Threonine Intake Research Articles

Dietary intakes of methionine, threonine, lysine, arginine and histidine increased risk of type 2 diabetes in Chinese population: does the mediation effect of obesity exist?

BackgroundPublished studies have shown positive associations of branched chain and aromatic amino acids with type 2 diabetes mellitus (T2DM), and the findings remain consistent. However, the associations of other essential and semi-essential amino acids, i.e., methionine (Met), threonine (Thr), lysine (Lys), arginine (Arg) and histidine (His), with T2DM remain unknown. Obesity is an important independent risk factor for T2DM, and excessive amino acids can convert into glucose and lipids, which might underlie the associations of amino acids with obesity. Therefore, we aimed to estimate the associations between dietary intakes of these 5 amino acids and T2DM risk, as well as the mediation effects of obesity on these associations, in a Chinese population.MethodsA total of 10,920 participants (57,293 person-years) were included, and dietary intakes of 5 amino acids were investigated using 24-h dietary recalls. Anthropometric obesity indices were measured at both baseline and the follow-up endpoints. Associations of amino acids with T2DM were estimated using COX regression models, hazard ratios (HRs) and 95% confidence intervals (95% CIs) were shown. The mediation effects of obesity indices were analyzed, and the proportion of the mediation effect was estimated.ResultsHigher intakes of the 5 amino acids were associated with increasing T2DM risk, while significant HRs were only shown in men after adjustments. No interaction by gender was found. Regression analyses using quintiles of amino acids intakes showed that T2DM risk was positively associated with amino acids intakes only when comparing participants with the highest intake levels of amino acids to those with the lowest intake levels. Adjusted correlation coefficients between amino acid intakes and obesity indices measured at follow-up endpoints were significantly positive. Mediation analyses showed that mediation effects of obesity indices existed on associations between amino acids intakes and T2DM risk, and the mediation effect of waist circumference remained strongest for each amino acid.ConclusionsWe found positive associations of dietary intakes of Met, Thr, Lys, Arg and His with increasing T2DM risk in general Chinese residents, on which the mediation effect of obesity existed. These findings could be helpful for developing more constructive guidance in the primary prevention of T2DM based on dietary interventions.

Higher intakes of lysine, threonine and valine are inversely associated with non-alcoholic fatty liver disease risk: A community-based case-control study in the Chinese elderly

The associations of individual amino acid with non-alcoholic fatty liver disease (NAFLD) risk remained unclear. The present study aimed to investigate the associations between the two in the Chinese elderly. MethodsA community-based health check-up program was conducted in Qingdao, China. NAFLD was diagnosed by ultrasonography accompanied by epidemiological investigation. The dietary intakes of amino acids were investigated with 3-day, 24-h dietary records and calculated by Nutrition Calculator software. Restricted cubic spline model was used to evaluate a nonlinear relationship between amino acid intake and NAFLD risk. Results400 NAFLD subjects were identified, and 400 participants were randomly selected as controls and matched by gender and age (± 3 years) Dose-response analysis showed that 1 000 mg increment of aromatic amino acids (AAAs) was associated with reduced 16 % risk of NAFLD. Dietary increments of 750 mg/d threonine, 950 mg/d valine, or 1 700 mg/d lysine were associated with a 20 % reduction in the NAFLD risk (all P for linearity < 0.05). ConclusionThe present study demonstrated that the dietary increases in milk, eggs and deep-sea fish, which are rich in the amino acids, might contribute to protecting against NAFLD in the elderly.

Length of Adaptation Has No Effect on the Threonine Requirement Determined in Healthy Young Adult Males Using the Indicator Amino Acid Oxidation Method

BackgroundThe indicator amino acid oxidation (IAAO) method is minimally invasive; therefore, it is applicable to study the amino acid (AA) requirements of individuals in various age groups. However, the accuracy of this method has been criticized because of the 8 h (1 d) protocol, which has been suggested to be too short an adaptation time for estimating AA requirements. ObjectivesThe IAAO method was used to determine whether 3 or 7 d of adaptation to each threonine intake alters the threonine requirement in adult men compared to 1 d of adaptation. MethodsEleven healthy adult men (19–35 y, body mass index (BMI) 23.4 in kg⋅m−2) were studied at 6 threonine intakes; each intake was studied over a 9 d period. Following 2 d of pre-adaptation to adequate protein intake (1.0 g·kg−1⋅d−1), subjects received experimental diets containing the randomly assigned test threonine intake (5, 10, 15, 20, 25, or 35 mg·kg−1·d−1) for 7 d. IAAO studies were performed on days 1, 3, and 7 of adaptation to the experimental diet. The rate of release of 13CO2 from the oxidation of L-[1-13C]phenylalanine (F13CO2) was measured, and the threonine requirement was determined by applying mixed-effect change-point regression to the F13CO2 data in R version 4.0.5. The 95% confidence interval (CI) was calculated using parametric bootstrap, and the requirement estimates on days 1, 3, and 7 were compared using analysis of variance (ANOVA). ResultsThe mean threonine requirements (upper, lower 95% CI) for days 1, 3, and 7 were 10.5 (5.7, 15.9), 10.6 (7.5, 13.7), and 12.1 (9.2, 15.0 mg·kg−1·d−1), respectively; and these requirements were not statistically different (P = 0.213). ConclusionsWe demonstrated that the short, 8 h IAAO protocol results in a threonine requirement that is not statistically different from that obtained on days 3 or 7 of adaptation in healthy adult males.This trial was registered at www.clinicaltrials.gov as NCT04585087.

Bi-objective optimization of nutrient intake and performance of broiler chickens using Gaussian process regression and genetic algorithm

This study investigated whether quantifying the trade-off between the maxima of two response traits increases the accuracy of diet formulation. To achieve this, average daily weight gain (ADG) and gain:feed ratio (G:F) responses of 7–21-day-old broiler chickens to the dietary supply of three nutrients (intake of digestible glycine equivalents, digestible threonine, and total choline) were modeled using a newly developed hybrid machine learning-based method of Gaussian process regression and genetic algorithm. The dataset comprised 90 data lines. Model-fit-criteria indicated a high model adjustment and no prediction bias of the models. The bi-objective optimization scenarios through Pareto front revealed the trade-off between maximized ADG and maximized G:F and provided information on the needed input of the three nutrients that interact with each other to achieve the trade-off scenarios. The trade-off scenarios followed a nonlinear pattern. This indicated that choosing target values intermediate to maximized ADG and G:F after single-objective optimization is less accurate than feed formulation after quantifying the trade-off. In conclusion, knowledge of the trade-off between maximized ADG and maximized G:F and the needed nutrient inputs will help feed formulators to optimize their feed with a more holistic approach.

Indicator Amino Acid Oxidation Does Not Require a Lengthy Period of Adaptation When Estimating Amino Acid Requirements in Healthy Young Men

ObjectivesThe objective of the current study was to determine whether 3 or 7 days, compared to 8 hours of adaptation to the test level of threonine intake alters the threonine requirement in healthy young men.Methods11 men (19–35 years) were studied at 6 levels of threonine intake (5, 10, 15, 20, 25 and 35 mg.kg−1.d−1), in random order. Participants were first habituated to a diet containing intact milk protein (1.0 g.kg−1.d−1) and adequate calories for 2 days. Subjects then received an experimental diet containing the test threonine intakes for 7 days, with IAAO studies performed on days 1, 3, and 7. A total of 162 IAAO studies were completed; 54 for each length of adaptation. The rate of release of 13CO2 from the oxidation of L-[1–13C]phenylalanine (F13CO2) was measured. Phenylalanine flux and kinetics were determined from urinary enrichment of L-[1–13C]phenylalanine. The threonine requirement was determined by applying mixed effect change-point regression in R to the F13CO2 data. The 95% CI of each breakpoint was calculated using parametric bootstrap and the threonine requirement estimates measured on days 1, 3, and 7 were compared using ANOVA. The effect of threonine intake and days of adaptation on phenylalanine flux and kinetics were assessed using marginal linear mixed models and ANOVA.ResultsThe mean threonine requirement (upper, lower 95% CI) for days 1, 3, and 7 was 10.2 (5.4, 15), 10.6 (8, 13.3), and 12.1(9.5, 14.7) mg.kg−1.d−1 respectively, and were not statistically different from each other (p = 0.502). Phenylalanine flux was not affect by threonine intake, however flux significantly decreased with increasing length of adaptation (p = 0.000). The interaction between threonine intake and days of adaptation on phenylalanine balance was significant (p = 0.0015); decreased with increasing length of adaptation at intakes below 10 mg.kg−1.d−1 threonine, and increased with increasing length of adaptation above 15 mg.kg−1.d−1.ConclusionsWe have demonstrated that the short, 8 hour IAAO protocol is valid for the determination of amino acid requirements in humans. This length of adaptation is better positioned to study the amino acid needs of vulnerable populations such as infants, children, and older adults.Funding SourcesThis study was funded by The Canadian Institute of Health Research.

Branched chain and other amino acid intakes are inversely associated with sarcopenia among community elders in Qingdao, China.

The present study aimed to investigate the hypothesis that dietary amino acid intakes are associated with the risk of sarcopenia through a community-based observational study. A total of 1,140 participants (72.7±6.3 y) were recruited from an annual health check-up program in Qingdao, China. Skeletal muscle mass, muscle mass functions and biochemical parameters were measured by standard methods. Dietary intake was assessed by 3-day, 24-hour food records. The odds ratios (ORs) and 95% confidence intervals (CIs) of sarcopenic risk across quartiles of amino acid intakes were calculated using a multivariable- adjusted logistic regression model. Generalized linear models were used to assess the associations between dietary amino acid intakes and muscle mass functions. The prevalence of sarcopenia was 4.1%. Compared with the lowest category intake, the highest category of branched chain amino acids (BCAAs) (OR=0.11; 95% CI: 0.01, 0.90; p for trend=0.119), isoleucine (OR=0.11; 95% CI: 0.01, 0.89; p for trend=0.122) and tryptophan (OR=0.10; 95% CI: 0.01, 0.87; p for trend=0.176) was negatively correlated with sarcopenic risk with adjustment for potential confounding factors. Generalized linear model analysis showed that gait speed was positively correlated with dietary intakes of lysine, threonine, leucine, valine, tryptophan, BCAAs and aromatic amino acids (p<0.05). Higher intakes of BCAAs were associated with a lower risk of sarcopenia, which might beneficially protect against sarcopenia and improve physical function of the elderly.

Evaluation of threonine requirements in mature horses fed 1:1 ratio of forage to concentrate using the indicator amino acid oxidation technique

Threonine has been considered as the second limiting amino acid in equine diets following the first limiting amino acid, lysine, and its digestibility and bioavailability may be affected by dietary fiber content. Therefore, evaluation of threonine requirements in horses fed different diet compositions will improve diet formulation. The objective of this study was to evaluate threonine requirements in mature horses fed a 1:1 ratio of timothy hay and concentrate using the indicator amino acid oxidation (IAAO) technique. Six threonine intake levels [45, 56, 67, 79, 90, and 102 mg/kg body weight (BW)/day] were prepared by mixing two experimental concentrates containing different threonine concentrations (2.9 and 14.8 g of threonine/kg of concentrate). Each of six treatments was administrated to six Thoroughbred mares (4–16 years old; 580.1 ± 47.2 kg) in a randomly determined order. After 5 days of adaptation to each treatment, pre-feeding and 90 min post-feeding blood samples were collected on day 6 to evaluate plasma amino acid concentrations using high performance liquid chromatography. The IAAO procedure was conducted on day 7 of each experimental period. During the first two hour intravenous infusion of [13C]sodium bicarbonate, total CO2 production was evaluated from breath samples. From the subsequent four-hour oral administration of [1-13C]phenylalanine, blood and breath samples were collected to estimate phenylalanine oxidation to CO2. Plasma [13C]phenylalanine concentration and breath 13CO2 enrichment were evaluated using gas chromatography–mass spectrometry and an infrared isotope analyzer, respectively. Experimental data were analyzed using a one-way analysis of variance, including orthogonal linear and quadratic contrasts, in the mixed procedures of SAS version 9.3. Increased threonine intake resulted in higher plasma threonine concentration before and 90 min after feeding (P > 0.05), indicating higher bioavailability of threonine. However, phenylalanine oxidation rate was not affected by threonine consumption as evidenced by the lack of a breakpoint (P > 0.05). The results suggest that threonine requirements might be lower than 45 mg/kg BW/day in mature horses fed a 50% concentrate diet.

Substitution of histone H3 arginine 72 to alanine leads to the deregulation of isoleucine biosynthesis in the budding yeast Saccharomyces cerevisiae.

Histone residues play an essential role in the regulation of various biological processes. In the present study, we utilized the H3/H4 histone mutant library to probe the functional aspects of histone residues in amino acid biosynthesis. We found that the histone residue H3R72 plays a crucial role in the regulation of isoleucine biosynthesis. Substitution of the arginine residue (H3R72) of histone H3 to alanine (H3R72A) renders yeast cells unable to grow in minimal medium. Histone mutant H3R72A requires external supplementation of either isoleucine, serine, or threonine for growth in minimal medium. We also observed that the H3R72 residue and leucine amino acid in synthetic complete medium might play a crucial role in determining the intake of isoleucine and threonine in yeast. Furthermore, gene deletion analysis of ILV1 and CHA1 in the H3R72A mutant confirmed that isoleucine is the sole requirement for growth in minimal medium. Altogether, we have identified that histone H3R72 residue may be crucial for yeast growth in minimal medium by regulating isoleucine biosynthesis through the Ilv1 enzyme in the budding yeast Saccharomyces cerevisiae.

Effect of digestible threonine on performance, egg quality, blood metabolites, and immune responses in laying hens fed a wheat-based diet in the second cycle

The current experiment was conducted to evaluate the effects of digestible threonine (dThr) on performance, egg quality, blood metabolites, and immune responses in laying hens fed a wheat-based diet during the second cycle. Also, dThr requirements were determined based on nutrient dose-response data. A total of 384, 105-week-old post-molt Hy-line-W36 laying hens were allocated to six groups, 0.02% increments, ranging from 0.44 to 0.54% dThr, with eight replicates/treatment and eight birds each, from 105 to 116 wk. By increasing, dThr levels improved egg weight with a linear trend (p <.01), and egg production (EP), egg mass (EM), and feed conversion ratio (FCR) with quadratic trends (p <.05). Hens fed diet contained 0.48% dThr, dThr/digestible Lys (dLys) of 66% showed the best egg production traits. However, feed intake, egg quality traits, blood metabolites, and immune responses were unaffected by dThr levels. Based on the quadratic broken‐line regression models, the dThr requirements of laying hens during the second production cycle for optimised the EP, EM, and FCR were estimated at 507, 514, and 520 mg/hen per day, respectively. These values correspond to 9.84–10.1 mg/g of EM. It is concluded, in the laying hens fed a wheat-based diet during the second cycle, the dietary dThr level of 0.48%, dThr/dLys of 66%, and a daily intake of 520 mg dThr/bird are adequate for optimised performance. The amino acids requirements of laying hens vary depending on trait is considered for optimisation. The dThr requirement estimated for FCR was higher than those for EP and EM. HIGHLIGHTS In the laying hens that feed a wheat-based diet during the second cycle. A dietary digestible threonine concentration of 0.48% and a daily intake of digestible threonine 520 mg/bird are adequate for optimised performance.

Risk Assessment of "Other Substances" – L-threonine

The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) has, at the request of the Norwegian Food Safety Authority (Mattilsynet; NFSA), assessed the risk of "other substances" in food supplements and energy drinks sold in Norway. VKM has assessed the risk of doses given by NFSA. These risk assessments will provide NFSA with the scientific basis while regulating "other substances" in food supplements.&#x0D; "Other substances" are described in the food supplement directive 2002/46/EC as substances other than vitamins or minerals that have a nutritional and/ or physiological e ffect. It is added mainly to food supplements, but also to energy drinks and other foods. In this series of risk assessments of "other substances" the VKM has not evaluated any claimed beneficial effects from these substances, only possible adverse effects.&#x0D; The present report is a risk assessment of specified doses of L-threonine in food supplements, and it is based on previous risk assessments and articles retrieved from literature searches.&#x0D; According to information from NFSA, L-threonine is an ingredient in food supplements sold in Norway. NSFA has requested a risk assessment of 1000, 1200, 1500, 2000 and 2400 mg/day of L-threonine from food supplements. &#x0D; L-threonine is an essential amino acid not known to cause any adverse health effects. Previous reports do not indicate a tolerable upper intake level, apart from an approval of a dose of 1150 mg/day by the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN). Long-term studies in humans were not found. The only available human studies were: a small uncontrolled one-year pilot study with doses ranging from 0.5 to 2.5 g/day, one eight-week randomised controlled trial (RCT) using a dose of 7.5 g/day, and two 2-week RCTs using doses of 6 and 4.5 g/day. No adverse effects (diary method of registration of adverse effects) were reported in the eight-week clinical trial, and the only adverse effects observed in the two-week trials were one case of indigestion and one case of diarrhoea. A four-week rodent toxicity study indicated a no observed adverse effect level (NOAEL) of 854.3 mg/kg bw per day (only dose tested, no adverse effects observed). &#x0D; The value used for comparison with the estimated exposure in the risk characterisation is the NOAEL defined in an 8-week randomised placebo controlled study in humans, 7500 mg/day. For a 70-kg individual, this corresponds to 107 mg/kg bw per day. Two human two-week studies and a small one-year pilot study support the notion that this dose will be well tolerated. The overall mean threonine intake according to NHANES III (3 g/day) is slightly larger than the doses requested for evaluation in the present risk assessment.&#x0D; No studies in children (10 to &lt;14 years) and adolescents (14 to &lt;18 years) were identified. Based on the included literature there was no evidence indicating that age affects the tolerance for relevant doses of threonine. Therefore, in this risk characterisation a tolerance as for adults, based on body weight, was assumed for these age groups.&#x0D; VKM concludes that:&#x0D; &#x0D; In adults (≥18 years), the specified doses 1000, 1200, 1500, 2000 and 2400 mg/day L-threonine in food supplements are unlikely to cause adverse health effects.&#x0D; In adolescents (14 to &lt;18 years), the specified doses 1000, 1200, 1500, 2000 and 2400 mg/day L-threonine in food supplements are unlikely to cause adverse health effects.&#x0D; In children (10 to &lt;14 years), the specified doses 1000, 1200, 1500, 2000 and 2400 mg/day L-threonine in food supplements are unlikely to cause adverse health effects.&#x0D; &#x0D; Children younger than 10 years were not within the scope of the present risk assessment.

Response of broilers to digestible sulfur amino acids and threonine intake: maximum economic return

Background: The determination of amino acid supplements for broiler chicken requirements based on performance does not always reflect maximum profitability. Objective: To estimate the optimal levels of digestible threonine (Thr) and sulfur amino acids (SAA) in diets for broilers based on an economic analysis. Methods: Two dose-response assays were conducted, and each assay was divided into three phases: initial (1-14 days), grower (15-28 days), and finisher (29-42 days). Five hundred and sixty male Cobb 500® broilers were randomly distributed to seven treatments with increasing levels of the amino acid (SAA or Thr), with four replicates and 20 birds each. Bodyweight gain (BWG) and feed intake (FI) were used to fit a segmented model. Gross income (GI), total feed costs (TFC) and gross margin (GM) were calculated based on local values. Results: Increasing levels of amino acid elicited a response in BWG and FI for all evaluated phases. The estimates for maximum profit based on GI and TFC were 223, 504, and 975 mg SAA/bird/d, and 236, 696, and 1,042 mg Thr/bird/d in starter, grower and finisher phases, respectively. Conclusion: Varying the AA prices affected only slightly the economic optimal intake of Thr and sulfur amino acids. Despite market fluctuations, the economic approach presented in this study demonstrates to be a helpful tool to choose the ideal inclusion level of amino acids in the feed.

Digestible Threonine to Lysine Ratios for Meat-Type Quails

ABSTRACT Three experiments were conducted to estimate the optimal digestible threonine to lysine ratios (Thr:Lys) of meat-type quails during the pre-starter (1 to 7 days), starter (8 to 14 days) and grower I (15 to 21 days) phases. In each experiment, 600 birds were distributed according to a completely randomized experimental design into five treatments, consisting of five dietary Thr:Lys ratios (0.66, 0.71, 0.76, 0.81 and 0.86%), with eight replicates of 15 quails each. Performance parameters and intestinal morphology were evaluated. During the pre-starter phase, feed intake, threonine intake, weight gain, and ileal villus height linearly increased (p<0.01) as dietary digestible Thr:Lys increased. During the starter phase, increasing digestible Thr:Lys ratios had a linear effect (p<0.01) on threonine intake and livability, and linear and quadratic effects (p<0.01) on feed intake. During the grower I phase, increasing digestible Thr:Lys ratios promoted linear increase in threonine intake and feed conversion ratio (p<0.05), and a linear decrease in weight gain. The estimated digestible Thr:Lys ratios recommended for meat-type quails are 0.85, 0.73 and 0.66%, for the pre-starter, starter and grower I phases, respectively.

Dietary threonine prevented stress-related mucosal diseases in rats.

Stress-related mucosal disease (SRMD), or stress ulceration, is a group of conditions ranging from stress-related superficial gastric mucosal damage to deep gastric ulcers that are primarily correlated with mucosal ischemia, and pharmacologic interventions that optimize tissue perfusion or preserve defensive mucus aim to decrease the occurrence of conditions, such as gastric acidity, or enhance gastric defenses. However, the identification of multifactorial pathogenesis may be effective in preventing SMRD, and the use of stress prophylaxis is generally preferred. Since threonine is a component in the polymerization and synthesis of gastric mucin and possibly enhanced defense actions and lignin may provide structural support for defense and antioxidative function, we hypothesized that dietary intake of threonine and/or lignin can enhance defense against SRMD. The water immersion-restraint stress (WIRS) was used in rats and additional groups were pretreated with threonine alone or the combination of threonine and lignin. Based on gross and microscopic evaluations, threonine alone or the combination of threonine and lignin, a natural antioxidant, significantly reduced the development of SRMD (P < 0.05). According to molecular explorations, the levels of inflammatory mediators, such as interleukin (IL)-8, IL-6, IL-1β, inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), and interferon gamma (IFN-γ), all of which are mediators that play a significant role in controlling WIRS, significantly decreased in the groups pretreated with either threonine alone or the combination of threonine and lignin (P < 0.01). WIRS significantly increased apoptosis in the stomach. However, the apoptotic index significantly decreased with threonine pretreatment. According to periodic acid Schiff staining results, the expression of gastric mucin was significantly preserved in groups pretreated with threonine but remarkedly decreased in the WIRS group. The gastric heme oxygenase-1 levels significantly increased in the group treated with threonine. In conclusion, the dietary intake of threonine or the combination of threonine and lignin is effective in preventing SRMD.

Maternal nutrient intake and fetal gastroschisis: A case-control study.

Fetal gastroschisis is a paraumbilical abdominal wall defect with herniation of the abdominal organs. This multifactorial malformation occurs in young pregnant women, and the underlying cause of the disease remains unknown; however, nutritional factors may play a role in its development. This case-control study explored the association of maternal nutrient intake with the occurrence of gastroschisis. The gastroschisis group (GG) comprised 57 pregnant women with fetuses with gastroschisis, and the control group (CG) comprised 114 pregnant women with normal fetuses matched for maternal age, gestational age, and preconception body mass index classification. Nutritional assessments related to the preconception period were obtained using the food consumption frequency questionnaire, and nutrient intakes were calculated using nutrition programs. The median daily calorie intake was higher (2,382.43 vs. 2,198.81; p = .041) in the GG than in the CG. The median intake of methionine (763.89 vs. 906.34; p = .036) and threonine (1,248.34 vs. 1,437.01; p = .018) was lower in the GG than in the CG. Pregnant women with fetuses with gastroschisis have a diet characterized by higher calorie intake and lower levels of essential amino acids (methionine and threonine) during the preconception period than pregnant women with normal fetuses.

Pigs receiving daily tailored diets using precision-feeding techniques have different threonine requirements than pigs fed in conventional phase-feeding systems

BackgroundThere is large variation in amino acids requirements among pigs, hence feeding pigs individually with daily tailored diets or in groups with a single feed may require different levels of nutrients. Thus, the response to different threonine levels (70%, 85%, 100%, 115%, and 130% of the ideal threonine:lysine protein ratio of 0.65) was studied in growing pigs raised in a conventional group phase-feeding (GPF) system or fed individually using individual precision-feeding (IPF) techniques. In a 21-day trial, 110 barrows (25 ± 0.80 kg body weight) were housed in the same room and fed using electronic feeders. Five pigs per treatment were slaughtered at the end of the trial.ResultsThreonine intake increased linearly for the IPF and GPF pigs (P < 0.05). Lysine intake was similar across the treatments. Average daily gain, gain:feed ratio, and protein deposition were affected linearly by threonine level (P < 0.05) in both feeding systems. Protein deposition in the GPF pigs was maximized at 150 g/d and a 0.65 threonine:lysine ratio, whereas protein deposition increased linearly in the IPF pigs. Plasma Met and serine levels were 11 and 7% higher, respectively, in the IPF pigs than in the GPF pigs (P < 0.05). Dietary threonine increased (P < 0.05) threonine concentration in the longissimus dorsi in a quadratic manner in the IPF pigs, whereas there was no effect in the GPF pigs. Longissimus dorsi collagen decreased as dietary threonine increased in the IPF and GPF pigs (P < 0.10). Carcass muscle crude protein was 2% higher in the GPF pigs than in the IPF pigs (P < 0.05).ConclusionsIndividual pigs are able to modulate growth and the composition of growth according to threonine intake. The average amino acid ratio value that is currently used for GPF cannot be used for IPF.

Immune system stimulation increases dietary threonine requirements for protein deposition in growing pigs.

Previous studies have reported an increase in the utilization of threonine (Thr) during immune system stimulation (ISS). However, increased utilization of an AA during ISS may not reflect an increased dietary requirement, as endogenous sources may supply AA to meet the need for enhanced utilization. The current study evaluated the impact of ISS on components of dietary Thr requirements, i.e., maintenance requirement and the efficiency of Thr utilization. Thirty-nine gilts (initial BW 32 ± 2.1 kg) of commercially relevant genetics were individually housed in metabolism crates and fed one of six experimental diets in which Thr was the first limiting among other AA. Three levels of dietary Thr were tested within each ISS group: 70%, 90%, and 110% of daily Thr requirements, which were estimated based on the potential of each ISS group for protein deposition (PD). Following adaptation to the experimental diets, pigs from each dietary treatment group were injected with either increasing amounts of Escherichia coli lipopolysaccharide (ISS+; 25 and 35 µg/kg BW) or saline (ISS-). Injections were given 48-h apart and whole-body nitrogen balance was measured for 72-h following the first injection. Body temperature (BT) was monitored and blood samples were collected 24 h after initiation of ISS and evaluated for measures of blood chemistry. Blood chemistry and BT results indicated an effective ISS in pigs (P < 0.03). Threonine intake increased PD in a linear fashion in both ISS groups (P < 0.01). The marginal efficiency of standardized ileal digestible (SID) Thr utilization for PD, represented by the slope, was not affected by ISS. However, ISS substantially increased the extrapolated maintenance SID Thr requirements, represented by the intercept at zero PD (ISS- vs. ISS+, -11.2 vs. -56.3 SE 13.2; P < 0.05). Collectively, our results indicated that the physiological changes associated with ISS increased the dietary SID Thr requirements for PD due to an increase in maintenance requirements.

Threonine to lysine ratio in diets of tambaqui juveniles (Colossoma macropomum)

The objective of this study was to determine the optimal digestible threonine to lysine ratios in diets of tambaqui (Colossoma macropomum) juveniles. Five-hundred fish with a mean ± SE initial weight of 2.16 ± 0.03 g were used in a completely randomized design, consisting of four treatments, five replicates per treatment, and 25 fish per experimental unit. The treatments consisted of four isoenergetic, isophosphoric, isocalcic, and isolisinic (1.45%) diets, consisting of a basal diet supplemented with four L-threonine levels (1.013, 1.085, 1.158, and 1.230%), resulting in different threonine to lysine ratios (70, 75, 80, and 85%). Fish were maintained in twenty 500-L aquaria with independent water supply, drainage, and aeration systems, and were fed to apparent satiation six times a day for 45 days. Performance, feed efficiency, daily protein and fat deposition, body moisture content, and nitrogen retention efficiency of fish were evaluated. The digestible threonine intake increased linearly, and the efficiency of threonine for weight gain decreased quadratically, with increasing digestible threonine to lysine ratios. Weight gain, specific growth rate, feed:gain ratio, protein efficiency for weight gain, and nitrogen retention efficiency of fish increased in a quadratic manner with increasing digestible threonine to lysine ratios up to the levels of 75.96, 76.06, 76.36, 76.47, and 74.02%, respectively. It was concluded that the digestible threonine to lysine ratio for use in diets of juvenile tambaqui to achieve optimal performance and nitrogen retention efficiency is 76 and 74%, respectively, which corresponds to a digestible threonine level of 1.102 and 1.073%.

Dietary Recall and Nutritional Index in Continuous Ambulatory Peritoneal Dialysis Patients

Maintenance of good nutrition forms an important component of management of Continuous Ambulatory Peritoneal Dialysis (CAPD) patients and can be achieved through regular assessment of dietary nutrient intake, appropriate dietary advice and monitoring of patient compliance with respect to adherence to dietary advice. Thirty one patients (18 males and 13 females) undergoing CAPD were studied. Information on their dietary intake was collected by dietary recall method. Data was analysed using nutrition software, “dietsoft” and dietary intake of various food components was compared with the prescribed and recommended allowance. Nutritional Risk Index (NRI) score was calculated to assess severity of malnourishment. Mean calorie intake was as per recommendation; carbohydrate and protein intake was lesser and fat intake was more than recommended intake in males and females. All essential amino acids measured in the diet of females was more than recommended levels; in males, intake of lysine, threonine, tryptophan and histidine was more and that of methionine was less than the recommendation. Among minerals measured, both groups of patients consumed lower amounts of sodium, potassium, iron, zinc and magnesium, and higher amounts of phosphorus than recommended. The intake of riboflavin, pyridoxine, niacin and vitamin A was lower in both groups, whereas in males, there was a deficient intake of thiamine, vitamin B12 and vitamin C also. 27% of the patients were at risk of severe malnourishment. Findings showed deficient intake of a majority of nutrients by CAPD patients which might result in adverse clinical outcomes. Thus, there is a need for periodical evaluation and appropriate modification of the diet plan of patients undergoing CAPD. The dietary assessment helps in monitoring adherence of patients to dietary advice, timely identification of deficient intake, and initiation of supplementation, if required.

Using the indicator amino acid oxidation technique to study threonine requirements in horses receiving a predominantly forage diet

Threonine has been reported to be the second limiting amino acid in typical equine diets, but its actual requirement has not been determined in horses. To evaluate amino acid metabolism and requirements, the indicator amino acid oxidation (IAAO) method has been successfully used in other species. The objective of this research was to estimate threonine requirements in mature horses fed timothy hay and concentrate in 4:1 ratio using the IAAO method. Six Thoroughbred mares (579.9±46.7kg) received each of 6 levels of threonine intake, 41, 51, 61, 70, 80 and 89mg/kg BW/day, in a randomly determined order. Each study period was 7-day long, and on day 6, blood samples were collected before and 90min after feeding to measure amino acid concentrations using HPLC. On day 7, horses underwent IAAO procedures, which included a 2-hr primed, constant intravenous infusion of [13 C]sodium bicarbonate to measure total CO2 production and a 4-hr primed, constant oral administration of [1-13 C]phenylalanine to estimate phenylalanine oxidation to CO2 . Blood and breath samples were collected to measure blood [13 C]phenylalanine, using GC-MS analysis and breath 13 CO2 enrichment, using an infrared isotope analyser. Increasing threonine intake levels did not affect plasma phenylalanine oxidation by the ANOVA test (p>0.05) but resulted in a linear decrease in phenylalanine oxidation (p=0.04) without a breakpoint by the orthogonal linear contrast. This study is the first attempt to evaluate threonine requirements in horses by the IAAO method; however, threonine requirements are still unknown in mature horses at this time.

Individual responses of growing pigs to threonine intake

ABSTRACT A nitrogen balance test was performed to evaluate the individual responses of growing pigs to threonine intake. Eight commercial barrows were used (body weight ranging from 15 to 20 kg). A dose-response study was performed, in which the threonine supply increased in seven equidistant steps (the seven dietary threonine levels ranged from 50 to 120% of the requirements) every three days for each pig. The levels of all other amino acids were 20% higher than the tested amino acid. [...]