Is the intestinal mucous layer a natural deep eutectic solvent-based digestion matrix?

In plants, a third solubilization matrix (besides water and lipids) has been proposed, composed of natural deep eutectic solvents (NADESs). Such matrices allow for the solubilization of many biologically important molecules, such as starch, which are insoluble in water or lipids. NADES matrices also support enzyme activity, such as amylase, at higher rates than water or lipid-based matrices. We contemplated if a NADES environment could play a role in small intestinal starch digestion. The intestinal mucous layer (encompassing both the glycocalyx and the secreted mucous layer) has a chemical composition that fits well with NADES (e.g., glycoproteins with exposed sugars, amino sugars, and amino acids like proline and threonine, as well as quaternary amines like choline and ethanolamine and organic acids like citric and malic acid). Various studies have indeed shown that amylase binds to glycoproteins within the mucous layer of the small intestine where it performs its digestive action. Dislodging amylase from these binding sites impedes starch digestion and it may well cause digestive health problems as a result. Hence, we propose that the mucous layer in the small intestines harbors digestive enzymes like amylase, while starch, due to solubility, redistributes from the lumen into the mucous layer where it is subsequently digested by amylase. The mucous layer would thus constitute a NADES-based digestion matrix in the intestinal tract.

Metabolomic Analysis of Wooden Breast Myopathy Shows a Disturbed Lipid Metabolism.

Myopathies have risen strongly in recent years, likely linked to selection for appetite. For white striping (WS), causes have been identified; but for wooden breast (WB), the cause remains speculative. We used metabolomics to study the breast muscle of 51 birds that were scored for both at 35 days of age to better understand potential causes. A partial least square discriminant analysis revealed that WS and WB had distinct metabolic profiles, implying different etiologies. Arginine and proline metabolism were affected in both, although differently: WB increased arginine in breast muscle implying that the birds did not use this pathway to increase tissue blood flow. Antioxidant defenses were impeded as shown by low anserine and beta-alanine. In contrast, GSH and selenium concentrations were increased. Serine, linked to anti-inflammatory properties, was increased. Taurine, which can stabilize the cell's sarcolemma as well as modulate potassium channels and cellular calcium homeostasis, was also increased. Mineral data and depressed phosphatidylethanolamine, cAMP, and creatine-phosphate suggested compromised energy metabolism. WB also had drastically lower diet-derived lipids, suggesting compromised lipid digestion. In conclusion, WB may be caused by impaired lipid digestion triggered by a very high appetite: the ensuing deficiencies may well impair blood flow into muscle resulting in irreparable damage.

Efficacy of l-glutamic acid, N,N-diacetic acid to improve the dietary trace mineral bioavailability in broilers.

Trace minerals are commonly supplemented in the diets of farmed animals in levels exceeding biological requirements, resulting in extensive fecal excretion and environmental losses. Chelation of trace metal supplements with ethylenediaminetetraacetic acid (EDTA) can mitigate the effects of dietary antagonists by preserving the solubility of trace minerals. Lack of EDTA biodegradability, however, is of environmental concern. l-Glutamic acid, N,N-diacetic acid (GLDA) is a readily biodegradable chelating agent that could be used as a suitable alternative to EDTA. The latter was tested in sequential dose-response experiments in broiler chickens. Study 1 compared the effect of EDTA and GLDA in broilers on supplemental zinc availability at three levels of added zinc (5, 10, and 20 ppm) fed alone or in combination with molar amounts of GLDA or EDTA equivalent to chelate the added zinc, including negative (no supplemental zinc) and positive (80 ppm added zinc) control treatments. Study 2 quantified the effect of GLDA on the availability of native trace mineral feed content in a basal diet containing no supplemental minerals and supplemented with three levels of GLDA (54, 108, and 216 ppm). In study 1, serum and tibia Zn clearly responded to the increasing doses of dietary zinc with a significant response to the presence of EDTA and GLDA (P < 0.05). These results are also indicative of the equivalent nutritional properties between GLDA and EDTA. In study 2, zinc levels in serum and tibia were also increased with the addition of GLDA to a basal diet lacking supplemental trace minerals, where serum zinc levels were 60% higher at the 216 ppm inclusion level. Similar to the reported effects of EDTA, these studies demonstrate that dietary GLDA may have enhanced zinc solubility in the gastrointestinal tract and subsequently enhanced availability for absorption, resulting in improved nutritional zinc status in zinc-deficient diets. As such, GLDA can be an effective nutritional tool to reduce supplemental zinc levels in broiler diets, thereby maintaining health and performance while reducing the environmental footprint of food-producing animals.