Total Sulfur Amino Acids Research Articles

PSLBI-17 Total sulfur amino acid requirements across the canine life cycle in Labrador Retrievers using the indicator amino acid oxidation (IAAO) technique

Abstract Methionine and cysteine are the principal sulfur-containing amino acids that are incorporated into proteins, although homocysteine and taurine also have important physiological roles in canines. As limited studies have been conducted for total sulfur-containing amino acids (TSAA) requirements across the canine life cycle, our objective was to determine the minimum requirements (MR) for TSAA at 4 life stages using the indicator amino acid oxidation (IAAO) technique. Labrador Retrievers (n = 24) were used in feeding studies to evaluate the changing requirements of TSAA as dogs mature: 6 puppies aged 10 to 14 wk, 6 puppies >14 wk to 9 mos, 6 adults 2 to 5 yr (yr), and 6 seniors > 8yr. Following a 2-d adaptation to a TSAA-adequate basal diet (TSAA = 1.12% dry matter), dogs underwent individual IAAO studies. In brief, all dogs were randomly fed one of six test diets with varying levels of TSAA ranging from deficient to sufficient (final TSAA content in experimental diets were 0.41, 0.46, 0.51, 0.98, 1.05, and 1.12% dry matter, with indispensable amino acids formulated at 1.6x NRC values). The test diet was divided into 13 equal meals; at the 5th meal, a tracer amino acid was included (a bolus L-[1-13C] phenylalanine based on body weight was first given, followed by [1-13C] Phe doses every 30 spanning 4 h). Breath samples were collected via a respiration mask every 30 min. Total CO2 production was determined via indirect calorimetry and production of 13CO2 at each dose was measured by enrichment of 13C in breath samples via isotope ratio mass spectrometry (IRMS). Results for IRMS data were converted to atom percent excess (APE) and analyzed using segmented linear regression. The Four Rivers mean and population requirements for TSAA were estimated to be 1.55 ± 0.069 g/1,000 kcal (mean ± 2 SD) for puppies 10 to 14 wk, 1.53 ± 0.21 g/1,000 kcal (mean ± 2 SD) for puppies 14 wk to 9 mo, 1.4 ± 0.30 g/1000 kcal (mean ± 2 SD) for adults 2 to 5 yr, and 1.27 ± 0.23 g/1,000 kcal (mean ± 2 SD) for seniors. These results may contribute to the formulation of diets that meet the age-appropriate requirements of TSAA for large-breed dogs at all life stages.

383 Performance of piglets in response to graded dietary supplementation of sulfur amino acids using either hydroxy-methionine or DL-Methionine during the post-weaning period

Abstract Providing piglets with their precise nutritional need is critical during the stressful post-weaning period. Methionine (Met), a sulfur-containing amino acid, has a crucial role in piglet growth and health. Stressful conditions may increase Met demand due to its involvement in maintaining redox balance via downstream metabolites such as glutathione. There are different sources of supplementary Met for pigs such as DL-methionine (DL-Met) and hydroxy-methionine. The latter comes mostly as an acidic liquid form (OH-Met) and to a lesser degree as a powder calcium-salt (OH-Met-Ca). This study investigates the effect of graded levels of dietary total sulfur amino acids (TSAA) by supplementing different sources of Met on the performance and capacity of post-weaning piglets to respond to stress. Two experiments were performed. In experiment 1, post-weaning piglets [n = 90; 28 d of age; body weight (BW) = 9.13 ± 0.65 kg] were fed with either DL-Met or OH-Met-Ca to provide 80%, 100%, and 125% TSAA recommendations of NRC and performance parameters were measured for 41 d. Treatments were replicated nine times, and blocking was done according to initial BW. For experiment 2, 720 post-weaning piglets (n = 720; 28 d of age; BW = 6.84 ± 1.07 kg) from three consecutive breeding batches were fed with either DL-Met, OH-Met, or OH-Met-Ca at or above (100% or 125%) TSAA requirements of FEDNA. Performance parameters and oxidative status through various plasma indicators were measured. Treatments were replicated 12 times. Data from both experiments were analyzed separately using a mixed effect model with Met source and level as fixed effects (and their interaction in experiment 2) and blocks and batch as random effects for experiments 1 and 2, respectively. In experiment 1, piglets fed 80% of TSAA requirement showed the least average daily weight gain, while those fed OH-Met-Ca at 100% or DL-Met at 125% requirement had the greatest BW gain among the treatments (P < 0.01). Feed conversion ratio was best for piglets fed with OH-Met-Ca at 100% requirement, while animals fed with 80% requirement were the least efficient (P = 0.04). Contrasts showed no differences between Met sources (P ≥ 0.51) and level of TSAA (P ≥ 0.56) for any of the parameters. Meanwhile in experiment 2, there were no interactions between Met source and TSAA level (P > 0.10). The Met source did not affect any parameter (P ≥ 0.14). However, there was a significant decrease in daily feed intake when piglets were fed above requirements (P = 0.02), and a significant increase in the concentration of plasma glutathione peroxidase when piglets were fed at TSAA requirements (P < 0.05). These results suggest that post-weaning piglet performance and oxidative status can be sustained regardless of the Met source tested. Feeding healthy and unchallenged piglets with excess dietary Met may not bring extra benefits.

Total sulfur amino acid requirements are higher during late gestation compared with early gestation in healthy Canadian pregnancies in a repeated-measures trial

BackgroundDietary Reference Intake (DRI) Recommendations for total sulfur amino acids (TSAAs; methionine + cysteine) during pregnancy are based on factorial calculations using data from adult males. To date, no data exist on TSAA requirements obtained directly during pregnancy. ObjectivesThe objective of this study was to examine whether TSAA requirements during early (11–20 wk) and late (31–40 wk) gestation in healthy females with singleton pregnancies are different than current recommendations, and different between early and late gestation using the indicator amino acid oxidation (IAAO) technique. MethodsTwenty-five females 20–40 y with a healthy singleton pregnancy were studied using the IAAO technique in a repeated measures design for a total of 70, 8-h d. On each study day a methionine test intake (range: 0–40 mg⋅kg−1⋅d−1) was provided in 8 hourly, isonitrogenous and isocaloric meals with cysteine excluded from the diet. Breath samples were collected at baseline and isotopic steady state of orally provided L-1-13C-Phenylalanine for measurement of phenylalanine oxidation. The requirement was determined using biphasic linear regression crossover analysis to identify a breakpoint in 13CO2 production, representing the estimated average requirement (EAR). ResultsThe TSAA requirement in healthy pregnant participants in early gestation was 11.1 mg⋅kg−1⋅d−1 {R2m = 0.79, R2c = 0.79; 95% confidence interval [CI] (8.9, 13.3 mg⋅kg−1⋅d−1)} and 15.0 mg⋅kg−1⋅d−1 (R2m = 0.72, R2c = 0.79; 95% CI [13.0, 17.0 mg⋅kg−1⋅d−1]) in late gestation. The difference between confidence intervals of the 2 breakpoints was = −3.9 ± 3.0, and statistically different. ConclusionsWe directly measured TSAA requirements in healthy pregnant mothers, and our findings suggest that requirements are lower than current DRI recommendations of 20 and 25 mg⋅kg−1⋅d−1, as the EAR, and Recommended Dietary Allowance, respectively. Late gestation TSAA needs are significantly different and increased 35% compared with early gestation. Recommendations for TSAA intake need to be tailored for gestational stage.This clinical trial was registered at clinicaltrials.gov as NCT04326322.

Methionine Source and Level Modulate Gut pH, Amino Acid Transporters and Metabolism Related Genes in Broiler Chickens.

This study determined the effects of two methionine (Met) sources at three total sulfur amino acids (TSAA) to lysine ratios (TSAA/Lys) on gut pH, digestive enzyme activity, amino acid transporter expression, and Met metabolism of broilers. The birds were randomly assigned to a 2 × 3 factorial arrangement with Met sources (dl-Met and dl-2-hydroxy-4-(methylthio)-butanoic acid (OH-Met)) and TSAA/Lys (0.58, 0.73, and 0.88) from 1 to 21 days. The results demonstrated that dl-Met and OH-Met supported the same growth performance, but high TSAA/Lys ratio reduced the feed intake and body weight (P < 0.05). OH-Met reduced the crop chyme pH and enhanced the jejunal lipase activity (P < 0.05). ATB0,+ expression decreased with increased dl-Met levels in the duodenum; the low TSAA/Lys ratio induced a stronger mRNA expression of basolateral Met transporters. OH-Met resulted in an increase of cystathionine β-synthase expression in the liver and a decrease in serum homocysteine levels at middle TSAA/Lys ratio compared with dl-Met treatment (P < 0.05). In conclusion, two Met sources support the same growth, but OH-Met acidified the crop chyme. The investigated transporter transcripts differed significantly along the small intestine. At the middle TSAA/Lys ratio, OH-Met showed a higher metabolic tendency of the trans-sulfuration pathway compared with dl-Met.

62 Sulphur Amino Acids: Assessing Requirements and Utilization in Dogs and Cats

Abstract Methionine (Met), cyst(e)ine (Cys), homocysteine and taurine are the four sulfur-containing amino acids. Met can serve as a substrate for protein synthesis or to produce homocysteine, which can be remethylated to Met or irreversibly catabolized to Cys. Unlike dogs, cats are unable to further metabolize Cys to taurine, making the latter an indispensable amino acid for the cat. Met, on the other hand, is a dietary indispensable amino acid for all mammals with Cys having the ability to spare part of the Met requirement (total sulfur amino acid requirement; Met + Cys). The amount of Met that cannot be replaced by Cys is defined as the Met requirement (NRC, 2006). Empirical determinations of the Met requirement in adult dogs and cats are still limited and the recommendations proposed by the NRC (2006) are based on studies that used insensitive techniques for mature animals. When a more robust technique, the indicator amino acid oxidation, and more practical experimental diets were used to empirically determine the Met requirement, a greater estimate was found in adult cats (Pezzali et al., 2022) and adult Labrador Retrievers and Beagles, but not in miniature Dachshunds (Mansilla et al., 2020), compared with the current recommendations proposed by the NRC (2006) and AAFCO (2023). Harrison et al. (2020), however, found a decreased estimate for the Met requirement in adult Labrador Retrievers compared with Mansilla et al. (2020), likely due to differences in experimental design and diet composition. This discrepancy highlights the need to standardize methodologies and to investigate the effect of other dietary factors on the Met and total sulfur amino acid requirements owing to their complex metabolism. Indeed, the metabolism of sulfur amino acids may differ between dog breeds, resulting in differences in Met requirements and potentially making taurine a conditionally indispensable amino acid in some breeds under specific dietary conditions. While dietary Met is usually provided in excess in commercial diets, excess of Met may lead to hyperhomocysteinemia, which has been associated with detrimental health effects in other species. Due to the complex metabolism of sulfur amino acids and the complex matrix of pet foods, determining the ideal provision of sulfur amino acids in commercial diets to maximize animal health is a challenge. More long-term studies investigating the effect of different doses and ratios (Met:Cys) of sulfur amino acids on overall metabolism are necessary, in addition to requirement studies, to optimize the dietary delivery of sulfur amino acids in dogs and cats.

Dietary methionine sources and levels modulate the intestinal health status of broiler chickens

Given the key role of methionine in biological processes, adequate methionine should be provided to meet the nutritional requirements. DL-2-hydroxy-4-(methylthio)-butanoic acid (DL-HMTBA) has been considered as an important source of methionine. However, the effects of different sources and levels of methionine on the intestinal health status have not been clarified yet. An experiment was carried out to investigate the effects of different dietary sources and levels of methionine on the intestinal epithelial barrier, inflammatory cytokines expression, ileal morphology, microbiota composition, and cecal short chain fatty acids (SCFA) profiles. For this purpose, 720 male Arbor Acre broiler chicks at 1 d old were randomly assigned to a 2 × 3 factorial arrangement with 2 methionine sources (DL-methionine and DL-HMTBA) and 3 total sulfur amino acids (TSAA) levels (80%, 100%, and 120% of Arbor Acre recommendation). The results showed that DL-HMTBA supplementation promoted intestinal physical barrier at both gene expression level of claudin-1 and serum diamine oxidase level (P < 0.05), and the inflammatory cytokine IL-6 mRNA expression was down-regulated by dietary DL-HMTBA supplementation compared with the DL-methionine group (P < 0.05). Meanwhile, an upregulated gene expression of claudin-1 and zonula occluden-1 (ZO-1) were observed in the low-TSAA treatment on d 14 (P < 0.05), whereas this treatment increased the expression of IL-1β and IL-6 (P < 0.05). Villus height to crypt depth ratio was high (P < 0.05) in the middle-level TSAA group. Furthermore, DL-HMTBA supplementation optimized the microbiota of the ileum especially the relative abundance of Lactobacillus, where the digestion and absorption were completed, and elevated the concentrations of SCFA (acetate, propionate, and butyrate) in the cecal content on d 21 (P < 0.01). In conclusion, dietary DL-HMTBA supplementation improved the intestinal barrier function, immune homeostasis and optimized the microbiota to promote intestinal health status in broiler chickens.

Exploring the physiological plasticity of giant grouper (Epinephelus lanceolatus) to dietary sulfur amino acids and taurine to measure dietary requirements and essentiality.

Giant grouper (Epinephelus lanceolatus) is an economically important yet under-researched species, still reliant on 'trash fish' or generic aquafeeds. The transition toward sustainable formulations is contingent on establishing requirements of target species for limiting nutrients, among which the sulfur amino acids (methionine and cysteine) commonly limit fish growth. Further, there remains significant conjecture around the role of the sulfonic acid taurine in marine aquafeed formulation and its relationship to sulfur amino acids. To develop a species-specific feed formulation for giant grouper, dietary methionine was modulated in a dose-response experiment to achieve five graded levels from 9.5 to 21.5 g/kg, including an additional diet with methionine at 18.6 g/kg supplemented with 8 g/kg taurine. The mean (±SD) cysteine level of the diets was 4.5 ± 0.3 g/kg. Each diet was randomly allocated to triplicate tanks of 14 fish (83.9 ± 8.4 g). The best-fit regression for growth showed that the optimal dietary methionine content was 15.8 g/kg and the total sulfur amino acid content was 20.3 g/kg. Inadequate dietary methionine content triggered physiological responses, including hepatic hyperplasia and hypoplasia at 9.5 and 21.5 g/kg, respectively, and high aspartate transaminase levels at 18.9 g/kg. Moreover, inadequate dietary methionine contents resulted in higher densities of mixed goblet cell mucin and reduced absorptive surface area of posterior intestinal villi. Our results suggest that adequate levels of methionine, but not taurine, improved posterior intestinal conditions and liver homeostasis. These findings may aid informulating aquafeeds to optimize gastrointestinal and liver functions in juvenile giant grouper.

P07-051-23 Total Sulfur Amino Acid Requirements Are Higher in Late Gestation Compared to Early Gestation During Healthy Human Pregnancy

P07-051-23 Total Sulfur Amino Acid Requirements Are Higher in Late Gestation Compared to Early Gestation During Healthy Human Pregnancy

Reevaluation of the dietary methionine requirement of gilthead seabream (Sparus aurata) juveniles: A comparison of the efficiency of hydroxy methionine with DL-methionine as a dietary methionine source

This work aimed to estimate the dietary methionine (Met) requirement of gilthead seabream (Sparus aurata) juveniles using hydroxy methionine (OH-Met) as Met source and compare its efficiency with the DL-Methionine form (DL-Met). For that purpose, triplicate groups of fish with 17 g initial body weight were fed for 83 days with diets including increasing dietary Met levels (0.66, 0.80, 0.94, 1.08, 1.22, and 1.36% - sulfur-equivalent) using OH-Met as a Met source. Three other diets were also formulated with 0.94, 1.08, and 1.22% DL-Met, to compare OH-Met with DL-Met as dietary Met source. Cysteine was maintained at 0.54% in all the diets.Fish growth increased with dietary OH-Met inclusion up to 1.22% plateauing thereafter. No effect on feed intake was observed between fish fed the different dietary Met levels and sources. Feed and protein efficiencies increased with the increase in dietary Met level. Dietary Met source did not affect growth performance, feed utilization, nitrogen, and energy retention. Based on the four-parameter logistic model, the dietary Met requirement for maximum growth was estimated to be 1.05%. The lowest hepatic level of reduced glutathione (GSH), oxidized glutathione (GSSG), total glutathione (tGSH), and malondialdehyde (MDA) were observed in fish fed the OH-Met 1.36 diet, but the oxidative stress index (OSI) and GSH/GSSG ratio were not affected by the dietary OH-Met level. In the muscle, GSH, GSSG, OSI, MDA, and GSH/GSSG ratio were not affected by the OH-Met level, while tGSH linearly decreased with increasing dietary OH-Met level. Dietary Met source did not affect the liver and muscle oxidative stress-related parameters measured. Overall, it is concluded that the Met requirement for growth of gilthead seabream juveniles is satisfied with 1.05% Met in the diets (corresponding to 1.59% total sulfur amino acids, TSAA). This corresponds to a Met requirement of 2.3 g/16 g N (3.5 g/ 16 g N of TSAA). It is also concluded that OH-Met and DL-Met can be used interchangeably as dietary Met sources and that the liver and muscle antioxidant status of fish is not affected by the dietary Met sources tested.

The dietary requirement for total sulfur amino acids in adults aged ≥60 years appears to be higher in males than in females

BackgroundThe total sulfur amino acid (TSAA) recommendation in older adults is based on data from young adults. Physiological evidence suggests that older adults have a higher requirement than young adults. ObjectivesThe objective of this study was to determine the TSAA requirement in healthy men and women aged ≥60 y. MethodsThe TSAA requirement was determined using the indicator amino acid oxidation method with L-[1-13C]phenylalanine as the indicator. At recruitment, 15 older adults (n = 7 men and n = 8 women; BMI < 30 kg/m2) were assigned to receive 7 methionine intakes (5, 10, 15, 19, 25, 35, and 40 mg/kg/d) without dietary cysteine. Intake levels were randomly assigned to each subject. Following enrollment, 2 subjects completed 2 intakes and 3 completed 3, while the remainder completed all 7. Mean TSAA requirement was determined from oxidation of L-[1-13C]phenylalanine using a mixed-effect change-point model. The 95% CI was calculated using parametric bootstrap. To test whether breakpoints were different between men and women, the overlap in the 95% CI was calculated. ResultsThe mean TSAA requirement was 26.2 (Rm2 = 0.39, Rc2 = 0.89; P < 0.001) and 17.1 mg/kg/d (Rm2 = 0.22, Rc2 = 0.79; P < 0.001) for men and women, respectively. The requirement was significantly higher in men than in women (difference in CI: 9.1 ± 8.85). ConclusionsTo our knowledge, this is the first study to determine the TSAA requirement in older adults. The requirement in older women is similar to current recommendations but is 75% higher in older men. These findings are important given recommendations for increased plant protein consumption. They will help in the assessment of diet quality and provide the basis of dietary guidelines for older adults consuming a plant-based diet.This trial was registered at clinicaltrials.gov as NCT04595188.

A systematic review of metabolism of methionine sources in animals: One parameter does not convey a comprehensive story.

The goal of this review article, based on a systematic literature search, is to critically assess the state of knowledge and experimental methodologies used to delineate the conversion and metabolism of the 2 methionine (Met) sources DL-methionine (DL-Met) and DL-2-hydroxy-4-(methylthio) butanoic acid (HMTBa). The difference in the chemical structures of HMTBa and DL-Met indicates that these molecules are absorbed and metabolized differently in animals. This review explores the methodologies used to describe the 2-step enzymatic conversion of the 3 enantiomers (D-HMTBa, L-HMTBa and D-Met) to L-Met, as well as the site of conversion at the organ and tissue levels. Extensive work was published documenting the conversion of HMTBa and D-Met into L-Met and, consequently, the incorporation into protein using a variety of invitro techniques, such as tissue homogenates, cell lines, primary cell lines, and everted gut sacs of individual tissues. These studies illustrated the role of the liver, kidney, and intestine in the conversion of Met precursors into L-Met. A combination of invivo studies using stable isotopes and infusions provided evidence of the wide conversion of HMTBa to L-Met by all tissues and how some tissues are net users of HMTBa, whereas others are net secreters of L-Met derived from HMTBa. Conversion of D-Met to L-Met in organs other than the liver and kidney is poorly documented. The methodology cited in the literature to determine conversion efficiency ranged from measurements of urinary, fecal, and respiratory excretion to plasma concentration and tissue incorporation of isotopes after intraperitoneal and oral infusions. Differences observed between these methodologies reflect differences in the metabolism of Met sources rather than differences in conversion efficiency. The factors affecting conversion efficiency are explored in this paper and are mostly associated with extreme dietary conditions, such as noncommercial crystalline diets that are very deficient in total sulfur amino acids with respect to requirements. Implications in the diversion of the 2 Met sources toward transsulfuration over transmethylation pathways are discussed. The strengths and weaknesses of some methodologies used are discussed in this review. From this review, it can be concluded that due to the inherent differences in conversion and metabolism of the 2 Met sources, the experimental methodologies (e.g., selecting different organs at different time points or using diets severely deficient in Met and cysteine) can impact the conclusions of the study and may explain the apparent divergences of conclusion found in the literature. It is recommended when conducting studies or reviewing the literature to properly select the experimental models that allow for differences in how the 2 Met precursors are converted to L-Met and metabolized by the animal to enable a proper comparison of their bioefficacy.

Effects of corn replacement by sorghum in broiler chickens diets on performance, blood chemistry, and meat quality

The influence of feeding a new hybrid of sorghum (ES Shamal, orange variety) in broiler chickens on growth, health, meat, and litter quality was evaluated from 1–42 d. A total of 360-day-old male Ross 308 broiler chicks (40.1 ± 2.3 g) were randomly assigned to 3 experimental diets: 100% corn-based diet (S0), partial replacement of corn with 50% sorghum (S50), total replacement of corn with sorghum (S100). All diets were calculated to be isonitrogenous and isocaloric with similar content of total lysine, total sulphur amino acids, calcium, and available phosphorous. The results indicated that partial or total replacement of corn by sorghum is suitable for broiler chicken diets with no adverse effects on growth, and slaughter performance, as well as litter quality over the whole trial period. Moreover, the substitution of corn with sorghum, reduced (p = .007) abdominal fat associated with an increase in breast and thigh meat colour (L* values; p < .001). Also, a significant (p = .002) decrease in plasma triglyceride was found in broilers fed sorghum-based diets. Except for collagen and hardness in the breast and thigh, and gumminess only in the thigh muscle, there were no differences in fundamental physicochemical (pH, protein, fat, moisture) or textural attributes of meat due to dietary treatment. However, sorghum alters the intestinal microflora, resulting in a lower count of E. coli in the caeca. It can thus, be concluded that sorghum (ES Shamal, orange variety) can be included in broiler feeds from hatching to day 42, without any adverse effects on the broiler’s performance. HIGHLIGHTS Climate changes become a threat to the livestock sector and finding novel nutritional solutions for feeding farm animals became a priority. New sorghum varieties are valuable in terms of drought-resistant plants. Replacement of corn with sorghum in broiler diets maintains growth performances and carcase characteristics.

Insights into the particle size, protein form, pasting and dough rheological properties of flour obtained from wheat grown at high and low altitude

SummaryFlours from four wheat varieties grown at high (~3180 m) and low altitude (~247 m) were compared for particle size distribution, protein composition (monomeric and polymeric), amino acids, pasting and dough rheological properties. High altitude wheat (HAW) flours showed greater proportion of large size particles and higher protein content, gluten, ash content and each category of gliadins and high molecular weight glutenins but revealed lower gluten index than low altitude wheat (LAW) flours. HAW showed higher extractable polymeric, unextractable monomeric proteins, pasting temperature, damaged starch and arabinoxylans while lower unextractable polymeric, extractable monomeric protein, paste viscosity, dough stability and development time than LAW flours. HAW flours from PBW725 and HD3086 showed higher concentration of total aromatic and lower of total sulphur amino acids than their counterpart LAW flour. Differences in flours characteristics of LAW and HAW were clearly due to differences in accumulation of protein, starch and arabinoxylans.

The Associations of Habitual Intake of Sulfur Amino Acids, Proteins and Diet Quality with Plasma Sulfur Amino Acid Concentrations: The Maastricht Study

BackgroundPlasma sulfur amino acids (SAAs), i.e., methionine, total cysteine (tCys), total homocysteine (tHcy), cystathionine, total glutathione (tGSH), and taurine, are potential risk factors for obesity and cardiometabolic disorders. However, except for plasma tHcy, little is known about how dietary intake modifies plasma SAA concentrations. ObjectiveTo investigate whether the intake of SAAs and proteins or diet quality is associated with plasma SAAs. MethodsData from a cross-sectional subset of The Maastricht Study (n = 1145, 50.5% men, 61 interquartile range: [55, 66] y, 22.5% with prediabetes and 34.3% with type 2 diabetes) were investigated. Dietary intake was assessed using a validated food frequency questionnaire. The intake of SAAs (total, methionine, and cysteine) and proteins (total, animal, and plant) was estimated from the Dutch and Danish food composition tables. Diet quality was assessed using the Dutch Healthy Diet Index, the Mediterranean Diet Score, and the Dietary Approaches to Stop Hypertension score. Fasting plasma SAAs were measured by liquid chromatography (LC) tandem mass spectrometry (MS) (LC/MS-MS). Associations were investigated with multiple linear regressions with tertiles of dietary intake measures (main exposures) and z-standardized plasma SAAs (outcomes). ResultsIntake of total SAAs and total proteins was positively associated with plasma tCys and cystathionine. Associations were stronger in women and in those with normal body weight. Higher intake of cysteine and plant proteins was associated with lower plasma tHcy and higher cystathionine. Higher methionine intake was associated with lower plasma tGSH, whereas cysteine intake was positively associated with tGSH. Higher intake of methionine and animal proteins was associated with higher plasma taurine. Better diet quality was consistently related to lower plasma tHcy concentrations, but it was not associated with the other SAAs. ConclusionTargeted dietary modifications might be effective in modifying plasma concentrations of tCys, tHcy, and cystathionine, which have been associated with obesity and cardiometabolic disorders.

Methionine Deficiency Decreases Protein Accretion and Synthesis but Not tRNA Acylation in Muscles of Chicks

The effect of supplementing a methionine-deficient, isolated soy protein diet (0.5% total sulfur amino acids) with 0.2% D,L-methionine (DL-MET) or a molar equivalent of D,L-2-hydroxy-4-(methylthio)butanoic acid (DL-HMB) was assessed in chicks over an 8-d feeding study. Chicks consumed DL-HMB diet ad libitum (HIGH) or were restricted to the level consumed ad libitum by chicks fed the basal diet. The DL-MET diet was fed at the same two levels as the DL-HMB diet. Supplementing with either methionine source resulted in significantly greater growth rate, efficiency of feed conversion, and accretion and synthesis of protein in the gastrocnemius and pectoralis muscles. These increases were greater for chicks consuming feed ad libitum as compared with feed-restricted chicks and were not affected by methionine source. Rate of muscle protein degradation appeared to increase with supplementation of either methionine source, but only when feed intake was permitted to increase. The relative in vivo conversion of DL-HMB vs. D-MET to L-MET was similar in all groups as indicated by pool sizes of methionine, tRNAmet, and tRNAcys, and rates of protein accretion and synthesis. These data demonstrate that dietary DL-HMB and DL-MET are used with similar efficacy to support skeletal muscle protein accretion and rates of protein synthesis when feed intake is equalized.

Revaluating the dietary methionine requirements in an improved strain of nile tilapia (Oreochromis niloticus)

It has been shown with terrestrial animals that the genetic improvement increases the nutrient requirements of the animal, which becomes more efficient in using these nutrients to achieve their higher growth potential. This study was conducted to estimate the dietary methionine requirements of different generations of the Genetically Improved Farmed Tilapia (GIFT) strain of Nile tilapia at the juvenile stage (17.51 g–19.55 g initial body weight). To achieve this objective, a completely randomized 2 × 6 factorial design was applied, with the genetic background of fish (generation) as the first independent variable with two levels, the 16th and 17th generations, and the methionine content of the diet as the second independent variable, with 6 graded levels, 0.52, 0.62, 0.84, 0.94, 1.04 and 1.27% of methionine in the diets, respectively. At the end of the 42-day experiment, the interaction effect of the generation × diet was not significant (P > 0.05) for any of the response parameters studied. The genetic improvement led to 15% more growth in the 17th generation than the 16th generation of the GIFT strain of Nile tilapia, which was accompanied with better feed conversion ratio, protein productive value, and energy productive value in the former generation (P < 0.05). Whatever the generation considered, the optimum dietary methionine requirement for the growth of the improved GIFT strain of Nile tilapia was estimated in this study, using the broken-line model, between 0.75% and 0.80% of the diet (with a cysteine level of 0.50% of the diet), which is higher than 0.49% of the diet previously estimated for conventional Nile tilapia at the juvenile stage. Therefore, the genetic improvement applied to the GIFT strain of Nile tilapia likely led to a higher methionine and total sulfur amino acid requirement than the conventional strains. The results of this study support the need to update the existing nutrient requirement databases of fish, in order to ensure that diets are formulated to effectively satisfy the requirements of not only conventional, but also improved strains of fish, for the full expression of their accrued growth potential of the latter strains.

Effects of levels of methionine supplementations in forms of L- or DL-methionine on the performance, intestinal development, immune response, and antioxidant system in broilers challenged with Eimeria spp.

The study was conducted to investigate the effects of 2 isoforms of methionine on growth performance and intestinal health induced by methionine (Met) deficiency and Eimeria infection in broilers. A total of 720 one-day old male chicks (Cobb500) were randomly allocated to 10 groups in a 2×5 factorial arrangement (6 reps/group, 12 birds/cage) with diets and Eimeria challenge as the main factors. Hundred percent DL-Met, 100% L-Met, 80% DL-Met, and 80% L-Met diets were formulated to meet approximately 100 or 80% of the total sulfur amino acid (TSAA) requirement with DL-Met or L-Met as Met supplementation sources. The 60% TSAA basal diet (60% Met) was formulated without Met supplementation. At d14, the challenge groups were gavaged with mixed Eimeria spp. Growth performance was recorded on d7, 14, 20 (6-day postinfection [DPI]), and 26 (12 DPI). The gut permeability was measured on 5 and 11 DPI. Antioxidant status and gene expression of immune cytokines and tight junction proteins were measured on 6 and 12 DPI. Data were analyzed by 1-way and 2-way ANOVA before and after the challenge, respectively. Orthogonal polynomial contrasts were used for post hoc comparison. Overall, the Eimeria challenge and 60% Met diet significantly reduced growth performance, antioxidant status, and mRNA expression of tight junction genes and immune cytokines. For other Met treatments, the L-Met groups had significantly higher BWG and lower FCR than the DL-Met group from d 1 to 20. The L-Met groups had less gut permeability than the DL-Met groups on 5 DPI. Compared to the 80% Met groups, the 100% Met groups reduced gut permeability. At 6 DPI, the 80% Met groups showed higher ZO1 expression than the 100% Met groups. The challenge groups had higher Muc2 expression and GSH/GSSG compared to the nonchallenge groups, and SOD activity was lower in the L-Met groups compared to the DL-Met groups at 6 DPI. The 100% Met groups had higher GPx activity than the 80% Met groups at 12 DPI. In conclusion, during coccidiosis, the 100% Met groups had better gut integrity and antioxidant status. Met supplementation in the form of L-Met improved growth performance in the starter phase and gut permeability in the challenge phase.

Dietary Methionine and Total Sulfur Amino Acid Restriction in Healthy Adults.

Dietary restriction of methionine (Met) and cysteine (Cys) delays the aging process and aging-related diseases, improves glucose and fat metabolism and reduces oxidative stress in numerous laboratory animal models. Little is known regarding the effects of sulfur amino acid restriction in humans. Thus, our objectives were to determine the impact of feeding diets restricted in Met alone (MetR) or in both Met and Cys (total sulfur amino acids, SAAR) to healthy adults on relevant biomarkers of cardiometabolic disease risk. A controlled feeding study. We included 20 healthy adults (11 females/9 males) assigned to MetR or SAAR diet groups consisting of three 4-wk feeding periods: Control period; low level restriction period (70% MetR or 50% SAAR); and high level restriction period (90% MetR or 65% SAAR) separated by 3-4-wk washout periods. No adverse effects were associated with either diet and level of restriction and compliance was high in all subjects. SAAR was associated with significant reductions in body weight and plasma levels of total cholesterol, LDL, uric acid, leptin, and insulin, BUN, and IGF-1, and increases in body temperature and plasma FGF-21 after 4 weeks (P<0.05). Fewer changes occurred with MetR including significant reductions in BUN, uric acid and 8-isoprostane and an increase in FGF-21 after 4 weeks (P<0.05). In the 65% SAAR group, plasma Met and Cys levels were significantly reduced by 15% and 13% respectively (P<0.05). These results suggest that many of the short-term beneficial effects of SAAR observed in animal models are translatable to humans and support further clinical development of this intervention.

Assessing the efficiency of using a local hybrid of rye for broiler chickens aged 1–42 d, with emphasis on performance and meat quality

Abstract This study was conducted to test the hypothesis that a new rye hybrid produced in Romania (Suceveana variety) could not impair the performance and meat quality of broiler chickens. A total of 360-day-old male Ross 308 broiler chicks (40.1±2.3 g) were randomly assigned to 3 dietary treatments replicated 6 times having 20 birds per replicate. Experimental diets were formulated to replace 25 and 50% of corn with rye (RYE 25 and RYE 50, respectively) as energy-yielding sources, whereas the control diet (CON) was 100% corn-based. All diets were formulated to be isocaloric and isonitrogenous, with similar total lysine and total sulfur amino acids. The results indicated similar outcomes of the local rye hybrid to commonly used corn-containing diets in terms of performance and carcasses. There were no differences in fundamental physicochemical (i.e., pH, protein, fat, moisture) or textural attributes of breast muscles due to dietary treatment, as well. However, the substitution of corn with rye reduced (P = 0.008) abdominal fat associated with an increase in CIE color (P&lt; 0.001). Thus, the Suceveana rye hybrid can be included in broiler diets, from hatching to day 42, without any adverse effects on the bird’s performance.

Effect of methionine and trace minerals (zinc, copper and manganese) supplementation on growth performance of broilers subjected to Eimeria challenge.

Coccidiosis is a major intestinal challenge that causes economic loss to the broiler industry. Two battery cage studies were conducted to evaluate the effect of trace minerals, source and dose of methionine on growth performance and gut health of broilers subjected to Eimeria challenge. Experiment #1 consisted of 9 treatments of 2 × 2 × 2 factorial design + 1 arrangement with main factors of methionine (Met) sources (DL-Met vs. 2-hydroxy-4-(methylthio)-butanoic acid (HMTBa)), total sulfur amino acid (TSAA) levels (high vs. low; ±5% of recommended level), and sources of trace minerals (TM) Zn:Cu:Mn in the form Inorganic trace minerals (ITM) in sulfates (80:20:100ppm) vs. mineral methionine hydroxy-analogue bis-chelate (MMHAC, 40:10:50ppm), each with 8 pens of 10 birds. Experiment #2 consisted of 2 treatments--ITM [ZnSO4:tribasic copper chloride (TBCC):MnSO4 110:125:120ppm] and MMHAC (Zn:Cu:Mn, 40:30:40ppm), each with 36 pens of 10 birds. All birds except for treatment 9 in experiment #1 were orally gavaged with 1x, 4x and 16x recommended dose of coccidiosis vaccine on d0, d7 and d14, respectively. Data were subjected to one-way and/or three-way ANOVA, and means were separated by Fisher's protected LSD test with significance at p ≤ 0.05. In experiment #1, factorial analysis revealed the main effects of TSAA level and TM, but not Met source. High TSAA level improved body weight and cumulative feed intake at 14, 20, and 27d. MMHAC improved body weight at 14, and 27d; feed intake at 14, 20, and 27d; and cumulative FCR at 27d vs. sulfates. One-way ANOVA analysis showed that birds fed MMHAC and high levels of TSAA regardless of Met source had similar body weight as unchallenged birds on d27. In experiment #2, MMHAC improved body weight and cumulative FCR, and reduced jejunal IL-17A gene expression on d28. In summary, in broilers subjected to Eimeria challenge, supplementation of the reduced levels of bis-chelated trace minerals MMHAC improved growth performance compared to high levels of ITM (sulfates or TBCC), which might partially result from better immune response, high levels of TSAA improved growth performance, Met source had no effect. Supplementation of both bis-chelated trace minerals MMHAC and high levels of TSAA could overcome the growth performance challenge issue due to coccidiosis.