, Fungi,
Parasites

8. PHYSIOLOGICAL MECHANISM OF STRESS
Exposure of birds to stress is an inevitable event in poultry husbandry, when
the threshold level of stress is crossed it results in distress to birds. Then the
birds show stress syndromes, which are classified into three stages
 Stage of alarm reaction (Neurogenic system) – short term.
 Stage of resistance or adaptation (Endocrine system) – Long term
 Stage of exhaustion

9. Sympatho adrenal system Endocrine system

10. CATEC
HOLA
MINES
HYPERGLYCEMIA
Depletion of liver
glycogen
cAMP
Formati
on of
Ab’s
Increased
peripheral
vasomotor activity
ALTERED
VENTILL
ATION
PITUATARY
• ACTH
ADRENAL
CORTICAL
HYPER
TROPHY
• CORTICO
STERON
E
Formation of
glucose, GI
disease, Ab
suppression
SYMPATHO ADRENAL HYPOTHALAMUS PITUATARY AXIS

11. Stage of Exhaustion:
 If the bird does not recover from the stressor and the
availability of body reserves and hormones are inadequate, a
third or exhaustion phase leads to fatigue of the homeostatic
mechanisms and death.

13. Effects of stress in birds
Increased B Temp Anorexia Increased H:L
Ascites Impaired growth of bone &cartilage Atrophy of thymus

14. • Atrophy of bursa
• Synthesis of heat shock proteins [HSP70, HSP90 &
HSP3(HO-1)].
• Decreased growth and muscle degeneration.
• Release of acute phase cytokines (lymphokines, monokines)
• Excess abdominal fat deposition (abdominal fat pad)
• Epinephrine content in the yolk of donor hens serves as a good
tool to reflect stress load in layer stock

15. STRESS MARKERS OR INDICATORS
When a bird is under heat stress several parameters are
altered which help in adaption of that bird to stressors.
• Bodyweight
• Physiological parameters :- Body Temperature (T),
Respiratory Rate (RR), Pulse Rate (PR).
• Hematological parameters:- PCV, Hb, Cell count, H:L ratio.
• Metabolic profile:- Glucose, protein, cholesterol, BUN.
• Enzymatic and endocrine profile:- T3, T4, Corticosterone, GH.

16. TEMPERATURE
55⁰F – 75⁰F Thermoneutral zone
65⁰F – 75⁰F Ideal temperature zone
75⁰F – 85⁰F A slight reduction in feed consumption
85⁰F – 90⁰F Feed consumption falls further, cooling should be started before this temp is reached.
90⁰F - 95⁰F Feed consumption continues to drop, danger of heat prostration among layers, cooling .
95⁰F-100⁰F Heat prostration, water consumption is high.
>100⁰F Emergency measures must be taken, survival is concern at these temperatures.

17. Respiratory Rate
Temperature Days of exposure Respiratory rate
39⁰C -40⁰C 0 50.67
39⁰C -40⁰C 3 87.50
39⁰C -40⁰C 7 110.33
 Thermal tachypnea
 Gular flutter PANTING

18. Variations in the broilers H:L as indicated by various authors
Factor value Reference
Age After hatch: 1.25
21 days : 0.25
42 days : 0.55
56 days :0.34
Gonzales et
al.,2003
Tyagi et al.,2007
Body weight HBW:1.35
MBW:1.20
LBW:1.39
Gogoi,2016
Strain CARIBRO Vishal :0.90
CARIBRO Mrityunjay:0.85
CARIBRO Tropicana:0.82
Amruktar,2012
Temperatue At 23⁰C: 0.53
41⁰C: 0.73
Shoaib,2011
Exposure time 0 days:0.71
3 days:1.67
7 days:1.56
Gogoi,2016

19. Biochemical parameters
 Hyperglycemia that is attributed to decrease in insulin levels
(Habibian et al., 2014).
 Albumin, rather than total protein or globulin, has been shown to be
the most sensitive indicator of protein status.
(Aksit et al., 2006).
 Heat stress also decreases blood Na, K and partial pressure of carbon
dioxide (pCO2), which may disturb acid-base balance and cause respiratory
alkalosis, respectively
(Borges et al., 2004).

20. STRESS HORMONES
Heat or transportation stress corticosterone delays proliferation of
intestinal epithelial cells
Decreased villus height and crypt depth
Damage of intestinal mucosa.
Pro inflammatory agents alters the tight junctions of intestinal epithelium
Increases permeability of pathogens
Factor Value Reference
Heat stress 31⁰C:92.69 ng/mL. Quinteiro-Filho et
al.,(2010)
36⁰C:109.60
ng/mL.
3hours post
exposure
35⁰C:20.84 ng/mL. Han et al., (2010)
Modulating levels of corticosterone
in various conditions
The circulating levels of corticosterone showed a significant rise from 0d to 3d and
consequently decreased on 7d (Gogoi, 2016).

21. STRESS HORMONES
Triiodothyronine (T3) is the main metabolism stimulating hormone that has
been found to be associated with temperature regulation.
 T3 could be considered as reliable indicator of long-term heat stress.
 Thermo tolerance involves the modulation of heat production through
changes in circulating T3. Circulating T3 concentrations significantly
reduced with linear increase in temperature
(Gogoi, 2016).
 Heat stress is accompanied by a decrease in plasma thyroid hormones,
which is associated with a decrease in the basic metabolic rate and heat
production

22. ERYTHROCYTE OSMOTIC FRAGILITY INDEX
• Osmotic behaviour of erythrocytes by determining the resistance or
strength of red blood cells (RBCs) to hemolysis when exposed to varying
osmotic gradients
(Aldrich et al., 2006).
• EOF provides indirect estimate of its anti-oxidant capacity.
• RBCs that are subjected to heavier stress tend to become fragile in osmotic
solutions.

23. HEAT SHOCK PROTEINS
• HSR is regulated mainly at the level of transcription by four heat shock
transcription factors (HSFs), HSF1, HSF2, HSF3 and HSF4 resulting in
stimulation of HSPs expression.
• In chicken, HSPs, especially HSP70, HSP90 and HSP32 (HO-1) are
considered as vitagenes
(Surai, 2015).

24. • High ambient temperature in the tropics accompanied by high
relative humidity is one of the most important stressor.
• Birds are more susceptible to high environmental temperature
than low due to
high body temperature (40.1°C to 41.6°C),
absence of sweat glands,
feathered body,
fatty nature.

25. Corticosterone

26. THERMOREGULATION

28. CONCEPTS AND STRATEGIES TO AMELIORATE
THE HEAT STRESS
1. Environmental strategies
Intermittent Photo schedule(light).
Humidity

30. 2. Housing management
Site selection, design and construction, ventilation, internal and roof
cooling, Density of birds.

32. 3. Nutritional strategies
Increasing energy density
Dietary Protein level and Amino acid composition
Vitamins – A, C, E.
Minerals.
Non nutrient feed additives.
Water and electrolyte balance.

33. 4. Feeding strategies
Early feeding
Intermittent or dual feeding
Sex separate feeding
Fasting or feed withdrawal.

34. 5. Genetic strategies
Selection for heat tolerance.
Selection for disease resistance.
Use of major genes – Naked neck (Na), Frizzle (F), Dwarf (dw),
Silky(h), Slow feathering (K).
6. Epigenetic programming through
Breeder diet,
Increase in Incubation temperature (Epigenetic temperature adaption).

35. SELECTION FOR HEAT TOLERANCE
• WLH shown to have greater tolerance than heavier breeds like RIR, barred
PR, white PR and Austarlop.
• Use of temperature controlled chambers for short periods(37⁰C & 60%
RH)
• Survivors were reproduced after recovery phase of 60 days
• Survivors rate improved from 16% to 69% in 7 generations.
• Superior egg production in thermotolerant birds
(Yamada and Tanaka, 1992)

36. SELECTION FOR DISEASE TOLERANCE
• Native germplasm – Aseel, Kadaknath.
• Conventional selection
• Genomic approaches - QTL & SNP
Candidate gene analysis
Genomic selection(MAS)
• Genetic modifications –Transgenesis and cloning
Genome editing
CARI NIRBHEEK CARI SHYAMA

37. USE OF MAJOR GENES
Gene Nature of
inheritance
Direct effect Side effect
Dwarf (dw) Sex linked recessive
multiple allelic
Reduction in body size
10 - 30%
Reduced metabolism
improved fitness,
disease tolerance.
Naked neck(Na) Incomplete dominant Loss of neck feathers,
reduction in secondary
feathers
Improved ability for
convection and adult
fitness
Frizzle (F) Incomplete dominant Curling of feathers,
reduced feathering
Improved ability for
heat tolerance
Silky (h) Recessive Long barbs at the
contour feathers
Improved ability for
convection
Slow feathering (K) Dominant sex linked
multiple allelic
Delay in feathering Increased heat loss,
reduced adult
mortality
Fibro melonosis
(fm)
Dominant with
multifactorial modifiers
Melanin deposition all
over body,sheats of
muscles and nerves
even blood vessels
Protection of skin
against UV radiation

38. CARI MRITYNGAY CARI TROPICANA
UPCARI HITCARI

39. EPIGENETIC PROGRAMMING
What is EPIGENETICS ?
“epi” – on ; Epigenetics - on the genome.
Epigenome – the protective package of proteins around which genetic
material is wrapped.
 Differs from tissue to tissue
 Controls differential expression of genes
 Crucial role in determining which genes actually expresses in an
individuals traits – switches certain genes on or off
regulates up or down in intensity

40.  Thermal manipulation at E7 to E16 significantly enhanced
thermotolerance, ↓ plasma corticosterone and reduced mortality rates to
half.
(Pietsun et al.,2008)
 Results of two incubation trails of chronic (38.2 – 38.4⁰C for 24 h daily) or
short term (38.2 – 38.4⁰C for 2h daily) increase in incubation temperature
D-18 until hatch did not diminish hatchability and chick quality
( Halle & Tzschentke, 2011)
 Epigenetic programming through breeder diet – methyl donors, choline,
betaine, folate, methionine, vit B12, D, A, selenium.

41. WORK DONE IN CARI
2014 Evaluation of stress alleviating agents in hot dry and hot humid
conditions
2015 Prenatal thermal conditioning influence on jejunal HSP-70 in broiler
chicken under post hatch acute heat stress
2016 Effects of dietary protein and photoperiod levels on performance in
guinea fowl.
2017 Growth performance and expression of heat stress related genes in
broiler chickens by stress alleviating agents in hot dry and hot humid
conditions

43. References
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current challenges in poultry production, 4 pp 38-44.
• Gautham Kolluri, Iqbal Hyder.2017 Stress and welfare: concept and strategies for
addressing current challenges in poultry production, 5 pp 45-51.
• J.S.Tyagi, Gopi.M.2017 Stress and welfare: concept and strategies for addressing current
challenges in poultry production, 30 pp 281-289.
• V.K.Saxena.2017 Stress and welfare: concept and strategies for addressing current
challenges in poultry production, 35 pp 329-336.
• Deepak Sharma.2000 poultry production under stress, 27 pp 199-203.
• D.P.singh. 2000 poultry production under stress, 29 pp 213-220
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