Heat Shock Protein 70 and Heat Tolerance in Early-Age Feed Restricted Broiler Chickens
The objectives of this study are to evaluate the effect of various degree of neonatal feed restrictions on heat tolerance later in life, the importance of heat shock protein 70 (HSP 70) in eliciting thermotolerance in broilers and the relationship between heat stress and occurrence of programmed...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2000
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/10525/1/FP_2000_17.pdf http://psasir.upm.edu.my/id/eprint/10525/ |
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| Summary: | The objectives of this study are to evaluate the effect of various degree
of neonatal feed restrictions on heat tolerance later in life, the importance of
heat shock protein 70 (HSP 70) in eliciting thermotolerance in broilers and the
relationship between heat stress and occurrence of programmed cell death
(apoptosis). Broiler chicks that were subjected to 80% feed restriction (F80).
60% feed restriction (F60) and 40% feed restriction (F40) or ad libitum feeding
from 4 to 6 days of age were exposed to high ambient temperatures (38±1·C)
for 2hr/day from 35 to 42 days of age. Short term feed restriction during the first week of life caused retardation
of growth. Although feed restriction reduced initial growth, birds grew more
rapidly than those fed ad libitum (AL) during refeeding. One day following the
imposition of feed limitation, higher levels of HSP 70 expression in the brain
tissues and increased helerophil/lympocyte (H/L) ratios were noted among
F60 and F40 birds.
Birds subjected to fasting early in life (F60) improved HSP 70
expression, growth, survivability, and reduced H/L ratios compared to those
fed AL and FBO in response to the heat treatment. The survivabile rate and
H/L ratios of F40 chicks were similar to those attained by other feeding
regimens (AL and FBO). Irrespective of feeding regimen, heat stress resulted
in an increase in serum glucose level and appearance of programmed cell
death (apoplosis) in the thymus glands. These resuHs suggest that neonatal
fasling evokes heat tolerance laler in life through enhanced expression of
HSP 70. Exposing birds to feed reslriction of either lower (FBO) or higher (F40)
severity do not to have profound influence on subsequent resistance to heat
stress later in life. |
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