Limiting Amino Acid Research Articles

Nutritional Value Evaluation of New Pea Genotypes (Pisum sativum L.) Based on Their Chemical, Amino Acids and Dietary Fiber Composition

This research concerned the assessment of the utility value of new pea breeding materials intended for registration in the European Union. The research material consisted of sixteen breeding lines and four reference pea varieties. The evaluation was carried out based on the chemical composition of seeds and its variability within the studied genotypes. The contents of protein, starch, lipids, ash and dietary fiber (DF) were determined. The nutritional value of the protein was assessed in vitro using the value of the limiting amino acid index chemical score (CS) and the integrated essential amino acid index (EAAI). The analyzed pea genotypes were characterized by significant diversity in terms of the content of the tested components. The obtained results combined with the PCA analysis were used to select pea genotypes of the highest quality, having the potential as a raw material for the production of food with health-promoting properties. The effect of the conducted research was the identification of three pea genotypes with the greatest potential in terms of protein content and dietary fiber complex.

Enhancing protein extraction from Pleurotus ostreatus using synergistic pH-shifting and ultrasonic technology: Optimization via RSM and 1H NMR-based metabolomic profiling

This study explores the impact of ultrasound and pH-shifting on protein extraction from P. ostreatus, employing 1H NMR techniques to monitor metabolites and elucidate the extraction mechanism. The NMR-based metabolic analysis demonstrated that extended sonication time significantly boosted amino acid release. To optimize conditions for maximizing protein yield, response surface methodology was performed. This research aims to enhance protein extraction from P. ostreatus by analyzing the interplay between ultrasound treatment and pH-shifting. The results indicate that the synergistic use of pH-shifting and ultrasound-assisted extraction (UAE) significantly improves protein yield. The amino acid profile of the protein concentrates revealed a high content of essential amino acids, with tryptophan identified as the limiting amino acid. Additionally, the combined extraction method enhanced the emulsifying properties and foaming stability of the protein concentrates. Thus, combining pH-shifting and UAE is a promising technique for extracting high-quality protein from P. ostreatus, enhancing functional properties and efficiency.

Defatted Flaxseed Flour as a New Ingredient for Foodstuffs: Comparative Analysis with Whole Flaxseeds and Updated Composition of Cold-Pressed Oil.

Flaxseeds are functional foods popular in current diets. Cold-pressing is a solvent-free method to extract flaxseed oil, resulting in a by-product-defatted flour. This study compared whole flaxseeds and defatted flour (proximate composition, fatty acids, vitamin E, total phenolics and flavonoids, antioxidant activity, amino acids, and protein quality) and updated the composition of cold-pressed oil (oxidative stability, peroxide value, UV absorbance, colour, fatty acids, vitamin E, total phenolics and flavonoids, and antioxidant activity) to assess the nutritional relevance and potential for food applications of these samples. The flour had higher ash (6% vs. 4%), fibre (36% vs. 34%), protein (28% vs. 16%), phenolics (205 vs. 143 mg gallic acid equivalents/100 g), and antioxidant activity than seeds (p < 0.05), so it should be valued as a novel high-fibre food ingredient with high-quality plant-based protein, as it contains all essential amino acids (106 mg/g) and a high essential amino acids index (112%), with L-tryptophan as the limiting amino acid. The oil, while low in oxidative stability (1.3 h), due to its high polyunsaturated fatty acids sum (75%), mostly α-linolenic acid (57%), contains a significant amount of vitamin E (444 mg/kg), making it a specialty oil best consumed raw. The exploration of the flour as a minimally processed food ingredient highlights its role in supporting food security, circular economy, and sustainability goals, aligning with consumer preferences for natural, low-fat foods. Future research should investigate the bioactivity and shelf-life of the samples, as well as the bioavailability of compounds after digestion.

Extraction and Nutritional Value of Soybean Meal Protein Isolate

The increasing protein demand driven by global population growth necessitates the search for an alternative protein source. Soybean meal (SM), with approximately 47–49% proteins, is a viable option. Soymeal protein isolate (SMPI) is a cost-efficient protein source with a well-balanced amino acid profile, making it suitable for addressing this demand. This study attempts to address the lack of information regarding the extractability and nutritional potential of SMPI obtained utilizing a weak base and recoverable solvent. In this work, the structural and compositional studies of SMPI, as well as the aqueous extractability of ammonium hydroxide (NH4OH), are investigated. Furthermore, we examined the effects of heat treatment during oil extraction, where a comparison between protein isolates from soymeal and whole soybeans was carried out. The maximum extraction yield of 24.1% was achieved by increasing the concentration of NH4OH from 0.25–1%. In comparison to the soy protein isolate from whole soybeans (SPI), the compositional analysis report revealed that SMPI had higher levels of crude protein, moisture, and ash content, but lower levels of fat and carbohydrates. Furthermore, the examination of the amino acid composition confirms the existence of vital amino acids in SMPI. The amino acid score indicates that methionine, lysine, and threonine are the limiting amino acids. SMPI and SPI share structural and functional group similarities, as demonstrated by Fourier-transform infrared spectroscopy. Gel electrophoresis using sodium dodecyl sulfate–polyacrylamide shows that the protein molecular weight distributions of SPI and SMPI are similar. This in-depth evaluation emphasizes the advantages of SM by advocating its application in other sectors beyond conventional animal feed, such as nutritional supplements and bio-based products, and by improving the environmental sustainability and global food chains.

Protein and lysine improvement harnessed by a signal chain of red light-emitting diode light in Chlorella pyrenoidosa

Microalgae are emerging as a novel single-cell protein source that can substitute traditional plant protein feeds. In this investigation, lysine and protein accumulation in Chlorella pyrenoidosa were significantly enhanced under red light-emitting diode light, addressing challenge of limiting amino acid in plant proteins. The study employed targeted metabolomics, HPLC, and qRT-PCR to validate the light-induced pathway triggering lysine biosynthesis. Specifically, the pathway involves Ca2+-CaM as an intermediary in signal transduction, which directly inhibits PEPC activity. This inhibition directs a significant carbon flux towards central carbon metabolism, resulting in increased pyruvate levels—a critical precursor for lysine biosynthesis via the diaminopimelate pathway. Ultimately, the content of protein and lysine under red light increased by 36.02 % and 99.56 %, respectively, compared to those under white light. These findings provide a novel orientation for the precise regulation of lysine accumulation in microalgae, and moreover lay a solid theoretical foundation for producing microalgal proteins.

A whole food, plant-based diet reduces amino acid levels in patients with metastatic breast cancer.

Amino acids are critical to tumor survival. Tumors can acquire amino acids from the surrounding microenvironment, including the serum. Limiting dietary amino acids is suggested to influence their serum levels. Further, a plant-based diet is reported to contain fewer amino acids than an animal-based diet. Here, we investigated the impact of a whole food, plant-based diet on lowering the serum levels of amino acids in patients with cancer. Patients with metastatic breast cancer (n=18) were enrolled in clinical trial NCT03045289 . An ad libitum whole food, plant-based diet was implemented for 8 weeks without calorie or portion restriction. We found that a whole food, plant-based diet resulted in a lower intake of calories, fat, and amino acids and higher levels of fiber. Additionally, body weight, serum insulin, and IGF-1 were reduced in participants. The diet contained lower levels of essential and non-essential amino acids. Importantly, the lowered dietary intake of amino acids translated to reduced serum levels of amino acids in participants (5/9 essential amino acids; 4/11 non-essential amino acids). These findings provide a tractable approach to limiting amino acid levels in cancer patients. This data lays a foundation for studying the relationship between amino acids in patients and tumor progression. Further, a whole-food, plant-based diet has the potential to synergize with cancer therapies that exploit metabolic vulnerabilities.

Metaproteogenomics resolution of a high-CO2 aquifer community reveals a complex cellular adaptation of groundwater Gracilibacteria to a host-dependent lifestyle

BackgroundBacteria of the candidate phyla radiation (CPR), constituting about 25% of the bacterial biodiversity, are characterized by small cell size and patchy genomes without complete key metabolic pathways, suggesting a symbiotic lifestyle. Gracilibacteria (BD1-5), which are part of the CPR branch, possess alternate coded genomes and have not yet been cultivated. The lifestyle of Gracilibacteria, their temporal dynamics, and activity in natural ecosystems, particularly in groundwater, has remained largely unexplored. Here, we aimed to investigate Gracilibacteria activity in situ and to discern their lifestyle based on expressed genes, using the metaproteogenome of Gracilibacteria as a function of time in the cold-water geyser Wallender Born in the Volcanic Eifel region in Germany.ResultsWe coupled genome-resolved metagenomics and metaproteomics to investigate a cold-water geyser microbial community enriched in Gracilibacteria across a 12-day time-series. Groundwater was collected and sequentially filtered to fraction CPR and other bacteria. Based on 725 Gbps of metagenomic data, 1129 different ribosomal protein S3 marker genes, and 751 high-quality genomes (123 population genomes after dereplication), we identified dominant bacteria belonging to Gallionellales and Gracilibacteria along with keystone microbes, which were low in genomic abundance but substantially contributing to proteomic abundance. Seven high-quality Gracilibacteria genomes showed typical limitations, such as limited amino acid or nucleotide synthesis, in their central metabolism but no co-occurrence with potential hosts. The genomes of these Gracilibacteria were encoded for a high number of proteins involved in cell to cell interaction, supporting the previously surmised host-dependent lifestyle, e.g., type IV and type II secretion system subunits, transporters, and features related to cell motility, which were also detected on protein level.ConclusionsWe here identified microbial keystone taxa in a high-CO2 aquifer, and revealed microbial dynamics of Gracilibacteria. Although Gracilibacteria in this ecosystem did not appear to target specific organisms in this ecosystem due to lack of co-occurrence despite enrichment on 0.2-µm filter fraction, we provide proteomic evidence for the complex machinery behind the host-dependent lifestyle of groundwater Gracilibacteria.38kgAxaMce3Yn9ghud_S2pVideo

PSI-16 Evaluation of protein quality of defatted black soldier fly (Hermetia illucens) larvae meal compared with traditional protein sources for dogs and cats

Abstract There is increased interest in the use of insects, such as black soldier fly (Hermetia illucens) larvae meal (BSFLM), as an alternative protein source in pet foods. However, additional information is needed to determine how BSFL protein quality compares with traditional pet food protein sources. Thus, the objectives of this study were to determine the chemical composition, amino acid digestibility, and protein quality of defatted BSFLM in comparison with whole egg powder (WEP) and chicken meal (CM) using the precision-fed cecectomized rooster assay. Fifteen cecectomized roosters (n = 5 per substrate) were randomly allocated to the test substrates BSFLM, CM, and WEP. After 26 h of feed withdrawal, 20 g of substrates were crop-fed and excreta were collected for 48 h. Digestible indispensable amino acid score (DIAAS)-like values were calculated using the Association of American Feed Control Officials (AAFCO), The European Pet Food Industry Federation (FEDIAF), and National Research Council (NRC) reference values for different life stages of dogs and cats. Data were analyzed using SAS Proc Mixed 9.4 with P ≤ 0.05 significance. On a dry matter basis, CM had the greatest crude protein (70.2%), followed by BSFLM (59.8%), and WEP (51.2%). In general, WEP had greater amino acid digestibility than BSFLM and CM. BSFLM (84%) and CM (84%) had comparable arginine digestibility, but less than WEP (92%). Lysine digestibility was greater for BSFLM (80%) in contrast with CM (74%), but less than WEP (91%). DIAAS-like values were calculated, revealing methionine + cysteine as the first limiting amino acids for growing puppies and adult dogs in BSFLM according to AAFCO, FEDIAF, and NRC, whereas for CM threonine was the first limiting amino acid based on AAFCO, and phenylalanine + tyrosine based on NRC and FEDIAF. NRC identified methionine and cysteine as limiting for all test substrates in adult dogs. Methionine and cysteine were limiting for growing kittens for BSFLM among AAFCO, FEDIAF, and NRC. For CM and WEP, phenylalanine and tyrosine was the first-limiting amino acid by NRC and FEDIAF. For adult cats, phenylalanine and tyrosine were the limiting amino acid for BSFLMand CM according to AAFCO and FEDIAF, with NRC identifying it as limiting across all protein sources. In summary, methionine and cysteine and/or phenylalanine and tyrosine were the primary limiting amino acids among the protein sources evaluated. In general, BSFLM had comparable indispensable standardized amino acid digestibility to CM.

PSIX-13 Methionine requirements across the life cycle of working Labrador Retrievers using the indicator amino acid oxidation (IAAO) technique

Abstract Methionine is a limiting amino acid in canine diets, but few requirement studies have been conducted across life stages in large-breed dogs. The objective of this study was to determine the minimum requirement (MR) for methionine (Met) in Labrador retrievers at 4 life stages using the indicator amino acid (AA) oxidation (IAAO) technique. In total, 24 dogs were used: 6 puppies aged 10 to 14 wk, 6 puppies aged 14 wk to 9 mo, 6 adults aged 2 to 5 yr, and 6 seniors aged over 8 yr in feeding studies to evaluate the changing requirements of methionine (Met) as canines age. After 2-d adaptation to Met-adequate basal diet (Met = 0.56% dry matter), dogs underwent individual IAAO studies. In brief, all dogs were randomly fed one of six test diets with varying levels of Met ranging from deficient to sufficient (final Met content in experimental diets was 0.1982, 0.2386, 0.279, 0.49, 0.525, 0.56% dry matter, with indispensable amino acids formulated at 1.6x NRC values. Test diet was divided into 13 equal meals; at the 5th meal, a tracer amino acid was supplied (a bolus L-[1-13C]phenylalanine based on body weight was first given, followed by [1-13C]Phe doses every 30 min spanning a 4-h period), and breath samples were collected via respiration mask every 30 min. Total production of 13CO2 during isotopic steady state was determined by enrichment of 13CO2 in breath samples and total CO2 production measured via indirect calorimetry and isotope ratio mass spectrometry (IRMS). Results for IRMS were converted to atom percent excess (APE) and analyzed using segmented linear regression. The Four Rivers mean and population requirements for Met were estimated to be 0.84 ± 0.05 g/1000 kcal (mean ± 2SD) for puppies 10 to 14 wk, 0.78 ± 0.16 g/1,000kcal (mean ± 2SD) for puppies 14 wk to -9 mo, 0.68 ± 0.19 g/1,000kcal (mean ± 2SD) for adults 2 to 5 yr, and 0.62 ± 0.17 g/1,000kcal (mean ± 2SD) for seniors. This research provides important information to assist in accurate formulation of diets that contain appropriate methionine for large breed dogs at all life stages.

304 Amino acid digestibility and protein quality of fermented soybean-based ingredients using the precision-fed cecectomized rooster assay

Abstract Fermented soybean-based ingredients may serve as an alternative protein source for pet foods because of their high-quality protein content. The amino acid (AA) content and protein quality of fermented soybean-based ingredients may vary depending on their composition and processing, however, so testing is required. Our objective was to measure the AA composition, AA digestibility, and protein quality of fermented soybean-based ingredients using the precision fed cecectomized rooster assay. The University of Illinois Institutional Animal Care and Use Committee approved all animal procedures prior to experimentation. Cecectomized roosters (n = 36; six roosters per substrate) were randomly allotted to one of five test substrates: 1) autoclaved soybean (ASB); 2) fermented soybeans (FSB); 3) fermented soybeans with probiotics (FSBP); 4) fermented soybean meal (FSBM); 5) fermented soybean meal with probiotics (FSBMP). After 26 h of feed withdrawal, roosters were tube-fed test substrates. Following crop intubation excreta samples were collected 48 h. Endogenous loss corrections for AA were made by using five additional cecectomized roosters. All data were analyzed using SAS version 9.4. All substrates had increased AA digestibilities, with all indispensable AA digestibilities being &amp;gt;80% except for lysine (78.1% to 86.9%). Tryptophan digestibility was less (P &amp;lt; 0.05) in FSB than other substrates, but other AA digestibilities were not different. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to nutritional guidelines for adult dogs, adult cats, growing puppies, and growing kittens. The most limiting AA was the same for all ingredients. In adult dogs, methionine was the most limiting AA based on National Research Council (NRC; DIAAS: 33.4-35.1), European Pet Food Industry Nutritional Guidelines (FEDIAF; DIAAS: 49.6-52.1), and Association of American Feed Control Officials (AAFCO; DIAAS: 60.2-63.2) guidelines. In adult cats, phenylalanine was the most limiting AA (DIAAS: 59.5-63.2) when using NRC guidelines, but DIAAS were above 100 for FEDIAF and AAFCO guidelines. In growing puppies, methionine was most limiting according to NRC (DIAAS: 56.7-59.6) and FEDIAF (DIAAS: 78.8-82.7) guidelines, but threonine was most limiting according to AAFCO (DIAAS: 68.8-72.3) guidelines. In growing kittens, methionine was most limiting according to NRC (DIAAS: 70.9-74.4) and AAFCO (53.4-56.0) guidelines, but phenylalanine was most limiting according to FEDIAF (DIAAS: 66.7-70.8) guidelines. Our results demonstrate that fermented soybean-based ingredients are high-quality protein sources. Even though they have one or more limiting AA, they would serve as strong complementary proteins for pet foods. Further research in dogs and cats is necessary to confirm sufficient palatability and digestibility, but these data suggest that they are valuable sources of protein for pet food.

Lysine requirement of weaned piglets

Lysine, often referred to as the ‘first limiting amino acid’ in pig nutrition, plays a pivotal role in growth performance. Variability in lysine requirements arises due to factors such as age, sex and environmental conditions. Optimising pig health and production efficiency and minimising nitrogen excretion require accurate knowledge of estimated lysine requirements accounting for factors such as genetics, feeding practices, scientific advancements, and environmental considerations. This study aimed to determine standardised ileal digestible (SID) lysine requirements of weaned piglets (5–30 kg) based on a literature review using meta-analytical approaches. The literature review yielded 344 studies that were screened for title and abstract. In total, 41 experiments met the inclusion criteria, resulting in a dataset of 206 treatment means. Linear, quadratic and linear-plateau models were used to gain insight into the effect of SID lysine addition on average daily gain and feed efficiency for the combined dataset and separately for the individual experiments. Regression analysis showed a predominant linear increase in average daily gain and feed efficiency as an overall response to increasing lysine levels across both the combined dataset and individual experiments. Breakpoint estimation from the linear-plateau models was inconclusive, indicating that the optimal SID lysine requirement to maximise piglet growth performance likely exceeded the upper lysine levels tested in most studies, thus surpassing 1.3 g SID lysine per MJ net energy. This review indicates high values for the lysine requirement to achieve maximum growth performance. Results may suggest that piglet feed formulation should focus on an optimal dietary SID lysine to CP ratio, rather than SID lysine per kg of diet or unit of net energy. However, more research is needed to investigate this suggestion.

Prevalence of Influenza B/Yamagata Viruses From Season 2012/2013 to 2021/2022 in Italy as an Indication of a Potential Lineage Extinction.

Influenza B/Yamagata viruses exhibited weak antigenic selection in recent years, reducing their prevalence over time and requiring no update of the vaccine component since 2015. To date, no B/Yamagata viruses have been isolated or sequenced since March 2020. The antibody prevalence against the current B/Yamagata vaccine strain in Italy was investigated: For each influenza season from 2012/2013 to 2021/2022, 100 human serum samples were tested by haemagglutination inhibition (HAI) assay against the vaccine strain B/Phuket/3073/2013. In addition, the sequences of 156 B/Yamagata strains isolated during the influenza surveillance activities were selected for analysis of the haemagglutinin genome segment. About 61.9% of the human samples showed HAI antibodies, and 21.7% had protective antibody levels. The prevalence of antibodies at protective levels in the seasons between the isolation of the strain and its inclusion in the vaccine was between 11% and 25%, with no significant changes observed in subsequent years. A significant increase was observed in the 2020/2021 season, in line with the increase in influenza vaccine uptake during the pandemic. Sequence analysis showed that from 2014/2015 season onward, all B/Yamagata strains circulating in Italy were closely related to the B/Phuket/2013 vaccine strain, showing only limited amino acid variation. A consistent prevalence of antibodies to the current B/Yamagata vaccine strain in the general population was observed. The prolonged use of a well-matched influenza vaccine and a low antigenic diversity of B/Yamagata viruses may have facilitated a strong reduction in B/Yamagata circulation, potentially contributing to the disappearance of this lineage.

Amino acid composition of canned main dish increased food value

It is relevant to reduce the meat raw material in the composition of canned main dishes – porridge with meat due to the unsatisfactory state of livestock production in Ukraine. It is promising to use in the technology of canned main dishes – porridge with meat of non-traditional cereals – spelt, which is superior in terms of amino acid composition to certain types of traditionally used cereals. The purpose of the article is to study the amino acid composition of the canned main dish – porridge with meat containing spelt groats. The mass fraction of essential amino acids was determined by the chromatographic method. The amino acid score, the coefficient of its discrepancy and the biological value determined by calculation method. According to the results of determining the content of essential amino acids in porridge with meat containing spelt groats (experimental sample), their amount was lower compared to the control, namely isoleucine – by 44.74 %, lysine – by 23.75 %, leucine – by 14.64 %, threonine – by 11.36 %, valine – by 9.26 %, methionine – by 12.00 %, tryptophan – by 7.69 %, phenylalanine – by 2.17 %, histidine – by 8.57 %. The developed canned main dish – porridge with meat containing spelt groats is a source of leucine and lysine. The calculation of the amino acid score in experimental sample showed that all essential amino acids have a value of 100 % and above, and the limited amino acid is isoleucine, the score of which is 100 %, and the highest score belongs to histidine – 181 %. It was established that the coefficient of divergence of the amino acid score in experimental sample is higher by 2.56 %, and the indicator of biological value is lower by 2.57 % compared to the control, which is not significant. Thus, the reduction of meat raw materials in the recipe composition of porridge with meat made it possible to preserve the amino acid composition due to the use of spelt groats, and the finished product can be classified as a complete food product.

Pork cuts, hams, and sausages have digestible indispensable amino acid scores (DIAAS) close to or over 100

AbstractBackgroundThe “Digestible Indispensable Amino Acid Score” (DIAAS) method measures protein quality in human foods. Animal‐based products generally have high protein quality, but DIAAS values for some pork products are not available. Therefore, the objective of this experiment was to determine standardized ileal digestibility (SID) of amino acids (AA) and DIAAS values for pork products, including three types of pork cuts, Italian hams, and sausages, and to test the hypothesis that all pork products have DIAAS equal to or greater than 100.ResultsThe mean SID of the indispensable AA in all pork products was above 90% and indicated excellent digestibility. For children from 6 months to 3 years old and individuals older than 3 years, prosciutto had greater (p &lt; 0.05) DIAAS than all other pork products. Tenderloin and Coppa had greater (p &lt; 0.05) DIAAS than back ribs, shoulder butt, chorizo, and bratwurst. There were no limiting AA in any of the pork products (DIAAS &gt;100) with the exception that sulfur AA (SAA: methionine + cysteine) were limiting in chorizo for children from 6 months to 3 years old (DIAAS = 99).ConclusionWith the exception of chorizo for children less than 3 years old, all pork products have “excellent” protein quality for individuals older than 6 months of age, with DIAAS greater than 100. Pork proteins can, therefore, complement proteins with low quality to produce a meal that is adequate in all AA.

Habitat-induced changes in forage quality and implications for fitness in Plateau Pika (Ochotona curzoniae)

Abstract Plateau pikas (Ochotona curzoniae) play a keystone role in the alpine meadow ecosystem on the Qinghai–Tibetan Plateau (QTP). For decades, QTP grasslands have become degraded to some degree, largely as a result of heavy livestock grazing. Concomitantly, the abundance of plateau pikas has increased dramatically as grassland degradation has altered the vegetation community structure and dominant species, shifting the plant nutrient contents toward higher protein conditions that favor them. Considerable research supports the hypothesis that the quantity and quality of food limit herbivore populations. Here, we examined the relationship between the availability of essential amino acids in the diets of plateau pikas and the degree of meadow degradation associated with livestock grazing intensity through a field survey, as well as the fitness of individuals by laboratory feeding experiments with 2 pelleted chows containing 0.26% and 0.45% methionine. Sulfur-containing methionine and cystine were the most limiting amino acids in the diets of pikas. During the pika breeding season, the concentrations of most essential acids, particularly methionine and cystine, were higher in heavily degraded meadows than in lightly and moderately degraded meadows. Individuals fed 0.45% methionine exhibited enhanced cell-mediated immunity, reduced intensity of coccidian infection, and increased concentrations of gonadotropin-releasing hormone, luteinizing hormone, estradiol, progesterone, and testosterone compared to those fed 0.26% methionine. These results showed that heavily degraded meadows provided relatively high-quality food that improved individual fitness, suggesting that the high-methionine food in the heavily degraded meadows may be a key factor in the generation and maintenance of high-density populations of plateau pikas.

Characterization and Techno-Functional Properties of High Protein Walnut Flour from an Oil by-Product.

A high protein walnut flour (HPWF) was obtained by defatting walnut flour (WF), which is a by-product of the oil industry. The objective of this study was the chemical and techno-functional characterization of HPWF. Composition, amino acid content, protein secondary structure, protein solubility and thermal transitions were measured. Besides, the techno-functional properties, emulsion activity and stability, and water holding and oil absorption capacities, of HPWF were evaluated. Also, the molecular mass of proteins under denaturing conditions and the microstructure of HPWF were evaluated by electrophoresis and confocal scanning laser microscopy, respectively. HPWF had 55.4% protein content and 21.5% total dietary fibre. In terms of HPWF amino acid composition, the limiting amino acids were the sulphurated cysteine and methionine. By FTIR analysis, the main secondary structures were β-sheet (49%) followed by α-helix (24%); both structures are considered to be ordered. Likewise, HPWF soluble proteins increased at basic pH and HPWF proteins were separated in 11 bands with molecular masses ranging from 97 kDa to 18kDa by electrophoresis. With respect to techno-functional properties, HPWF presented good emulsion activity (51%) and high thermal emulsion stability (46%). In addition, HPWF retained 571% and 242% of water and oil by weight, respectively. Finally, the micrograph showed the predominance of protein structures and fibre fragments, and the presence of few lipids mostly trapped. These results showed that HPWF is an interesting source of plant-based proteins and walnut flour can be used to obtain high protein ingredients from non-traditional sources.

Effects of the photovoltaic fishery culture model on muscle nutritional quality and volatile flavor compounds of Litopenaeus vannamei

This study used Litopenaeus vannamei to compare the muscle nutritional quality and volatile flavor compounds of animals raised in the photovoltaic fishery culture model (PM) and the common pond breeding model (CM). Amino acids, fatty acids, and volatile flavor substances were identified and analyzed using an automatic amino acid analyzer and headspace solid phase microextraction(HS-SPME) combined with GC/MS. There were no significant differences between the two culture models in terms of general nutrients, mineral contents, and amino acid compositions in the muscles of L. vannamei. In the PM group, the proportion of flavor amino acids in total amino acids was higher. Based on the amino acid score (AAS) and chemical score (CS), it was found that methionine and cystine were the first limiting amino acids in the muscle samples. The essential amino acid index (EAAI) value was approximately 77 for both models, indicating high-quality proteins. The muscles contained nine types of fatty acids, with the PM group showing significantly higher levels of both monounsaturated and total fatty acids. A total of 23 volatile flavor compounds were identified in both models. The contents of 1-nonanal, n-tridecane, and alpha-terpineol were higher when cultured in the PM. Conversely, the contents of hexanal, 2-ethylhexanol, and dipentene were lower in the PM group. The photovoltaic fishery culture model has the potential to enhance income through photovoltaic power generation. In addition, this study found that the fatty acid composition of L. vannamei was improved in the PM, without compromising muscle composition or flavor. These results provide a theoretical basis for evaluating the meat quality of L. vannamei under different culture models and offer data to support and guide the promotion of the PM.

Effects of dietary tryptophan levels on growth performance, serotonin metabolism, brain 5-HT and cannibalism activities in tiger puffer, Takifugu rubripes fingerlings

Essential amino acid (EAA) requirements of aquaculture fish species can be used as a guideline for commercial feed formulation. Several EAA requirements have been quantified in tiger puffer (Takifugu rubripes). However, as the third limiting amino acid (AA) of many plant protein sources, tryptophan requirement of this species has yet to be quantified. This study was conducted to determine dietary tryptophan requirement of tiger puffer, and investigate the effect of dietary tryptophan supplementation on the cannibalism, brain serotonin (5-hydroxytryptpamine, 5-HT) metabolism and serum cortisol levels. Six experimental diets were prepared using fish meal, gelatin and corn protein concentrate as intact protein, and then supplemented with crystalline AA premix. The analyzed tryptophan levels in the experimental diets were 3.5, 4.1, 4.5, 5.5, 7.0 and 11.8 g/kg of dry diet. Experimental diets were randomly fed in triplicate to tiger puffer (initial average weight of 17.5 g) for 58 days. The weight gain (WG), feed conversion ratio (FCR) and protein efficiency ratio (PER) were significantly affected by dietary tryptophan, and the break points were observed at 5.07, 4.82 and 4.99 g/kg of dry diet, respectively. Compared to the basal diet, the cannibalism (the rate of bite mark appearance) was significantly lower and survival rate was significantly higher when fish were given diets containing 7.0 and 11.8 g/kg tryptophan. The concentrations of free tryptophan and phenylalanine in the brain exhibited a nonlinear increase in response to the incremental levels of dietary tryptophan. Brain 5-HT concentration was significantly affected by dietary tryptophan levels, but did not show a significant dose-dependent response. The expression of genes related to 5-HT metabolism (tph1a, ddc and aldh) and serotonin reuptake (sert) in the brain varied significantly and exhibited a nonlinear relationship with the graded levels of dietary tryptophan. In addition, serum cortisol levels showed a decreasing trend till the 5.5 g/kg tryptophan inclusion level, at which point there appeared to be the lowest level. In conclusion, based on nonlinear regression analysis of the WG, FCR and PER, dietary tryptophan requirement of tiger puffer was determined to be range between 4.82 and 5.07 g/kg of dry diet (10.48–11.03 g/kg of dietary protein). Dietary tryptophan supplementation above requirement could mitigate cannibalism and improve the survival of tiger puffer, which may be attributed to regulating the synthesis and catabolism of 5-HT and its availability in the synaptic cleft, and subsequently the reduction of serum cortisol content.

Nutritional Evaluation of Milk Thistle Meal as a Protein Feedstuff for Diets of Dairy Cattle.

The objective of this work is to investigate the chemical and nutritional value of milk thistle meal (MTM) in order to improve it and to provide theoretical support for its application in dairy cattle production. MTM was assessed in comparison with seven conventional protein feed sources, namely, soybean meal (SBM), cottonseed meal (CS), canola meal (CN), palm kernel meal (PK), rice bran meal (RB), corn germ meal (CG), and sesame meal (SS). The chemical composition of these feedstuffs was assessed using wet chemical analysis, the Cornell Net Carbohydrate and Protein System was used to evaluate the carbohydrate and protein fractions, and the in situ nylon bag technique and the modified three-step in vitro method were used to assess the rumen degradation and intestinal digestibility. Additionally, Fourier transform infrared technology was used to determine the feedstuff protein spectral molecular structure and its amino acid profile was also assessed. The result showed that MTM acid detergent fiber, lignin, unavailable nitrogen, and non-degradable carbohydrate content were higher than those of the other feedstuffs. It had a 17% and 36% rumen effective degradation rate of neutral detergent fiber and dry matter, respectively, and had the lowest small intestinal rumen undegradable protein digestibility rate. It was low in leucine, histidine, arginine, and proline, but high in methionine. The total area of amide I and amide II in the protein secondary structure was similar to that of CN and CS, and the amide I and II ratio was not different from that of RB. To sum up, MTM has a poor carbohydrate composition and is high in fiber but, in comparison to most other protein feeds, has a higher crude protein rumen effective degradation rate, similar to that of SBM, and it is a good source of methionine, a limiting amino acid. Hence, its nutritional value can be further improved for application in dairy feeding through processes such as microbial or enzymatic fermentation.

Use of Directed Lactic Fermentation to Obtain Plant-Based, Upcycled Beverage from Milk Thistle Endosperm

This study aimed to evaluate the possibility of using milk thistle endosperm (MTE) extract with a protein content of &gt;2 g/100 mL to obtain a fermented product, an alternative to milk beverages. Directed lactic fermentation with Lacticaseibacillus rhamnosus was carried out. The course of the process was monitored. The changes in pH, the saturation of the medium with dissolved oxygen, and temperature were measured. The values of the main nutritional parameters, silymarin content, amino acid profile/content, and the PDCAAS value (Protein Digestibility-Corrected Amino Acid Score) were determined in the extract before and after fermentation. The lactic acid fermentation of the MTE extract took place in four phases, with the activity of L. rhamnosus being the most intense between 4 and 8 h into the process. As a result of fermentation, there were changes in the total amino acid content in the tested medium, suggesting the catabolism of aspartic acid, arginine, proline, and isoleucine via LAB took place. Particularly significant was the increase in the content of lysine and valine (4.95 and 4.68 g/100 g of total AA, respectively), which are the limiting amino acids in MTE. Although MTE contained approximately 1% silymarin, no presence of this flavonolignan complex was found in the extracts.