Immunological, oxidoreductive, biochemical indicators, microbial enzymes in biological material taken from rats fed a high-fat diet with the addition of chromium

Obesity is one of the most prevalent diseases of civilization in the 21st century. It can be influenced by genetic, epigenetic, socio-economic, biological, and behavioural factors. However, a high-fat diet seems to be of particular importance in the pathophysiology of obesity. Chromium (III) (Cr) is a key microelement involved in the metabolism of carbohydrates, proteins, and fats in humans and animals. Due to these properties of Cr, it is popularly used as a factor supporting the treatment of type 2 diabetes and as a component of supplements used in slimming treatments. Currently, the most popular form of Cr used in dietary supplements is picolinate (Cr-Pic), an organic compound of trivalent Cr. The use of Cr-Pic has many benefits, including weight reduction and increased muscle mass. However, due to the relatively low bioavailability of chromium picolinate, other forms of this element are sought that could be better utilized by the body. For this reason, researchers are increasingly interested in complexes of Cr with amino acids as well as inorganic chromium nanoparticles. Recently, nanoparticles have emerged as important players in modern science, including nutritional status of the host in health and disease. But, in the recent own experiment on young growing rats fed high-fat diet supplemented with different forms of chromium (Cr (III) picolinate, Cr (III) methionine, Cr nanoparticles) some important worrying results have been obtained. It has been shown that one should be careful when using chromium supplementation to counteract obesity, because it may be associated with the risk of deterioration of the functioning of some internal organs. In the present project the experimental schema is more adapted to common dietary and physiological environment that an obese consumer face. The laboratory growing rats will be first subjected to high-fat diet in order to induce undesired changes in the body functions (initial period of the experiment); then the obese animals will be divided into several groups and subjected to dietary treatments imitating different dietary behaviours and decisions of obese consumers (stick – or not, to an “old” dietary high-fat patterns with or without chromium supplementation support). Two forms of supplemental Cr will be used, namely most popular chromium picolinate (Cr-Pic) and novel chromium nanoparticles (Cr-NP). In the project we postulate that negative intestinal, vascular and hepatic effects associated with chronic consumption of high-fat diet could be subsequently alleviated through dietary supplementation of various forms of chromium and/or switching to low-fat diet. We hypothesized that the switch away from high-fat dietary habits combined with chromium supplementation (picolinate or nanoparticles) would beneficially affect physiological responses in the gastrointestinal tract and thus positively modulate the health status of the body. Moreover, the effects observed in the treatments with Cr-Pic will be more pronounced upon Cr-NP due to higher absorbability and reactivity of nanoparticles. The rat Wistar (Cmdb:Wi CMDB) will be used as a research model, i.e. an established host model for nutritional/metabolic studies, including the intestinal, immunological, vascular and hepatic responses to nutritional interventions. The main intention of the project’s authors is to bring as much as possible new insight with regard to the question whether negative intestinal, vascular and hepatic effects associated with chronic consumption of high-fat diet could be subsequently alleviated through dietary supplementation of various forms of chromium and/or switching to low-fat diet. Taking into account an urgent need to establish true action of dietary nanoparticles in the gastrointestinal tract and the whole body, a paramount attention will be paid to Cr-NP and their action will be compared to commonly used dietary supplement Cr-Pic. The negative or positive impact of supplemental Cr on the microbiota living in the lower gut (with novel approach assessing microbial intra- and extracellular enzymatic activities), thus affecting local (in the upper and lower gastrointestinal tract), hepatic and systemic (metabolic, i.e. blood haematology and biochemistry parameters) health status of the obese host with different eating habits will be assessed. Jerzy Juskiewicz, Instytut Rozrodu Zwierzat i Badan Zywnosci Polskiej Akademii Nauk 497818 ZSUN/