Betaine is as effective as folate at re-synthesizing methionine for protein synthesis during moderate methionine deficiency in piglets

Postprandial plasma and whole blood amino acids are largely indicative of dietary amino acids in adult dogs consuming diets with increasing whole pulse ingredient inclusion

BACKGROUND

Pulse ingredients often replace grains in grain-free dog diets due to their high protein content. However, research to ascertain the benefit of this modification is limited.

OBJECTIVE

To correlate food compounds in one corn-inclusive control diet (Ctl) and three grain-free diets with increasing inclusions of whole pulses (up to 45%; Pulse15, Pulse30, Pulse45), formulated to meet similar macro and micronutrient targets with postprandial amino acids (AA) in healthy dogs over 20-weeks.

METHODS

Diets were analyzed for biochemical compounds using tandem-MS. Twenty-eight outdoor-housed, healthy, adult Siberian Huskies were allocated to diet and meal responses took place at baseline and weeks 2, 4, 8, 16 and 20 with samples collected at fasted and 15, 30, 60, 90, 120 and 180 minutes after meal presentation. Blood AAs were analyzed by UPLC and differences across week, treatment and time post-meal were analyzed in SAS Studio. Partial least squares regression was performed in SAS Studio using biochemical compounds in the diet as predictor variables and blood AAs as response variables.

RESULTS

In plasma, Pulse45 had ∼32% greater postprandial Asn compared to Pulse15, and Ctl had ∼34% greater postprandial Leu and ∼35% greater Pro compared to Pulse15 (P < 0.05). In whole blood, Pulse30 had ∼23% greater postprandial Lys compared to Ctl, and Ctl had ∼21% greater postprandial Met and ∼18% greater Pro compared to Pulse45 and Pulse30, respectively (P < 0.05). Several phospholipids were correlated with postprandial AAs. Compounds in the 'urea cycle' and 'glycine and serine metabolism' were more enriched (P < 0.05) in plasma and whole blood, respectively.

CONCLUSIONS

In macro and micronutrient balanced canine diets that differ in their inclusion of corn- versus pulse-derived ingredients, postprandial changes in circulating AAs are largely indicative of the dietary AAs. This helps further our understanding of AA metabolism in healthy dogs fed grain-free diets.

One-carbon metabolism in children with marasmus and kwashiorkor

BACKGROUND

Kwashiorkor is a childhood syndrome of edematous malnutrition. Its precise nutritional precipitants remain uncertain despite nine decades of study. Remarkably, kwashiorkor's disturbances resemble the effects of experimental diets that are deficient in one-carbon nutrients. This similarity suggests that kwashiorkor may represent a nutritionally mediated syndrome of acute one-carbon metabolism dysfunction. Here we report findings from a cross-sectional exploration of serum one-carbon metabolites in Malawian children.

METHODS

Blood was collected from children aged 12-60 months before nutritional rehabilitation: kwashiorkor (N = 94), marasmic-kwashiorkor (N = 43) marasmus (N = 118), moderate acute malnutrition (N = 56) and controls (N = 46). Serum concentrations of 16 one-carbon metabolites were quantified using LC/MS techniques, and then compared across participant groups.

FINDINGS

Twelve of 16 measured one-carbon metabolites differed significantly between participant groups. Measured outputs of one-carbon metabolism, asymmetric dimethylarginine (ADMA) and cysteine, were lower in marasmic-kwashiorkor (median µmol/L (± SD): 0·549 (± 0·217) P = 0·00045 & 90 (± 40) P < 0·0001, respectively) and kwashiorkor (0·557 (± 0·195) P < 0·0001 & 115 (± 50) P < 0·0001), relative to marasmus (0·698 (± 0·212) & 153 (± 42)). ADMA and cysteine were well correlated with methionine in both kwashiorkor and marasmic-kwashiorkor.

INTERPRETATION

Kwashiorkor and marasmic-kwashiorkor were distinguished by evidence of one-carbon metabolism dysfunction. Correlative observations suggest that methionine deficiency drives this dysfunction, which is implicated in the syndrome's pathogenesis. The hypothesis that kwashiorkor can be prevented by fortifying low quality diets with methionine, along with nutrients that support efficient methionine use, such as choline, requires further investigation.

FUNDING

The Hickey Family Foundation, the American College of Gastroenterology, the NICHD, and the USDA/ARS.

Neuroprotective Roles of the Reverse Transsulfuration Pathway in Alzheimer's Disease

The reverse transsulfuration pathway has emerged as a central hub that integrates the metabolism of sulfur-containing amino acids and redox homeostasis. Transsulfuration involves the transfer of sulfur from homocysteine to cysteine. Cysteine serves as the precursor for several sulfur-containing molecules, which play diverse roles in cellular processes. Recent evidence shows that disruption of the flux through the pathway has deleterious consequences. In this review article, I will discuss the actions and regulation of the reverse transsulfuration pathway and its links to other metabolic pathways, which are disrupted in Alzheimer’s disease (AD). The potential nodes of therapeutic intervention are also discussed, which may pave the way for the development of novel treatments.

Effect of dietary folate level on organ weight, digesta pH, short-chain fatty acid concentration, and intestinal microbiota of weaned piglets

Folate is increasingly thought to promote gastrointestinal health and regulate the diversity of gut microbiota to alleviate weaning stress in piglets. The present study was conducted to investigate the effects of folate on organ weight, digesta pH, short-chain fatty acids (SCFAs) concentration, and intestinal microbiota in weaned piglets. A total of 28 piglets (6.73 ± 0.62 kg) were allocated to four dietary treatments consisting of a control group, 3, 9, and 18 mg/kg of folate supplementation in a 14-d feeding trial. The results showed that piglets fed with 9 and 18 mg/kg of folate supplementation had greater (P < 0.05) average liver and spleen weight than the control group. Folate supplementation (9 and 18 mg/kg) can significantly increase (P < 0.05) the stomach pH and tend (P < 0.10) to decrease the cecum pH. Folate treatment (9 and 18 mg/kg) had a positive effect on the metabolism of SCFAs in piglets, in particular, compared with the control group, and the content of acetic acid (AA) and valeric acid was markedly increased (P < 0.05) in the cecum and colon, respectively. Moreover, isobutyric acid, butyric acid, and isovaleric acid were tended (P < 0.10) to increase in the colon. Cecum contents samples were used to determine bacterial community diversity by 16S rRNA gene amplicon sequencing. At the genus level, in the cecum, there was a higher (P < 0.05) relative abundance of Lactobacillus reuteri, Lactobacillus salivarius, and Lactobacillus mucosae in the 9 mg/kg folate supplementation group. The functional pathways analysis predicted that folate may modify nutrient metabolism by changing the gut microbiota function of weaned piglets. Furthermore, the data showed that Lactobacillus was positively correlated with AA in the cecum. Overall, these findings suggested that folate treatment could increase the organ weight and the stomach pH of weaned piglets and had beneficial effects on gut health, which might be attributed to the alteration in intestinal microbiota induced by folate and the interaction of the intestinal microbiota with SCFAs.

Metabonomic Responses of Grazing Yak to Different Concentrate Supplementations in Cold Season

Supplementation plays an important role in reversing the weight loss of grazing yaks during cold season. However, little is known about the effect of supplementation on the serum metabolites of grazing yaks. The objective of this study was to explore the effects of supplementary feeding on average daily gain (ADG) and serum metabolites with nuclear magnetic resonance (NMR)-based metabolomics method in growing yaks during cold season on the Qinghai-Tibetan plateau. Twenty 1.5-year-old female yaks (91.38 ± 10.43 kg LW) were evenly divided into three treatment groups and a control group (CON) (n = 5 per group). All the yaks were released to graze during daytime, whereas the yaks in the treatment groups were supplemented with highland barley (HLB), rapeseed meal (RSM), and highland barley plus rapeseed meal (HLB + RSM) at night. The whole experiment lasted for 120 days. Results indicated that the ADG of growing yak heifers was increased by concentrate supplementations, and ADG under HLB and HLB + RSM group was 37.5% higher (p < 0.05) than that with RSM supplementation. Supplementary feeding increased the plasma concentrations of total protein (TP), albumin (ALB), and blood urea nitrogen (BUN) of those in the CON group, and concentrations of BUN were higher in the RSM group than in the HLB and HLB + RSM group. Compared with the CON group, serum levels of glutamine, glycine, β-glucose were lower and that of choline was higher in the HLB group; serum levels of lactate were lower and that of choline, glutamate were higher in the HLB + RSM group. Compared with the HLB + RSM group, serum levels of glycerophosphoryl choline (GPC) and lactate were higher, and those of choline, glutamine, glutamate, leucine, N-acetyaspartate, α-glucose, and β-glucose were lower in the HLB group; serum levels of citrate, GPC and lactate were higher, and those of 3-Hydroxybutyrate, betaine, choline, glutamate, glutamine, N-acetylglycoprotein, N-acetyaspartate, α-glucose, and β-glucose were lower in the RSM group. It could be concluded that concentrate supplementations significantly improved the growth performance of growing yaks and supplementation with HBL or HLB plus RSM was better than RSM during the cold season. Supplementation with HBL or HLB plus RSM affected the serum metabolites of grazing yaks, and both treatments promoted lipid synthesis. Supplementation of yaks with HBL plus RSM could improve energy-supply efficiency, protein and lipid deposition compared with HLB and RSM.

Overcoming nature’s paradox in skeletal muscle to optimise animal production

Nature’s paradox in skeletal muscle describes the seemingly mutually exclusive relationship between muscle fibre size and oxidative capacity. In mammals, there is a constraint on the size at which mitochondria-rich, high O2-dependent oxidative fibres can attain before they become anoxic or adapt to a glycolytic phenotype, being less reliant on O2. This implies that a muscle fibre can hypertrophy at the expense of its endurance capacity. Adaptations to activity (exercise) generally obey this relationship, with optimal muscle endurance generally being linked to an enhanced proportion of small, slow oxidative fibres and muscle strength (force and/or power) being linked to an enhanced proportion of large, fast glycolytic fibres. This relationship generally constrains not only the physiological limits of performance (e.g. speed and endurance), but also the capacity to manipulate muscle attributes such as fibre size and composition, with important relevance to the livestock and aquaculture industries for producing specific muscle traits such as (flesh) quality, texture and taste. Highly glycolytic (white) muscles have different traits than do highly oxidative (red) muscles and so the ability to manipulate muscle attributes to produce flesh with specific traits has important implications for optimising meat production and quality. Understanding the biological regulation of muscle size, and phenotype and the capacity to manipulate signalling pathways to produce specific attributes, has important implications for promoting ethically sustainable and profitable commercial livestock and aquaculture practices and for developing alternative food sources, including ‘laboratory meat’ or ‘clean meat’. This review describes the exciting potential of manipulating muscle attributes relevant to animal production, through traditional nutritional and pharmacological approaches and through viral-mediated strategies that could theoretically push the limits of muscle fibre growth, adaptation and plasticity.

Betaine reduces β-amyloid-induced paralysis through activation of cystathionine-β-synthase in an Alzheimer model of Caenorhabditis elegans

BACKGROUND

The neurodegenerative disorder Alzheimer's disease is caused by the accumulation of toxic aggregates of β-amyloid in the human brain. On the one hand, hyperhomocysteinemia has been shown to be a risk factor for cognitive decline in Alzheimer's disease. On the other hand, betaine has been demonstrated to attenuate Alzheimer-like pathological changes induced by homocysteine. It is reasonable to conclude that this is due to triggering the remethylation pathway mediated by betaine-homocysteine-methyltransferase. In the present study, we used the transgenic Caenorhabditis elegans strain CL2006, to test whether betaine is able to reduce β-amyloid-induced paralysis in C. elegans. This model expresses human β-amyloid 1-42 under control of a muscle-specific promoter that leads to progressive, age-dependent paralysis in the nematodes.

RESULTS

Betaine at a concentration of 100 μM was able to reduce homocysteine levels in the presence and absence of 1 mM homocysteine. Simultaneously, betaine both reduced normal paralysis rates in the absence of homocysteine and increased paralysis rates triggered by addition of homocysteine. Knockdown of cystathionine-β-synthase using RNA interference both increased homocysteine levels and paralysis. Additionally, it prevented the reducing effects of betaine on homocysteine levels and paralysis.

CONCLUSION

Our studies show that betaine is able to reduce homocysteine levels and β-amyloid-induced toxicity in a C. elegans model for Alzheimer's disease. This effect is independent of the remethylation pathway but requires the transsulfuration pathway mediated by cystathionine-β-synthase.

Metabolite and gene expression profiles suggest a putative mechanism through which high dietary carbohydrates reduce the content of hepatic betaine in Megalobrama amblycephala

BACKGROUND

High-carbohydrate diets (HCD) are favoured by the aquaculture industry for economic reasons, but they can produce negative impacts on growth and induce hepatic steatosis. We hypothesised that the mechanism behind this is the reduction of hepatic betaine content.

OBJECTIVE

We further explored this mechanism by supplementing betaine (1%) to the diet of a farmed fish Megalobrama amblycephala.

METHODS

Four diet groups were designed: control (CD, 27.11% carbohydrates), high-carbohydrate (HCD, 36.75% carbohydrates), long-term betaine (LBD, 35.64% carbohydrates) and short-term betaine diet (SBD; 12 weeks HCD + 4 weeks LBD). We analysed growth performance, body composition, liver condition, and expression of genes and profiles of metabolites associated with betaine metabolism.

RESULTS

HCD resulted in poorer growth and liver health (compared to CD), whereas LBD improved these parameters (compared to HCD). HCD induced the expression of genes associated with glucose, serine and cystathionine metabolisms, and (non-significantly, p = .20) a betaine-catabolizing enzyme betaine-homocysteine-methyltransferase; and decreased the content of betaine, methionine, S-adenosylhomocysteine and carnitine. Betaine supplementation (LBD) reversed these patterns, and elevated betaine-homocysteine-methyltransferase, S-adenosylmethionine and S-adenosylhomocysteine (all p ≤ .05).

CONCLUSION

We hypothesise that HCD reduced the content of hepatic betaine by enhancing the activity of metabolic pathways from glucose to homocysteine, reflected in increased glycolysis, serine metabolism, cystathionine metabolism and homocysteine remethylation. Long-term dietary betaine supplementation improved the negative impacts of HCD, inculding growth parameters, body composition, liver condition, and betaine metabolism. However, betaine supplementation may have caused a temporary disruption in the metabolic homeostasis.

Protein Synthesis in Mucin-Producing Tissues Is Conserved When Dietary Threonine Is Limiting in Piglets

BACKGROUND

The neonatal gastrointestinal tract extracts the majority of dietary threonine on the first pass to maintain synthesis of threonine-rich mucins in mucus. As dietary threonine becomes limiting, this extraction must limit protein synthesis in extraintestinal tissues at the expense of maintaining protein synthesis in mucin-producing tissues.

OBJECTIVE

The objective was to determine the dietary threonine concentration at which protein synthesis is reduced in various tissues.

METHODS

Twenty Yucatan miniature piglets (10 females; mean ± SD age, 15 ± 1 d; mean ± SD weight, 3.14 ± 0.30 kg) were fed 20 test diets with different threonine concentrations, from 0.5 to 6.0 g/100 g total amino acids (AAs; i.e., 20-220% of requirement), and various tissues were analyzed for protein synthesis by administering a flooding dose of [³H]phenylalanine. The whole-body requirement was determined by [1-¹⁴C]phenylalanine oxidation and plasma threonine concentrations.

RESULTS

Breakpoint analysis indicated a whole-body requirement of 2.8-3.0 g threonine/100 g total AAs. For all of the non-mucin-producing tissues as well as lung and colon, breakpoint analyses indicated decreasing protein synthesis rates below the following concentrations (expressed in g threonine/100 g total AAs; mean ± SE): gastrocnemius muscle, 1.76 ± 0.23; longissimus dorsi muscle, 2.99 ± 0.50; liver, 2.45 ± 0.60; kidney, 3.81 ± 0.97; lung, 1.95 ± 0.14; and colon, 1.36 ± 0.29. Protein synthesis in the other mucin-producing tissues (i.e., stomach, proximal jejunum, midjejunum, and ileum) did not change with decreasing threonine concentrations, but mucin synthesis in the ileum and colon decreased over threonine concentrations <4.54 ± 1.50 and <3.20 ± 4.70 g/100 g total AAs, respectively.

CONCLUSIONS

The results of this study illustrate that dietary threonine is preferentially used for protein synthesis in gastrointestinal tissues in piglets. If dietary threonine intake is deficient, then muscle growth and the functions of other tissues are likely compromised at the expense of maintenance of the mucus layer in mucin-producing tissues.

The dynamics of methionine supply and demand during early development

Methionine is an indispensable amino acid that, when not incorporated into protein, is converted into the methyl donor S-adenosylmethionine as entry into the methionine cycle. Following transmethylation, homocysteine is either remethylated to reform methionine or irreversibly trans-sulfurated to form cysteine. Methionine flux to transmethylation and to protein synthesis are both high in the neonate and this review focuses on the dynamics of methionine supply and demand during early development, when growth requires expansion of pools of protein and transmethylation products such as creatine and phosphatidylcholine (PC). The nutrients folate and betaine (derived from choline) donate a methyl group during remethylation, providing an endogenous supply of methionine to meet the methionine demand. During early development, variability in the dietary supply of these methionine cycle-related nutrients can affect both the supply and the demand of methionine. For example, a greater need for creatine synthesis can limit methionine availability for protein and PC synthesis, whereas increased availability of remethylation nutrients can increase protein synthesis if dietary methionine is limiting. Moreover, changes to methyl group availability early in life can lead to permanent changes in epigenetic patterns of DNA methylation, which have been implicated in the early origins of adult disease phenomena. This review aims to summarize how changes in methyl supply and demand can affect the availability of methionine for various functions and highlights the importance of variability in methionine-related nutrients in the infant diet.