Development and Growth of Farm Animals Hw 1

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- What were the results of thermal conditioning in broilers?

The hatched broilers were more thermotolerant. The core body temperature of these birds is lower and have lower concentrations of thyroid hormone T3 in the blood which promotes metabolism and the creation of heat. Also, the broilers’ comb temperatures are higher when exposed to heat. Thirty genes were differently expressed at normal temperatures, and six times more at high temperatures. The genes expressed differently involved metabolism, vascularization, and stress.

- “Foie gras”

- How does the amount of the amino acid methionine in a mother’s diet affect her offspring’s liver weight? What did the researchers argue could be the underlying cause?

Methionine is an essential amino acid and donates activated methyl groups. Therefore, if the mother has a deficiency of methionine, she will also have a deficiency of methyl groups and will pass on less to her offspring. The eggs are then nutrient deficient and DNA or histone hypomethylation occurs on the offspring genes. The hypomethylation of these genes results in an increase in liver weight in males and a decrease in liver weight in females.

- Epigenome of cattle – What did the French Institute’s researchers conclude when they compared the methylation pattern (the “methylome”) between

- Different cell types within a cow (liver cell v. fibroblast v. sperm cell)

There were 5634 differences in the methylation patterns of sperm cells and liver cells, showing different epigenetic profiles. Liver cells had hypomethylated genes associated with the innate immune system as compared to the sperm cells. So, these genes are more easily expressed in liver cells which shows they are important in the immune system’s function.

- Two cattle breeds

There were 3642 differences in methylation patterns between Holstein cows and Japanese Black cows. The differences were on genes associated with gestation and placental implantation. This is thought to be due to varied artificial selection, different production goals, and differences in metabolic processes during gestation.

- Liver cells of two different age groups

There were 257 regions with different methylation patterns between young and adult bovine liver cells. This is thought to be due to the liver becoming more used to a regular, autonomous, herbivorous diet over time.