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A. M. M. Hamdy
7.10 Genetic Impact
Climate change is expected to increase the average global temperature and negatively
impact on the food supply. Increasing population and economies increase demand for
dietary animal protein. Heat stress in chicken decreases production and increases disease susceptibility. Understanding the genetic control of response to heat in chickens
could enable breeding of more climate-adaptable chickens that are heat and/or disease resistant. At the population level, a highly advanced intercross line originating
from the broiler (heat susceptible) and Fayoumi (heat resistant) were applied.
Not only, it is desirable to determine the genetic component by estimating heritability and performing association, but also another approach to understanding
genetic control is to quantify the expression of transcripts. The most wide transcripts
are mRNA which is transcribed from DNA, processed within the nucleus, and subsequently translated into amino acids on ribosomes within the cytoplasm [100].
There are many technologies to quantify mRNA expression including northern blot,
RT-PCR, and whole transcriptome profiling using RNA-sequencing methods. RNAsequencing is currently the preferred method to assay transcriptional levels because
it is an a priori approach that doesn’t require investigators to choose genes to assay
expression but, rather, assays expression for all genes that are transcribed. RNAsequencing can reveal genes and pathways that are responsive to treatment effects.
The transcriptomic response to heat stress in chickens has been documented in several tissues and cell lines. The liver of heat stressed broilers revealed 43 differentially
expressed genes using RNA-sequencing technology. In Silkie fowl, the breast muscle
revealed 110 genes differentially expressed using microarray technology [100]. In
male white leghorn liver cancer cell line, RNA-sequencing revealed 812 transcripts
that were responsive to in vitro heat treatment [101]. In meat-type birds exposed to
heat stress, the hypothalamus was evaluated using microarray, which showed 1,967
genes to be differentially expressed [101]. No studies, however, have been done to
investigate the global transcriptomic response in an immune tissue to the double
stressor of heat stress and immune stimulation.
8 Conclusions
Climate change is defined as increased severity and variability of weather patterns.
This includes increasing the severity and incidence of droughts, flooding, cold bouts,
and heat waves. Weather variability is the overarching theme, but it is expected
that the global average temperature will increase by 4 °C by 2100. The changing
environmental temperatures require adaptation from all forms of life.
Under stress conditions, avian blood tolerates a change from acid—base balance
to alkaline balance. There is a decline in the plasma, a reduce level of vitamin C in the
adrenal cortex, a reduction in lymphocytes and a depression of immune response.
A. M. M. Hamdy
7.10 Genetic Impact
Climate change is expected to increase the average global temperature and negatively
impact on the food supply. Increasing population and economies increase demand for
dietary animal protein. Heat stress in chicken decreases production and increases disease susceptibility. Understanding the genetic control of response to heat in chickens
could enable breeding of more climate-adaptable chickens that are heat and/or disease resistant. At the population level, a highly advanced intercross line originating
from the broiler (heat susceptible) and Fayoumi (heat resistant) were applied.
Not only, it is desirable to determine the genetic component by estimating heritability and performing association, but also another approach to understanding
genetic control is to quantify the expression of transcripts. The most wide transcripts
are mRNA which is transcribed from DNA, processed within the nucleus, and subsequently translated into amino acids on ribosomes within the cytoplasm [100].
There are many technologies to quantify mRNA expression including northern blot,
RT-PCR, and whole transcriptome profiling using RNA-sequencing methods. RNAsequencing is currently the preferred method to assay transcriptional levels because
it is an a priori approach that doesn’t require investigators to choose genes to assay
expression but, rather, assays expression for all genes that are transcribed. RNAsequencing can reveal genes and pathways that are responsive to treatment effects.
The transcriptomic response to heat stress in chickens has been documented in several tissues and cell lines. The liver of heat stressed broilers revealed 43 differentially
expressed genes using RNA-sequencing technology. In Silkie fowl, the breast muscle
revealed 110 genes differentially expressed using microarray technology [100]. In
male white leghorn liver cancer cell line, RNA-sequencing revealed 812 transcripts
that were responsive to in vitro heat treatment [101]. In meat-type birds exposed to
heat stress, the hypothalamus was evaluated using microarray, which showed 1,967
genes to be differentially expressed [101]. No studies, however, have been done to
investigate the global transcriptomic response in an immune tissue to the double
stressor of heat stress and immune stimulation.
8 Conclusions
Climate change is defined as increased severity and variability of weather patterns.
This includes increasing the severity and incidence of droughts, flooding, cold bouts,
and heat waves. Weather variability is the overarching theme, but it is expected
that the global average temperature will increase by 4 °C by 2100. The changing
environmental temperatures require adaptation from all forms of life.
Under stress conditions, avian blood tolerates a change from acid—base balance
to alkaline balance. There is a decline in the plasma, a reduce level of vitamin C in the
adrenal cortex, a reduction in lymphocytes and a depression of immune response.