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Modulating Fatty Acid Metabolism to Enhance Hatchability of Chicken Eggs
Travis Schaal
Dr. Gita Cherian
Department of Animal Sciences
Background Chicken egg incubation lasts 21 days
12 billion broiler and turkey eggs incubated commercially in US annually
20% of eggs incubated do not hatch
USDA Image Number:95CS1974
Background
Hatchability resulted in 500 million dollar loss to the US poultry industry in 2005
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1985 1990 1995 2000 2005
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Eggs Set
Hatchability
Schaal and Cherian, 2005
Background Embryos are dependent upon nutrients stored in
the egg for sustaining growth and development
An average chicken egg contains 5.5 to 6 g of fat (yolk)
Lipid-rich yolk is the only source of fatty acids available to the developing embryo.
USDA Image Number:95cs1973
Background During incubation, over 80% of yolk fatty acids
(FA) are absorbed by the developing chick embryo.
In addition, FA are the major fuel and provides over 70 percent of the energy requirements for chick’s heart.
USDA Image Number: 97cs0748
Hatching A Stressful Act
Hatching is characterized by:The internal pipping by the beak, accompanied by a gradual shift from yolk sac-based respiration to pulmonary respiration
Purpose
To determine the effect of exogenous supply of fatty acids on chicken embryo
health and hatchability.
Hypothesis
Embryos having an exogenous supply of fatty acids will produce more
energy during the stressful process of hatching and will have a higher
hatchability rate
Methods - In Ovo Injection
Two trials conductedPractice technique
Trial 1A total of 72 eggs were injected in-ovo
with fatty acids (0.2 ml) or saline at day 14 of incubation with trans fat, no trans fat, or saline.
Methods - Trial 2
A total of 135 eggs were incubated, 90 eggs were injected in-ovo with fatty acids (Palmitate, 0.2 ml) or carrier at day 15 of incubation.
MethodsEggs set in same tray in the same
incubator.
Incubation conditions:37.5°C dry and 28.3°C wet bulb until hatching when the dry bulb temperature will be reduced to 36.3°C and the wet bulb temperature will be increased to 30.2°C.
Injection Methods
Methods
Hatched chicks were counted.
Non-hatched eggs were broken open to determine the embryo status (infertile, early or late dead).
Methods
Hatched chicks were sacrificed and tissues/blood collected for FA assays. Heart = oxidation Liver = synthesis Brain = tissue with high levels FA Yolk sac = reservoir
Results – Trial 1
Hatchability Saline = 80% Trans fats = 29.6% No trans fats = 45%
Tissue and blood FA assays pending
Results
Under Construction
Results – Trial 2
Hatchability Trial 2 Palmitate = 64% Carrier = 54% No injection = 81%
Tissue and blood FA assays pending
Results – Trial 2
Effect of injection on hatched chick weight
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Control Palmitate Non-Inj
(gm
)
Effect of injection on hatched chick heart weight
0.6
0.62
0.64
0.66
0.68
0.7
0.72
Control Palmitate Non-Inj
Body weight (%)
Results - Trial 2
0.00
2.00
4.00
6.00
8.00
10.00
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14.00
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18.00
Control Palmitate Non-Inj
Body weight (%)
Effect of injection on hatched chick yolk sac weight
Results – Trial 2
1.80
1.90
2.00
2.10
2.20
2.30
2.40
Control Palmitate Non-Inj
Body weight (%)
Effect of injection on hatched chick liver weight
Results – Trial 2
ConclusionsTrial 1
Optimization of in-ovo injection techniques In-ovo injection did not affect hatchability Trans fat reduced hatchability
Trial 2 Palmitate chick higher body weight (BW) Injected chicks higher heart weight (% BW) Injected chicks higher yolk sac weight (% BW) No effect on liver weight (% BW)
So What?Poultry Production
Hatchability, Body weight
Animal Models Chick embryo could be used as a model to
study fatty acid metabolism during early growth in humans
Link discovered between fatty acid metabolism sudden infant death syndrome (SIDS)
Acknowledgements
Howard Hughes Medical Institute
Dr. Gita Cherian
Dr. Kevin Ahern
Mare Goeger
