Thiamine status, metabolism and application in dairy cows: a review

Abstract

As the co-enzyme of pyruvate dehydrogenase and α-ketoglutarate dehydrogenase, thiamine plays a critical role in carbohydrate metabolism in dairy cows. Apart from feedstuff, microbial thiamine synthesis in the rumen is the main source for dairy cows. However, the amount of ruminal thiamine synthesis, which is influenced by dietary N levels and forage to concentrate ratio, varies greatly. Notably, when dairy cows are overfed high-grain diets, subacute ruminal acidosis (SARA) occurs and results in thiamine deficiency. Thiamine deficiency is characterised by decreased ruminal and blood thiamine concentrations and an increased blood thiamine pyrophosphate effect to >45 %. Thiamine deficiency caused by SARA is mainly related to the increased thiamine requirement during high grain feeding, decreased bacterial thiamine synthesis in the rumen, increased thiamine degradation by thiaminase, and decreased thiamine absorption by transporters. Interestingly, thiamine deficiency can be reversed by exogenous thiamine supplementation in the diet. Besides, thiamine supplementation has beneficial effects in dairy cows, such as increased milk and component production and attenuated SARA by improving rumen fermentation, balancing bacterial community and alleviating inflammatory response in the ruminal epithelium. However, there is no conclusive dietary thiamine recommendation for dairy cows, and the impacts of thiamine supplementation on protozoa, solid-attached bacteria, rumen wall-adherent bacteria and nutrient metabolism in dairy cows are still unclear. This knowledge is critical to understand thiamine status and function in dairy cows. Overall, the present review described the current state of knowledge on thiamine nutrition in dairy cows and the major problems that must be addressed in future research.

Effects of Partial Replacment of Dietary Forage Using Kelp Powder (Thallus laminariae) on Ruminal Fermentation and Lactation Performances of Dairy Cows

“…In ruminal conditions, glucose digested into pyruvate through glycolytic pathway [20], and then hydrolyzed into acetyl-CoA, which was the precursor of acetate with the help of pyruvate formate-lyase (PFL) [21]. When provided more high-fermentable carbohydrate, pyruvate accumulated and then turn to form more lactate, oxaloacetic acid [22], and further developed into propionate. This might contribute to the significant decrease of acetate/propionate.…”

Compositional and functional properties of milk and dairy products derived from cows fed pasture or concentrate‐based diets

“…In addition to dietary intake, vitamin B synthesis occurring in the rumen provides sufficient levels to prevent deficiency (Schwab et al., 2006). However, by depression of rumen cellulolytic microflora, sub‐clinical acidosis arising from concentrate over‐feeding can lead to insufficient synthesis of thiamine (Pan et al., 2018) and biotin (Rosendo et al., 2003). The ability to influence the relative abundance of vitamins in milk through dietary means is an important nutritional consideration, as standard portions of milk and dairy products offer a significant proportion of the RDA for some vitamins (Magan et al., 2020).…”

Metagenomic Insights into Effects of Thiamine Supplementation on Carbohydrate-Active Enzymes’ Profile in Dairy Cows Fed High-Concentrate Diets

“…Acetate is produced from acetyl-coA [34], while thiamine supplementation promoted pyruvate into acetyl-coA instead of oxaloacetic acid, providing more substrates for the synthesis of acetate rather than propionate [35]. This could possibly explain why HCT increased rumen acetate concentration compared with HC.…”