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

Abstract

The immune system provides host protection to infection with pathogenic organisms, while at the same time providing tolerance upon exposure to harmless antigens. Thus, an impaired immune function is associated with increased susceptibility to infections with increased disease severity and thereby necessitating the therapeutic use of antibiotics. Livestock performance and feed efficiency, in addition to their health status, are dependent on the microbial load of their gut, the barrier function of the intestinal epithelium and the activity of the mucosal immune system, all of which can be modulated by dietary components. The majority of feeds that are consumed in pets and livestock have been processed. Processing promotes a non-enzymatic reaction between proteins and sugars called Maillard reaction (MR). Maillard reaction products (MRPs) and advanced Maillard reaction products (AGEs) determine taste, smell, and color of many food products therefore the MR is highly relevant for the feed industry. MRPs interact with different types of immune receptors, including the receptor for advanced glycation end products (RAGE) and immunomodulatory potential of feed proteins can be modified by Maillard reaction. This MR has become an important concern since MRPs/AGEs have been shown to contribute to increasing prevalence of diet-related chronic inflammatory states in the gut with negative health consequences and performance. The immunomodulatory effects of dietary MRPs and AGEs in livestock and pet animals are far less well-described, but widely considered to be similar to the relevant concepts and mechanisms obtained in the human field. This review will highlight immunological mechanisms underlying initiation of the innate and adaptive immune responses by MRPs/AGEs present in animal feeds, which are currently not completely understood. Bridging this knowledge gap, and taking advantage of progress in the human field, will significantly improve nutritional quality of feed and increase the prevention of diet-mediated inflammation in animals.

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

“…A standard autoclave protocol for sterilizing grain-based diets increased the concentration of the commonly assessed AGEs, CML, and the dicarbonyl precursor of AGEs, MG. It should be noted that the CML and MG content of the Non-AC diets was not zero, as all pelleted food undergoes extrusion and drying with heat and this may set a "baseline" dietary AGE concentration [11]. Importantly, we found that the higher dietary AGEs concentration varied depending on the location within the autoclave, where the highest concentrations of CML and MG were found near the heat source in the autoclave.…”

Improved radical scavenging activity and stabilised colour of nipa palm syrup after ultrasound‐assisted glycation with glycine

“…The degree of the browning development was governed by several factors, especially temperature–time regime and types, concentration and ratio of reactants (Ajandouz et al ., 2001; Ajandouz et al ., 2008). The Maillard reaction is correlated well with the reaction temperature and time (Teodorowicz et al ., 2018; Asghar et al ., 2020b).…”

“…As mentioned above, nipa palm syrup shows some free radical scavenging activity. This free radical scavenging activity can be improved via the Maillard reaction, which is a nonenzymatic glycation reaction (Zhang et al ., 2009; Teodorowicz et al ., 2018; Asghar et al ., 2020a). However, thermal Maillard reaction had a detrimental effect on the colour of the final syrup because dark syrup could be rejected by consumers (Jiang et al ., 2013).…”

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

“…Dietary AGEs have previously been described as potent ligands for a number of cell surface receptors expressed on APCs including RAGE, CD36 and the extracellular unit of the AGE-R complex galectin-3 [ 42 ]. However, the knowledge on the particular binding sides of these receptors to MR-modified proteins is very limited because of complexity of the structural rearrangements during the heat treatment and glycation.…”