Modulating Fatty Acid Metabolism to Enhance Hatchability of Chicken Eggs

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Modulating Fatty Acid Metabolism to Enhance
Hatchability of Chicken Eggs

• Travis Schaal
• Dr. Gita Cherian
• Department of Animal Sciences

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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 Number95CS1974
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Background
Schaal and Cherian, 2005
Hatchability resulted in 500 million dollar loss
to the US poultry industry in 2005
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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 Number95cs1973
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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
  chicks heart.

USDA Image Number 97cs0748
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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

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Purpose

• To determine the effect of exogenous supply of
  fatty acids on chicken embryo health and
  hatchability.

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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

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Methods - In Ovo Injection

• Two trials conducted
• Practice technique
• Trial 1
• A 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.

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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.

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Methods

• Eggs set in same tray in the same incubator.
• Incubation conditions
• 37.5C dry and 28.3C wet bulb until hatching
  when the dry bulb temperature will be reduced to
  36.3C and the wet bulb temperature will be
  increased to 30.2C.

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Injection Methods
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Methods

• Hatched chicks were counted.
• Non-hatched eggs were broken open to determine
  the embryo status (infertile, early or late
  dead).

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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

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Results Trial 1

• Hatchability
• Saline 80
• Trans fats 29.6
• No trans fats 45
• Tissue and blood FA assays pending

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Results
Under Construction
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Results Trial 2

• Hatchability Trial 2
• Palmitate 64
• Carrier 54
• No injection 81
• Tissue and blood FA assays pending

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Results Trial 2

• Effect of injection on hatched chick weight

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Results - Trial 2
Effect of injection on hatched chick heart weight
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Results Trial 2
Effect of injection on hatched chick yolk sac
weight
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Results Trial 2
Effect of injection on hatched chick liver weight
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Conclusions

• Trial 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)

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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)

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Acknowledgements

• Howard Hughes Medical Institute
• Dr. Gita Cherian
• Dr. Kevin Ahern
• Mare Goeger