Total Amino Acids Research Articles

Effects of different trophic conditions on total fatty acids, amino acids, pigment and gene expression profiles in Euglena gracilis.

Euglena gracilis is a unique microalga that lacks a cell wall and is able to grow under different trophic culture conditions. In this study, cell growth, biomass production, and changes in the ultrastructure of E. gracilis cells cultivated photoautotrophically, mixotrophically, and under sequential-heterotrophy-photoinduction (SHP) were assessed. Mixotrophy induced the highest cell growth and biomass productivity (6.27 ± 0.59mg/L/d) in E. gracilis, while the highest content of fatty acids, 2.69 ± 0.04% of dry cell weight (DCW) and amino acids, 38.16 ± 0.08% of DCW was obtained under SHP condition. E. gracilis also accumulated significantly higher saturated fatty acids and lower unsaturated fatty acids when cultivated under SHP condition. Transcriptomic analysis showed that the expression of photosynthetic genes (PsbA, PsbC, F-type ATPase alpha and beta) was lower, carbohydrate and protein synthetic genes (glnA, alg14 and fba) were expressed higher in SHP-culture cells when compared to other groups. Different trophic conditions also induced changes in the cell ultrastructure, where paramylon and starch granules were more abundant in SHP-cultured cells. The findings generated in this study illustrated that aerobic SHP cultivation of E. gracilis possesses great potential in human and animal feed applications.

Optimal Light Intensity for Lettuce Growth, Quality, and Photosynthesis in Plant Factories.

In agriculture, one of the most crucial elements for sustained plant production is light. Artificial lighting can meet the specific light requirements of various plants. However, it is a challenge to find optimal lighting schemes that can facilitate a balance of plant growth and nutritional qualities. In this study, we experimented with the light intensity required for plant growth and nutrient elements. We designed three light intensity treatments, 180 μmol m-2 s-1 (L1), 210 μmol m-2 s-1 (L2), and 240 μmol m-2 s-1 (L3), to investigate the effect of light intensity on lettuce growth and quality. It can be clearly seen from the radar charts that L2 significantly affected the plant height, fresh weight, dry weight, and leaf area. L3 mainly affected the canopy diameter and root shoot ratio. The effect of L1 on lettuce phenotype was not significant compared with that of the others. The total soluble sugar, vitamin C, nitrate, and free amino acid in lettuce showed more significant increases under the L2 treatment than under the other treatments. In addition, the transpiration rate and stomatal conductance were opposite to each other. The comprehensive evaluation of the membership function value method and heatmap analysis showed that lettuce had the highest membership function value in L2 light intensity conditions, indicating that the lettuce grown under this light intensity could obtain higher yield and better quality. This study provides a new insight into finding the best environmental factors to balance plant nutrition and growth.

Evaluation of physicochemical and flavor characteristics and primary on lipid oxidation of crucian carp under different cooking methods

This study aimed to reveal the effects of steaming, frying and boiling on the sensory and quality of the cooked crucian carp. 46, 27 and 37 volatiles were detected in the steamed fish, fried fish (FF) and boiled fish (BF), respectively, of which 7 were identified as the key volatiles. Compared with the BF and FF, the SF was richer in esters, aldehydes, alkenes and the kinds and contents of the key volatiles. The contents of moisture and crude protein were the highest in the SF. The FF exhibited the most distinctive aroma profile, much possibly associated with the highest thiobarbituric acid reactive substances (TBARS) value observed in the FF. The content of total free amino acid in the BF was the lowest while the content of umami amino acid content in the SF was the highest (p < 0.05). The nutrition of fatty acids was highest in the SF due to its highest ƩUFA/ƩSFA ratio. PLS-DA analysis showed that SF was positively correlated with the most key volatiles and several free fatty acids. These results indicated that the flavor and nutrition of SF were the highest, providing appropriate cooking methods of crucian carp for the standardized production of bean paste fish.

Comparable glucagon-stimulated amino acid suppression in individuals with and without hepatic steatosis or steatohepatitis.

Hepatic amino acid (AA) metabolism and glucagon secretion are linked in a feedback cycle in which circulating AAs stimulate glucagon secretion, while glucagon stimulates hepatic AA catabolism. It has been proposed that metabolic dysfunction-associated steatotic liver disease (MASLD) leads to hepatic glucagon resistance, which may result in hyperaminoacidemia and hyperglucagonemia. We tested the glucagon effect on AA metabolism in subjects with obesity; 11 with steatohepatitis (MASH), 10 with steatosis (MAS), and seven subjects (CON) without steatosis. We performed a somatostatin clamp with infusions of insulin and low-dose followed by high-dose glucagon. We measured plasma levels of 17 AAs and assessed hepatic fat content (FF%) and body fat distribution (visceral and subcutaneous adipose tissue mass) by MRI. HighGlucagon suppressed plasma total AA equally in all groups; MASH 13% (SD 9%), MAS 14% (7%), CON 11% (5%), respectively. In univariate regression analyses visceral adipose tissue mass (β = 0.471, P = 0.011) and AA concentration at LowGlucagon (β = ─0.524, P = 0.004), but not FF% (β = ─0.243, P = 0.213), were significant predictors of AA reduction. Using a stepwise backward multiple regression approach revealed similar results. Total and specific AA levels (glutamic acid, tyrosine) were higher in both MASLD groups during the study and FF% was positively correlated to a number of individual AAs. Though finding elevated AA concentrations in subjects with MASLD, we conclude that in MASLD patients that do not have elevated glucagon at baseline, glucagon suppresses circulating AA levels equally in subjects with and without MASLD. NCT04042142.

The Role of Camellia Shell Substrates in Modulating the Nutritional Characteristics of Pleurotus pulmonarius.

Camellia shells are the main by-product of camellia seed processing and are usually incinerated or disposed of as agricultural waste. In this study, camellia shells were employed in the Pleurotus pulmonarius cultivation process using five distinct formulae substituting for cottonseed shells. Our results show that as the substitution rate of camellia shells increased from 0% to 35%, the protein content in P. pulmonarius significantly increased from 34.05% to 53.35%. The polysaccharide content reached a peak value of 5.62% at 30% substitution of camellia shells. The DPPH free radical scavenging rate reached its maximum of 82.70% at 20% substitution of camellia shells. Furthermore, increases in the total amino acid contents in P. pulmonarius were positively correlated with the substitution rate of camellia shells. Considering the yield characteristics, the formula of 20% camellia shell substitution tested in this study appears to be optimal for P. pulmonarius cultivation. These findings not only provide a substrate to enhance the nutritional quality of P. pulmonarius but also demonstrate a novel approach for the ecological utilization of camellia shells.

Microfluidic paper-based analytical devices for simple and nondestructive durian fruit maturity assessment

Accurately predicting durian maturity is a critically unresolved worldwide issue. Farmers currently determine durian ripeness based on their own observation and experience leading to inconsistencies in harvest timing. This reliance on human judgment often results in premature or overripe harvests, impacting fruit quality, yield, and market value. Existing technological solutions, such as sensors are often complex and require specialized expertise, hindering their adoption by farmers and consumers. Developing sensors that can accurately measure durian ripeness without damaging the fruit, are easy to use, and affordable remains a challenge. We introduce a microfluidic paper-based analytical device (μPAD) for on-site, safe matching to meet the demands of durian maturity evaluation. The μPAD automatically collected peduncle fluid without destroying the durian fruit for dual detection of total sugar and amino acid. For determining total sugar including sucrose, glucose, and fructose, several enzymatic steps were reduced to a single step of invertase for sucrose hydrolysis before total reducing sugar was measured using gold nanoparticle (AuNP) generation. Kinetics study of invertase on the μPAD showed Vmax and Km values of 1.42 mM min−1 and 2.17 mM, respectively, that agreed with the direct study of sucrose conversion. To increase device reliability, amino acid was also simultaneously measured with sugar using the simple ninhydrin test with the addition of SnCl2. The developed sensor provided LODs of 3.50, 3.10, 3.30 μM, and 0.02 mg mL−1 for glucose, fructose, sucrose, and amino acid respectively. The μPADs were able to nondestructively discriminate between the mature and immature durians, showing high linear correlation with the standard dry weight method. The development of this μPAD technology has the potential to revolutionize durian cultivation practices, reduce post-harvest losses, and enhance the overall sustainability and profitability of the durian value chain, and can be further developed for maturity tests of other fruits.

Hemp Seed Protein Hydrolysate Enriched with γ-Aminobutyric Acid and Peptides by Microbial Bioconversion

Hemp seed protein (HSP), a by-product of hemp oil processing, was converted into a functional protein ingredient enriched with γ-aminobutyric acid (GABA) and peptides through a two-step microbial fermentation process. To enhance peptide and free amino acid production from HSP, it was hydrolyzed using alkaline protease produced by Bacillus subtilis HA. The HSP was hydrolyzed at a degree of 40% at 55 °C for 24 h, yielding a pH of 6.55, an acidity of 1.22%, and 205.45 mg% tyrosine equivalents. This process resulted in the production of low molecular-weight peptides. (&lt;5000 Da) The total amino acid content and branched-chain amino acids (leucine, isoleucine, and valine) were 6.78 mg/g and 1.47 mg/g. Subsequently, the production of γ-aminobutyric acid (GABA) in the HSP hydrolysate was optimized through co-fermentation with lactic acid bacteria in the presence of 5% MSG at 30 °C for 5 days. The serial co-fermented HSP hydrolysate exhibited a GABA content of 33.98 mg/g and a viable bacterial count of 9.51 log CFU/mL for Lb. plantarum KS2020. This serial co-fermentation process, combining proteolysis and lactic acid fermentation, not only increased the peptide content but also promoted GABA accumulation, positioning HSP hydrolysate as a promising candidate for functional foods with potential health benefits.

Amino acid requirements of the infant: the amino acid composition of human breast milk.

The recommended amino acid requirements of the infant are based on the amino acid composition of mature human breast milk. The amino acid composition of breast milk is usually determined following either acid or alkaline (for tryptophan) hydrolysis. For accuracy, however, the known effect of hydrolysis time on amino acid composition should be accounted for. Also, ideally the amino acid composition of breast milk should be given in units of digested (assumed to be absorbed) amino acids. A review of the literature is presented which gives mean total amino acid concentrations in mature human milk (n = 26 studies), mean hydrolysis correction factors (n = 3 studies) and mean true ileal amino acid digestibility coefficients (n = 3 studies, suckling piglet). There were differences between the estimates of amino acid concentration corrected for hydrolysis time and digestibility, and current FAO (2013) recommendations that were not corrected for these factors. The values based on the published literature up until 2023 (mg/g true protein) corrected for hydrolysis time and digestibility gave higher values (more than 16% higher) for leucine, lysine and threonine, and considerably higher values (greater than 30%) for histidine and tryptophan. Current recommendations may need revision.

Effects of fasting on golden pompano Trachinotus ovatus: Physiological and biochemical responses

In practice, golden pompano (Trachinotus ovatus) reared in offshore cages may experience short-term fasting during extreme weather conditions, yet their physiological and biochemical responses remain poorly understood. To investigate the responses of this species to fasting, golden pompano weighing 138.0 ± 2.1 g were deprived of food for 0, 7, 14, 21 and 28 days, followed by assessments of body mass, somatic parameters, proximate composition, muscle glycogen, intestinal digestive enzymes, muscle amino acid and fatty acid profiles, nutritional value, and muscle texture and water holding capacity. Lower condition factor, hepatosomatic index, viscerosomatic index, hepatic glycogen, and intestinal activities of amylase, lipase and trypsin were found in the fasted fish than in the non-fasted fish, while a sharp decline in these parameters occurred on the first week of fasting. Fresh mass, dry mass, whole body and muscle contents of crude protein and lipid tended to decrease with prolonged fasting, while no statistical differences were found in these parameters between fish fasted for 7 days and the non-fasted fish. Furthermore, the decline rate of whole body crude lipid was consistently higher than that of whole body crude protein throughout the different stages of the 28-day fasting period, with the exception of the second week of fasting. No statistical differences were found in the total essential amino acids (∑EAA), non-essential amino acids (∑NEAA), ratio of ∑EAA to∑NEAA, chemical score, amino acid score, and essential amino acid index in the fasted fish compared to the non-fasted fish of group 0d. Fasting altered the muscle profile of SFA, MUFA and PUFA, sometimes reducing muscle springiness (groups 7d and 14d) and hardness (group 21d). Compared to non-fasted fish, fish fasted for 7 and 14 days exhibited statistically lower or equal drip loss, water loss rate, storage losses, and frozen exudate rate, whereas higher cooked meat rate. The above results indicate that during the 28-day fasting period, the visceral fat and hepatic glycogen are initially metabolized, followed by body proteins and lipids, to maintain the normal metabolism in fasted fish. Fasting has beneficial effects on the nutritional value of amino acids and fatty acids in muscle, although it modifies the muscle SFA, MUFA and PUFA composition and sometimes has negative effects on muscle texture. Considering the balance between body weight loss and flesh quality improvement, the duration of fasting for cultured golden pompano prior to harvesting should not exceed 14 days.

Underlying mechanisms of different polysaccharides on the texture characteristics and protein digestibility of soybean curd

This study aimed to investigate the effects of the addition of potato starch (PS) and guar gum (GG) at different concentrations (0.4 and 0.8%) on the physical properties, protein conformation, and in vitro digestibility of soybean curd. The results indicated that the PS acted as a filler in the protein structure, enhancing the firmness, springiness, and chewiness of the soybean curd. GG encapsulated the disorganized filamentous protein matrix, increasing the adhesiveness of the soybean curd. The addition of GG and PS reduced the hydrophobic interactions and disulfide bonds responsible for cross-linking soybean curd proteins, while forming more hydrogen bonds with the proteins (p < 0.05). GG formed the most hydrogen bonds with the proteins, as well as reduced β-sheet content and transformed into more random coil and β-turn (p < 0.05). Also, the addition of GG (particularly at 0.8%) significantly reduced the degree of protein hydrolysis (31.98%) in soybean curd, resulting in fewer small molecular weight peptides and lower total amino acid content (3386.79 μg/g protein) at the end of in vitro digestion (p < 0.05). In contrast, the addition of a small amount of PS (0.4%) did not affect the protein digestibility of soybean curd. This study clarified the impact of polysaccharide additions on modifying the soybean curd texture and protein digestibility.

PSVI-29 Effect of pig weight and exogenous enzyme supplementation on ileal endogenous amino acid losses and standardized ileal amino acid digestibility of soybean meal produced from Kentucky-grown soybeans

Abstract There is increasing interest in using locally sourced soybeans and soybean meal. Ileal amino acid digestibility (IAAD) of soybean meal from Kentucky-grown soybeans was evaluated in 25- and 50-kg cannulated pigs. The experiment used sixteen pigs in a randomized complete block design consisting of four treatments with 4 pigs per treatment. This was repeated in time resulting in eight replicates per treatment for both body weight (BW)groups. After cannulation at about 20 kg BW, all pigs were allowed to recover from the surgery and were fed a corn-SBM-based diet that met all nutrient and energy requirements. The experimental diets consisted of two nitrogen-free diets [NFD] with or without exogenous enzyme supplementation (phytase and a combination of phytase and carbohydrase enzymes) and two semi-purified diets containing soybean meal from Kentucky-grown soybeans as the only source of protein with or without exogenous enzyme supplementation. Each diet was fed for 7 consecutive d with 10-h ileal digesta collection on d 6 and 7. The same diets were fed to the same set of pigs at about 50 kg BW. Data were analyzed as a factorial arrangement of treatments (BW x diet) for ileal endogenous amino acid losses (IEAAL), apparent IAAD and standardized IAAD (SIAAD). Data from the NFD were used to determine the SIAAD from the AIAAD values. Exogenous enzyme supplementation increased (P &amp;lt; 0.05) IEAAL except for Gly and Pro while samples collected during phase 2 had greater (P &amp;lt; 0.05) IEAAL (10 amino acids). Pig BW did not influence IEAAL. Enzyme supplementation did not increase AIAAD except for Arg, Ala, Gly, N, and total AA while apparent ileal N, Met, Thr, and Val digestibility was greater (P &amp;lt; 0.05) in 50 kg pigs. Interactions between BW and diets showed that 50 kg pigs fed the SBM diet containing enzyme supplementation had greater (P &amp;lt; 0.05) N, Arg, and total AA digestibility compared with 50 kg pigs without enzyme supplementation. Digestibility of Val and Asp was greater (P &amp;lt; 0.05) in samples collected during phase 2. After correction for basal IEAAL, 50 kg pigs had greater (P &amp;lt; 0.05) SIAAD values for 12 of the AA analyzed while exogenous enzyme supplementation resulted in greater (P &amp;lt; 0.05) SIAAD for 9 of the AA analyzed. The SIAAD values for four AA (His, Phe, Val, and Asp) were greater (P &amp;lt; 0.05) for samples collected in phase 2. Results from this study showed that exogenous enzyme supplementation increased IEAAL and that IAAD of SBM produced from Kentucky-cultivated soybeans was high and that exogenous enzyme supplementation improved the SIAAD values of several amino acids. The IAAD values of SBM produced from soybeans cultivated in KY was high and are similar to values reported in the literature.

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 &amp;gt;14 wk to 9 mos, 6 adults 2 to 5 yr (yr), and 6 seniors &amp;gt; 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.

Investigating the temporal evolution of physicochemical attributes and flavorome profiles in Sichuan shai vinegar utilizing diverse aging techniques

Sichuan shai vinegar (SSV) is an acidic condiment with a long history and unique flavor. Aging is an important production process that determines the unique flavor of shai vinegar. This study compared the differences in physicochemical properties, volatile flavor, and non-volatile flavor substances between the constant temperature aging and natural aging methods of SSV Cupei. The results showed that the total acid and amino acid nitrogen content in naturally aged vinegar was higher than that in constant temperature aged vinegar. Furthermore, 20 different volatile flavor substances and 65 different non-volatile flavor substances were obtained after 21 and 25 days of constant temperature aging and 1, 3, and 5 years of natural aging SSV samples. This indicates that the temperature environment during natural aging was more moderate, allowing acidic compounds to form and stably exist in the aging environment. Correlation analysis further demonstrated that there were more differentiated non-volatile substances significantly related to the Maillard reaction under constant temperature aging condition and related to antioxidant activity under natural aging condition. The results of this study provide a comprehensive understanding of the characteristics and applications of the two aging methods of SSV and guide strategy for factories in the selection of aging methods.

Comparative Study of Nutritional Composition, Physiological Indicators, and Genetic Diversity in Litopenaeus vannamei from Different Aquaculture Populations.

This study aimed to evaluate the quality and genetic diversity of farmed Litopenaeus vannamei across three distinct populations from Maoming City (MM), Zhanjiang City (ZJ), and Yangjiang City (YJ) in Guangdong Province. Muscle tissues from L. vannamei were analyzed for phenotypic traits, conventional nutrients, amino acids, and fatty acids, while genetic diversity was assessed using whole genome sequencing techniques. The analysis revealed that the crude protein content in shrimp across the three populations ranged from 20.87 to 21.95 g/100 g, crude fat content ranged from 0.90 to 1.50 g/100 g, essential amino acid content ranged from 5.55 to 5.86 g/100 g, total amino acid content ranged from 14.73 to 15.27 g/100 g, total fatty acid content ranged from 682.73 to 793.97 mg/100 g, total antioxidant capacity (T-AOC) ranged from 2.68 to 2.72 μmol/g, superoxide dismutase (SOD) activity ranged from 1021.97 to 1057.21 U/g, and catalase (CAT) activity ranged from 78.65 to 81.33 μmoL/min. No significant differences were observed in ash and crude fat levels among conventional nutrients, nor in the biochemical indexes T-AOC, CAT, and SOD. Genetic analysis showed that the single nucleotide polymorphism density (SNP/Kb) ranged from 15.323 to 17.461, nucleotide diversity (π) ranged from 2.98 × 10-5 to 15.84 × 10-5, polymorphism information content (PIC) ranged from 0.300 to 0.317, heterozygosity (Ho) ranged from 0.033 to 0.048, and inbreeding coefficients (FIS) ranged from 0.834 to 0.887. The genetic differentiation index (FST) values among the three populations ranged from 0.056 to 0.106. This study provides an evaluation of the germplasm resources and genetic diversity of farmed L. vannamei, offering insights for the efficient management and sustainable utilization of this species' germplasm resources.

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 &amp;lt; 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 &amp;gt; 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 &amp;lt; 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.

Be prepared: how does discontinuous hydration in Tabebuia heterophylla seeds induce stress tolerance in seedlings?

Discontinuous hydration and dehydration (HD) cycles refer to controlled imbibition followed by dehydration before seed germination. Here, we investigated whether the level of imbibition before HD cycles affects the physiology of Tabebuia heterophylla seeds and seedlings. Seeds were imbibed for 10 h (T1; phase I of imbibition) or 35 h (T2; phase II), dehydrated, and progressively rehydrated one to four times (HD cycles). Germination and biochemical parameters (membrane integrity; total soluble, reducing, and nonreducing (NRS) sugars; proteins, amino acids, proline, H2O2, catalase, ascorbate peroxidase, and glutathione reductase activity) were quantified at the last rehydration step of each cycle. Biometric and biochemical parameters (including pigments) were analysed in seedlings 60 days after germination. HD cycles at T1 led to reduced seed germination and greater plasma membrane damage, higher enzyme activity (catalase and glutathione reductase) and accumulation of NRS, total amino acids, and proline compared to the controls and T2 treatment. Cellular damage became more severe with more HD cycles. HD cycles at T2 synchronized germination regardless of the number of cycles and also had a priming effect. T2 seeds had less NRS, total amino acids, and proline content than T1. HD cycles at T1 produced seedlings with higher carotenoid and total chlorophyll content than controls and T2, while seedlings from HD cycles at T2 had higher amounts of osmoprotectants. HD cycles at T2 benefited seeds and seedlings more than at T1. This suggests that the physiological and biochemical effects of HD cycles in seeds modulate seedling plasticity, depending on water availability, potentially promoting increased tolerance to recurrent droughts that will be intensified with ongoing climate changes.

Elucidating the underlying mechanisms of silicon to suppress the effects of nitrogen deficiency in pepper plants

In many regions, nitrogen (N) deficiency limits pepper cultivation, presenting significant cultivation challenges. This study investigates the impact of N deficiency and silicon (Si) supplementation on physiological responses and antioxidant modulation in pepper plants, focusing particularly on the homeostasis of carbon (C), nitrogen, and phosphorus (P), and their effects on growth and biomass production. Conducted in a factorial design, the experiment examined pepper plants under conditions of N sufficiency and deficiency, with and without Si supplementation (0.0 mM and 2.0 mM). Results showed that N deficiency sensitizes pepper plants, leading to increased electrolyte leakage (39.59%) and disrupted C, N, and P homeostasis. This disruption manifests as reductions in photosynthetic pigments (−64.53%), photochemical efficiency (−14.92%), and the synthesis of key metabolites such as total free amino acids (−86.97%), sucrose (−53.88%), and soluble sugars (−39.96%), ultimately impairing plant growth. However, Si supplementation was found to alleviate these stresses. It modulated the antioxidant system, enhanced the synthesis of ascorbic acid (+30.23), phenolic compounds (+33.19%), and flavonoids (+7.52%), and reduced cellular electrolyte leakage (−25.02%). Moreover, Si helped establish a new homeostasis of C, N, and P, optimizing photosynthetic and nutritional efficiency by improving the utilization of C (+17.46%) and N (+13.20%). These Si-induced modifications in plant physiology led to increased synthesis of amino acids (+362.20%), soluble sugars (+51.34%), and sucrose (77.42%), thereby supporting enhanced growth of pepper plants. These findings elucidate the multifaceted biological roles of Si in mitigating N deficiency effects, offering valuable insights for more sustainable horticultural practices.

A novel approach to produce soy protein isolate: Direct enzymatic hydrolysis of high-temperature soybean meal using proteinase produced by microbial solid-state fermentation

This study proposed a novel extraction method for soy protein isolate, which involved solid-state fermentation of high-temperature soybean meal. The proteinases secreted by microorganisms acted on the high-temperature soybean meal, making the SPI easier to extract. The study concludes that Bacillus amyloliquefaciens subsp. plantarum CICC 10265 could be used for solid-state fermentation of soybean meal, and the fermentation effect was good, with a yield of 41.91 % for SPI. Compared to the direct extraction of SPI from high-temperature soybean meal, the yield had increased by 130.19 %. Meanwhile, we also conducted research on the losses during the SPI extraction process. Through experiments, the study identified the patterns of protease activity changes and microbial colony growth during solid-state fermentation of soybean meal by Bacillus amyloliquefaciens subsp. plantarum CICC 10265. It was concluded that extracting SPI after 8 h of fermentation is more suitable. The experimental results indicated that the total amino acid content of SPI extracted from fermented soybean meal was 2.1 % higher compared to SPI extracted from low-temperature soybean meal. The extracted SPI also met the microbial standards.

Metabolomics ravels flavor compound formation and metabolite transformation in rapid fermentation of salt-free fish sauce from catfish frames induced by mixed microbial cultures

This study demonstrates that the co-inoculation with Lactiplantibacillus plantarum, Pichia fermentans and Staphylococcus saprophyticus accelerates catfish frame fish sauce fermentation. Over a 3-day period, significant changes occurred in physicochemical properties, microbial profiles, flavor compounds, and metabolomic spectra. Notable increases in acidity coupled with decreases in glucose underscored the robust environmental adaptability of the employed microorganisms. A reduction in total amino acids, alongside a rise in umami amino acids, suggested flavor enhancement. GC–MS analysis identified 40 key volatile compounds, with esters and aldehydes crucial for aroma development. UPLC-QTOF-MS-based untargeted analysis identified 934 metabolites, with 377 differential metabolites being vital (VIP > 1.5, P < 0.05), including amino acids, peptides, organic acids, nucleic acids, and fatty acids. Metabolites linked to amino acid metabolism, particularly phenylalanine and arginine, were associated with fermentation duration. These findings offer a theoretical basis for optimizing flavor and quality in fish sauces from fish by-products through accelerated fermentation.

Nutritional status and extended metabolic screening in Egyptian children with uncomplicated type 1 diabetes

Nutritional status assessment, including amino acids, carnitine, and acylcarnitine profile, is an important component of diabetes care management, influencing growth and metabolic regulation. A designed case–control research included 100 Egyptian participants (50 T1DM and 50 healthy controls) aged 6 to 18 years old. The participants' nutritional status was assessed using the Body Mass Index (BMI) Z-score. Extended metabolic screening (EMS) was performed using a high-performance liquid chromatography-electrospray ionization-mass spectroscopy system to evaluate the levels of 14 amino acids, free carnitine, and 27 carnitine esters. T1DM children had considerably lower anthropometric Z-scores than the control group, with 16% undernutrition and 32% short stature. Total aromatic amino acids, phenylalanine, phenylalanine/tyrosine ratio, proline, arginine, leucine, isoleucine, free carnitine, and carnitine esters levels were considerably lower in the diabetic group, suggesting an altered amino acid and carnitine metabolism in type 1 diabetes. BMI Z-score showed a significant positive correlation with Leucine, Isoleucine, Phenylalanine, Citrulline, Tyrosine, Arginine, Proline, free carnitine, and some carnitine esters (Acetylcarnitine, Hydroxy-Isovalerylcarnitine, Hexanoylcarnitine, Methylglutarylcarnitine, Dodecanoylcarnitine, Tetradecanoylcarnitine, and Hexadecanoylcarnitine). HbA1c% had a significant negative correlation with Total aromatic amino acids, Branched-chain amino acid/Total aromatic amino acids ratio, Glutamic Acid, Citrulline, Tyrosine, Arginine, Proline, and certain carnitine esters (Propionylcarnitine, Methylglutarylcarnitine, Decanoylcarnitine, Octadecanoylcarnitine and Octadecenoylcarnitine), suggest that dysregulated amino acid and carnitine metabolism may be negatively affect the glycaemic control in children with TIDM. In conclusion, regular nutritional assessments including EMS of T1DM patients are critical in terms of diet quality and protein content for improved growth and glycemic management.