The effects of Zinc-Methionine on glucose metabolism and insulin resistance during late pregnancy in ewes.

This study investigated the effects of dietary supplements of Zinc-Methionine (Zn-Met) on the zinc concentration of the blood and indices such as insulin resistance and glucose tolerance in late-pregnancy ewes to provide a practical solution to prevent metabolic diseases associated with energy status. In this research, 18 Makouei pregnant ewes were selected and randomized into 3 experimental groups: Group 1: Basal diet containing 10.3 mg Zn/kgDM and no zinc supplementation = CTR (Control); Group 2: Basal diet supplemented with low-dose zinc equivalent to the pregnancy requirements (30 mg Zn/kgDM) = LZN; Group 3: Basal diet supplemented with high-dose zinc (300 mg Zn/kgDM) = HZN. Blood samples for insulin resistance and glucose tolerance indices were collected according to standard methods. The results of this study indicated that supplementation of high-dose Zn-Met decreased (P < 0.05) blood glucose and tended (P < 0.1) to reduce the beta-hydroxybutyrate (BHB) concentrations. After intravenous injection of glucose and insulin, none of the glucose tolerance and insulin resistance indices were significant among groups (P > 0.05). However, the intravenous glucose tolerance test (IGTT) showed that the area under the curve (AUC) of serum glucose in the HZN group was numerically lower than that of the LZN and CTR groups. Furthermore, the numerically higher clearance rate (CR) of glucose and more negative glucose AUC following intravenous administration of insulin in Zinc-supplemented groups suggested that the ewes had greater insulin response than control group. The results showed a decrease in blood glucose concentration due to higher zinc intake after insulin injection and supported the evidence for improving insulin sensitivity. In addition, our results showed that ewes receiving zinc supplementation experienced a more favorable state of BHB or NEFA values. In conclusion, Zn-Met supplementation was found to have promising effects in improving energy metabolism in late pregnant ewes. However, further studies are needed to understand the mechanisms involved in regulating lipolysis and energy metabolism.

Assessment of oxidative/nitrosative stress biomarkers and DNA damage in Teladorsagia circumcincta following exposure to zinc oxide nanoparticles.

Drug resistance to helminth parasites is one of the most serious problems to threaten the livestock industry. The problem also poses a major threat to public health. Therefore, novel and safe agents should urgently be investigated to control parasitic infections. The current study was conducted to evaluate the possible antiparasitic effects of zinc oxide nanoparticles (ZnO-NPs) on one of the most prevalent gastrointestinal nematodes, Teladorsagia circumcincta. The worms were incubated with various concentrations of ZnO-NPs: 1, 4, 8, 12 and 16 ppm for 24 hours. Mobility and mortality of the parasites were recorded at four-hour intervals. At the endpoint, several biomarkers of oxidative/nitrosative stress, including superoxide dismutase, glutathione peroxidase and catalase, as well as lipid peroxidation, protein carbonylation, total antioxidant status, nitric oxide contents and DNA damage, were measured in the homogenized samples. ZnO-NPs showed significant anthelminthic effects, depending on time and concentration. Furthermore, the nanoparticle induced severe oxidative/nitrosative stress and DNA damage. ZnO-NPs could be considered as a novel and potent anthelminthic agent.

Experimental hyperlipidemia induces insulin resistance in sheep.

This study aimed to evaluate the effects of intravenous infusion of a soybean-based lipid emulsion on some blood energy-related metabolites and insulin sensitivity indexes in sheep. Four clinically healthy ewes were assigned into a 2-treatment, 2-period cross-over design. Either normal saline (NS) or lipid emulsion (LE) was intravenously introduced at a rate of 0.025 mL·kg(-1) min(-1) for 6 h. The concentrations of blood nonesterified fatty acid (NEFA), beta-hydroxybutyrate, triglyceride, cholesterol, urea, creatinine, cortisol, glucose, and insulin were measured at different time points. After 6 h, intravenous glucose tolerance test was performed. Lipid infusion elicited an increase (P < 0.05) in the NEFA, beta-hydroxybutyrate, and triglyceride concentrations compared with the baseline value and NS infusion. Infusion of NS did not influence blood glucose concentration; however, LE infusion increased plasma glucose concentration (P < 0.05). At time point 12 h, serum insulin concentrations were increased (P < 0.05) in NS treatment; however, such an increase was not observed in the LE treatment. Insulin sensitivity index for the LE infusion was lower (P < 0.05) than that for the NS treatment. The glucose effectiveness was not (P > 0.05) different among treatments. In the LE treatment, acute-phase insulin responses increased (P < 0.05) and disposition index decreased (P < 0.001) compared with NS treatment. The results showed that experimentally induced NEFA in blood could cause insulin resistance in sheep. The current model could be used to evaluate the pathogenesis of conditions associated with increased lipid mobilization and insulin resistance.

Comparison of seminal oxidants and antioxidants in subjects with different levels of physical fitness.

The purpose of this study was to evaluate the seminal 8-Isoprostane, reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), catalase, total antioxidant capacity (TAC) in subjects with different level of physical fitness. A total of 161 semen samples were obtained from three groups of healthy males, including elite athletes (23.8 ± 5.2 years, n = 56) who had regular training (4-5 days per week), recreationally active men (24.2 ± 4.9 years, n = 52) who participated in educational or recreational physical activities for 4-5 h per week and non-active men (23.9 ± 5.0 years, n = 53) who did not participate in any exercise programmes for at least 6 months prior to the study. The results showed significantly higher levels of SOD, catalase and TAC as well as lower levels of 8-Isoprostane, ROS and MDA in recreationally active men compared with either elite athletes or non-active men (p < 0.001). Also, elite athletes revealed significantly higher seminal 8-Isoprostane, ROS and MDA as well as lower SOD, catalase and TAC levels compared with recreationally active and non-active men (p < 0.001). In conclusion, the results of the present study indicate that there are differences in seminal oxidants and antioxidants of elite athletes, recreationally active and non-active men. These differences are more likely related to indices that favour decrement of oxidative stress-induced peroxidative damage in spermatozoa from recreationally active men. Hence, recreationally active men seem to have a healthier semen production. The physiological significance of this observation is worthy of further investigation.

Evaluation of 'Section-Ligation-Release (SLR)' technique devised for castration in the stallion.

A novel technique [Section-Ligation-Release (SLR)] was evaluated for castration in the horse. Clinical traits, serum testosterone concentrations after challenge with human chorionic gonadotrophin (hCG), and histopathological changes of the testicular tissue were assessed. Five stallions, aged 24-48 months, were castrated using SLR technique under general anaesthesia. Both spermatic cords in each stallion were exposed at the scrotal neck by two 5-cm long incisions, followed by sharp dissection through the parietal vaginal tunic. Both vascular and non-vascular structures in the cords were triple clamped, transected and ligated. Both testes were left in situ. Serum testosterone concentrations were measured pre-operatively and at 2 months after castration following IV administration of 1 x 10(4) IU of hCG. Both testes from each castrate were collected at 2 months for histopathologic examination. SLR castration was successfully achieved. Moderated scrotal and preputial swelling was the only experienced short-term complication. Serum testosterone concentrations were significantly lower than basal pre-operative levels at 2 months after castration, and did not respond to hCG. On histopathology, hyalinization of the seminiferous tubules and loss of testicular interstitial tissue were indicative of complete avascular necrosis. This novel primary closure castration technique of stallion is a simple practical method, with minimal post-operative complications; and could be safely advocated as an alternative to the traditional castration techniques allowing for second intention healing of scrotal wounds.

Evaluation of antioxidant status and oxidative stress in cattle naturally infected with Theileria annulata.

To assess the antioxidant status and oxidative stress in bovine theileriosis due to Theileria annulata blood samples were collected from 35 clinically affected cattle referred to Veterinary Teaching Hospital, School of Veterinary Medicine, Urmia University, Urmia, Iran. Complete blood count, piroplasm parasitemia percentage, erythrocyte glutathione peroxidase, superoxide dismutase, catalase and glucose-6-phosphate dehydrogenase activities, malondialdehyde concentration, osmotic fragility test and median corpuscular fragility were determined and the results were compared with those of 50 healthy controls. Of 35 affected cattle, 12 (34.28%) had severe anemia and 23 had mild to moderate anemia and parasitemia varied from 5 to 40%. The activities of erythrocyte glutathione peroxidase, superoxide dismutase and glucose-6-phosphate dehydrogenase were significantly lower (P<0.0001) and the activity of catalase was significantly higher in the affected cattle than in healthy ones (P<0.001). Malondialdehyde concentration in erythrocytes of affected cattle was significantly more than those of healthy cattle (P<0.001). The affected cattle showed increased fragility of erythrocytes, so that median corpuscular fragility (MCF) in affected group was significantly lower than those of healthy group (P<0.0001). Median corpuscular fragility showed a positive correlation with the severity of parasitemia (r=0.81, P<0.0005) and a negative correlation with the activities of GSH-Px (r=-0.78, P<0.0001), SOD (r=-0.71, P<0.0005), catalase (r=-0.53, P<0.018) and G6PD (r=-0.58, P<0.0005). The results of this study suggest that oxidative damage to RBCs may contribute to the pathogenesis of anemia in bovine theileriosis.