Research conducted on non-ruminant animals clearly shows the relationship between choline and methionine, whose common feature is donating a methyl group.
By taking choline, you can consume less methionine. Choline is an essential nutrient for transitioning cows, but only for fat cows.
Methionine can prevent fatty liver.
Co-biology of choline and methionine in transition period cows
Dietary choline and methionine are extensively broken down in the rumen and therefore should be fed in such a way as to minimize rumen breakdown and maximize flow to the small intestine.
Both compounds contain methyl groups (-CH3). Choline is the main component of phosphatidylcholine (PC), which is present in all cell membranes in the body and is also a component of milk fat globule membranes.
Phosphatidylcholine is also a component of lipoproteins that are responsible for transporting fat throughout the body. As a substance containing very low-density lipoproteins (VLDL), phosphatidylcholine is essential for the removal of fat from the liver.
Fatty liver is a classic complication of choline deficiency, and the development of fatty liver in 50% of transition cows is due to a lack of choline absorption during the transition period.
Cattle can synthesize phosphatidylcholine in vivo, and endogenous synthesis is often sufficient, except during the transition period, when uptake of fatty acids from adipose tissue is high and increases dramatically.
Endogenous synthesis of phosphatidylcholine occurs by methylation of phosphatidylethanolamine. The required methyl groups can be derived from methionine.
Therefore, the close metabolic relationship of these two compounds has been observed in non-ruminants, where methionine can be used instead of choline or choline instead of methionine.
It has recently been discovered that gene expression can be regulated by DNA methylation; Therefore, choline and methionine could potentially be involved in the regulation of a number of metabolic pathways.
Using the liver cell culture method, University of Wisconsin researchers showed that increasing the concentration of methionine in the culture medium reduces the expression of the methionine synthetase gene (an important gene that controls the formation of methionine).
Compared to non-ruminants, the known interactions of choline and methionine are very few. A study conducted in goats showed that 28% of methionine is used to make choline and 6% of choline reserves are derived from methionine. Interestingly, methylcholine groups are not used to make methionine. found greater milk production responses in dairy cows following retroruminal injection of choline (compared to methionine) in the presence of a methylation inhibitor, indicating that methylmethionine groups can be used to make choline.
Effects of choline and methionine on fatty liver
During the transition period, the uptake of fatty acids by the liver increases from 100 to about 1300 grams per day.
If there is not enough phosphatidylcholine to synthesize VLDL to release fatty acids in the form of triglycerides, it can lead to fatty liver.
Most studies show that feeding protected choline before and after delivery can reduce fat accumulation in the liver during periods of fatty acid withdrawal.
Effects of choline and methionine on milk production
In a meta-analysis of 13 studies, it has been shown that prenatal protected choline supplements increase dry matter intake, milk production, fat and protein after delivery.
Responses to choline supplementation up to 120 days postpartum differed, however, in milk production for cows supplemented less than thirty days postpartum compared to those supplemented more than thirty days postpartum. , there is no difference.
Effects of choline and methionine on reproduction
It has been shown in numerous studies that a significant increase in the fertility rate of the first insemination occurs when consuming protected choline.
The mechanism of action for increasing the fertility rate is not known, but it may be related to the requirement of choline for fetal development. Feeding protected methionine from calving to flushing alters gene expression in the embryo.
Some gene changes are related to fetal growth and immune responses. When the protected methionine nutrition is done in the mother from three weeks before birth to 30 days after birth, the fetus has more lipid content.
The researchers hypothesized that improving fetal energy status may improve fetal survival. Although the fertility rate of the first insemination is not affected due to the consumption of protected methionine, the embryo loss after the first insemination is reduced.
Conclusion
There is limited evidence of an interaction between choline and methionine during the transition period. It is clear that both choline and methionine are essential nutrients and both should be fed in rumen-protected form to transition cows.
Choline and methionine have a unique role and cannot easily replace each other in the diet of cows during the transition period.
For example, choline increases milk production, dry matter consumption, and milk fat percentage, while methionine increases milk protein production and percentage, as well as increasing dry matter consumption.
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