Effect of dietary cereal type, crude protein and butyrate supplementation on metabolic parameters of broilers

This study investigates the metabolic effects of maize- or wheat-based diets with normal (NP) and lowered (LP) dietary crude protein level [the latter supplemented with limiting amino acids and sodium (n-)butyrate at 1.5 g/kg diet] at different phases of broiler fattening. Blood samples of Ross 308 broilers were tested at the age of 1, 3 and 6 weeks. Total protein (TP) concentration increased in wheat-based and decreased in LP groups in week 3, while butyrate reduced albumin/TP ratio in week 1. Uric acid level was elevated by wheat-based diet in week 1 and by wheat-based diet and butyrate in week 3, but decreased in LP groups in weeks 3 and 6. Aspartate aminotransferase activity was increased by wheat-based diet in week 3, and creatine kinase activity was intensified by LP in weeks 3 and 6. Blood glucose level decreased in wheat-based groups in week 3; however, triglyceride concentration was augmented in the same groups in week 3. No change of glucagon-like peptide 1, glucose-dependent insulinotropic polypeptide and insulin concentration was observed. In conclusion, an age-dependent responsiveness of broilers to dietary factors was found, dietary cereal type was a potent modulator of metabolism, and a low crude protein diet supplemented with limiting amino acids might have a beneficial impact on the growth of chickens

Effects of butyrate on the insulin homeostasis of chickens kept on maize- or wheat-based diets

The aim of the present study was to investigate the effects of butyrate as a feed supplement on the expression of insulin signalling proteins as potent regulators of metabolism and growth in Ross 308 broiler chickens fed maize- or wheat-based diets. Both diets were supplemented with non-protected butyrate (1.5 and 3.0 g/kg of diet, respectively) or with protected butyrate (0.2 g/kg of diet); the diet of the control groups was prepared without any additives (control). On day 42 of life, systemic blood samples were drawn for analyses of glucose and insulin concentrations, and tissue samples (liver, gastrocnemius muscle and subcutaneous adipose tissue) were taken for Western blotting examinations. The expression of key insulin signalling proteins (IRβ, PKCζ and mTOR) was assessed by semiquantitative Western blotting from the tissues mentioned. The type of diet had a remarkable influence on the insulin homeostasis of chickens. The wheat-based diet significantly increased IRβ and mTOR expression in the liver as well as mTOR and PKCζ expression in the adipose tissue when compared to animals kept on a maize-based diet. IRβ expression in the liver was stimulated by the lower dose of non-protected butyrate as well, suggesting the potential of butyrate as a feed additive to affect insulin sensitivity. Based on the results obtained, the present study shows new aspects of nutritional factors by comparing the special effects of butyrate as a feed additive and those of the cereal type, presumably in association with dietary non-starch polysaccharide- (NSP-) driven enteric shortchain fatty acid release including butyrate, influencing insulin homeostasis in chickens. As the tissues of chickens have physiologically lower insulin sensitivity compared to mammals, diet-associated induction of the insulin signalling pathway can be of special importance in improving growth and metabolic health

The role of intestinal mucosa in the metabolism of xenobiotics with particular regard to the cytochrome P450 enzyme system - Literature review

SUMMARY The aim of the present review is to summarize the recent knowledge about the role of intestinal mucosa in the biotransformation of xenobiotics. Liver is the most important organ of biotransformation; however, the small intestinal mucosa could have an important role in the bioavailability of xenobiotics, as well. As most of the xenobiotics are absorbed from the small intestine, it could have a function as a primary barrier, determining the proportion and form of derivates transported from the gut into the portal circulation, thus it could facilitate the biotransformation function of the liver. Several factors can have impact on the efficiency of intestinal mucosal biotransformation. Cytochrome P450 (CYP) enzymes play central role in the metabolism of molecules in the intestinal epithelial cells; the expression and activity of them can be highly influenced by the interaction with dietary factors or other xenobiotics. Therefore, their significance in the bioavailability of certain drugs and feed additives cannot be neglected

Role of Kupffer-cells in the regulation of hepatic inflammatory and metabolic processes - Literature review

SUMMARY Based on literature data, the authors present the central role of Kupffer cells as resident liver macrophages in the regulation of hepatic inflammatory response and metabolic processes. Lipopolysaccharide (LPS) type endotoxins originated from Gram negative bacteria causing enteric infections, may trigger inflammation in the liver via the mediation of Kupffer cells, which is of special importance in the veterinary medicine, as well. Kupffer cells are being activated by binding LPS to cell surface receptors, stimulating pro-inflammatory cytokine, eicosanoid and chemokine production, thus regulating the systemic immune response. The authors showed that according to recent studies, the function of Kupffer cells could be affected by alterations of lipid homeostasis, and Kupffer cells are playing pivotal role in the pathogenesis of hepatic lipidosis. Furthermore, Kupffer cells are highly involved in the complex regulation of metabolic processes, being potent effectors of insulin sensitivity, carbohydrate and lipid metabolism as key cells in immunometabolic interactions

Investigation of the effect of butyrate supplementation of the diet on hepatic cytochrome P450 enzymes in rats

Orally applied butyrate as a nutritional supplement has a huge impact on the health of the gastrointestinal epithelium and the gut microflora. In addition, as an epigenetically active molecule, it can also influence the expression of certain genes. Regarding the results of some in vitro studies, butyrate, absorbed from the intestines and taken to the liver by the portal circulation, may alter the action of hepatic microsomal cytochrome P450 (CYP) enzymes, involved in the biotransformation of xenobiotics, having a remarkable importance in food safety, as well. The authors aimed to study the possible effects of orally applied butyrate on hepatic CYP activity in rats after weaning, also serving as a monogastric mammalian model. Animals were fed with normal pelleted stock diet without or with sodium butyrate (1.5 g/kg diet) for 21 days. As a positive control, a group of rats was treated with intraperitoneal phenobarbital injection. Animals were euthanized on day 21, microsomal fractions were separated from the exsanguinated livers by differential centrifugation. The activity of the most important (VP subfamilies was screened by specific enzyme assays (aminopyrine N-demethylation: CYP2B/3A, testosterone 6 beta-hydroxylation: CYP3A). According to the results, butyrate as a feed supplement did not cause any changes in the drug-metabolising activity of the examined hepatic microsomal CYP enzymes. However, phenobarbital significantly (P<0,05) increased the microsomal CYP2B and CYP3A activity of the liver. These data indicate that the supplementation of the diet with butyrate probably may not have any pharmacokinetic interactions with simultaneously applied xenobiotics in monogastric mammals, so it can be applied safely as a nutritional supplement