Search Results (180)

The aim of this study was to develop a dynamic factorial model for predicting amino acid requirements in Hy-Line Gray laying hens during critical early growth stages (0–84 days), addressing the need for precision feeding in modern poultry production systems. Methods: Four sequential trials were conducted. In Trial 1, growth curves and protein deposition equations were developed based on fortnightly body composition analyses, with parameters evaluated using the Akaike and Bayesian information criteria (AIC and BIC). In Trial 2, the carcass and feather amino acid profiles were characterized via HPLC. And established the amino acid composition patterns of chicken feather protein and carcass protein (AAF and AAC). In Trial 3, maintenance requirements were quantified through nitrogen balance studies, and in Trial 4, amino acid patterns of feather protein (APD) and apparent protein digestibility (ADD) were established using an endogenous indicator method. These datasets were integrated through factorial modeling to predict age-specific nutrient demands. Results: The developed model revealed the following quantitative requirements (g/day) for 18 amino acids across developmental stages: aspartic acid (0.1–0.863), glutamic acid (0.170–1.503), serine (0.143–0.806), arginine (0.165–0.891), glycine (0.258–1.279), threonine (0.095–0.507), proline (0.253–1.207), alanine (0.131–0.718), valine (0.144–0.737), methionine (0.023–0.124), cysteine (0.102–0.682), isoleucine (0.086–0.458), leucine (0.209–1.067), phenylalanine (0.086–0.464), histidine (0.024–0.133), lysine (0.080–0.462), tyrosine (0.050–0.283), and tryptophan (0.011–0.060). The model demonstrated strong predictive validity throughout the 12-week growth period. Conclusion: This integrative approach yielded the first dynamic requirement model for Hy-Line Gray layers during early development. The factorial framework enables precise adjustment of amino acid provisions to match changing physiological needs and has high potential value in optimizing feed efficiency and supporting sustainable layer production practices. Full article

End-stage kidney disease is preferably treated by kidney transplantation. The function of the allograft often determines kidney-controlled processes and requires long-term monitoring. Kidneys are organs with a very high metabolic rate, and, thus, a metabolomics approach is suitable to observe systemic metabolic changes that are related to graft adaptation. To understand these ongoing changes in post-transplant pediatric patients, we applied a targeted liquid chromatography/tandem mass spectrometry-based metabolomics approach. Time-dependent changes of 140 metabolites in plasma samples prospectively collected from 23 pediatric kidney graft recipients receiving tacrolimus-based immunosuppression were monitored over the first 4 years after transplantation and compared to levels prior to transplantation. Furthermore, by comparing the pre-transplant metabolite levels to those measured in healthy children, we were able to obtain insights into the pathways associated with kidney failure. Arginine biosynthesis, alanine, aspartate, glutamine, and glutamate metabolism, taurine and tryptophan metabolism were the most affected pathways that separate the pediatric patients with and without kidney failure. Accumulation of uremic toxins such as various tryptophan/kynurenine and tryptophan/indole metabolism pathway intermediates, and betaine and methionine cycle metabolites was evident in patients with restricted kidney function. Furthermore, reduced nicotinamide production, insufficient hydroxylation of phenylalanine to tyrosine, lowered cysteine, arginine, glutamine, taurine, and overall amino acid utilization, as well as diminished levels of protective antioxidants such as glutathione and vitamins B6 and C, were all the result of progressive kidney failure leading to transplantation. Importantly, following kidney transplantation and recovery of kidney function, the levels of most of the previously described metabolites normalized toward the levels observed in healthy participants. The here identified metabolic patterns could be used as markers to monitor the progression of pediatric chronic kidney disease patients towards kidney failure, and assuming their direct association with kidney function, they could serve as markers of successful graft adaptation. Full article

To explore the effects of dietary lysine level (DLLs) on growth performance, carcass traits, meat quality and flavor characteristics in finishing pigs under large-scale commercial farming conditions, approximately 450 Duroc × Landrace × Yorkshire crossbred finishing pigs (initial body weight: 103.65 ± 4.28 kg) were randomly assigned to four treatment groups in this study. Each group consisted of four replicate pens, with 25~30 pigs per pen. The Lys100 group received a diet formulated according to the NRC (2012) standard. The standardized ileal digestible lysine (SID Lys) levels in the diets for the Lys115, Lys130 and Lys145 groups were set at 115%, 130% and 145% of the level in the Lys100 group, respectively. The trial lasted for 31 days. The results showed that increasing DLLs by 15%, 30% or 45%, while safeguarding the lysine requirement and maintaining the ideal ratios of other essential amino acids to lysine, had no negative impact on growth performance or meat quality. For carcass traits, increasing lysine levels in diets linearly increased loin eye area (p = 0.018) and tended to reduce backfat thickness at the 10th rib (p = 0.096). Methionine and glycine contents in the longissimus thoracis (LT) muscle linearly increased with an increase in DLLs (p = 0.014 and 0.073, respectively). Furthermore, increasing lysine levels by 45% significantly increased the percentage of volatile flavor compounds (VOCs) belonging to nitrogen compounds (p = 0.040), ethers (p = 0.026) and aldehydes (p = 0.040), as well as increased contents of key VOCs, such as (E)-2-Nonenal (p = 0.005), (E)-2-Octenal (p = 0.005) and 1-Octen-3-one (p = 0.008), contributing to enhanced sweet, fruity, fatty and waxy flavor profiles. According to various indexes, better carcass traits and pork flavor could be achieved by increasing lysine levels by 45% in diets based on the recommended value for finishing pigs. Full article

The growing demand for sustainable protein sources has boosted interest in Andean pseudocereals, particularly quinoa (Chenopodium quinoa), cañihua (Chenopodium pallidicaule), and kiwicha (Amaranthus caudatus), due to their complete nutritional profile, high digestibility, and low allergenic potential. Their inclusion in vegetarian and vegan diets represents a viable alternative that can replace animal proteins without compromising on nutritional quality. This study presents a critical review of indexed scientific literature analyzing essential amino acid composition, protein quality values—such as PDCAAS (Protein Digestibility-Corrected Amino Acid Score) and DIAAS (Digestible Indispensable Amino Acid Score)—and the impact of various processing technologies on the functionality of Andean proteins. Results show that these grains contain between 13 and 18 g of protein per 100 g of dry product and provide adequate levels of lysine, methionine, and threonine, meeting FAO (Food and Agriculture Organization) requirements for adult nutrition. Processes such as germination, fermentation, enzymatic hydrolysis, and extrusion have demonstrated improvements in both amino acid bioavailability and functional properties of proteins, enabling their application in gluten-free breads, meat analogs, and functional beverages. Furthermore, emerging strategies such as nanotechnology, bioactive peptide generation, and gene editing via CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)—a precise genome editing tool—open new possibilities for enhancing the nutritional and functional value of pseudocereals in the food industry. Taken together, the findings consolidate the strategic role of Andean grains as key ingredients in the development of sustainable, functional, and plant-based foods. Full article

Sanitary challenges (SCs) may alter the health status, growth performance, and pigs’ welfare. Changes in amino acid (AA) plasma concentrations have been observed in inflammatory-challenged pigs which may be associated with key factors, such as: (1) the synthesis of immune components to support innate and/or adaptive immune responses, (2) the redistribution of nutrients from growth and production functions toward cells and tissues involved in inflammatory and immune responses, and (3) decreased anabolism and/or increased catabolism of skeletal muscle to increase the availability of nutrients, often as a consequence of reduced feed intake. Due to their health-promoting effects, nutritional strategies involving AA may help mitigate the negative impacts of SC. Methionine, tryptophan, and threonine, beyond serving as protein building blocks, are considered functional AA because they support immune system function, enhance intestinal barrier integrity, modulate inflammatory responses, and limit oxidative stress. Additionally, the review highlights the influence of individual variability, such as differences in body weight, on nutritional requirements and responses to AA supplementation for pigs under SC. The integration of nutritional strategies tailored to immune-challenged pigs offers promising avenues to improve productivity and animal welfare in commercial swine production systems with increasing restrictions on antibiotic use. Full article

To evaluate the response of broiler breeder hens submitted to different amino acid intakes of methionine+cystine, lysine, and threonine, and to determine the coefficients for egg output and body weight for maintenance. Three studies were performed using 160 broiler breeder hens housed individually in metabolic cages. A summit diet and a nitrogen-free diet were formulated. The levels ranged from 1.79 to 7.13, 2.49 to 8.3, and 2.04 to 6.79 g/kg of methionine+cystine, lysine, and threonine, respectively. The variables measured were feed intake, amino acid intake, rate of lay, egg weight, and egg output. The broken line model was used to evaluate the responses. It was verified that higher values of the rate of lay, egg weight, and egg output were observed for the higher concentrations of amino acids studied. A significant difference was observed for the variables rate of lay, egg weight, egg output, and body weight (p < 0.05) for the three amino acids evaluated. The amount of each amino acid required to produce one gram per egg was estimated at 12.4 mg, 14.5 mg, and 11.2 mg for methionine+cystine, lysine, and threonine, respectively. The values estimated by coefficient b that represent the amino acid for maintenance requirement were methionine+cystine, lysine, and threonine of 30.2, 32.2, and 42.4 mg/kg BW, respectively. The coefficients may be used to design additional models to study requirements nutrition in broiler breeders, allowing a better understanding of how these birds respond to different dietary amino acids. Full article

This study aimed to optimize the inoculation dosage and fermentation duration to enhance the protein content and reduce soluble oligosaccharides in soybean meal using Aspergillus oryzae and assessed its performance in dog food extrusion. A 3 × 5 factorial design was used to determine the optimal fermentation conditions. These conditions were applied to ferment soybean meal in bulk for nutritional analysis. Finally, the impact of fermentation on extrusion processing was assessed by formulating and extruding four diets: SBM (30% soybean meal), AMF (30% soybean meal with 1% Amaferm^®—A. oryzae biomass), FSBM (30% fermented soybean meal), and SPI (18% soy protein isolate). Diets were extruded with a single-screw extruder, and physical characteristics of kibbles, particle size distribution, and viscosity of raw mixes were analyzed. The optimal fermentation conditions were 1 × 10⁴ spore/g substrate for 36 h, which increased the crude protein content by 4.63% DM, methionine and cysteine total content by 0.15% DM, and eliminated sucrose, while significantly reducing stachyose, raffinose, and verbascose (95.22, 87.37, and 41.82%, respectively). The extrusion results showed that FSBM had intermediate specific mechanical energy (SME), in-barrel moisture requirements, and sectional expansion index (198.7 kJ/kg, 28.2%, and 1.80, respectively) compared with SBM (83.7 kJ/kg, 34.5%, and 1.30, respectively) and SPI (305.3 kJ/kg, 33.5%, and 2.55, respectively). The FSBM also exhibited intermediate particle size distribution and the least raw mix viscosity. These findings demonstrate that A. oryzae fermentation enhances the nutrient profile of soybean meal while improving extrusion efficiency and kibble quality, supporting its potential use as a sustainable pet food ingredient. Full article

The use of methane as a carbon source for producing bacterial single-cell protein (SCP) has been one of the most interesting developments in recent years. Most of these upcoming industries are using a methanotroph, Methylococcus capsulatus Bath, for SCP production using natural gas as the substrate. In the present study, we have explored the possibility of using an indigenously isolated methanotroph from a rice field in India, Methylomagnum ishizawai strain KRF4, for producing SCP from biogas [derived from cow dung]. The process was eco-friendly, required minimal instruments and chemicals, and was carried out under semi-sterile conditions in a tabletop fish tank. As the name suggests, Methylomagnum is a genus of large methanotrophs, and the strain KRF4 had elliptical to rectangular size and dimensions of ~4–5 µm × 1–2 µm. In static cultures, when biogas and air were supplied in the upper part of the growing tank, the culture grew as a thick pellicle/biofilm that could be easily scooped. The grown culture was mostly pure, from the microscopic observations where the large size of the cells, with rectangular-shaped cells and dark granules, could easily help identify any smaller contaminants. Additionally, the large cell size could be advantageous for separating biomass during downstream processing. The amino acid composition of the lyophilized biomass was analyzed using HPLC, and it was seen that the amino acid composition was comparable to commercial fish meal, soymeal, Pruteen, and the methanotroph-derived SCP-UniProtein^®. The only difference was that a slightly lower percentage of lysine, tryptophan, and methionine was observed in Methylomagnum-derived SCP. Methylomagnum ishizawai could be looked at as an alternative for SCP derived from methane or biogas due to the comparable SCP produced, on the qualitative level. Further intensive research is needed to develop a continuous, sustainable, and economical process to maximize biomass production and downstream processing. Full article

Methionine residues in proteins and peptides are frequently oxidized by losing one electron. The presence of nearby amide groups is crucial for this process, enabling methionine to participate in long-range electron transfer. Hydroxyl radical (HO^•) plays an important role being generated in aerobic organisms by cellular metabolisms as well as by exogenous sources such as ionizing radiations. The reaction of HO^• with methionine mainly affords the one-electron oxidation of the thioether moiety through two consecutive steps (HO^• addition to the sulfur followed by HO⁻ elimination). We recently investigated the reaction of HO^• with model peptides mimicking methionine and its cysteine-methylated counterpart, i.e., CH₃C(O)NHCHXC(O)NHCH₃, where X = CH₂CH₂SCH₃ or CH₂SCH₃ at pH 7. The reaction mechanism varied depending on the distance between the sulfur atom and the peptide backbone, but, for a better understanding of various suggested equilibria, the analysis of the flux of protons is required. We extended the previous study to the present work at pH 4 using pulse radiolysis techniques with conductivity and optical detection of transient species, as well as analysis of final products by LC-MS and high-resolution MS/MS following γ-radiolysis. Comparing all the data provided a better understanding of how the presence of nearby amide groups influences the one-electron oxidation mechanism. Full article

This study evaluated an established dynamic prediction model for protein and amino acid nutritional requirements on growth performance and health in layer chicks. A total of 288 one-day-old healthy Jing Tint 6 chicks were randomly divided into four treatment groups with 6 replicates of 12 chicks each. The chicks in the four groups were fed a basal diet (BD) according to the feeding standards and a model diet (MD) based on the dynamic prediction model for protein and amino acid values at 90%, 100%, or 110% for 6 weeks. The results showed that, compared to the BD, the 110% MD increased (p < 0.05) the FI and the 100% MD had no effect (p > 0.05) on FI, BWG, and FCR of chicks throughout the entire feeding phase. The 90% MD, however, significantly reduced (p < 0.05) FI and BWG, while also increasing (p < 0.05) FCR during the 3–6- and 0–6-week periods. Additionally, compared to the BD, the 100% MD had a lower (p < 0.05) intake of crude protein, methionine, lysine, and threonine than that of the BD. Both the 100% and 110% MDs increased (p < 0.05) bursa weight and its index at the 2nd week, while the 90% MD reduced (p < 0.05) the weights of the liver, spleen, and pancreas at the 6th week when compared to the BD. Moreover, the 100% MD increased (p < 0.05) the weights of the duodenum and jejunum, while the 90% MD decreased (p < 0.05) jejunum and ileum length at the 2nd or 6th week. Furthermore, no differences (p > 0.05) were found in serum ALT, AST, BUN, and UA between the 100% MD and BD groups. In conclusion, the dynamic prediction model can minimize protein waste while supporting healthy growth and development in layer chicks. Full article

Environmental pollution remains a significant challenge in animal production. The “ideal protein” concept refers to an amino acid profile that precisely meets the animal’s nutritional requirements, optimizing nutrient utilization and minimizing waste excretion. This study applied untargeted metabolomics to explore metabolic changes induced by limiting AA. Two experimental diets were used in 47-day-old growing rabbits: Met+ (with a methionine level balanced to its optimal utilization) and Met− (with a methionine level that was clearly limiting). A total of 68 blood samples were taken for untargeted metabolomics analysis and 88 were taken for targeted plasmatic urea nitrogen analysis, collected at 08:00 (in ad libitum feeding animals) and 21:00 (after a feeding event in 10 h fasting animals). Our results revealed that both sampling time and diet (at each time point) exerted a significant modulatory influence on the metabolome. Interestingly, the difference between the metabolomes obtained with the different diets was less pronounced at 08:00, likely due to the caecotrophy effect, compared to 21:00, when higher intake and lower caecotrophy frequency were observed. This study identifies pseudourine, citric acid, pantothenic acid, and enterolactone sulfate as promising metabolites that could be targeted in order to refine the ideal protein concept, thus improving nutrient efficiency and reducing the environmental impact of animal production. Full article

Maternal overnutrition and targeted supplements during pregnancy strongly affect fetal development in beef cattle, influencing gene expression, tissue development, and productivity after birth. As modern feeding practices often result in cows receiving energy and protein above requirements, understanding the balance between adequate nutrition and overconditioning is critical for sustainable beef production. This review synthesizes findings from recent studies on maternal overnutrition and supplementation, focusing on macronutrients (energy, protein, methionine) and key micronutrients (e.g., selenium, zinc). It evaluates the timing and impact of supplementation during different gestational stages, with emphasis on fetal muscle and adipose tissue development, immune function, and metabolic programming. The role of epigenetic mechanisms, such as DNA methylation and non-coding RNAs, is also discussed in relation to maternal dietary inputs. Mid-gestation supplementation promotes muscle growth by activating muscle-specific genes, whereas late-gestation diets enhance marbling and carcass traits. However, maternal overnutrition may impair mitochondrial efficiency, encourage fat deposition over muscle, and promote collagen synthesis, reducing meat tenderness. Recent evidence highlights sex-specific fetal programming differences, the significant impact of maternal diets on offspring gut microbiomes, and breed-specific nutritional responses, and multi-OMICs integration reveals metabolic reprogramming mechanisms. Targeted trace mineral and methionine supplementation enhance antioxidant capacity, immune function, and reproductive performance. Precision feeding strategies aligned with gestational requirements improve feed efficiency and minimize overfeeding risks. Early interventions, including protein and vitamin supplementation, optimize placental function and fetal development, supporting stronger postnatal growth, immunity, and fertility. Balancing nutritional adequacy without excessive feeding supports animal welfare, profitability, and sustainability in beef cattle systems. Full article

Freshwater fish species play an important role in global aquaculture. Currently, sturgeon, carp, and tilapia are at the forefront of this industry. However, as human populations continue to grow, the demand for new sources of animal protein increases, making the use of other freshwater species in aquaculture essential. The pikeperch (Sander lucioperca) is one of the most promising fish species for European aquaculture, but its usage has been hindered by a lack of effective larval-rearing protocols. Most studies focus on using cultured or nutrient-rich zooplankton for larval cultivation, while natural zooplankton from the local environment are rarely used. In this study, we aim to investigate the nutritional requirements of pikeperch larvae by describing the taxonomic diversity and biochemical composition of zooplankton collected from a natural oligotrophic lake in Northwest Russia. The chemical composition of zooplankton is characterized by a high protein content (up to 70% of dry matter), a moderate lipid content (up to 25%), and a deficiency of certain fatty acids and amino acids. Specifically, there is a low concentration of docosahexaenoic acid and methionine. The dry matter content in the zooplankton averages 10%, with nitrogen-free extracts accounting for 4% and ash making up 4%. These biochemical parameters meet the nutritional requirements of freshwater pikeperch larvae, with the notable exception of the lower levels of DHA and methionine, which are typically characteristic of freshwater zooplankton. This information sheds light on the nutritional requirements of pikeperch larvae and the development of more efficient rearing methods. Full article

In aging, chronic diseases such as obesity accelerate metabolic dysfunction through chronic inflammation and insulin resistance. This review compared three different dietary strategies to evaluate their mechanisms and benefits for metabolic health and longevity. A comprehensive database search was conducted, selecting studies in animal models and in humans with or without obesity which have been published since 2004. Fasting-mimicking diets reduce IGF-1, promote autophagy, and improve insulin sensitivity, although long-term adherence remains a challenge. Time-restricted feeding synchronizes food intake with circadian rhythms, benefiting inflammation, glycemic control, and body composition. Protein and amino acid restriction, particularly methionine and branched-chain amino acids, modulates mTOR and reduces oxidative stress but requires adjustments in older adults. According to the available evidence, each intervention offers a non-invasive and adaptive approach to mitigating the effects of aging, provided it is applied in a personalized manner with appropriate follow-up. Full article

Methionine, an essential amino acid, is obtained by dietary intake to fulfill the requirements of our bodies. Accumulating evidence indicates that methionine plays a pivotal role in various biological processes, including protein synthesis, energy metabolism, redox balance maintenance, and methylation modifications. Numerous advances underscore the heightened dependence of cancer cells on methionine, which is a significant factor in cancer pathogenesis and development. A profound comprehension of the intricate relationship between methionine metabolism and tumorigenesis is imperative for advancing the field of cancer therapeutics. Herein, we delve into the role of methionine in supporting cancer growth, the impact on epigenetic modifications, and the interaction between methionine and the tumor microenvironment. Additionally, we provide insights into the development of various methionine-targeted therapy strategies. This paper summarizes the current state of research and its translational potential, emphasizing the challenges and opportunities associated with harnessing methionine dependence as a target for innovative cancer treatments. Full article