Effect of environmental temperature during the of brooding period on growing period of pullets viscera and tibia
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Kuupäev
2019
Kättesaadav alates
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Abstrakt
Poultry production in subtropical and tropical regions faces many problems, one of
which is the high air temperature causing thermal stress, particularly dangerous in high-producing
birds. Thus, the negative effects caused by heat stress (HS) must be managed. The objective of
this study was to evaluate the effects of four different levels of HS in viscera and tibia of pullets.
A total of 648 chicks (Lohmann LSL Lite) were used in this study in two different phases. The
pre-experimental phase (PEP) was from day 1 through 6 weeks of age. The birds were reared
with three different environmental temperatures: thermal comfort, hot and cold. The experimental
phase (EP) was conducted from the 7th to the 17th week. Pullets from each thermal environment
of the PEP were submitted to: 20 °C, 25 °C, 30 °C, 35 °C. At the end of the 17th week of age 120
pullets were euthanatized and the organs, heart, liver, spleen and gizzard were weighed, as also
their tibias. Effects of PEP, and its interaction with EP, were not significant (P < 0.05) for viscera
and tibia weight. However, a significant increase (P < 0.05) in heart weight with the decrease of
the environmental temperature was observed, being the pullets subject to 20ºC and 25 °C with
the heaviest weights. For the liver, pullets subject to the 35 °C had the lowest weight and were
different (P < 0.05) from the other three treatments. For gizzard, the difference (P < 0.05) was
between the treatments 20ºC and 35 °C. These results indicate that brooding temperatures tested
during the first 6 weeks of life did not affect the viscera and bone weight during the growing
phase.
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Märksõnad
heat stress, poultry, pullet, thermoregulation, viscera, articles