جستجوی مقالات مرتبط با کلیدواژه "تنش اکسیداتیو" در نشریات گروه "کشاورزی"

Artificial insemination is one of the important management tools to control reproductive activities and increase the productivity of the livestock industry. This technique can play an important role in genetic improvement even in small herds. Sperm preparation is of particular importance for reproductive techniques, such as artificial insemination, but many harmful factors, such as temperature shock and oxidative stress, reduce sperm quality and directly affect sperm fertility during sperm preparation and storage. Therefore, the addition of protective substances and antioxidants in the diluent is considered essential in maintaining sperm quality during the cooling and freezing stages. Curcumin is a yellow substance obtained from the root of turmeric, and its biochemical structure contains a phenolic ring and a beta-di-ketone part in its structure. It can neutralize free radicals, but it has low solubility in hydrophilic environments. To solve this problem, the nanoliposome method has been proposed. Using this method can solve the problem of curcumin's low solubility in aqueous solutions and, additionally, curcumin nanoparticles can be guided to exert their effects in a completely targeted manner inside the target cell. On the other hand, sucrose protects sperm from cold shock by first rinsing sperm cells and maintaining the osmotic pressure of the diluting medium. This study aimed to investigate the effects of separate and mixed use of different levels of curcumin nanoparticles and sucrose sugar in ram epididymal sperm diluent during storage at 5 ˚C at different cooling times.

The present study was conducted in the Animal Physiology Laboratory of the Department of Animal and Poultry Sciences, Aburihan Agricultural Campus, the University of Tehran. The testicular tissues were prepared from a slaughterhouse on the day of the experiment and transported to the laboratory with special flux in less than an hour. Sperm samples were collected from the epididymal tail of the ram testicular tissue in the laboratory. Sperm was sampled after initial evaluation, with progressive motility of more than 75% and abnormality of less than 10%, and were added to the diluent at 37 °C. In this study, the diluent consisted of Tris (27.1 g/L), citric acid (14 g/L), fructose (10 g/L), egg yolk (20%), and glycerol (7%), with a pH of around 6.2-7.8. The osmolarity was set at about 310-320 milliosmoles. Sucrose sugar was obtained from the Sigma Aldridge Company, and curcumin nanoparticles were prepared from pure curcumin powder (Sigma Aldridge) by the nanoliposome method and using rotary devices, a homogenizer, and a prop sonicator. A DLS device was used to examine the particle size of curcumin nanoparticles (less than 80 nanograms). The experimental groups included 25 and 50 μM of nanoparticles of curcumin (NC), sucrose (S) at 100 and 150 mM separately, combined levels (25NC100S, 25NC150S, 50NC100S, and 50NC150S), and a group without these additives (control), which were added to the diluent at 37 °C. The diluents containing different levels of the treatments were refrigerated in 15 ml falcones and inside a water container at the same temperature, which gradually reached a temperature of 5 ˚C in about 2 hours. After stabilization at this temperature, total motility parameters, progressive motility using the KASA system, the viability with the eosin-nigrosin method (16.7 g of eosin, 100 g of nigrosin, and 29 g of citrate buffer in 1 L of double-distilled water), membrane integrity by the HOST solution method (9 g of fructose and 4.9 g of sodium citrate in 1 L of double-distilled water with an osmolarity of 100 milliosmoles), and the percentage of sperm abnormalities using Hancock's solution (5 62/L of 37% formalin, 150 ml of saline solution, 150 ml of a buffer solution, and 500 ml of double distilled water) were evaluated at 6, 12, 24, and 48 hours.The experimental results were analyzed in a completely random design by SAS software (9.2) and the GLM procedure at a significance level of P < 0.05. The means of the treatments were compared with Tukey's test.

The use of 25NC100S in the diluent improved the parameters of total motility, progressive motility, viability, and integrity of ram epididymal sperm membrane in all evaluated times compared to the other groups, especially the control group (p < 0.05). No significant differences were observed between the treatments in the percentage of sperm abnormalities at 6 and 12 hours (p > 0.05). At 24 and 48 hours, however, the 25NC100S concentration significantly reduced the percentages of sperm abnormalities compared to the other concentrations (p < 0.05). Compared to the control group, adding different levels of curcumin nanoparticles and sucrose sugar separately significantly improved the evaluated parameters, but the best performance was observed in the combined treatment, indicating the synergistic role of these two compounds.

The results of the present study demonstrate that using a mixture of curcumin nanoparticles with sucrose in the diluent can protect sperm against oxidative damage and cold shock. The antioxidant effects of curcumin nanoparticles and the protective effects of sucrose sugar can result in positive effects on the quality of ram epididymal sperm during cooling. Therefore, it is recommended to use the 25NC100S level in ram sperm diluents.

Cold stress is one of the major factors limiting rice (Oryza sativa L.) productivity and yield. Two rice cultivars were chosen for this study: a japonica rice, ‘Gerde’, and an indica rice, ‘Shiroodi’, representing tolerant and sensitive cultivars, respectively. In this work, the early physiological and molecular responses of these two cultivars to 4°C cold stress were investigated. We found that cold stress caused a significant decrease in the content of chlorophyll a, chlorophyll b, and carotenoids in both rice cultivars. However, the photosynthetic pigment content in the Shiroodi cultivar decreased to a greater extent, indicating its limited genetic capacity to protect its photosynthetic machinery. During cold stress, the amounts of hydrogen peroxide and malondialdehyde produced by the Shiroodi cultivar were significantly higher than those in Gerde, suggesting a lower capacity of Shiroodi to scavenge reactive oxygen species. The higher level of beta-glucosidase gene expression in the final hours of cold treatment in the Gerde cultivar indicates the involvement of this enzyme in elevating cellular levels of active abscisic acid. Moreover, the significant increase observed in the transcript level of phenylalanine-ammonia-lyase in Gerde indicates the induction of defense responses related to the phenylpropanoid pathway. Altogether, one can conclude that the higher cold tolerance of the Gerde cultivar is multifaceted, involving various factors such as its ability to protect its photosynthetic machinery, its greater capacity for cell protection against oxidative stress, and the expression modulation of genes involved in abscisic acid metabolism and secondary metabolism.

Soil contamination with heavy metals is one of the most important challenges related to the protection of water and soil resources. Heavy metals are metals that have a density of more than 5 grams per cubic centimeter. Among heavy metals, cadmium is of special importance due to its high solubility in water and quick and easy absorption by the plant root system. This element has been introduced as the fourth dangerous element for vascular plants (Kok et al., 2010). By accumulating in the root environment, cadmium can cause a decrease in growth, respiration, damage to the mechanisms involved in photosynthesis, and inhibit the activity of enzymes and the lack of nitrogen and phosphorus in the plant. Borage (Borago officinalis L.) is a valuable annual medicinal herb suitable for cultivation in many countries, including Iran. Borage (Borago officinalis L.) is considered as a native of both Europe and Asia. Several species around the globe fall under the denomination of “borage”. The presence of the highest γ-linolenic acid content in the seeds of borage makes borage distinctively important mainly for the nutraceutical and pharmaceutical research. γ-Linolenic acid is an omega-6 polyunsaturated fatty acid which cannot be synthesized in the body and hence falls into the category of essential fatty acids (Evesh et al., 2019). The present study was carried out with the aim of investigating the physiologic and biochemical responses of the medicinal plant Borage (Borago officinalis L.) to cadmium stress.

This experiment was conducted in the form of a completely random design in the greenhouse of Shahid Bahnar University, Bardsir College of Agriculture, Shahid Bahnar University, Kerman, at an average temperature of 25 degrees Celsius during the day and 20 degrees Celsius during the night, with a relative humidity of 60%. First, concentrations of cadmium (0, 1.25, 2.5, 5, 10, 20, 40, 80, 120, 160 mg kg-1) were prepared using cadmium chloride (Merck company) and the soil was uniformly contaminated with cadmium. The contaminated soil was incubated under constant humidity and temperature conditions for 30 days and then poured into pots with a capacity of 3 kg of soil. Plant seeds were disinfected with alcohol and 5% sodium hypochlorite solution and immediately washed several times with distilled water. Five seeds were planted in the pots containing the studied treatments and at a depth of 2 to 3 cm. Two months after planting, when the plant was in the 50% flowering stage, the growth and performance characteristics of the plant including the number of flowers, number of leaves, branch length, root length, shoot weight, root weight, flower weight were measured. Some biochemical characteristics (catalase, ascorbate peroxidase, guaiacyl peroxidase, protein, proline and photosynthetic pigments) were measured.

The studied treatments significantly (p≤0.01) affected the biochemical, physiologic and performance characteristics of European borage. Increasing the concentration of cadmium had an inhibitory effect on the growth parameters of the plant, and this effect was clearly evident in pollution above 80 mg kg-1. Number of flowers, number of leaves, flower weight, root weight, total weight, root length and branch length decreased significantly with increasing cadmium concentration. The flowering of the plant was 71% at the pollution level of 120 mg per kilogram. At this level of pollution, the root weight was reduced by 69.9%. The weight of aerial parts decreased by 59.7% at the pollution level of 160 mg kg-1. The activity of ascorbate peroxidase enzyme increased up to 20 mg kg-1 treatment and after that the activity of ascorbate peroxidase enzyme decreased with the increase of cadmium concentration. Proline concentration increased with increasing cadmium contamination. Photosynthetic pigments also decreased in high concentrations of cadmium. The cause of the adverse effects of cadmium on plants in contaminated soils can be attributed to more absorption of cadmium by the plant and growth disturbance caused by cadmium toxicity in the plant, reduction of growth rate, reduction of water absorption and absorption of other ions affecting the activities plant growth (Veselov et al., 2003), the reduction of cytokinin hormone activity, which has a significant effect on cell proliferation and growth, or the negative effect of cadmium on energy production in mitochondria was attributed (Fotohi et al., 2011). Cadmium causes disturbances in the overall metabolism of cells. (Xie et al., 2021) Cadmium toxicity in plants can lead to negative effects on the photosynthesis process. This action takes place through damage to some photosynthetic enzymes, especially those involved in the Kelvin cycle and chlorophyll biosynthesis (Mishra et al., 2006).

The results showed that the yield of European borage was not affected by cadmium up to a concentration of 1.25 mg kg-1. The activity of antioxidant enzymes increased up to the treatment of 20 mg kg-1 and then decreased with increasing cadmium concentration, which indicates oxidative stress. Photosynthetic pigments and chlorophyll fluorescence index decreased with increasing cadmium concentration. Considering the tolerance and resistance of some medicinal plants to the conditions in soils contaminated with heavy metals, it is possible to use the cultivation of some medicinal plants as a solution for the management and exploitation of lands that have medium contamination with heavy metals. Considering the number of flowers, flower durability and high yield, the European borage plant can be a suitable candidate for cultivation in polluted areas, of course, additional studies with the approach of reducing the adverse effects of stress and reducing the concentration of cadmium element in the soil are needed.

The present research was conducted to evaluate the response of different almond cultivars to drought stress. The experiment was carried out as split plot arrangement is in randomized complete block design with three replications in the Agricultural and Natural Resources Research Center of Chaharmahal and Bakhtiari, ShahreKord, Iran, in 2020 and 2021. Different irrigation periods based on the available soil moisture; 70%, 50%, 30% and 10% of field capacity were assigned to the main plots and 13 commercial almond cultivars; Mamaei, Rabie, Saba, Araz, Eskandar, Aidin, Shahrood 6, 7, 8, 10, 12, 13, 21 and GN clonal rootstock, were randomized in the subplots. All commercial almond cultivars were grafted on GN clonal rootstock. The plants were under water stress for four months and antioxidant enzymes activity was measured at the middle (two months after application of stress) and the end (four months after application of stress) of drought stress period. The results showed that drought stress significantly decreased fresh and dry weight of the above-ground parts of all cultivars. The lowest effect of drought stress was recorded in cv. Shahrood 8 and GN clonal rootstock. Malondialdehyde content and electrolyte leakage in all almond cultivars significantly increased with increasing drought intensity. In both the middle and end of drought stress period, cv. Shahrood 8, cv. Shahrood 12 and GN clonal rootstock showed the highest chlorophyll index and the lowest malondialdehyde content and electrolyte leakage under severe drought stress (10% FC). Under severe drought stress, the highest antioxidant capacity of enzymes was recorded in cv. Shahrood 12, cv. Shahrood 8 and GN clonal rootstock. Considering the results of this research, under different levels of drought stress, cv. Shahrood 8, cv. Shahrood 12 and GN clonal rootstock had the highest above-ground fresh and dry weight, chlorophyll index and antioxidant enzymes activity, and the lowest peroxidation level that showed the high level of tolerance to water deficit stress.

Lentil (Lens culinaris Medik.) is one of the main food legume crops in Iran, where it is grown as a rainfed crop in spring in cold regions. One of the obstacles of spring cultivation in cold regions is drought stress exposure at the end of the growing season in the late cultivation date, which dramatically increases null pods and decreases seed yield. Until introducing autumn cultivation, specific, and cold-tolerant lentil varieties, the only solution for this problem is to find ways to deal with the damage of drought stress. Nanotechnology serves as a precursor of the new industrial revolution that has the potential to bring alteration in agricultural production. Nanoparticles (NPs) have been applied for enhancing seed germination, growth, physiology, productivity, and quality traits of various crops under normal or stressful conditions. Therefore, to reduce the negative effect of drought stress at dryland conditions in late cultivations, the effect of ZnSO4 and Fe2O3 NPs at 0.5% and 1% were studied on the agronomic, physiologic, root traits, and antioxidant system of lentils in the cold region.

A field study was carried out at the Dryland Agricultural Research Center (DARI) in Maragheh during the 2019-2020 growing season. Experiments were conducted in rainfed conditions using a complete block design with three replications. Treatments were no spray, 0.5% nano ZnSO4, 1% nano ZnSO4, 0.5% ZnSO4, 1% ZnSO4, 0.5% nano Fe2O3, 1% nano Fe2O3, 0.5% Fe2O3, and 1% Fe2O3. Treatments were applied at two stages (10 days after the plant first establishment and 50% of flowering) in the early morning and not on windy days. The Bilesavar variety, which is suitable for spring cultivation in cold regions, was used in this experiment. Plant height, relative water content (RWC), cell membrane stability (CMS), canopy temperature, and the normalized difference in the vegetative index (NDVI) were recorded during the growing season. The seed yield and 100 seed weight (HSW) were calculated after harvesting. The activity of ascorbate peroxidase (ASP), catalase (CAT), glutathione peroxidase (GPX), superoxide dismutase (SOD), peroxidase (POX), and the contents of proline, chlorophyll a, chlorophyll b, and carotenoids were calculated in gathered leaf samples during the growing season.

Differences between treatments were significant for RWC, CMS, canopy temperature, NDVI, and seed yield at 1%, and for HSW at 0.5%. The highest seed weight was observed in using nano Fe2O3 0.5%, and the lowest belonged to no spray treatment. The lowest RWC, CMS, and the highest canopy temperature were recorded in no spray treatment. Analysis of variance results showed that differences between treatments for all biochemical traits were significant at the 1% level. Chlorophylls a and b contents increased using NPs, and the highest level belonged to 1% nano ZnSO4 treatment and as expected the lowest calculated in no spray treatments. The highest carotenoids, and the activities CAT, ASP, GPX, and SOD were observed in 1% nano ZnSO4 treatment. The lowest activity of these enzymes as well as the highest H2O2, proline, and malondialdehyde (MDA) belonged to no spray treatment. According to the results, seed yield was significantly correlated with CAT (0.81), GPX (0.88), SOD (0.80), H2O2 (-0.82), MDA (-0.90), proline (-0.89), chlorophyll a (0.83), chlorophyll b (0.64), carotenoids (0.74), HSW, (0.50), NDVI (0.86), canopy temperature (-0.76), RWC (0.84), and CMS (0.95) at the 1% level. The highest root length was respectively measured in 1% nano ZnSO4, 0.5% nano ZnSO4, 0.5% nano Fe2O3, and 1% nano Fe2O3. NPs had no effect on average diameter while applying 1% Fe2O3 led to the highest effect on the root volume. Root surface showed the highest increase by using 1% nano Fe2O3, 0.5% nano ZnSO4, and 0.5% nano ZnSO4. The highest root length belonged to 1% nano ZnSO4 and 0.5% nano ZnSO4 while this trait was lowermost in no spray treatment.

According to the results, 1% Fe2O3 exerted the highest effect on agronomic and physiological traits while 0.5% ZnSO4 was effective on the antioxidant system, and ZnSO4 NPs positively affected the root length and average diameter. While Fe2O3 NPs were effective in improving the root surface area and volume.

In agricultural systems, several environmental stresses can remarkably alter the growth, physiological, and biochemical responses of plants under stress. One of these factors is the biochemical reactions between plants along with the production of secondary compounds. Allelochemicals mainly have defence and cell wall ligninization roles in plants and do not directly play a role in the growth processes of plants. Thus, an experiment was carried out to evaluate the effect of allelopathic stress of Hypericum perforatum on the germination, physiological, biochemical, and antioxidant activity characteristics of green pea, the benchmark plant sensitive to allelochemicals.

The treatments included different concentrations of H. perforatum at 11 levels (i.e., 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100% of the aqueous extract). This research was carried out as a completely randomized design with three replications at the weed science laboratory of Gonbad Kavous University in 2023.

The results of this study showed that one of the factors influencing the physiological, and biochemical characteristics of green pea is the concentration of the H. perforatum extract. In most cases, the percentage and rate of green pea germination, radicle and plumule length, and dry weight of radicle and plumule decreased with increased concentration of aqueous extract compared to the control, so that the greatest reduction in these characteristics was observed in 100% of H. perforatum extract. In contrast, the content of compatible osmolytes such as proline and soluble sugars, phenolic and flavonoid compounds, and antioxidant activity of green pea roots and plumules increased significantly in all studied treatments, with the highest increase in these characteristics observed at the concentration of 100% of H. perforatum aqueous extract. In general, the decrease in the dry weight of green pea seedlings due to the increase in the concentration of the aqueous extract of H. perforatum, despite the relative increase in the content of physiological and biochemical traits, indicates the high intensity of allelopathic stress of H. perforatum extract and their insufficiency, which leads to cytotoxicity against oxidative stress.

Considering the heterotoxicity effect of H. perforatum on green pea sensitive to allelochemicals and its distribution in gardens, barren lands, and wheat and corn fields, the possible effect of their residues in the next planting and even in case of presence in mixed cultivation should be considered.

Antioxidants are diverse groups of biological compounds, including phenolic compounds, flavonoids, alkaloids, and terpenoids, which act as free radical scavenging. Fruits are the natural antioxidant resources that constitute principal dietary components. Therefore, identifying the type and amount of antioxidant compounds in different fruits and the factors affecting them is crucial to achieving a diet rich in antioxidants. The quality and quantity of antioxidant compounds in fruits are influenced by various factors such as climate, species and cultivars, fruit developmental stage, processing methods, and storage conditions. In horticulture, fruits are divided into three categories based on climatic origin, including temperate fruits (rich in anthocyanins and phenolic acids) such as apples, grapes, and berries, subtropical fruits (rich in flavonoids and phenolic acids) such as pomegranate and olives, and tropical fruits (rich in flavonoids and carotenoids) such as bananas and mangoes. Also, there is a significant variation in the quantity and quality of antioxidant compounds in a specimen of fruits, which can be the basis for selecting parents by breeders to achieve antioxidant-rich cultivars. The amount of phenolic compounds in fruits is related to the degree of fruit maturity or ripening, and usually, with increasing age, the amount of phenolic compounds increases. From a processing point of view, recently, the use of wine and olive industry waste products has been considered as a potential source of dietary or food preserving antioxidants. In this review, various antioxidant compounds in different fruits have been considered, and the factors affecting their quality and quantity are discussed.

Reactive oxygen species (ROS) produced in organelles such as mitochondria, chloroplast, and peroxisome play an important role in plant signaling and signal transduction pathways. ROSs basically are able to regulate oxidation-reduction (known as redux) reactions, plant growth and defense responses to environmental stimuli. Therefore, they affect every aspect at all life cycle stages of plants. ROSs such as hydrogen peroxide, superoxide, hydroxyl radicals, and singlet oxygen act as secondary messengers in plant cells to regulate a diverse range of protein functions (with post-translational modifications) and gene expression. They are produced naturally during the plant responses to environmental conditions and intra-/inter-cellular communications. Recent researches are indicating that ROS compounds play a key role in the plants response under both biotic and abiotic stresses. Biotic stresses such as fungi, viruses, mites, insects and other organisms, along with abiotic stresses such as drought, salinity and heavy metals, increase the production of ROS in plant cells. Plants possess various mechanisms to deal with the destructive effects of ROS increased production. ROS removal in plants is usually performed by two main groups of enzymatic and non-enzymatic antioxidant molecules. Antioxidant molecules play important roles in plant tolerance under stressful conditions by neutralizing ROS and converting them into water molecules. However, under severe stress conditions, plants are not able to eliminate the entire content of extra produced ROS molecules; as a result, the high amount of ROS causes oxidative stress in plants leading to various damages to the main components of the cells, such as proteins, lipids, DNA, carbohydrates, and ultimately cell death. There are still many unanswered questions regarding the plant specific responses to oxidative stress and regulation of cell communication during stress conditions. This review article tries to introduce the origin, location, and pathways of ROS production along with their types and effects on the cellular signal transduction system in stimulating adaptive responses of plants under stress conditions. Moreover, this review discusses the effectiveness of antioxidants systems in maintaining cell homeostasis and neutralizing the negative impacts of oxygen free radicals in plants.

Introduction : 

 Oxidative stress is an imbalance between oxidants and antioxidants at the cellular level which leads to the condition of infertility in male. Oxidation of cell macromolecules, cell death by necrosis, apoptosis and damage of tissue structure are the results of another oxidative stress damage. This process eventually leads to a variety of diseases, reduced growth performance and even death (Min et al. 2018). Poultry face a variety of environmental, technological, nutritional, and biological stresses that reduce their productivity and reproductive performance. Most of these stresses at the molecular level are associated with oxidative stress and damage to biologically important molecules (Surai et al. 2019). Qualitative characteristics of sperm, blood testosterone level, and plasma lipid peroxidation are affected by severe oxidative stress (Khan, 2011). Vitamin E is an important known antioxidant and protect cell membrane of sperm cell from damage of reactive oxygen species in male reproductive system of animal. Feeding of this vitamin has beneficial effect on testes weight, semen quality indexes, testosterone and antioxidant enzymes such as glutathione peroxidase and superoxide dismutase in birds and mammals. The objective of this experiment was to investigate the effect of diet vitamin E supplementation on fresh sperm quality in broiler breeder roosters challenged with oxidative-stress.

Eighteen Ross 308 male broiler breeder at 28 weeks of age were randomly assigned into 3 experimental groups including control group, dexamethasone group (subcutaneous injection of 4 mg dexamethasone per kg body weight) and dexamethasone group receiving supplemented diet with of vitamin E (200 mg per kg of feed). Each experimental group consisted of 6 birds. Sperm samples were taken from roosters using abdominal massage method and analyzed for quality characteristics and antioxidant status. Sperm concentration was determined by counting spermatpzoa using hemocytometer. The pooled sperm sample was diluted by using poultry semen extender and then 10 µl of diluted sperm mixed with 10 ml of 3% NaCl. The chambers of hemacytometer filled with 10 µl sperm suspension and allowed to settle for 3 mines.  Numbers of sperm cell in 5 of the large squares of chamber were assessed. Computer assisted semen analyses (CASA) were performed to determine sperm motility, with settings adjusted to detecting domestic fowl according to a previously described method (Froman and Feltmann, 2000). Total, progressive and non-progressive motility (%), as well as immotile sperms were measured. Also, sperm kinematic values including straight line velocity (VSL (µm/s)), curvilinear velocity (VCL (µm/s), average path velocity (VAP (µm/s), amplitude of lateral head displacement (ALH (µm), and beat-cross frequency (BCF (Hz) were measured. Progression ratios were also calculated using the mentioned velocity measurements: straightness (STR = VSL/VAP) and linearity (LIN = VSL/VCL).

The results indicate that dexamethasone-induced oxidant stress caused an increase in MDA levels (5.4) and a decrease in the activity of antioxidant enzymes such as glutathione peroxidase (52.51) and superoxide dismutase (108.62), as well as sperm motility parameters and sperm cell membrane integrity in comparison to the control group. However, when vitamin E was added to the roosters' diet, it improved the negative effects of oxidative stress on sperm motility parameters, antioxidant status (Total antioxidant capacity (1.65), superoxide dismutase (155.10) and glutathione peroxidase (87.77) enzymes), sperm viability (88.05), and sperm cell membrane integrity (89.72) (P<0.05). These findings suggest that dexamethasone injection caused a sharp decline in sperm quality by reducing sperm motility, antioxidant enzyme activity, and plasma membrane integrity, while vitamin E supplementation improved sperm quality by enhancing the antioxidant status and protecting the sperm cell membrane from the damage caused by reactive oxygen species in broiler breeders. Avian sperm are highly susceptible to lipid peroxidation due to their high content of long-chain polyunsaturated fatty acids. Lipid peroxidation produces reactive species that damage sperm membrane function and motility, ultimately reducing the fertility potential of aged roosters. Therefore, the antioxidant defense plays a critical role in maintaining semen quality (Surai et al., 2006).

It can be concluded that the inclusion of vitamin E in diet remarkably improved the sperm motility characteristics and antioxidant status of sperm in broiler breeder roosters challenged with oxidative stress. On bases of this finding it’s recommended to use of vitamin E in the rooster diet to elucidate negative effect of oxidative stress.

Rams usually experience summer heat stress. In addition, rams due to high sexual activity during joining season experience doubled stress. Following the stress, the production of free radicals increases and oxidative stress related damages occur. High levels of free radicals cause sperm viability reduction, infertility and alter post-absorptive carbohydrate metabolism and glucose tolerance. There are various strategies to reduce the harmful effects of oxidative stress. The supplementation of antioxidants and some trace elements are important nutritional strategies have been recommended to combat harmful effects of oxidative stress. Therefore, the aim of this study was to investigate the synergistic effect of organic chromium or selenium on post-absorptive glucose metabolism and blood plasma antioxidant status in Mehraban rams.

Sixteen Mehraban rams (2-4 years old, with a body score of 2.5-3.5 and 70.14 kg in initial body weight) were randomly divided in to four groups (n=4). Treatments included two levels of Se 0 and 0.6 mg/ram/day (in form of yeast selenium) and, two levels of Cr, 0 and 1 mg/ram/day (in form of Cr-Methionine). The experiment lasted for 60 days. The supplements were fed daily and with the morning meal and total antioxidant capacity and malondyaldehyde levels were determined at days 30 and 60 of experiment. At the end of the experiment an intravenous glucose tolerance test was performed. To do this, 0.5 g of glucose/kg BW as sterile 50 % dextrose solution (w/v) was infused by jugular vein and subsequently blood glucose concentrations were determined at 5, 10, 15, 20, 25, 30, 45, 60, 90, 120, 150, and 180 min post-infusion. Then plasma glucose kinetics was calculated.

Time effect and treatment×time interaction did not impact malondialdehyde level and total antioxidant capacity. Interaction of chromium × selenium did impact total antioxidant capacity (P < 0.05) but, did not affect malondialdehyde level. Total antioxidant capacity was higher and malondialdehyde level was lower in chromium and selenium groups compared to control. Glucose basal and peak concentrations and amount of change (peak-basal concentrations) after glucose tolerance test did not differ among groups. Glucose concentrations were lower in chromium and selenium co-supplemented compared to chromium or selenium supplemented group at 15, 150 and 180 min glucose post-infusion and a significant chromium × selenium interaction was found (P < 0.05). Interaction of chromium × selenium did not impact glucose concentration at 20, 25 and 120 min post-infusion but glucose concentration at the mentioned time points in 1 mg level showed tendency to decrease compared to 0 levels. Plasma glucose clearance rate at 5 to 15 min post-infusion was higher and half-life was lower in chromium and selenium co-supplemented compared to selenium-supplemented group (P < 0.05). Main effect of chromium at the mentioned time interval was significant and 1 mg Cr/day had higher glucose clearance rate and lower half life (P < 0.05). Area under the curve at 5 to 15 min post-infusion did not differ between groups. Regardless of whether area under the curve was calculated from 0 to 30 min or 0 to 45 min, area under the curve was lower for chromium co-supplemented group compared to Se-supplemented group (P < 0.05).

Results of this study showed that organic chromium and selenium supplements alone or their combination improve the antioxidant status of rams in summer but, only the use of chromium alone or combined with selenium improves the post-absorption glucose metabolism characteristics. Also, the combined use of those two elements does not have a synergistic effect on post-absorptive glucose metabolism and blood plasma antioxidant status in Mehraban rams.