جستجوی مقالات مرتبط با کلیدواژه "insulin resistance" در نشریات گروه "علوم دام"

To investigate the effect of fatty liver on insulin resistance in the liver of laying hens, an experiment using 80 laying hens of commercial line strains (w-36) after peak production (age 43 weeks) for eight weeks were performedin a completely randomized design with two treatments. The experimental treatments included control group (no injection) and the estradiol group  (injection of two mg estradiol benzoate per kg body weight). In order to induce fatty liver disease, the injection of 17-beta estradiol started from the third week of experiment (age 46), and was performed three times a week for 21 days. Blood samples were taken to evaluate the concentration of triglycerides, cholesterol and liver enzymes (aspartate transaminase (AST), alanin transaminase (ALT) and alkaline phosphatase (ALP) at the end of the experiment using 20 hens from each treatment. At the end of experiment, five hens of each treatment were selected and sacrificed, then 50 g of liver tissue was removed to study gene expression of insulin receptor (InR), glucose transporter1 (Glut1), sterol regulatory element binding protein (SREBP1), Ribosomal S6 kinase1 (S6K1), Target of Rapamycin (TOR) and Forkhead box protein O1 (FOXO1). The results showed that the injection of estradiol induced fatty liver and increased plasma concentrations of cholesterol and triglyceride as well as activity of AST, ALT and ALP.  In hens with fatty liver, expression of FOXO1 (4.1-fold), TOR (3.9-fold), S6K1 (3.3-fold) genes increased, and conversely, expression of InR (4.6-fold), Glut1 (7.5-fold) decreased. In conclusion results of the present study showed that the fatty liver induction in laying hens increased expression of insulin resistance-related genes.

The aim of this study was to evaluate the effect of different source of magnesium in prepartum diets on productive performance, blood metabolites, insulin resistance and health disorders in transition cows. Sixty cows from 21 days prepartum were randomly assigned to 4 experimental treatments. Treatments were control treatment (Mg at NRC recommendation), magnesium sulfate treatment, magnesium carbonate treatment and magnesium oxide treatment (Mg was 0.60% of ration DM). Experimental diets increased DM and NDF digestibility (P<0.05). However, Calf and placenta weight, body weight changes and BCS were not affected by treatments. The incidence of retained placenta and hypomagnesemia decreased in experimental treatments (P<0.05). Magnesium oxide and carbonate treatments tended to increase milk yield (P=0.08). Milk fat increased in the control diet (P<0.05). Experimental diets decreased plasma NEFA and cholesterol and improved plasma Mg and Ca (P<0.05). Control treatment had the lowest rate of glucose CR (%) and RQUICKI (P<0.05).

The aim was to determine the effect of different dietary n-6/n-3 fatty acid (FA) ratio during the postpartum period on plasma haptoglobin, metabolic profile, and insulin resistance in Holstein dairy cows. 24 multiparous cows were randomly assigned to three treatments with a ratio of omega-6 fatty acids to omega-3: 2.5 to 1 (low ratio); 4.5 to 1 (average ratio); and 6.5 to 1 (high ratio) were distributed. Blood samples were collected on d 7, 14, 28, 42, 56 and 70 postpartum to determine blood metabolites and haptoglobin concentrations. Intravenous glucose tolerance tests and insulin challenges were performed on d 28 and 42 of experiment. Plasma concentrations of haptoglobin were significantly higher in the cows fed with high ratio than the other two treatments. The 42-day postpartum results of insulin challenge test indicates that the change in the ratio of fatty acids to moderate treatment causes an increase in the clearance rate and a decrease in the area under the curve of the insulin. The results of this study indicate that the moderate ratio of omega-6 to omega-3 fatty acids in dairy cows decreases insulin resistance by reducing inflammatory factors.

Chromium (Cr) plays an important role in ruminant’s metabolism. Situations such as accelerating growth, stress and low bioavailability of Cr in feedstuffs, result in depletion of chromium stores of body, therefore, metabolic disorders and growth retardation occurs. In addition, L-carnitine (LC), a compound of lysine and methionine, is involved in many metabolic processes. It affects energy production and performance by influencing lipid metabolism. Using Cr and LC together, a positive interaction has been reported on lipids and carbohydrates metabolism in some species. Therefore, the aim of this study was to evaluate the effect of organic chromium in form of chromium methionine (Cr-Met) and L-carnitine as a dietary supplement for feedlot lambs on growth performance, glucose metabolism and some blood parameters.
Material and This experiment was performed for 60 days with twentyfour 3-4 month-old male lambs in a completely randomized design (CRD) with four treatments of six lambs each. The treatments were included: 1- control (basal diet) 2- treatment of chromium (Cr) (500 µg Cr per lamb per day) 3- treatment of L-carnitine (LC) (500 mg L-carnitine per lamb per day) 4- treatment of chromium and L-carnitine (Cr × LC) (500 µg Cr and 500 mg of LC per lamb per day). Supplements were added to the basal diet as topdress. At the end of experiment, feed intake, average daily gain (ADG) and feed conversion ratio (FCR) were calculated. In order to evaluate blood metabolites and rumen liquid parameters, blood and rumen liquid samples were taken at the end of experiment. Four lambs randomly were selected from each groups for intravenous glucose tolerance test (IVGTT). For this purpose, 0.5 ml/Kg BW dextrose (50%) was infused and blood samples were taken at 5, 10, 20, 30, 40, 60, 80, 100 and 120 min after glucose infusion, Then glucose clearance rate (CR), half-life (t1/2) and area under curve (AUC) was calculated.
Feed intake, ADG and FCR and also rumen volatile fatty acids and ammonium was not different between treatments (P>0.05). Interactions of chromium and L-carnitine for performance parameters and also rumen volatile fatty acids and ammonium were not significant (P>0.05). High density lipoproteins (HDL) in treatments two and four was significantly higher in compared to treatments three and one (P0.05). Activity of alanine aminotransferase (ALT) was lower in treatments three and four than treatments one and two (P0.05). Area under curve was lower in treatment three in compared to treatment one and four (P0.05).
Results of this experiments showed that, adding chromium and Lcarnitine to feedlot lambs diet (the concentrations used in this study) did not impact fattening performance, but resulted in an increase in HDL and improvement of glucose metabolism.