Responses to rumen-protected choline in transition cows do not depend on prepartum body condition

Graduate Student Literature Review: Exploring choline's important roles as a nutrient for transition dairy cows

In late gestation and in the first weeks postpartum, lipid droplets accumulate in the hepatic tissue resulting in approximately 40% to 50% of the dairy cows developing hepatic lipidosis in the first weeks of lactation. Elevated concentrations of triacylglycerol in the hepatic tissue are associated with increased risk of peripartum diseases and impaired productive performance. Cows with hepatic lipidosis need to dispose the excess of hepatic triacylglycerol, but this is a slow process in the bovine liver and relies on primary mechanisms such as complete oxidation and ketogenesis because of the limited export of triacylglycerols as lipoproteins. Choline is a lipotropic compound because, among other functions, it facilitates the export of lipids from the liver. Supplementing choline as rumen-protected choline (RPC) to diets of feed-restricted dairy cows reduces the degree of triacylglycerol infiltration into the hepatic parenchyma in part by enhancing export of triacylglycerol as nascent lipoprotein. The reduced accumulation of triacylglycerol in hepatic tissue in feed-restricted cows fed RPC might affect secondary pathways involved in hepatic disposal of fatty acids such as increased cellular autophagy and lipophagy and minimize endoplasmic reticulum stress response and hepatocyte inflammation. Collectively, these effects on secondary pathways might further reduce the severity of hepatic lipidosis in cows. One of the benefits of supplementing RPC is improved fat digestibility, perhaps because choline, through phosphatidylcholines, facilitates lipid transport within the enterocyte by increasing the synthesis of chylomicrons. Finally, when supplemented during the transition period, RPC improves productive performance of cows, irrespective of their body condition, that extends well beyond the period of supplementation. This review summarizes the current understanding of hepatic lipidosis in early lactation, recapitulates the absorption, transport and metabolism of choline, and discusses its role on hepatic metabolism and gastrointestinal functions, which collectively results in improved performance in dairy cows.

Growth Performance, Blood Metabolites, Carcass Characteristics and Meat Quality of Lambs Fed Diets Containing Different Energy Levels Supplemented with Rumen-Protected Choline

This study aimed to examine the effects of metabolizable energy (ME) level and rumen-protected choline (RPC) supplementation on the growth performance, carcass characteristics, meat quality, serum energy, lipid, and protein profiles of Karayaka lambs. Twenty-eight Karayaka lambs, with an initial body weight (BW) of 26.85 ± 0.26 kg, were randomly assigned (2 × 2 factorial design) to one of four dietary treatments with two levels of ME (optimum: 2750 or low: 2500 kcal ME/kg dry matter) and two levels of RPC (0 or 4 g/d/lamb). Lambs of each group were housed in individual pens. The experiment lasted 66 d, with the first 10 d consisting of acclimation and the next 56 d of the formal experimental period. The data on BW, dietary matter intake (DMI), and serum glucose concentrations confirm that our model successfully induced low energy using 250 kcal/kg less energy than the optimum level. RPC supplementation did not significantly affect average daily DMI, total average daily gain (ADG), or feed conversion ratio (FCR) at any energy level. Additionally, there was no substantial effect on carcass characteristics, meat quality, serum lipids, energy metabolism indicators, and liver function parameters. There was also no interaction effect of RPC × ME on the parameters tested. However, at 56 d into the experiment, the interaction effect of RPC × ME on serum urea-N was highly significant, and RPC supplementation led to lower serum urea-N levels (p = 0.001). These results suggest that while RPC supplementation did not enhance overall performance and carcass characteristics in Karayaka lambs, it may play a role in modulating nitrogen metabolism, as indicated by the significant reduction in serum urea-N levels.

Enhancing Metabolism and Milk Production Performance in Periparturient Dairy Cattle through Rumen-Protected Methionine and Choline Supplementation

For dairy cattle to perform well throughout and following lactations, precise dietary control during the periparturient phase is crucial. The primary issues experienced by periparturient dairy cows include issues like decreased dry matter intake (DMI), a negative energy balance, higher levels of non-esterified fatty acids (NEFA), and the ensuing inferior milk output. Dairy cattle have always been fed a diet high in crude protein (CP) to produce the most milk possible. Despite the vital function that dairy cows play in the conversion of dietary CP into milk, a sizeable percentage of nitrogen is inevitably expelled, which raises serious environmental concerns. To reduce nitrogen emissions and their production, lactating dairy cows must receive less CP supplementation. Supplementing dairy cattle with rumen-protected methionine (RPM) and choline (RPC) has proven to be a successful method for improving their ability to use nitrogen, regulate their metabolism, and produce milk. The detrimental effects of low dietary protein consumption on the milk yield, protein yield, and dry matter intake may be mitigated by these nutritional treatments. In metabolic activities like the synthesis of sulfur-containing amino acids and methylation reactions, RPM and RPC are crucial players. Methionine, a limiting amino acid, affects the production of milk protein and the success of lactation in general. According to the existing data in the literature, methionine supplementation has a favorable impact on the pathways that produce milk. Similarly, choline is essential for DNA methylation, cell membrane stability, and lipid metabolism. Furthermore, RPC supplementation during the transition phase improves dry matter intake, postpartum milk yield, and fat-corrected milk (FCM) production. This review provides comprehensive insights into the roles of RPM and RPC in optimizing nitrogen utilization, metabolism, and enhancing milk production performance in periparturient dairy cattle, offering valuable strategies for sustainable dairy farming practices.

[The lipidosis in the liver of the dairy cow: Part 2 Genetic predisposition and prophylaxis]

Hepatic lipidosis in dairy cows is the result of a disturbed balance between the uptake of non-esterified fatty acids (NEFA), their metabolism in the hepatocytes, and the limited efflux of TG as very-low-density lipoprotein (VLDL). Lipidosis and the associated risk for ketosis represents a consequence of selecting dairy cows primarily for milk production without considering the basic physiological mechanisms of this trait. The overall risk for lipidosis and ketosis possesses a genetic background and the recently released new breeding value of the German Holstein Friesian cows now sets the path for correction of this risk and in that confirms the assumed genetic threat. Ectopic fat deposition in the liver is the result of various steps including lipolysis, uptake of fat by the liver cell, its metabolism, and finally release as very-low-density lipoprotein (VLDL). These reactions may be modulated directly or indirectly and hence, serve as basis for prophylactic measures. The pertaining methods are described in order to support an improved understanding of the pathogenesis of lipidosis and ketosis. They consist of feeding a glucogenic diet, restricted feeding during the close-up time as well as supplementation with choline, niacin, carnitine, or the reduction of milking frequency. Prophylactic measures for the prevention of ketosis are also included in this discussion.

[The lipidosis of the liver of dairy cows: Part 1 - Role of insulin and the Growth Hormone-IGF-1 axis]

Lipidosis of the liver of dairy cows is a metabolic disease known since many years and is caused by an uptake of nonesterified fatty acids (NEFA) into the liver cells, limited metabolism of NEFA (oxidation and production of β-hydroxybutyrate), and resynthesis in relation to a low efflux as triglyceride (TG). The pathogenesis of lipidosis includes a) an augmented release of NEFA by mobilisation of adipose tissue, b) uptake of NEFA into the liver cells, c) metabolism of NEFA and d) re-synthesis of triglyceride and e) an efflux of TG as very low density lipoprotein (VLDL). The steps a-e are postpartum modified by hormones as an increase of growth hormone, a pronounced insulin resistance in combination with a decreased insulin and of IGF-1 concentrations. These hormonal changes are related to an uncoupling of the growth hormone-IGF-1-axis with enhanced lipolysis and consequences mentioned above. These alterations are associated with inflammation, oxidative and endoplasmatic stress. The metabolic and hormonal alterations are the result of the selection of dairy cows primarily for milk production without adequate food intake with the consequence of lipidosis, ketosis and further health risks (production diseases).

Effect of the Supplementation Using an Herbal Mixture as a Choline Source during Early Gestation in Rambouillet Ewes

Previous research indicates that adequate choline nutrition during late gestation improves fetal development. However, there is a lack of studies describing choline's role during early gestation. Thus, the current study hypothesizes that an herbal mixture as a source of choline (Biocholine) positively affects offspring development from ewes supplemented during early gestation. Therefore, the objectives were to evaluate the impact of biocholine on the programming of the offspring early in life through the evaluation of dams and newborn performance. Twenty-eight four-year-old Rambouillet ewes were assigned randomly to two treatments: non-supplementation and 4 gd^-1 of biocholine during the early gestation. Compared with the dams without supplementation, the ewes supplemented using biocholine showed no increase in parameters such as birth and weaning weight (p > 0.05). Additionally, the milk yield and quality of colostrum and milk did not present statistical differences (p > 0.05). However, the placental membrane development was reduced in the ewes that received supplementation with biocholine; interestingly, those dams increased the weight of the newborns during the lambing period (p < 0.05). Finally, the current study proposes necessary elucidation of how placental size is programmed and if less placental development has potential benefits in the fetus's development.

Overview of the effect of rumen-protected limiting amino acids (methionine and lysine) and choline on the immunity, antioxidative, and inflammatory status of periparturient ruminants

Overproduction of reactive oxygen species (ROS) is a well-known phenomenon experienced by ruminants, especially during the transition from late gestation to successful lactation. This overproduction of ROS may lead to oxidative stress (OS), which compromises the immune and anti-inflammatory systems of animals, thus predisposing them to health issues. Besides, during the periparturient period, metabolic stress is developed due to a negative energy balance, which is followed by excessive fat mobilization and poor production performance. Excessive lipolysis causes immune suppression, abnormal regulation of inflammation, and enhanced oxidative stress. Indeed, OS plays a key role in regulating the metabolic activity of various organs and the productivity of farm animals. For example, rapid fetal growth and the production of large amounts of colostrum and milk, as well as an increase in both maternal and fetal metabolism, result in increased ROS production and an increased need for micronutrients, including antioxidants, during the last trimester of pregnancy and at the start of lactation. Oxidative stress is generally neutralized by the natural antioxidant system in the body. However, in some special phases, such as the periparturient period, the animal's natural antioxidant system is unable to cope with the situation. The effect of rumen-protected limiting amino acids and choline on the regulation of immunity, antioxidative, and anti-inflammatory status and milk production performance, has been widely studied in ruminants. Thus, in the current review, we gathered and interpreted the data on this topic, especially during the perinatal and lactational stages.

Prediction of Liver Triglyceride Content in Early Lactation Multiparous Holstein Cows Using Blood Metabolite, Mineral, and Protein Biomarker Concentrations

Bovine fatty liver syndrome (bFLS) is difficult to diagnose because a liver tissue biopsy is required to assess liver triglyceride (TG) content. We hypothesized that a blood biomarker panel could be a convenient alternative method of liver TG content assessment and bFLS diagnosis. Our objectives were to predict liver TG using blood biomarker concentrations across days in milk (DIM; longitudinal, LT) or at a single timepoint (ST; 3, 7, or 14 DIM), as well as different biomarker combination based on their perceived accessibility. Data from two separate experiments (n = 65 cows) was used for model training and validation. Response variables were based on the maximum liver TG observed in 1 and 14 DIM liver biopsies: Max TG (continuous), Low TG (TG > 13.3% dry matter; DM), Median TG (TG > 17.1% DM), and High TG (TG > 22.0% DM). Model performance varied but High TG was well predicted by sparse partial least squares—discriminate analysis models using LT and ST data, achieving balanced error rates ≤ 15.4% for several model variations during cross-validation. In conclusion, blood biomarker panels using 7 DIM, 14 DIM, or LT data may be a useful diagnostic tool for bFLS in research and field settings.

Multifaceted role of one-carbon metabolism on immunometabolic control and growth during pregnancy, lactation and the neonatal period in dairy cattle

Dairy cattle undergo dramatic metabolic, endocrine, physiologic and immune changes during the peripartal period largely due to combined increases in energy requirements for fetal growth and development, milk production, and decreased dry matter intake. The negative nutrient balance that develops results in body fat mobilization, subsequently leading to triacylglycerol (TAG) accumulation in the liver along with reductions in liver function, immune dysfunction and a state of inflammation and oxidative stress. Mobilization of muscle and gluconeogenesis are also enhanced, while intake of vitamins and minerals is decreased, contributing to metabolic and immune dysfunction and oxidative stress. Enhancing post-ruminal supply of methyl donors is one approach that may improve immunometabolism and production synergistically in peripartal cows. At the cellular level, methyl donors (e.g. methionine, choline, betaine and folic acid) interact through one-carbon metabolism to modulate metabolism, immune responses and epigenetic events. By modulating those pathways, methyl donors may help increase the export of very low-density lipoproteins to reduce liver TAG and contribute to antioxidant synthesis to alleviate oxidative stress. Thus, altering one-carbon metabolism through methyl donor supplementation is a viable option to modulate immunometabolism during the peripartal period. This review explores available data on the regulation of one-carbon metabolism pathways in dairy cows in the context of enzyme regulation, cellular sensors and signaling mechanisms that might respond to increased dietary supply of specific methyl donors. Effects of methyl donors beyond the one-carbon metabolism pathways, including production performance, immune cell function, mechanistic target or rapamycin signaling, and fatty acid oxidation will also be highlighted. Furthermore, the effects of body condition and feeding system (total mixed ration vs. pasture) on one-carbon metabolism pathways are explored. Potential effects of methyl donor supply during the pepartum period on dairy calf growth and development also are discussed. Lastly, practical nutritional recommendations related to methyl donor metabolism during the peripartal period are presented. Nutritional management during the peripartal period is a fertile area of research, hence, underscoring the importance for developing a systems understanding of the potential immunometabolic role that dietary methyl donors play during this period to promote health and performance.