Met Levels Research Articles

Effects of Methionine on Milk Performance and Milk Constituents of Lactating Donkeys.

This study investigated the effects of adding methionine (Met) in milk production and the milk and blood metabolites of lactating donkeys. Eighteen healthy multiparous donkeys in early-stage lactation were selected for this study. The donkeys were randomly divided into three groups and fed diets with different levels of Met: control group (C, Met 0 g/d), Met group I (M1, Met 5 g/d), and Met group II (M2, Met 15 g/d). The total duration of the experiment was 5 weeks. Donkey milk and blood samples were collected at the end of the experiment. The milk yield and composition, milk, and serum metabolites were analyzed. The results showed that the addition of 5 g of Met significantly increased milk yield as well as the milk composition contents of protein, fat, lactoferrin, polyunsaturated fatty acid (PFA), solids, and solids-not-fat (SNF) (p < 0.05). Significant differences in metabolites were detected among the different samples of milk (p < 0.05). The addition of Met increased the levels of milk metabolites, such as myristic acid, d-glutamine, l-aspartic acid, and LPS 16:0. A total of 753 metabolites were detected in the serum, including 17 differential metabolites between C and M1 and 48 differential metabolites between C and M2. The levels of serum metabolites, such as l-ascorbate, inositol, and l-lysine, were up-regulated by the addition of Met (p < 0.05). The above results indicated that Met increased donkey milk production and milk composition yield and improved milk metabolites by regulating serum metabolites. These results provide a foundation for improving the nutritional needs of lactating donkeys and the nutritional regulation of donkey milk synthesis.

Evaluation of the relationship between xanthine oxidase activity and metabolic syndrome in a population group in Bangladesh

Xanthine oxidase (XO) is an enzyme that converts hypoxanthine into xanthine and xanthine into uric acid, which is then eliminated by the kidneys. Serum XO has been linked to diabetes, hypertension, liver dysfunction, and cardiovascular diseases. However, limited information exists on the relationship between serum XO activity and MetS. This study aimed to analyze the relationship between XO activity and metabolic syndrome (MetS) and its components in an adult population group in Bangladesh A total of 601 participants aged ≥18 years were included in the study. MetS was defined based on the criteria set by the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III). Serum XO activity was measured using the enzyme-linked immunosorbent assay (ELISA), while other biochemical parameters were measured using colorimetric methods. The relationship between serum XO and MetS levels was determined through multivariate logistic regression analysis. Serum XO activity was found to be significantly higher in females (6.17 ± 3.77 U/L) as compared to males (4.00 ± 2.77 U/L) (p < 0.001). Furthermore, participants with MetS had significantly higher mean levels of serum XO (5.34 ± 3.39 U/L) than those without MetS (3.86 ± 2.90 U/L) (p < 0.001). The prevalence of MetS and its components, such as blood pressure and blood glucose increased across the XO quartiles (p < 0.001). Regression analysis indicated that XO activity was significantly and independently associated with the prevalence of MetS (at least p < 0.05 for all cases) and its components, including elevated blood pressure, high blood glucose, and low HDL-C (at least p < 0.05 for all cases). In conclusion, individuals with MetS had significantly higher XO levels than those without MetS. Serum XO activity showed an independent association with MetS and some of its components. Therefore, XO might serve as a useful marker of MetS. Prospective studies are needed to determine the underlying mechanisms linking XO and MetS.

Performance of Commercial Broilers under Separate Sex Rearing and Feeding during the Finisher Period

The performance of commercial broiler chicken was evaluated under separate sex rearing and feeding during the finisher stage (22-42 days age). A total of 210, (21 days-old) commercial broilers were randomly allocated to five groups, viz., A (male &amp; female mixed), B (male), C (male), D (female), and E (female) containing 42 birds in each group. The birds from groups A, C, and E were fed with a commercial broiler finisher diet containing 3250 kcal ME/kg, 19.5% CP, 1.00% Dig. Lysine (Dig. Lys) and 0.49% Dig. Methionine (Dig, Met). The males in group B were fed a special male diet containing 3000 kcal ME/kg, 18% Crude Protein (CP), and females from group D were fed a special female diet containing 3100 kcal ME/kg, 19.5 % CP. The Dig. Lys and Dig. Met levels in group B and D finisher diets were 2% higher than in group A. The results of the study concluded that the separate sex rearing of broilers may be followed by feeding special finisher diets to males (B) and females (D) to achieve similar body weight, weight gain, and feed efficiency to that of males (C) and females fed with a commercial finisher diet. Separate sex rearing of commercial broilers with special feeding is more economical than commercial diets fed to mixed and separate sex. Females fed on a special finisher diet had significantly (P &lt; .05) higher serum total protein, albumin, and A/G ratio than males fed on a special finisher diet.

Amino acids inhibit the photodynamic inactivation effect by hindering cellular oxidative stress

Photodynamic inactivation (PDI) could utilize light to activate reactive oxygen species (ROS) produced by photosensitizers to kill bacteria for preservation. To delve into the complex effects arising during the post-harvest PDI processing, we conducted experiments using Pseudomonas reinekei, a food spoilage bacteria extracted from rotten Pakchoi. Through analyzing the metabolomics results, we discovered that methionine (Met) and glutamate (Glu) exhibited significant inhibitory effects during the PDI process. The oxidative stress generated by light treatment resulted in a reduction of 30.31% and 36.37% in the levels of Met and Glu, respectively. The data also showed that exogenous Met and Glu reduced intracellular oxidative stress levels, increased peroxidase activity, and prevented the damage of intracellular material and cell membrane deformation. That amino acids could inhibit the effect of PDI by hindering oxidative stress. Therefore, the amino acid content should be considered when applying PDI to treat Met- or Glu-rich foods.

Effects of dietary methionine and taurine interaction on growth performance, the profiles of amino acids, and protein metabolism of Chinese mitten crab, Eriocheir sinensis

The purpose of this study is to explore the interaction between dietary methionine and taurine levels on growth performance, the profiles of amino acids, protein metabolism, and how taurine spares methionine of Chinese mitten crab (Eriocheir sinensis). The crabs were divided into six groups which were fed six diets formulated with two Tau levels (0 and 0.4%) and three Met levels (0.6%, 0.9% and 1.2%). The results showed that the weight gain rate and specific growth rate were the highest in the crabs fed 0.4% Tau and 0.6% Met. Crabs fed 1.2% Met had the highest survival rate and lowest feed conversion ratio. Furthermore, the hepatopancreas and muscle amino acid content were significantly influenced by the interactive effects of Met and Tau (P < 0.05). Moreover, interactive effects of dietary methionine and taurine were significantly observed in the expressions of amino acid metabolism-related genes (P < 0.05). Additionally, crabs fed 1.2% Met and 0% Tau had the highest activities of cysteine decarboxylase (CSD) and cysteine dioxygenase (CDO). In conclusion, the addition of appropriate amount of taurine to the diet can reduce the requirement of methionine for Chinese mitten crab by regulating the activities of CSD and CDO. At the same time, the addition of methionine and taurine could affect the amino acids metabolism. Therefore, the diet formula of Chinese mitten crab needs to consider the metabolism of sulfur-containing amino acids.

Transcriptome analysis of the gene expression of M. iliotibialis lateralis affected by dietary methionine restriction.

Introduction: Methionine (Met) is an important amino acid related to the development of skeletal muscle. This study investigated the effects of dietary Met restriction on the gene expression of M. iliotibialis lateralis. Methods: A total of 84 day-old broiler chicks (Zhuanghe Dagu) with a similar initial body weight (207.62 ± 8.54 g) were used in this study. All birds were divided into two groups (CON; L-Met) based on the initial body weight. Each group consisted of six replicates with seven birds per replicate. The experimental period was 63 days (phase 1, days 1-21; phase 2, days 22-63). According to the nutritional requirements of Zhuanghe Dagu chickens, we provided a basal diet (0.39% Met levels during phase 1 and 0.35% Met levels during phase 2, as-fed basis) to the birds in the CON group, while we provided a Met-restricted diet (0.31% Met levels during phase 1 and 0.28% Met levels during phase 2, as-fed basis) to the birds in the L-Met group. The growth performance of broiler chicks and their M. iliotibialis lateralis development parameters were measured on days 21 and 63. Results and Discussion: In this study, dietary Met restriction did not affect the growth performance of broiler chicks but hindered the development of M. iliotibialis lateralis at both sampling timepoints. On the final day, three birds selected from each group (three from CON and three from L-Met) were used to obtain M. iliotibialis lateralis samples from leg muscle for further transcriptome analysis. Transcriptome analysis revealed that dietary Met restriction significantly upregulated 247 differentially expressed genes (DEGs) and downregulated 173 DEGs. Additionally, DEGs were mainly enriched in 10 pathways. Among DEGs, we observed that dietary Met restriction downregulated the expression of CSRP3, KY, FHL1, LMCD1, and MYOZ2 in M. iliotibialis lateralis. Therefore, we considered that dietary Met restriction had negative effects on the development of M. iliotibialis lateralis, and CSRP3, KY, FHL1, LMCD1, and MYOZ2 may serve as potential functional genes involved in this process.

Amino Acids Content in Brassica napus L. and × Triticosecale Wittm. ex A. Camus on Soil Contaminated with Fluorine

The study was conducted to determine the influence of fluorine soil contamination (100, 200 and 300 mg kg−1 of soil) on the levels of exogenous amino acids (ExAAs) and endogenous amino acids (EnAAs) in the above-ground parts of winter oilseed rape and spring triticale grain. Fluorine soil contamination had a much more pronounced influence on the content of the tested amino acids in spring triticale grain than in the above-ground parts of winter oilseed rape. Soil contamination with fluorine had the greatest influence on leucine (Leu), arginine (Arg) and lysine (Lys), alanine (Ala), glycine (Gly) and glutamic acid (Glu), increasing their content, and on tyrosine (Tyr), methionine (Met) and aspartic acid (Asp), decreasing their concentration in the winter oilseed rape above-ground parts. Under the influence of fluorine soil contamination, an increase in the content of Arg, phenylalanine (Phe), histidine (His), Leu, Tyr, Gly, serine (Ser), Asp and especially, proline (Pro) and Glu, and a decrease in the level of Met and cysteine (Cys) in spring triticale grain have been confirmed. The highest fluorine contamination (300 mg kg−1 of soil) had the most favourable influence on the total amino acid content in the spring triticale. The lowest fluorine dose (100 mg kg−1 of soil) had the same effect in winter oilseed rape. Spring triticale protein had a higher nutritive value than that of winter oilseed rape. Fluorine soil contamination caused a gradual increase in the nutritive value of protein in spring triticale grain (in contrast to rape).

Gut microbiota contributes to the methionine metabolism in host.

Methionine (Met) metabolism provides methyl groups for many important physiological processes and is implicated in multiple inflammatory diseases associated with the disrupted intestinal microbiota; nevertheless, whether intestinal microbiota determines Met metabolism in the host remains largely unknown. Here, we found that gut microbiota is responsible for host Met metabolism by using various animal models, including germ-free (GF) pigs and mice. Specifically, the Met levels are elevated in both GF pigs and GF mice that mainly metabolized to S-adenosine methionine (SAM) in the liver. Furthermore, antibiotic clearance experiments demonstrate that the loss of certain ampicillin- or neomycin-sensitive gut microbiota causes decreased Met in murine colon. Overall, our study suggests that gut microbiota mediates Met metabolism in the host and is a prospective target for the treatment of Met metabolism-related diseases.

Methionine and total homocysteine in hypertensive patients with renal excretory dysfunction.

The role of the kidneys in the metabolism and homeostasis of sulfur-containing amino acids is great, so the levels of methionine (Met), total homocysteine (tHcy) and their ratios can be of diagnostic value in chronic kidney disease (CKD), in a course of the arterial hypertension (AH). The aim of the study was to evaluate the Met/tHcy ratio in hypertensive patients with CKD. We used blood plasma of 76 patients aged 40-75 years with AH and the excretory dysfunction of the kidneys; subgroups: 1 - with proteinuria (n=37); 2 - without proteinuria with glomerular filtration rate (GFR) < 90 ml/min/1.73 m2 (n=39) and comparison group 3 - patients with AH without renal excretory dysfunction (n=28). Significantly lower Met levels were in subgroup 1. THcy levels were higher in subgroups 1 and 2 than in group 3. The Met/tHcy ratio revealed differences in subgroups 1 and 2 vs group 3. No differences were found in Arg and Lys levels. Positive correlations of the Met/tHcy ratio with the number of erythrocytes, but not with the level of hemoglobin, were revealed. In the ROC analysis, the cut-off points for the Met/tHcy ratio compared to group 3 were 3.08 for subgroup 1 and 3.36 for subgroup 2. With the progression of CKD, there is an increase in the levels of tHcy in the blood, and a decrease in the content of Met. A decrease in GFR, especially in a case with proteinuria, is accompanied by a decrease in the level of Met. The Met/tHcy ratio above 3.36 can be considered as the minimum of the balance between these sulfur-containing amino acids contents in a blood necessary for hypertensive patients with CKD.

Does Leisure-time Physical Activity Variety Lead To Better Cognitive Function Despite Not Meeting Pa Guidelines?

PURPOSE: Examine whether engaging in a variety of leisure-time physical activities (LTPA), despite not meeting physical activity (PA) guidelines, leads to better cognitive function in older adults. METHODS: Data was retrieved from the 1999-2002 National Health and Nutrition Examination Survey (NHANES). Older adults (N = 2,773, M age = 71.4 yrs, 50.6% ♀, 60.9% non-Hispanic White) reported their moderate- and vigorous-intensity LTPA during the past 30 days, including the specific type (e.g., hiking, tennis, or running), frequency (e.g., d·wk-1), and average duration. Moderate-to-vigorous physical activity (MVPA) was calculated by multiplying the metabolic equivalent values of the activities MET) by the frequency and duration (MVPA-min·wk-1 = MET level x frequency x duration). A dichotomous variable was created categorizing those who met PA guidelines (n = 831) based on federal guidelines (≥600 MVPA-min·wk-1). LTPA-variety was calculated as the total number of activities participated in at least once a month. Cognitive function was assessed via the Digit Symbol Substitution Task (DSST). Age, sex, education, race, and whether the reported PA was similar over the previous 10-years were used as covariates in all analyses. Total minutes spent in MVPA was controlled for in all analyses as it was possible to engage in some PA and not meet PA guidelines. RESULTS: A multivariable linear regression model revealed a significant effect of LTPA-Variety on DSST (β = 7.14, 95% CI: 4.78-9.50, P < 0.01); MVPA--min·wk-1 was not a significant predictor (P = 0.41). Univariate analysis of covariance (ANCOVA) of those not meeting PA guidelines (n = 1942) revealed a significant effect (F1,29 = 7.99, r2 = 0.41, P < 0.01) for LTPA-Variety on DSST. In those not meeting PA guidelines, engaging in 2 or more different types of LTPA, compared to less, resulted in significantly greater cognitive functioning (M = 45.60 vs M = 40.09, P < 0.01) when accounting for MVPA--min·wk-1. CONCLUSIONS: These results suggest that, for older adults, engaging in a greater variety of leisure-time physical activities can promote greater cognitive function regardless of the amount of time spent in moderate-to-vigorous activities. This has future implications for examining the primary metric of focus for physical activity engagement in this population.

Effect of guanidinoacetic acid supplementation on nitrogen retention and methionine methyl group flux in growing steers fed corn-based diets.

Six ruminally cannulated Holstein steers (256 ± 14 kg) were used in a 6 × 6 Latin square design to assess effects of guanidinoacetic acid (GAA) supplementation on N retention and methionine (Met) methyl group flux in growing cattle fed corn-based diets. Factorial treatments were two levels of Met (0 or 5 g/d) and three levels of GAA (0, 7.5, or 15 g/d) delivered by continuous abomasal infusion. Periods were 10 d in length and included 6 d of treatment adaptation, 3 d for total fecal and urine collections, and 1 d for blood sampling and flux measurements. Urinary N linearly increased (P < 0.01) with GAA supplementation and decreased (P < 0.05) with Met supplementation. Fecal N excretion was unaffected (P ≥ 0.42) by treatment. Retained N was not affected by GAA supplementation, but it was increased (P < 0.01) by Met supplementation. Use of methionine for transmethylation reactions, as well remethylation of homocysteine, was not affected by GAA supplementation when Met was not supplemented, but tended to be linearly increased by GAA supplementation when Met was supplemented (GAA-linear × Met interaction; P = 0.07), with the increases matching the amount of GAA provided. This response suggests that methylation reactions for compounds other than GAA were reduced by GAA supplementation when Met supply was deficient. Plasma concentrations and urinary excretion of creatine increased linearly (P = 0.03 and P = 0.06, respectively) when GAA was supplemented. There was a linear increase (P < 0.01) in urinary GAA excretion with GAA supplementation. Neither plasma concentration nor urinary excretion of creatinine was affected (P ≥ 0.17) by treatment. No treatment differences (P ≥ 0.13) were observed for plasma haptoglobin concentrations. Plasma urea-N linearly increased (P < 0.05) with GAA supplementation. Concentrations of Met and taurine increased (P < 0.05) when Met was supplemented. Plasma arginine was greatest at the intermediate level of supplemental GAA (quadratic, P < 0.05). The increase in N retention when Met was supplemented demonstrates Met was limiting in the corn-based diet. Supplementation of GAA alone or with Met as a methyl donor did not increase N retention in growing steers, perhaps because creatine production was favored over protein deposition as a use for Met.

Adequate levels of dietary sulphur amino acids impart improved liver and gut health in juvenile yellowtail kingfish (Seriola lalandi).

The sulphur amino acids methionine (Met) and cysteine (Cys) and their derivative taurine (Tau) are metabolically active molecules with interlinked roles in nutritional requirements. Deficiencies in these nutrients are linked to poor growth and health; however, the impacts of these deficiencies on organ structure and function are largely unknown. This study examined the effects of dietary Met, Cys and Tau fed at different levels on yellowtail kingfish (YTK) liver histology and surface colour, plasma biochemistry and posterior intestine histology. Samples were collected from two dose-response feeding trials that quantified (1) the Tau requirement and sparing effect of Met by feeding YTK diets containing one of seven levels of Tau at one of two levels of Met and (2) the Met requirement and sparing effect of Cys by feeding YTK diets containing one of five levels of Met at one of two levels of Cys. YTK fed inadequate levels of dietary Met, Cys and Tau exhibited thicker bile ducts, less red livers, more intestinal acidic goblet cell mucus and supranuclear vacuoles and less posterior intestinal absorptive surface area. Further, thicker bile ducts correlated with less red livers (a*, R), whereas increased hepatic fat correlated with a liver yellowing (b*). Our results indicate a shift towards histological properties and functions indicative of improved intrahepatic biliary condition, posterior intestinal nutrient absorption and homoeostasis of YTK fed adequate amounts of Met, Cys and Tau. These findings may assist in formulating aquafeed for optimised gastrointestinal and liver functions and maintaining good health in YTK.

Increased arginine, lysine, and methionine levels can improve the performance, gut integrity and immune status of turkeys but the effect is interactive and depends on challenge conditions

Arginine (Arg), lysine (Lys), and methionine (Met) can be used to support the health status of turkeys. The present study investigated selected performance, gut integrity, and immunological parameters in turkeys reared in optimal or challenge conditions. The experiment lasted for 28 days, and it had a completely randomized 2 × 3 factorial design with two levels of dietary Arg, Lys and Met (high or low) and challenge with Clostridium perfringens (C. perfringens), Escherichia coli lipopolysaccharide (LPS) or no challenge (placebo). Increased dietary levels of Arg, Lys and Met had a beneficial effect on turkey performance and immunological parameters, and it improved selected indicators responsible for maintaining gut integrity in different challenge conditions. Under optimal conditions (with no challenge), high ArgLysMet diets did not compromise bird performance and they improved selected performance parameters in challenged birds. The immune system of turkeys was not excessively stimulated by high ArgLysMet diets, which did not disrupt the redox balance and had no negative effect on gut integrity. High ArgLysMet diets increased the expression levels of selected genes encoding nutrient transporters and tight junction proteins. However, the influence exerted by different dietary inclusion levels of Arg, Lys and Met on gut integrity was largely determined by the stressor (C. perfringens vs. LPS). Further studies are required to investigate the role of Arg, Lys and Met levels in the diet on the immune response, gut function and performance of turkeys in different challenge conditions.

Establishment of reference intervals of homocysteine, cysteine, and methionine in apparently healthy Chinese adults

Background It has been widely reported that the key biomarkers of homocysteine metabolic pathways have emerged as markers or independent risk factors for cardiovascular disease and many other diseases. To improve the accuracy of evaluation in China, we establish the reference intervals of serum homocysteine (Hcy), cysteine (Cys), and methionine (Met) in apparently healthy Chinese adults. Methods We examined 1553 subjects aged ≥20 years who underwent Hcy metabolic pathway tests, in the Chaoyang Central Hospital between January 2019 and December 2020. The serum Hcy, Cys, and Met levels were simultaneously determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Multiple regression analysis was performed to identify sources of variation. A nonparametric method was used to establish the reference intervals. Results Gender differences were observed in Hcy and Met, with higher levels in males. Reference intervals for males were 6.09–17.00 μmol/L (Hcy) and 19.31–33.68 μmol/L (Met); conversely, the reference intervals for females were 4.61–14.61 μmol/L (Hcy) and 16.16–30.35 μmol/L (Met). The serum Cys reference intervals were seen to be gender-independent, but age-dependent reference intervals were needed; those for Cys were 188.85–334.27 μmol/L, 200.48–340.66 μmol/L, and 216.03–349.67 μmol/L in <40, 40–50, and ≥50 years, respectively. Conclusions By this study, the gender- or age-specific reference intervals of Hcy, Cys, and Met that were matched with the Chinese population were established, providing valuable references for clinical work and laboratory researches.

Association of sedentary behaviour and physical activity with cardiometabolic health in Japanese adults

Although the Asian population exhibits excessive sedentary behaviour and has a high susceptibility to metabolic syndrome (MetS), the nature of these associations remains unclear. This study aimed to investigate the association of sedentary time with cardiometabolic health and examine the association of reallocating sedentary time to light physical activity (LPA) or moderate-vigorous physical activity (MVPA) on cardiometabolic health in Japanese adults. A cross-sectional study was performed using data obtained from 758 Japanese adults. We assessed sedentary time, LPA, and MVPA using an accelerometer. Linear and logistic regression models were used to analyse the association between sedentary time and cardiometabolic risk factors. An isotemporal substitution model was used to estimate the theoretical influence of reallocating sedentary time to LPA or MVPA. A longer sedentary time was associated with worse cardiometabolic health, including MetS. Reallocating 30 min of sedentary time to LPA was significantly associated with lower body mass index, visceral fat, insulin resistance, triglyceride, and MetS levels and increased muscle mass and HDL-C (all P < 0.05). Reallocating 30 min of sedentary time to MVPA was strongly associated with the aforementioned factors. These results demonstrate the potential beneficial effects of reallocating sedentary time to LPA and MVPA on cardiometabolic health of Asians.

A High-Methionine Diet for One-Week Induces a High Accumulation of Methionine in the Cerebrospinal Fluid and Confers Bipolar Disorder-like Behavior in Mice

Methionine (Met) is considered the most toxic amino acid in mammals. Here, we investigated biochemical and behavioral impacts of ad libitum one-week feeding of high-Met diets on mice. Adult male mice were fed the standard rodent diet that contained 0.44% Met (1×) or a diet containing 16 graded Met doses (1.2×–13×). High-Met diets for one-week induced a dose-dependent decrease in body weight and an increase in serum Met levels with a 2.55 mM peak (versus basal 53 µM) on the 12×Met diet. Total homocysteine (Hcy) levels were also upregulated while concentrations of other amino acids were almost maintained in serum. Similarly, levels of Met and Hcy (but not the other amino acids) were highly elevated in the cerebrospinal fluids of mice on the 10×Met diet; the Met levels were much higher than Hcy and the others. In a series of behavioral tests, mice on the 10×Met diet displayed increased anxiety and decreased traveled distances in an open-field test, increased activity to escape from water soaking and tail hanging, and normal learning/memory activity in a Y-maze test, which were reflections of negative/positive symptoms and normal cognitive function, respectively. These results indicate that high-Met ad libitum feeding even for a week can induce bipolar disorder-like disease models in mice.

Physical Activity and Executive Function in Children with ADHD: A Systematic Review

ABSTRACT As of 2016, the Centers for Disease Control and Prevention states that approximately 9.4% (6.1 million) of children 2–17 yr of age have been diagnosed with attention deficit hyperactivity disorder (ADHD). Recent studies have looked at physical activity (PA) as a possible alternative and/or adjunct treatment option for children with ADHD. There is no clear picture on the amount of PA needed to elicit an improvement or what type of exercise is most beneficial. The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were used to search six databases to identify studies that assessed the relationship between PA and executive functioning (EF) in children with ADHD. Cochrane’s Risk of Bias tool was used, and dose response using MET levels was attempted. Eligibility criteria included (a) peer-reviewed, experimental, quantitative study designs that included a control group or a within-subject design; (b) published in English between January 1997 and December 31, 2019; (c) children 5–18 yr of age; and (d) assessed the relationship between PA and EF in children with ADHD. A total of 49 full-text manuscripts were identified, with 24 studies being included in the final review. Although results should be interpreted with caution because of variability across studies and a high risk of bias, there seems to be consensus that acute and training PA positively influence inhibition and cognitive flexibility. More rigorous study protocols that clearly identify which EF component they are assessing and how they are addressing areas of bias will provide a more cohesive representation of the evidence on how to effectively incorporate PA to enhance EF in children with ADHD. Dose response using MET levels is also needed to improve our knowledge of how much exercise is needed to affect EF in this population.

Nutrient metabolism in the liver and muscle of juvenile blunt snout bream (Megalobrama amblycephala) in response to dietary methionine levels

A 75-day rearing trial was designed to study the response of juvenile Megalobrama amblycephala to dietary methionine (Met) levels. Three practical diets with graded Met levels (0.40%, 0.84% and 1.28% dry matter) were prepared to feed the juvenile fish. The results showed that the 0.84% Met diet significantly improved the growth compared with 0.40% diets. Compared with 0.84% and 1.28% Met, 0.40% Met significantly increased the hepatic lipid content, while decreasing the muscular lipid and glycogen contents. 0.40% Met decreased the protein levels of phospho-Eukaryotic initiation factor 4E binding protein-1 (p-4e-bp1), 4e-bp1 and Ribosomal protein S6 kinase 1 in the liver, compared with 0.84% diet, while an increasing trend was observed in the muscle. Met supplementation tended to decrease and increase lipid synthesis in the liver and muscle, respectively, via changing mRNA levels of sterol regulatory element-binding protein 1, fatty acid synthetase and acetyl-CoA carboxylase. 1.28% dietary Met promoted fatty acid β-oxidation and lipolysis in both the liver and muscle by increasing carnitine palmitoyl transferase 1, peroxisome proliferator activated receptor alpha, lipoprotein lipase and lipase mRNA levels. Compared with 0.40% and 0.84% dietary Met, 1.28% Met enhanced the mRNA levels of hepatic gluconeogenesis related genes phosphoenolpyruvate carboxykinase (pepck), and glucose-6-phosphatase, and muscular glycolysis related genes phosphofructokinase (pfk), and pyruvate kinase (pk). The mRNA levels of hepatic pfk, pk and glucokinase were markedly downregulated by 1.28% Met compared with 0.84% level. Muscular pepck, glycogen synthase, and hepatic glucose transporters 2 mRNA levels were induced by 1.28% Met. Generally, deficient Met level decreased the growth of juvenile Megalobrama amblycephala, and the different nutrient metabolism responses to dietary Met were revealed in the liver and muscle.

Effects of Different Methionine Levels in Low Protein Diets on Production Performance, Reproductive System, Metabolism, and Gut Microbiota in Laying Hens.

This study investigated the effects of different levels of methionine (Met) in a low protein diet on the production performance, reproductive system, metabolism, and gut microbial composition of laying hens to reveal the underlying molecular mechanism of Met in a low protein diet on the host metabolism and gut microbial composition and function of hens. A total of 360 healthy 38-week-old Peking Pink laying hens with similar body conditions and egg production (EP) were randomly divided into four groups with nine replicates per treatment and 10 hens per replicate. The hens in each treatment group were fed low protein diets containing different levels of Met (0.25, 0.31, 0.38, and 0.47%, respectively) for 12 weeks. Feed and water were provided ad libitum throughout the trial period. The results showed that, compared with the 0.25% Met group, the final body weight (FBW), average daily gain (ADG), EP, egg weight (EW), and average daily feed intake (ADFI) in the other groups were significantly increased and feed egg ratio (FER) was decreased. Meanwhile, the EW and yield of abdominal fat (AFY) in the 0.47% Met group were higher than those in other groups. The triglyceride (TG), estradiol (E2), total protein (TP), albumin (ALB), and immunoglobulin A (IgA) in the 0.38 and 0.47% Met groups were higher than those in other groups. In addition, 16S rRNA gene sequencing revealed that there was no difference in the Sobs index, ACE index, and Shannon index among all groups. However, it is worth noting that feeding low protein diets with Met changed the gut microbial composition (e.g., the supplementation of Met increased the level of Lactobacillus and decreased the proportion of Faecalibacterium). Also, our results showed that the changes in gut microbial composition induced by the diets with different levels of Met were closely related to the changes of key parameters: ADFI, EW, FBW, TG, EM, EP, ADG, FER, and uric acid (UA). Our results highlight the role of adding an appropriate amount of Met to the low protein diet in laying hens, which could improve the gut microbial composition, production performance, reproductive system, and nutrient metabolism of laying hens. In conclusion, this study suggested that when the Met level was 0.38%, the production performance of the laying hens was pretty good.

Effects of Feeding Varying Levels of DL-Methionine on Live Performance and Yield of Broiler Chickens.

Simple SummaryThe use of DL-methionine (MET) in poultry diet formulation is vital for poultry growth because poultry do not synthesize sufficient amounts of MET needed for proper growth and performance, and currently there are insufficient natural sources of MET to fulfill the dietary needs of broiler chickens. However, the use of MET is restricted in the United States in organic poultry diets. Therefore, the objective of this study was to examine the effect of feeding different levels of dietary MET on organic broiler live performance and yield of a modern commercial broiler strain. This study gives us insight into how broiler growth and yield is affected when the allowable levels of methionine for organic broilers is further reduced, or zero methionine is used.This study was designed to evaluate the effects of dietary supplemental DL-methionine (MET) on live performance and meat yield for broilers raised to a common weight. A total of 1552 one-day old Ross 708, sexed broilers were randomly distributed to 32 pens resulting in eight treatments (TRT) of four replicates with 44 male or 53 female/pen. A randomized complete block with a 2 × 4 (sex × 4 MET levels 0, 0.5, 1, and 2 g/kg) factorial arrangement of TRT was used. A common weight of 2400 g was approached by day 46 (1 and 2 g MET/kg feed) and day 48 (0 and 0.5 g MET/kg feed). Supplementation of MET at 1, and 2 g/kg had a lower (p < 0.01) feed conversion ratio (FCR) at day 46/48 than broilers fed 0.5 g MET/kg. Broilers without supplemental MET had the worst (p < 0.01) feed conversion and average daily gain (ADG) at day 46/48. Birds fed 0 g MET/kg of feed had lower (p < 0.05) whole eviscerated carcass without giblets (WOG), yield than birds fed 2 g MET/kg of feed. Additionally, birds fed 0 g MET/kg of feed had lower (p < 0.05) breast fillet and tender percent yields than birds fed supplemental MET. Elimination of MET from organic broiler diets resulted in reduced ADG, breast fillet yield and feed efficiency of meat yield of broilers raised to day 46/48. Reduction in MET supplementation below current levels reduced the efficiency of meat production of organic broilers raised to day 46/48.