Immunomodulation by Processed Animal Feed: The Role of Maillard Reaction Products and Advanced Glycation End-Products (AGEs)

Effect of advanced glycation end-products in a wide range of medical problems including COVID-19

Glycation is a physiological process that determines the aging of the organism, while in states of metabolic disorders it is significantly intensified. High concentrations of compounds such as reducing sugars or reactive aldehydes derived from lipid oxidation, occurring for example in diabetes, atherosclerosis, dyslipidemia, obesity or metabolic syndrome, lead to increased glycation of proteins, lipids and nucleic acids. The level of advanced glycation end-products (AGEs) in the body depends on rapidity of their production and the rate of their removal by the urinary system. AGEs, accumulated in the extracellular matrix of the blood vessels and other organs, cause irreversible changes in the biochemical and biomechanical properties of tissues. As a consequence, micro- and macroangiopathies appear in the system, and may contribute to the organ failure, like kidneys and heart. Elevated levels of AGEs also increase the risk of Alzheimer's disease and various cancers. In this paper, we propose a new classification due to modified amino acid residues: arginyl-AGEs, monolysyl-AGEs and lysyl-arginyl-AGEs and dilysyl-AGEs. Furthermore, we describe in detail the effect of AGEs on the pathogenesis of metabolic and old age diseases, such as diabetic complications, atherosclerosis and neurodegenerative diseases. We summarize the currently available data on the diagnostic value of AGEs and present the AGEs as a therapeutic goal in a wide range of medical problems, including SARS-CoV-2 infection and so-called long COVID.

Extrusion of lupines with or without addition of reducing sugars: Effects on the formation of Maillard reaction compounds, partition of nitrogen and Nε-carboxymethyl-lysine, and performance of dairy cows

The extrusion of leguminous seeds induces the formation of Maillard reaction compounds (MRC) as a product of protein advanced glycation and oxidation, which lowers protein degradability in the rumen. However, the quantitative relationship between the parameters of pretreatment (i.e., addition of reducing sugars) and extrusion, and the formation of MRC has not been established yet. Moreover, the fate of the main stable MRC, Nε-carboxymethyl-lysine (CML), in the excretory routes has never been investigated in ruminants. We aimed to test the effects of the temperature of extrusion of white lupines with or without addition of reducing sugars on the formation of MRC, crude protein (CP) degradability in the rumen, N use efficiency for milk production (milk N/N intake), and performance of dairy cows. Two experiments with a replicated 4 × 4 Latin square design were conducted simultaneously with 16 (3 rumen-cannulated) multiparous Holstein cows to measure indicators of ruminal CP degradability (ruminal NH3 concentration, branched-chain volatile fatty acids), metabolizable protein supply (plasma essential AA concentration), N use efficiency (N isotopic discrimination), and dairy performance. In parallel, apparent total-tract digestibility of dry matter, organic matter, neutral detergent fibers, N, total Lys and CML, and partition of N and CML were measured with 4 cows in both experiments. The diets consisted on a DM basis of 20% raw or extruded lupines and 80% basal mixed ration of corn silage, silage and hay from permanent grasslands, pelleted concentrate, and a vitaminized mineral mix. Expected output temperatures of lupine extrusion were 115°C, 135°C, and 150°C, without and with the addition of reducing sugars before extrusion. The extrusion numerically reduced the in vitro ruminal CP degradability of the lupines, and consequently increased the predicted supply of CP to the small intestine. Nitrogen balance and urinary N excretion did not differ among dietary treatments in either experiment. Milk yield and N use efficiency for milk production increased with extrusion of lupines at 150°C without addition of reducing sugars compared with raw lupines. Nitrogen isotopic discrimination between dietary and animal proteins (the difference between δ15N in plasma and δ15N in the diet) were lower with lupines extruded at 150°C without and with addition of reducing sugars. Regardless of sugar addition, milk true protein yield was not affected, but milk urea concentration and fat:protein ratio were lower with lupines extruded at 150°C than with raw lupines. In the CML partition study, we observed that on average 26% of the apparently digested CML was excreted in urine, and a much lower proportion (0.63% on average) of the apparently digested CML was secreted in milk, with no differences among dietary treatments. In conclusion, we showed that the extrusion of white lupines without or with addition of reducing sugars numerically reduced enzymatic CP degradability, with limited effects on N partition, but increased milk yield and N use efficiency at the highest temperature of extrusion without addition of reducing sugars.

Examination of sleep in relation to dietary and lifestyle behaviors during Ramadan: A multi-national study using structural equation modeling among 24,500 adults amid COVID-19

Background

Of around 2 billion Muslims worldwide, approximately 1.5 billion observe Ramadan fasting (RF) month. Those that observe RF have diverse cultural, ethnic, social, and economic backgrounds and are distributed over a wide geographical area. Sleep is known to be significantly altered during the month of Ramadan, which has a profound impact on human health. Moreover, sleep is closely connected to dietary and lifestyle behaviors.

Methods

This cross-sectional study collected data using a structured, self-administered electronic questionnaire that was translated into 13 languages and disseminated to Muslim populations across 27 countries. The questionnaire assessed dietary and lifestyle factors as independent variables, and three sleep parameters (quality, duration, and disturbance) as dependent variables. We performed structural equation modeling (SEM) to examine how dietary and lifestyle factors affected these sleep parameters.

Results

In total, 24,541 adults were enrolled in this study. SEM analysis revealed that during RF, optimum sleep duration (7-9 h) was significantly associated with sufficient physical activity (PA) and consuming plant-based proteins. In addition, smoking was significantly associated with greater sleep disturbance and lower sleep quality. Participants that consumed vegetables, fruits, dates, and plant-based proteins reported better sleep quality. Infrequent consumption of delivered food and infrequent screen time were also associated with better sleep quality. Conflicting results were found regarding the impact of dining at home versus dining out on the three sleep parameters.

Conclusion

Increasing the intake of fruits, vegetables, and plant-based proteins are important factors that could help improve healthy sleep for those observing RF. In addition, regular PA and avoiding smoking may contribute to improving sleep during RF.

The effect of puppyhood and adolescent diet on the incidence of chronic enteropathy in dogs later in life

Diet has a key role in the homeostasis of the gut microenvironment, influencing the microbiome, the gut barrier, host immunity and gut physiology. Yet, there is little information on the role of early diet in the onset of inflammatory gastrointestinal disorders later in life, especially in dogs. Therefore, the aim of the present cross-sectional, epidemiological study with longitudinal data, was to explore associations of companion dogs' early life diet style and food items with owner-reported chronic enteropathy (CE) incidence in later life. Food frequency questionnaire data from Finnish companion dogs was analyzed using principal component analysis and logistic regression. We found that feeding a non-processed meat-based diet and giving the dog human meal leftovers and table scraps during puppyhood (2-6 months) and adolescence (6-18 months) were protective against CE later in life. Especially raw bones and cartilage as well as leftovers and table scraps during puppyhood and adolescence, and berries during puppyhood were associated with less CE. In contrast, feeding an ultra-processed carbohydrate-based diet, namely dry dog food or "kibble" during puppyhood and adolescence, and rawhides during puppyhood were significant risk factors for CE later in life.

A review of food additives to control the proliferation and transmission of pathogenic microorganisms with emphasis on applications to raw meat-based diets for companion animals

Raw meat-based diets (RMBDs) or sometimes described as biologically appropriate raw food (BARFs) are gaining in popularity amongst dog and cat owners. These pet guardians prefer their animals to eat minimally processed and more “natural” foods instead of highly heat-processed diets manufactured with synthetic preservatives. The market for RMBDs for dogs and cats is estimated at $33 million in the United States. This figure is likely underestimated because some pet owners feed their animals raw diets prepared at home. Despite their increasing demand, RMBDs have been plagued with numerous recalls because of contamination from foodborne pathogens like Salmonella, E. coli, or Campylobacter. Existing literature regarding mitigation strategies in RMBD's for dogs/cats are very limited. Thus, a comprehensive search for published research was conducted regarding technologies used in meat and poultry processing and raw materials tangential to this trade (e.g., meats and poultry). In this review paper, we explored multiple non-thermal processes and GRAS approved food additives that can be used as potential antimicrobials alone or in combinations to assert multiple stressors that impede microbial growth, ultimately leading to pathogen inactivation through hurdle technology. This review focuses on use of high-pressure pasteurization, organic acidulants, essential oils, and bacteriophages as possible approaches to commercially pasteurize RMBDs effectively at a relatively low cost. A summary of the different ways these technologies have been used in the past to control foodborne pathogens in meat and poultry related products and how they can be applied successfully to impede growth of enteric pathogens in commercially produced raw diets for companion animals is provided.

Impact of ROS-Dependent Lipid Metabolism on Psoriasis Pathophysiology

Psoriasis is the most common autoimmune disease, yet its pathophysiology is not fully understood. It is now believed that psoriasis is caused by the increased activation of immune cells, especially Th1 lymphocytes. However, in psoriasis, immune cells interfere with the metabolism of keratinocytes, leading to their increased activation. Therefore, the pathophysiology of psoriasis is currently associated with the overproduction of ROS, which are involved in the activation of immune cells and keratinocytes as well as the modulation of various signaling pathways within them. Nevertheless, ROS modulate the immune system by also boosting the increasing generation of various lipid mediators, such as products of lipid peroxidation as well as endocannabinoids and prostaglandins. In psoriasis, the excessive generation of ROS and lipid mediators is observed in different immune cells, such as granulocytes, dendritic cells, and lymphocytes. All of the above may be activated by ROS and lipid mediators, which leads to inflammation. Nevertheless, ROS and lipid mediators regulate lymphocyte differentiation in favor of Th1 and may also interact directly with keratinocytes, which is also observed in psoriasis. Thus, the analysis of the influence of oxidative stress and its consequences for metabolic changes, including lipidomic ones, in psoriasis may be of diagnostic and therapeutic importance.

Structural and immunoendocrine remodeling in gut, pancreas and thymus in weaning rats fed powdered milk diets rich in Maillard reactants

Western diet is extending worldwide and suspected to be associated with various metabolic diseases. Many food products have skim milk powder added to it and, during processing, lactose reacts with milk proteins and Maillard reaction products (MRPs) are formed. Dietary MRPs are suggested risk factors for metabolic dysregulation, but the mechanisms behind are still enigmatic. Here we describe that weaning rats fed diets rich in MRPs are affected in both their immune and endocrine systems. Marked structural changes in pancreas, intestine and thymus are noted already after 1 week of exposure. The pancreatic islets become sparser, the intestinal mucosa is thinner, and thymus displays increased apoptosis and atrophy. Glucagon- like peptide-1 (GLP-1) seems to play a key role in that the number of GLP-1 expressing cells is up-regulated in endocrine pancreas but down-regulated in the intestinal mucosa. Further, intestinal GLP-1-immunoreactive cells are juxta positioned not only to nerve fibres and tuft cells, as previously described, but also to intraepithelial CD3 positive T cells, rendering them a strategic location in metabolic regulation. Our results suggest dietary MRPs to cause metabolic disorders, dysregulation of intestinal GLP-1- immunoreactive cells, arrest in pancreas development and thymus atrophy.

Native Liquid Chromatography and Mass Spectrometry to Structurally and Functionally Characterize Endo-Xylanase Proteoforms

Xylanases are of great value in various industries, including paper, food, and biorefinery. Due to their biotechnological production, these enzymes can contain a variety of post-translational modifications, which may have a profound effect on protein function. Understanding the structure–function relationship can guide the development of products with optimal performance. We have developed a workflow for the structural and functional characterization of an endo-1,4-β-xylanase (ENDO-I) produced by Aspergillus niger with and without applying thermal stress. This workflow relies on orthogonal native separation techniques to resolve proteoforms. Mass spectrometry and activity assays of separated proteoforms permitted the establishment of structure–function relationships. The separation conditions were focus on balancing efficient separation and protein functionality. We employed size exclusion chromatography (SEC) to separate ENDO-I from other co-expressed proteins. Charge variants were investigated with ion exchange chromatography (IEX) and revealed the presence of low abundant glycated variants in the temperature-stressed material. To obtain better insights into the effect on glycation on function, we enriched for these species using boronate affinity chromatography (BAC). The activity measurements showed lower activity of glycated species compared to the non-modified enzyme. Altogether, this workflow allowed in-depth structural and functional characterization of ENDO-I proteoforms.

Receptor Mediated Effects of Advanced Glycation End Products (AGEs) on Innate and Adaptative Immunity: Relevance for Food Allergy

As of late, evidence has been emerging that the Maillard reaction (MR, also referred to as glycation) affects the structure and function of food proteins. MR induces the conformational and chemical modification of food proteins, not only on the level of IgG/IgE recognition, but also by increasing the interaction and recognition of these modified proteins by antigen-presenting cells (APCs). This affects their biological properties, including digestibility, bioavailability, immunogenicity, and ultimately their allergenicity. APCs possess various receptors that recognize glycation structures, which include receptor for advanced glycation end products (RAGE), scavenger receptors (SRs), galectin-3 and CD36. Through these receptors, glycation structures may influence the recognition, uptake and antigen-processing of food allergens by dendritic cells (DCs) and monocytes. This may lead to enhanced cytokine production and maturation of DCs, and may also induce adaptive immune responses to the antigens/allergens as a result of antigen uptake, processing and presentation to T cells. Here, we aim to review the current literature on the immunogenicity of AGEs originating from food (exogenous or dietary AGEs) in relation to AGEs that are formed within the body (endogenous AGEs), their interactions with receptors present on immune cells, and their effects on the activation of the innate as well as the adaptive immune system. Finally, we review the clinical relevance of AGEs in food allergies.

Growth Performance, Nutrient Digestibility, Blood Profiles, and Gut Integrity of Growing Pigs Fed Pickled Fish Residue with Decreased Salt Content

This study investigated the growth performance, nutrient digestibility, blood profiles and gut integrity of growing pigs, in response to an increase in pickled freshwater fish residue (PFR) intake following a decrease in salt content. Ninety-six crossbred growing pigs [(Landrace × Large White) × Duroc] with a body weight of 23.65 ± 0.24 kg were randomly assigned to one of four treatments (6 pens/treatment, 4 pigs/pen) in a randomized complete block design. The treatments included: a corn-soybean meal based diet without PFR inclusion (CON) or with PFR addition at 5 (PFR5), 10 (PFR10), and 15% (PFR15), respectively. Desalting via soaking and stirring caused a positive reduction in the salt present on the surface of PFR. Over the 42-day feeding period, an increased level of PFR quadratically increased gain:feed ratio such that gain:feed ratio for PFR10 was greater than that for CON (p < 0.05). Pigs fed PFR10 had greater crude protein digestibility, and lower aspartate aminotransferase and crypt depth than those fed the CON diet (p < 0.05). The linear improvements in crude protein and ether extract digestibility, duodenal villus height, and villus:crypt ratio were observed as the PFR content increased (p < 0.05). However, there were no significant effects on average daily feed intake, dry matter and ash digestibility, blood metabolites (total Ca, P, creatinine, and alkaline phosphatase). Altogether, up to 10% PFR can be included in corn-soybean meal diet without impairing protein digestibility and hepatic enzyme alteration. In fact, administering PFR with lower salt content to growing pigs ultimately promotes their growth performance and gut integrity.

Effects of graded inclusion levels of raw garbanzo beans on apparent total tract digestibility, fecal quality, and fecal fermentative end-products and microbiota in extruded feline diets

Garbanzo beans (GB; Cicer arietinum) are a readily available pulse crop that have gained popularity as a plant-based protein source in the pet food industry. However, raw GB contain anti-nutritional factors that can reduce digestibility and cause digestive upsets in pets that are undesirable to owners. The objective of this study was to determine the effects of the inclusion of raw or cooked GB in extruded feline diets on macronutrient digestibility, gastrointestinal tolerance, and fermentative end-products in cats. Five diets were formulated to contain raw GB at 0%, 7.5%, 15%, or 30% or cooked GB at 30%. Ten adult, male cats (mean age: 1.0 ± 0.0 yr, mean BW: 4.7 ± 0.4 kg) were used in a replicated 5 × 5 Latin square design. Each period consisted of 14 d, with 10 d of diet adaptation followed by 4 d of total fecal and urine collection. At the end of each period, 4 mL of blood were collected and analyzed for a serum chemistry and complete blood count to ensure all animals remained healthy throughout the study. Cats were fed twice daily and food intake was calculated to maintain body weight. Food intake was highest (P < 0.05) for cats fed 0% raw GB (72.2 g/d, dry matter basis [DMB]) compared with GB inclusions of 7.5% or greater (average 70.3 g/d, DMB). Dry matter and organic matter apparent total tract digestibility (ATTD) were lowest (P < 0.05) for cats consuming the 30% cooked GB diet (77.3% and 81.7%, respectively). Cats fed 7.5% raw GB had greater (P < 0.05) crude protein ATTD (86.2%) than cats fed 15% raw GB (82.3%) or 30% cooked GB (81.6%). Total short-chain fatty acid concentrations were highest (P < 0.05) for 30% cooked GB at 682 μmol/g but not different (P > 0.05) than 15% GB (528 μmol/g) or 30% raw GB (591 μmol/g) diets. In terms of fecal microbial abundance, the predominant phyla were Firmicutes, Bacteroidota, and Actinobacteria. Cats fed the 0% GB diet had a greater relative abundance of Firmicutes (62.1%) and Fusobacteria (4.0%) than the remaining diets (average 54% and 1.6%, respectively). In conclusion, all inclusion levels of raw GB resulted in high digestibility (average > 80%) and ideal fecal scores (average 2.9), demonstrating their adequacy as a protein source in feline diets up to a 30% inclusion level.

Role of Advanced Glycation End-Products and Other Ligands for AGE Receptors in Thyroid Cancer Progression

To date, thyroid cancers (TCs) remain a clinical challenge owing to their heterogeneous nature. The etiopathology of TCs is associated not only with genetic mutations or chromosomal rearrangements, but also non-genetic factors, such as oxidative-, nitrosative-, and carbonyl stress-related alterations in tumor environment. These factors, through leading to the activation of intracellular signaling pathways, induce tumor tissue proliferation. Interestingly, the incidence of TCs is often coexistent with various simultaneous mutations. Advanced glycation end-products (AGEs), their precursors and receptors (RAGEs), and other ligands for RAGEs are reported to have significant influence on carcinogenesis and TCs progression, inducing gene mutations, disturbances in histone methylation, and disorders in important carcinogenesis-related pathways, such as PI₃K/AKT/NF-kB, p21/MEK/MPAK, or JAK/STAT, RAS/ERK/p53, which induce synthesis of interleukins, growth factors, and cytokines, thus influencing metastasis, angiogenesis, and cancer proliferation. Precursors of AGE (such as methylglyoxal (MG)) and selected ligands for RAGEs: AS1004, AS1008, and HMGB1 may, in the future, become potential targets for TCs treatment, as low MG concentration is associated with less aggressive anaplastic thyroid cancer, whereas the administration of anti-RAGE antibodies inhibits the progression of papillary thyroid cancer and anaplastic thyroid cancer. This review is aimed at collecting the information on the role of compounds, engaged in glycation process, in the pathogenesis of TCs. Moreover, the utility of these compounds in the diagnosis and treatment of TCs is thoroughly discussed. Understanding the mechanism of action of these compounds on TCs pathogenesis and progression may potentially be the grounds for the development of new treatment strategies, aiming at quality-of-life improvements.

Effect of sugar metabolite methylglyoxal on equine lamellar explants: An ex vivo model of laminitis

Laminitis is one of the most devastating diseases in equine medicine, and although several etiopathogenetic mechanisms have been proposed, few clear answers have been identified to date. Several lines of evidence point towards its underlying pathology as being metabolism-related. In the carbonyl stress pathway, sugars are converted to methylglyoxal (MG)-a highly reactive α-oxoaldehyde, mainly derived during glycolysis in eukaryotic cells from the triose phosphates: D-glyceraldehyde-3-phosphate and dihydroxyacetone phosphate. One common hypothesis is that MG could be synthesized during the digestive process in horses, and excessive levels absorbed into peripheral blood could be delivered to the foot and lead to alterations in the hoof lamellar structure. In the present study, employing an ex vivo experimental design, different concentrations of MG were applied to hoof explants (HE), which were then incubated and maintained in a specific medium for 24 and 48 h. Macroscopic and histological analyses and a separation force test were performed at 24 and 48 h post-MG application. Gene expression levels of matrix metalloproteinase (MMP)-2 and -14 and tissue inhibitor of metalloproteinase (TIMP)-2 were also measured at each time point for all experimental conditions. High concentrations of MG induced macroscopic and histological changes mimicking laminitis. The separation force test revealed that hoof tissue samples incubated for 24 h in a high concentration of MG, or with lower doses but for a longer period (48 h), demonstrated significant weaknesses, and samples were easily separated. All results support that high levels of MG could induce irreversible damage in HEs, mimicking laminitis in an ex vivo model.

Dietary advanced glycation end-products elicit toxicological effects by disrupting gut microbiome and immune homeostasis

The aging immune system is characterized by a low-grade chronic systemic inflammatory state ("inflammaging") marked by elevated serum levels of inflammatory molecules such as interleukin (IL)-6 and C-reactive protein (CRP). These inflammatory markers were also reported to be strong predictors for the development/severity of Type 2 diabetes, obesity, and COVID-19. The levels of these markers have been positively associated with those of advanced glycation end-products (AGEs) generated via non-enzymatic glycation and oxidation of proteins and lipids during normal aging and metabolism. Based on the above observations, it is clinically important to elucidate how dietary AGEs modulate inflammation and might thus increase the risk for aging-exacerbated diseases. The present narrative review discusses the potential pro-inflammatory properties of dietary AGEs with a focus on the inflammatory mediators CRP, IL-6 and ferritin, and their relations to aging in general and Type 2 diabetes in particular. In addition, underlying mechanisms - including those related to gut microbiota and the receptors for AGEs, and the roles AGEs might play in affecting physiologies of the healthy elderly, obese individuals, and diabetics are discussed in regard to any greater susceptibility to COVID-19.

New progress in drugs treatment of diabetic kidney disease

Diabetic kidney disease (DKD) is not only one of the main complications of diabetes, but also the leading cause of the end-stage renal disease (ESRD). The occurrence and development of DKD have always been a serious clinical problem that leads to the increase of morbidity and mortality and the severe damage to the quality of life of human beings. Controlling blood glucose, blood pressure, blood lipids, and improving lifestyle can help slow the progress of DKD. In recent years, with the extensive research on the pathological mechanism and molecular mechanism of DKD, there are more and more new drugs based on this, such as new hypoglycemic drugs sodium-glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) inhibitors, and dipeptidyl peptidase-4 (DPP-4) inhibitors with good efficacy in clinical treatment. Besides, there are some newly developed drugs, including protein kinase C (PKC) inhibitors, advanced glycation end product (AGE) inhibitors, aldosterone receptor inhibitors, endothelin receptor (ETR) inhibitors, transforming growth factor-β (TGF-β) inhibitors, Rho kinase (ROCK) inhibitors and so on, which show positive effects in animal or clinical trials and bring hope for the treatment of DKD. In this review, we sort out the progress in the treatment of DKD in recent years, the research status of some emerging drugs, and the potential drugs for the treatment of DKD in the future, hoping to provide some directions for clinical treatment of DKD.

Use of Legumes and Yeast as Novel Dietary Protein Sources in Extruded Canine Diets

The popularity of plant-based protein sources has increased as consumer demand for grain-free and novel protein sources increase. Minimal research has been conducted as regards to use of legumes and yeast and their effects on acceptability and digestibility in canine diets. The objective of this study was to evaluate macronutrient apparent total tract digestibility (ATTD), gastrointestinal tolerance, and fermentative end-products in extruded, canine diets. Five diets were formulated to be isocaloric and isonitrogenous with either garbanzo beans (GBD), green lentils (GLD), peanut flour (PFD), dried yeast (DYD), or poultry by-product meal (CON) as the primary protein sources. Ten adult, intact, female beagles (mean age: 4.2 ± 1.1 yr, mean weight: 11.9 ± 1.3 kg) were used in a replicated, 5 × 5 Latin square design with 14 d periods. Each experimental period consisted of 10 d of diet adaptation, followed by 4 d of total fecal and urine collection. A fasted, 5 ml blood sample was collected at the end of each period and analyzed for serum metabolites and complete blood count. Serum metabolites were within normal ranges and all dogs remained healthy throughout the study. Fecal quality, evaluated on a 5-point scale, was considered ideal. Macronutrient ATTD was similar among dietary treatments, with diets highly digestible (>80%). Total fecal branched-chain fatty acid concentrations were highest (P < 0.05) for DYD (23.4 μmol/g) than GLD (16.1 μmol/g) and PFD (16.0 μmol/g) but not different (P > 0.05) than other treatments. The plant-based protein treatments had greater (P < 0.05) total fecal short chain fatty acid (SCFA) concentrations (average 627.6 μmol/g) compared with CON (381.1 μmol/g). Fecal butyrate concentration was highest (P < 0.05) for DYD than all other dietary treatments (103.9 μmol/g vs. average 46.2 μmol/g). Fecal microbial communities showed Firmicutes, Bacteroidetes, Fusobacteria, and Proteobacteria as abundant phyla. There was greater β-diversity for dogs fed DYD which differed from all other diets in both weighted and unweighted UNIFRAC analyses. Inclusion of these novel, plant-based, protein sources showed no detrimental effects on nutrient digestibility or fecal characteristics and represent viable protein sources in canine diets that can produce beneficial shifts in fecal metabolites.

Insights into Commercial Pet Foods

Veterinarians are faced with the challenge of understanding and discussing the wide array of commercial pet foods with their clients. To promote these discussions, a pet food processing categorization system is applied to define familiar heat processed dry and can pet foods as ultra-processed commercial diets (UPCD) and other less processed diets as minimally processed commercial diets. A review of the FDA pet food recalls on commercial diets are used to discuss well-known health risks, such as nutritional imbalances, bacterial pathogens, aflatoxin, and toxic contaminations. A less-known concern of advanced glycation end products found in UPCDs is presented.

Effect of toasting grain silages from field peas (Pisum sativum) and field beans (Vicia faba) on in vitro gas production, methane production, and post-ruminal crude protein content

Legume grains such as field peas and field beans can be produced on a local level, and may be reliable sources of dietary protein and energy apart from common soybean and rapeseed meals. In ruminants, protein, starch, and carbohydrates from peas and field beans are fermented in large part before reaching the small intestine. The objective of this study was to evaluate the effects of a combination of ensiling and hydro-thermic treatment (i.e., toasting at 160 °C for 30 min) of grains of peas and field beans on the concentrations of post-ruminal crude protein (PRCP) and rumen-undegraded protein (RUP). Moreover, 24-h gas production and methane production were measured. For this, an in vitro batch culture system with ruminal fluid from sheep was used. Rumen-undegraded protein was determined using the Streptomyces griseus protease test. Scanning electron micrographs were used to visualize morphological changes of starch granules and their joint matrices in peas and field beans after ensiling, toasting, or a combination of both. Native pea grains contained crude protein (CP) at 199 g/kg DM, PRCP at 155 g/kg DM at a ruminal passage rate of 0.08/h (Kp8), RUP at 33 g/kg DM at Kp8, and starch at 530 g/kg DM. Native field beans contained CP at 296 g/kg DM, PRCP at 212 g/kg DM at Kp8, RUP at 54 g of/kg DM at Kp8, and starch at 450 g/kg DM. The PRCP did not considerably differ among native and treated peas or field beans. Especially in the peas, RUP at Kp8 increased after ensiling by 10 g/kg DM (i.e., 30%; P < 0.05). Toasting increased RUP (Kp8) in ensiled peas by another 28% (P < 0.05). Toasting had no effect on PRCP or RUP when the peas or field beans were not ensiled before. Gas and methane production were not affected by any treatment, and scanning electron micrographs did not reveal structural changes on the starches doubtless of any treatment. Protein seemed to be more affected by treatment with ensiled + toasted peas than with ensiled + toasted field beans, but starches and other carbohydrates from both legumes remained unaffected.

Binding of CML-Modified as Well as Heat-Glycated β-lactoglobulin to Receptors for AGEs Is Determined by Charge and Hydrophobicity

Intake of dietary advanced glycation end products (AGEs) is associated with inflammation-related health problems. Nε-carboxymethyl lysine (CML) is one of the best characterised AGEs in processed food. AGEs have been described as ligands for receptors present on antigen presenting cells. However, changes in protein secondary and tertiary structure also induce binding to AGE receptors. We aimed to discriminate the role of different protein modifications in binding to AGE receptors. Therefore, β-lactoglobulin was chemically modified with glyoxylic acid to produce CML and compared to β-lactoglobulin glycated with lactose. Secondary structure was monitored with circular dichroism, while hydrophobicity and formation of β-sheet structures was measured with ANS-assay and ThT-assay, respectively. Aggregation was monitored using native-PAGE. Binding to sRAGE, CD36, and galectin-3 was measured using inhibition ELISA. Even though no changes in secondary structure were observed in all tested samples, binding to AGE receptors increased with CML concentration of CML-modified β-lactoglobulin. The negative charge of CML was a crucial determinant for the binding of protein bound CML, while binding of glycated BLG was determined by increasing hydrophobicity. This shows that sRAGE, galectin-3, and CD36 bind to protein bound CML and points out the role of negatively charged AGEs in binding to AGE receptors.

Non-enzymatic covalent modifications: a new link between metabolism and epigenetics

Epigenetic modifications, including those on DNA and histones, have been shown to regulate cellular metabolism by controlling expression of enzymes involved in the corresponding metabolic pathways. In turn, metabolic flux influences epigenetic regulation by affecting the biosynthetic balance of enzyme cofactors or donors for certain chromatin modifications. Recently, non-enzymatic covalent modifications (NECMs) by chemically reactive metabolites have been reported to manipulate chromatin architecture and gene transcription through multiple mechanisms. Here, we summarize these recent advances in the identification and characterization of NECMs on nucleic acids, histones, and transcription factors, providing an additional mechanistic link between metabolism and epigenetics.

Adverse Effects of Autoclaved Diets on the Progression of Chronic Kidney Disease and Chronic Kidney Disease-Mineral Bone Disorder in Rats

BACKGROUND

Autoclaving rodent diets is common in laboratory animals, but autoclaving increases the formation of dietary advanced glycation end-products (AGE). We studied the effect of autoclaved (AC) diet alone or in combination with a diet high in bioavailable phosphorus on biochemistries of chronic kidney disease-mineral and bone disorder (CKD-MBD), intestinal gene expression, and oxidative stress.

METHODS

Male CKD rats (Cy/+) and normal littermates were fed 1 of 3 diets: AC 0.7% phosphorus grain-based diet for 28 weeks (AC); AC diet for 17 weeks followed by non-autoclaved (Non-AC) 0.7% phosphorus casein diet until 28 weeks (AC + Casein); or Non-AC diet for 16 weeks followed by a Non-AC purified diet until 30 weeks (Non-AC + Casein).

RESULTS

AC diets contained ~3× higher AGEs and levels varied depending on the location within the autoclave. Rats fed the AC and AC + Casein diets had higher total AGEs and oxidative stress, irrespective of kidney function. Kidney function was more severely compromised in CKD rats fed AC or AC + Casein compared to Non-AC + Casein. There was a disease-by-diet interaction for plasma phosphorus, parathyroid hormone, and c-terminal fibroblast growth factor-23, driven by high values in the CKD rats fed the AC + Casein diet. Compared to Non-AC + Casein, AC and AC + Casein-fed groups had increased expression of receptor of AGEs and intestinal NADPH oxidase dual oxidase-2, independent of kidney function.

CONCLUSIONS

Autoclaving rodent diets impacts the progression of CKD and CKD-MBD, highlighting the critical importance of standardizing diets in experiments.

Issues surrounding consumer trust and acceptance of existing and emerging food processing technologies

The purpose of food processing today is to make food safer, more nutritious and tastier, and to increase storage life. Consumers have a lack of trust in the way food is produced, formulated and processed, particularly with possible contaminants or chemical residues from production. Food manufacturers are not seen as being highly trusted sources. This may partly result from manufacturers' reluctance to share all information and to protect intellectual property via patents and thus maintain a competitive edge. There is a need to inform the consumer better about what operations the involved ingredients are subjected to and why. Various ways of food processing are reviewed. New food processing technologies face challenges when introduced and factors influencing consumers' and other stakeholders' acceptance should be part of decision-making process when adopting new technologies. Consumers' perception of risks is not the same as the risk assessment made by experts. A few specific cases are being discussed to further highlight the multiplicity of factors that may contribute to the development of a certain consumer perception about a product or a class of products. This is also linked to the emergence of certain terminologies that are associated with an increasingly negative perception of the processing of foods. We recommend more transparency on food formulation and food processing to restore consumer trust, which enables to take the advantage of the benefits different processing methods offer. Food manufacturers must make an effort to let consumers know how their food is being processed within the walls of the factory and highlight the benefits vis-à-vis preparing foods in a domestic environment.

Advanced glycation end products (AGEs) and their soluble receptors (sRAGE) as early predictors of reno-vascular complications in patients with uncontrolled type 2 diabetes mellitus

AIM

To evaluate the role of advanced glycation end-products (AGEs) and their soluble receptors (sRAGE) expression levels as predictors of vascular complications in uncontrolled type 2 diabetes mellitus (T2DM).

METHODS

Cross-sectional study was conducted on T2DM adults of both sexes who attended the outpatient service of Al-Karak Teaching Hospital, Jordan during the period from June 2017 to August 2018. Participants were categorized in two groups according to their glycemic control and the presence of reno-vascular complications. Twenty healthy subjects were recruited as control group. Blood sample was obtained from all participants and used for the assessment of FBG, HbA1c, serum AGEs and sRAGE, serum urea and creatinine; 24 h urine was also collected for the determination of urinary albumin.

RESULTS

Diabetic subjects with vascular complication had a significantly higher serum AGEs 50.3 ± 13 vs. 28.9 ± 8 pg/ml) and AGEs/sRAGE ratio (0.058 ± 0.02 vs. 0.037 ± 0.02) associated with significantly lower serum sRAGE (868.7 ± 50.8 vs. 912.8 ± 294.3) compared to those with no complications. Serum AGEs and sRAGE showed weak negative and non-significant association in both groups of patients. However, the AGEs/sRAGE ration was inversely and significantly associated with the urinary albumin/creatinine ratio (r = - 0.51, P = 0.009) only in DM patients with reno-vascular complications.

CONCLUSION

We found an association between AGEs/sRAGE ratio and urinary albumin/serum creatinine ratio in T2DM patients with reno-vascular complications; providing evidence that serum AGEs and sRAGE can be considered as predictors of vascular complications in uncontrolled T2DM patients.