An international group of scientists from Brazil, Columbia and the US examined the use of rumen-protected methionine (Met) on neonatal calf development when given as a maternal supplement. The team published its results in the Journal of Dairy Science.
“The specific objective of this study was to profile the abundance of 17 genes in the 1-carbon and Met metabolism cycles as well as the activity of betaine-homocysteine S-methyltransferase (BHMT) in liver tissue of calves born to cows supplemented with Met during the last 21 d of pregnancy,” the researchers said.
The group found that supplementing pregnant cows with methionine toward the end of gestation can influence or “nutritional programing” calf development. However, more work is needed to better understand the mechanisms involved.
“Our findings provide evidence that the maternal supplementation with Met during the last 3 to 4 weeks of gestation directly through an effect in utero or indirectly through altering colostrum metabolite composition can affect the hepatic abundance of genes associated with Met metabolism, DNA methylation, and transsulfuration,” they said. “The observed changes at the mRNA abundance level agree with data demonstrating faster maturation of gluconeogenesis, and underscore the metabolic interrelationships among these pathways.”
Why rumen-protected methionine?
Maternal diet composition and nutrient levels have been considered elements that can influence fetal development and provide long-lasting effect on an animal’s productive life, said the researchers.
“Nutritional ‘programming’ due to changes in the intake of micronutrients (e.g., folate, vitamins, and EAA, both pre- and postnatally) has been linked to alterations in mRNA abundance,” they said.
Methionine is a needed amino acid animals gather from feed during the Met cycle and that is necessary for protein, antioxidant and S-adenosylmethionine (SAM) synthesis – which is involved in cellular functioning and gene transcription, they said.
Previous research in non-ruminants has found that added essential nutrients, including Met, to maternal diets alters gene transcription in the offspring in ways that can provide long-term changes in health and metabolism, said the researchers.
Essential amino acids (EAA) in dairy cows is used in diet formulation to limit the need for crude protein (CP), improve nitrogen (N) use and EAA levels in MP (?), they said. Met and lysine have been the focus as they are the first and second limiting AA for milk synthesis and Met concentration in plasma drops before parturition, which highlights the potential for little to be available for a developing embryo.
However, the AA is necessary for normal embryonic development, they said. But, little is known about some of the effects caused by supplementing diets with additional Met.
“To our knowledge, no studies are available dealing with supplementation of methyl donors to dairy cows during the dry period that have evaluated residual effects on the transcription of genes related to methyl donor metabolism in the calf liver,” said the researchers.
Methods and materials
In the study, 40 multiparous cows were given a standard early-diet from days -50 to -25 before expected birth, said the researchers. Cows were changed to a higher energy diet for days -21 through +30 after calving.
In addition to the diets, half the cows received supplemental Met at 0.08% of the diet, they said. The product used is commercially available.
Dry matter intake was recorded daily, first-milking colostrum was noted and IgG was calculated, they said.
After birth, calves were given a common diet, said the researchers. Blood samples were collected for plasma analysis and checked for AA.
Calves were weighed, and growth performance and body weight were recorded, they said. Liver samples also were collected and checked for RNA, target gene abundance and BHMT activity.
Cow body weights (BW) and body condition scores did not alter based on diet, said the researchers. In the calves, no difference was found for colostrum IgG concentration, apparent IgG absorption, calf birth BW, weekly BW, weekly BW gain, milk replacer intake, starter intake or withers height
Cows getting the supplemented feed had higher concentrations of Met in plasma before calving and amounts of several AA were increased, they said. But, there was no influence on yield of colostrum, protein or total AA.
“The data indicate that calves from MET-supplemented cows underwent alterations in Met, choline, and homocysteine metabolism partly to synthesize taurine and glutathione, which would be advantageous for controlling metabolic-related stress,” said the researchers. “Whether the effects in MET calves were directly related to increased Met supply in utero remains to be determined.”
Calves from supplemented cows saw an increase in several genes, including those related to glutathione metabolism, they said. Overall BHMT was not affected, but there was a trend for increased activity in supplemented calves from day 14-28 post birth.
“Perhaps the most striking response underscoring the potential carry-over effect of maternal Met was the greater abundance of BHMT2 and SAHH at 4 and 14 d of age in MET than CON calves,” they said. “Because feed intake did not differ, we speculate that the liver of MET calves might have been better equipped to metabolize choline and homocysteine to Met or to channel homocysteine through the transsulfuration pathway (e.g., increase flux through the cycle) at least during the first 14 d of age when calves relied the most on milk replacer as a source of nutrients.”
Source: Journal of Dairy Science
Title: Maternal supplementation with rumen-protected methionine increases prepartal plasma methionine concentration and alters hepatic mRNA abundance of 1-carbon, methionine, and transsulfuration pathways in neonatal Holstein calves
Authors: C. Jacometo, Z. Zhou, D. Luchini, M. Corrêa, J. Loor