Impacts of feeding zinc-methionine or chromium-methionine on performance, antioxidant status and physiological responses to transportation stress on lambs

Context Road transportation of farm animals is an unavoidable activity in animal husbandry, which may lead to the stress. Metabolic modifiers, such as minerals, may be an effective strategy to improve the performance and immune system of animals. Aims The present study examined the effects of chromium-methionine (Cr-Met) and zinc-methionine (Zn-Met) supplementation on animal performance and response to transportation stress. Methods Eighteen lambs (18–20 weeks of age) were randomly assigned to the following three dietary treatments for 10 weeks: (1) basal diet (control, 0.021 g/kg Zn and 0.0001 g/kg Cr); (2) basal diet with addition of 10 Cr-Met mg/kg DM (containing 1 mg/kg Cr); and (3) basal diet with addition of 500 Zn-Met mg/kg DM (containing 50 mg/kg Zn). After a 6-week supplementation period, the lambs were transported by road for 3 h. Key results Mineral supplements did not affect final bodyweight, average daily gain or feed conversion ratio. The blood cortisol and aspartate aminotransferase concentrations were increased (P < 0.05) immediately after transportation (AT1) in all groups; however, they were lower in supplemented lambs than in the control (P < 0.05). Animals fed Cr-Met or Zn-Met diets had a higher albumin concentration at AT1 than did the control group (P < 0.05). Lambs on the Zn-Met diet showed a higher blood triiodothyronine and triiodothyronine to thyroxin ratio at AT1 and at 24 h after transportation (AT2) than did lambs receiving the control diet (P < 0.05). Lambs fed the Cr-Met diet had a lower blood malondialdehyde at AT1 and AT2 than did the control lambs (P < 0.05). Total antioxidant capacity (TAC) was higher in the Zn-Met-supplemented group than in other groups (P < 0.05). Supplementation with dietary Zn-Met increased serum TAC concentration in the kidney tissue compared with the control (P < 0.05), but had no effect on superoxide dismutase and glutathione peroxidase activities. The Cr-Met group showed also a lower malondialdehyde concentration (P < 0.05) and higher TAC, superoxide dismutase and glutathione peroxidase activities in the liver tissue (P < 0.05). Conclusions Dietary supplementation with 10 mg Cr-Met/kg (1 mg Cr) in comparison to 500 mg Zn-Met/kg (50 mg Zn) improved the stress response of lambs subjected to a short-time road transportation, whereas growth performance was not affected. Implications The administration of Cr-Met or Zn-Met to diet of lambs before transportation could reduce the adverse effects of road transportation stress.

Influence of dietary glutamine supplementation on performance, biochemical indices and enzyme activities in broilers with cold-induced ascites

This study was conducted to investigate the effects of dietary glutamine supplementation on performance and biochemical indices of broilers with cold-induced ascites. A total of 240 1-day-old male broiler chicks (Ross 308) were randomly allotted to three treatment groups, with four replicate pens per treatment and 20 birds per pen. The control birds were kept in a thermoneutral chamber and fed a basal diet, whereas the other two experimental groups were kept in a cold chamber to induce ascites and fed the basal diet supplemented with either 0 or 100 mg of glutamine/kg. The cold-treated birds consumed less (P < 0.05) feed and had lower (P < 0.05) weight gain compared with the control birds. Dietary glutamine supplementation had no effect (P > 0.05) on broiler performance. The cold-treated birds had higher (P < 0.05) right ventricle to total ventricle ratio and mortality due to ascites compared with the control birds. However, mortality due to ascites and right ventricle to total ventricle ratio was reduced (P < 0.05) by dietary glutamine supplementation. The cold-treated birds had higher (P < 0.05) red blood cell counts, haematocrit percentage and haemoglobin concentration compared with the control birds at 21 and 42 days of age. The activities of plasma lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase were increased (P < 0.05) in cold-treated birds compared with the control birds at 42 days of age, but dietary glutamine supplementation reduced (P < 0.05) the activities of alanine aminotransferase and aspartate aminotransferase near to the control levels. The plasma and liver glutathione peroxidase activities were increased (P < 0.05) in cold-treated birds compared with the control birds at 21 and 42 days of age, whereas the reverse was true for malondialdehyde concentrations. The glutathione peroxidase activity was increased (P < 0.05), whereas the malondialdehyde concentration was decreased (P < 0.05) by dietary glutamine supplementation compared with the cold-treated birds at 42 days of age. The results indicated that the beneficial effect of glutamine is probably related to its ability to maintain near to normal free radical scavenging enzymes and the level of glutathione peroxidase bioactivity, thereby protecting cell membranes from oxidative damage via decreased lipid peroxidation.

Effects of Dietary Selenium and Vitamin E on Growth Performance, Meat Yield, and Selenium Content and Lipid Oxidation of Breast Meat of Broilers Reared Under Heat Stress

This study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E (0, 125, and 250 mg/kg), selenium (0, 0.5, and 1 mg/kg), or their different combinations on performance, meat yield, and selenium content and lipid oxidation of breast meat of broilers raised under either a thermoneutral (TN, 24 °C constant) or heat stress (HS, 24 to 37 °C cycling) condition. There was a reduction (P < 0.05) in body weight and feed intake and an increase (P < 0.05) in feed conversion ratio when broilers exposed to HS. In the overall period of the study (1 to 49 days), growth performance of TN broilers was not affected (P < 0.05) by vitamin E and selenium supplementation. However, under HS condition, broilers receiving 250 mg/kg vitamin E and 0.5 mg/kg selenium consumed more (P < 0.05) feed than that of broilers receiving 250 mg/kg vitamin E alone, but similar (P > 0.05) to that of broilers receiving 250 mg/kg vitamin E and 1 mg/kg selenium. The malondialdehyde (MDA) content of the breast meat was increased (P < 0.05), but its selenium content was decreased (P < 0.05) by exposure to HS. The breast meat selenium content was increased (P < 0.05) by selenium supplementation. The breast meat selenium content was decreased (P < 0.05) by supplementation of 250 mg/kg vitamin E to diet of TN birds. However, the breast meat selenium content was increased (P < 0.05) by supplementation of vitamin E under HS condition. The breast meat MDA content was not affected (P > 0.05) by dietary treatments under TN condition. However, the breast meat MDA content was decreased (P < 0.05) by both vitamin E and selenium supplementation under HS condition, and the lowest MDA content was observed in the breast meat of broilers receiving combination of 125 mg/kg vitamin E and 1 mg/kg selenium. The results showed that supplementation of selenium and vitamin E was capable of increasing the selenium content of the breast meat and could improve the lipid oxidation of the breast meat when broilers reared under HS condition.

Selenium as a feed supplement for heat-stressed poultry: a review

Heat stress is associated with compromised performance and productivity in poultry due to declines in feed intake, nutrient utilization, growth rate, egg production and quality, and feed efficiency. Emerging evidences have shown that acute heat exposure results in increased production of free radicals and causes oxidative damage to lipids, proteins, and DNA. Additionally, heat stress can influence immune response by changing the expression of cytokines and by making the immune cells more susceptible to oxidative stress. Selenium, as a part of specific selenoproteins, can help to maintain antioxidant defenses, thereby preventing damages to tissues. An optimum response with supplementation of selenium in diet has been found to improve feed intake, body weight gain, feed efficiency, egg production and quality, and antioxidant status in heat-stressed poultry. Selenium compounds are also known to improve immune responses by altering the production of certain cytokines secreted by cells of the immune system and by enhancing the resistance of the immune cells to oxidative stress. It was reported that selenium supplementation had inhibitory effects on tumor necrosis factor alpha levels in heat-stressed broiler chicks, but the details are not completely elucidated. In the present review, the effect of selenium on production performance, nutrient utilization, antioxidative status, and immune responses of heat-stressed poultry is summarized.

Effects of dietary selenium and vitamin E on immune response and biological blood parameters of broilers reared under thermoneutral or heat stress conditions

A study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E (0, 125 and 250 mg/kg), selenium (Se, 0, 0.5 and 1 mg/kg), or their different combinations on immune response and blood biological parameters of broilers raised under either thermoneutral (TN, 23.9 °C constant) or heat stress (HS, 23.9 to 37 °C cycling) conditions. Humoral immunity was assessed by intravenous injection of 7% sheep red blood cell (SRBC) followed by evaluation of serum for antibody titers in primary and secondary responses. Heterophil to lymphocyte (H/L) ratio also determined as an indicator of stress. Furthermore, at the end of the experiment, birds were bled for determination of some biological parameters. There was a significant reduction in body weight and feed intake, but the feed conversion ratio increased when the birds were exposed to HS (P<0.05). Body weight and feed intake were not influenced significantly by dietary vitamin E and Se (P>0.05), whereas feed conversion was improved significantly by 125 mg/kg vitamin E (P<0.05). The liver and lymphoid organ weights as well as IgM and IgG, antibody titers for primary and secondary antibody responses to SRBC were reduced significantly under HS (P<0.05). Heat stress also resulted in a significant increase in H/L ratio (P<0.05). Dietary vitamin E resulted in improvement of primary and secondary antibody responses both in TN and HS broilers (P<0.05). The HS birds also showed an improved antibody titer in secondary response with high concentration of Se (P<0.05). Vitamin E and Se had interactive effects on anti-SRBC titers; however, no consistent differences were found between dietary levels during the study. The H/L ratio decreased by feeding vitamin E at both levels either under HS or TN conditions (P < 0.05). The serum concentrations of glucose, triglycerides, total cholesterol, and LDL-cholesterol were increased but serum HDL-cholesterol decreased in HS broilers (P<0.05).

Lack of effect of dietary chromium supplementation on growth performance and serum insulin, glucose, and lipoprotein levels in broilers reared under heat stress condition

This study evaluated the effects of supplemental dietary chromium (Cr) on the performance, carcass traits, and some serum parameters of broilers under a heat stress (23.9 to 37 °C cycling) condition. A total of 150 1-day-old broiler chicks (Cobb 500) according to a completely randomized design were assigned into five treatment groups. Each treatment consisted of three replicates and each replicate contained ten chicks. Treatments were supplemented with 0 (control), 600, and 1,200 μg kg(-1) Cr in the form of Cr chloride (CrCl3) and Cr L-methionine from 1 to 49 days of age. Blood samples were collected from two birds in each replicate to determine serum parameters at 35 and 49 days of age. The body mass, feed intake, and conversion ratio were not influenced by dietary Cr (P > 0.05). Dietary supplementation of Cr from either CrCl3 or Cr L-methionine caused increased serum concentrations of Cr (P < 0.05), but had no effect on serum insulin and glucose concentrations at both sampling times (P > 0.05). Serum triglycerides, very low-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were also not significantly affected (P > 0.05) by dietary treatments, whereas total cholesterol concentration decreased in chicks fed Cr L-methionine compared to the control (P < 0.05).

Effects of dietary selenium, vitamin E, and their combination on growth, serum metabolites, and antioxidant defense system in skeletal muscle of broilers under heat stress

This experiment was conducted to evaluate the effects of dietary vitamin E, selenium (Se), and a combination of the two, on the performance, serum metabolites and oxidative stability of skeletal muscle of broilers during heat stress. The broilers raised in either a thermoneutral (23.9°C constant) or heat stress (23.9°C to 37°C cycling) environment were assigned to 6 dietary treatments (0, 0.5, or 1 mg/kg Se; 125 and 250 mg/kg vitamin E; or 0.5 mg/kg Se plus 125 mg/kg vitamin E) from 1 to 49 days of age. At the end of the experiment, blood samples were collected from chicks, the chicks sacrificed, and pectoralis superficialis muscle was used for measurement of malondialdehyde (MDA) concentration and enzyme activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD). The heat-stressed chicks consumed less feed, gained less weight, and had higher feed conversion ratio when compared to thermoneutral chicks (P<0.05). Serum concentrations of iron (Fe) and zinc (Zn) were decreased by heat stress (P<0.05), whereas the serum concentrations of copper (Cu), glucose, and uric acid were significantly increased under heat stress (P<0.05). The chicks that received supplemental of vitamin E exhibited significantly higher serum concentrations of Zn (P<0.05) and significantly lower concentrations of Cu, glucose, and uric acid (P<0.05) when exposed to heat stress. Dietary Se also caused a significant decrease in serum glucose, uric acid, and Cu concentrations of heat-stressed broilers (P<0.05), but had no significant effect on Zn concentration (P>0.05). The GPx activity remained relatively constant (P>0.05), though SOD activity and MDA levels in skeletal muscle were enhanced on exposure to heat stress (P<0.05). The heat-stressed chicks that received the combined supplementary level of vitamin E and Se had the lowest concentration of MDA and the highest activity of SOD in the skeletal muscle (P<0.05). Dietary Se also caused a significant increase in enzyme activity of GPx in the skeletal muscle (P<0.05). These results indicate that the derangement of blood parameters and oxidative stability in broilers under heat stress are improved by supplemental vitamin E and Se.

Effects of different levels of organic and inorganic chromium on growth performance and immunocompetence of broilers under heat stress

This experiment was carried out to investigate the effects of different levels of organic and inorganic chromium on the performance, immune function and some serum mineral concentrations of broilers under heat stress condition (23.9-37°C cycling). A total of 150 one-day-old broiler chicks according to a completely randomized design were assigned into five treatment groups. Each treatment consisted of three replicates and each replicate contained ten chicks. Chicks were fed on corn-soybean meal basal diets with added different concentrations of chromium (0, 600 and 1,200 μg kg(-1) chromium chloride or 600 and 1,200 μg/kg chromium L-methionine) from 1 to 49 days of age. Humoral immunity was assessed by intravenous injection of 7% sheep red blood cell (SRBC) followed by evaluation of serum for antibody titers in primary and secondary responses. Cell-mediated immunity was assessed by the cutaneous basophil hypersensitivity (CBH) test to phytohemagglutinin (PHA)-P at day 32 and PHA-M at day 48. Heterophil/lymphocyte (H/L) ratio was also measured as a reliable indicator of stress. The body mass, feed intake and conversion ratio were not influenced by dietary chromium (P > 0.05). Dietary supplementation of both organic and inorganic chromium significantly increased primary and secondary antibody responses (P < 0.01), and also improved H/L ratio (P < 0.05), CBH response (P < 0.01) as well as relative weights of thymus (P < 0.05) and spleen (P < 0.01). Both dietary organic and inorganic chromium caused an increase in serum concentrations of Cr and Zn (P < 0.01), but decreased the serum concentration of Cu (P < 0.01). These results suggest that supplemental chromium especially in organic form offers a good management practice to reduce heat stress-related depression in immunocompetence of broiler chicks.

Effect of prepartum supplementation of selenium and vitamin E on serum Se, IgG concentrations and colostrum of heifers and on hematology, passive immunity and Se status of their offspring

Forty heifers at the late stage of gestation were randomly assigned into five groups. Heifers were balanced for age, weight, and time of calving in each group. Four and 2 weeks before expected time of calving, the heifers were injected with 0 ml (C), 10 ml (T1), 20 ml (T2), 30 ml (T3), and 40 ml (T4) Se and VE supplements, respectively. Each milliliter of the supplement contained of 0.5 mg Se as sodium selenite and 50 IU of dl-alpha-tocopheryl acetate. Blood samples were collected from the heifers 4 weeks before expected calving and at calving day and from the calves at birth and 7 days of age. The serum Se and immunoglobulin G (IgG) concentrations, white blood cell and differential leukocyte counts were measured. The Se concentrations in the sera of the heifers before the injections of Se and VE supplements were the same among the groups (P > 0.05), but after calving were significantly increased in the treated heifers (P < 0.05). Similarly, the serum Se levels of calves of the treated heifers were higher (P < 0.05). The Se concentrations in the colostrums of the heifers were affected by treatments (P < 0.05). Colostrum and daily milk productions at 8-week lactation were increased in treated heifers compared with the controls (P < 0.05). Likewise, the milk somatic cell counts decreased in the treated heifers compared with the controls. The changes of the mean serum IgG levels did not differ among calves (P > 0.05). The white blood cell counts were higher in calves of heifers in groups T3 and T4 compared with the control group at 7 days of age (P < 0.05).

The effect of different levels of organic and inorganic chromium supplementation on production performance, carcass traits and some blood parameters of broiler chicken under heat stress condition

A total of 250 broilers in a completely randomized design selected to evaluate the effect of different levels of chromium (Cr) supplementation on performance, carcass traits and some blood parameters of heat-stressed broiler chicks. All birds were kept under heat stress temperature (33 ± 3°C) and divided into five treatments groups. Each treatment consisted of five pens with 10 birds in each pen. The basal diets were supplemented with 0 ppb (control), 800 ppb Cr-L-Met (T(1)), 1,200 ppb Cr-L-Met (T(2)) or 800 ppb CrCl(3) (T(3)), and 1,200 ppb CrCl(3) (T(4)). The feed intake and body mass were measured at 10, 21, and 42 days of age. Blood samples were collected from two birds in each replicates to determine biological and hematological values at 28 and 42 days of age. There were no significant difference in mass gain and feed conversion of broilers that received Cr supplementations compared with controls. The serum glucose concentration decreased in broilers received organic chromium methionine supplements compared with other treatments groups. Slight but not significant increases were observed in serum high-density lipoprotein (HDL) concentration of treated groups than controls while the mean serum HDL concentration was significantly higher in T(2) group compared with control group. Serum low-density lipoprotein level decreased in broiler received organic Cr supplements (p < 0.05).

Effect of selenium and vitamin E supplementation during the late pregnancy on reproductive indices and milk production in heifers

A trial was performed to determine the effects of supplementation of selenium (Se) and vitamin E (VE) on reproductive indices and milk production in Holstein heifers. Sixty heifers at the late stage of gestation were randomly assigned into three groups. Heifers were balanced for age, weight and time of calving. Four and 2 weeks before expected calving the heifers were injected 0 ml (C), 20 ml (T1), and 40 ml (T2) Se and VE supplements. Each ml contained 0.5mg Se and 50 IU of D, L-alpha-tocopheryl acetate. Blood samples were collected from heifers 4 weeks before expected calving and at calving day. Se concentrations in serum and colostrums were measured. The reproductive parameters were recorded. The effects of Se and VE supplements on somatic cell count (SCC) and milk yield also were measured. Supplementation of Se increased the level of Se in serum of treated heifers at calving day (P<0.05). Se concentration of colostrums were affected by the treatments (P<0.05). Concerning reproductive performance of treated heifers; gestation length was similar among groups but in comparison with controls, T1 and T2 had no incidence of retained fetal membrane (i.e., beyond 12h.). In addition, open days were fewer in T1 and T2 heifers and the number of services per conception was fewer in T2 compared with controls (P>0.05). Daily milk production at 8 weeks lactation was significantly increased in T2 compared with controls (P<0.05). Likewise, the milk SCC decreased in treated heifers compared with controls (P<0.05).

Effect of molybdenum and sulphur on copper status and mohair quality in Merghoze goat

This study was made on the effects of a normal diet containing 12.8 mg Cu kg(-1) DM which added gradually molybdenum and sulphur on the copper status and fibre quality in eight 1-year Merghoze goat. One group (n = 4 mean weight 31 +/- 2.0 kg) was treated with Mo and S supplements for 20 weeks, the second group (n = 4 mean weight 32 +/- 2.1 kg) served as controls. In addition of blood sampling for measuring copper status in plasma, the copper content and quality of fleeces were measured every 6 weeks. Mohair measurements were carried out by taking patch samples (10 x 10 cm2) from the mid-side area of the goat. The analytical set consists of plasma copper concentrations (Pl Cu), Trichloroacetic acid soluble copper concentrations (TCA-Cu), and fleece copper content. The results indicated that the addition of 20-30 mg Mo and 2-2.5 g S kg(-1) DM to the normal diet did produce sub clinical copper deficiency in treated goats. One such visual symptom was the loss of fleeces pigmentation and poorer crimp being observed. The Pl Cu minus TCA-Cu plasma became more than 2 microM in the blood of treated goat, indicating that there was a significant thiomolybdate formation in the body. The results showed that there was a significant decrease in Pl Cu (p < 0.05) along with a significant increase in thiomolybdate (MoS) production after 4 months. The sub clinical signs of copper deficiency and mohair quality are likely to be from high molybdenum intake and thiomolybdate formation in the body.

Effects of breed and progestin source on estrus synchronization and rates of fertility and fecundity in Iranian Sanjabi and Lori ewes

A trial was conducted to evaluate the effects of FGA (Fluorogestone acetate) and CIDR (Controlled internal drug release) on the induction of estrus and pregnancy and fecundity rates of the Sanjabi and Lori sheep. A total of 360 Sanjabi and Lori sheep were randomly grouped into two treatments with intravaginal devices inserted for 13 days: Group FGA (40 mg FGA, n = 180) and Group CIDR (n = 180). All ewes received an i.m. injection of 400 IU eCG (equine chorionic gonadotrophin) at devices removal. Estrous was assessed by exposing all ewes to vasectomized rams at 12 h intervals. Cervical artificial insemination was performed 12 h after estrus onset. The overall estrus response was 72.5%. The source of progestin did not influence the efficiency of estrus response but a significant difference (p<0.05) was found between the breed groups (Lori: 88.6%, Sanjabi: 58.3%). Among the sheep that received either CIDR or FGA, estrus response was significantly (p<0.05) higher in the Lori (CIDR: 82.2%, FGA: 91.1%) than in the Sanjabi (CIDR: 64.4%, FGA: 52.2%) breed. The lambing and fecundity rates for all groups were 60.2% and 1.2 +/- 0.03, respectively. No significant differences in term of the lambing and fecundity rates were recorded between CIDR and FGA groups and among Lori and Sanjabi breed. The results of this study indicate the source of progestin or sheep breed did not influence the pregnancy and fecundity rates. The sheep breed influences the estrous response rate while the source of progestin did not affect the estrous response.

The effect of administration of different levels of GnRH on the day 0, 5 and 12 post-insemination on progesterone concentration in dairy heifers

This study was carried out to evaluate the effects of different levels of GnRH in different days of reproductive cycle on progesterone concentration in dairy heifers. Two hundred heifers were divided into ten experimental treatment: control group with no injection (1) administration of 2.5 mL Gonadorelin (a GnRH analogue) in day of insemination (2) administration of 5 mL GnRH in day of insemination (3) administration of 10 mL GnRH in day of AI insemination (4) administration of 2.5 mL GnRH in day 5 post-insemination (5) administration of 5 mL GnRH in day5 post-insemination (6) administration of 10 mL GnRH in day5 post-insemination (7) administration of 2.5 mL GnRH in day 12 post-insemination (8) administration of 5 mL GnRH in day 12 post-insemination (9) administration of 10 mL GnRH in day 12 post-insemination. Blood samples were collected in days 0, 5, 12 and 19 post insemination (AI = Day 0) for analysis of serum P4 concentration. There was no significant difference among experimental groups on day of insemination. Evaluation of P4 concentration on day 19 illustrated differences in progesterone concentration between groups on day 19 post-insemination. P4 concentration of serum in the day 19 post-insemination significantly increased in groups either by 5 or 10 mL injection of GnRH whether in day 5 or 12 post-insemination versus control group (9.24 +/- 2.2, 8.6 +/- 1.96, 9.43 +/- 2.15 and 9.42 +/- 2.14 versus 5.5 +/- 0.8, respectively; p < 0.05). GnRH administration in the day 5 and 12 post-AI significantly increased progesterone concentration that may decline early embryonic death and improve pregnancy rate.

The relationship between plasma leptin and FSH concentrations with ovulation rate in Iranian native sheep

The aim of this study was to determine the relationship between plasma leptin and FSH concentration in Iranian sheep. Forty female Mehraban and Sanjabi sheep were used. All ewes were cyclic and synchronized with cloprestenol. The ewes were divided into two breed groups: Mehraban breed (n = 20) and Sanjabi breed (n = 20), feeding at maintenance level. On the first and second days of estrus cycle, blood samples were collected from the jugular vein. Ovulation number was determined by endoscopy 7 days after the second injection. Mean Plasma leptin concentrations on second day (4.74 +/- 0.15 and 4.68 +/- 0.10 ng mL(-1)) were significantly higher than those on first day (2.64 +/- 0.11 and 2.56 +/- 0.04 ng mL(-1)) for Mehraban and Sanjabi sheep, respectively (p<0.01). Mean plasma FSH concentrations on second day (2.75 +/- 0.17 and 2.74 +/- 0.15 ng mL(-1)) were also significantly greater than those on first day (1.19 +/- 0.05 and 1.19 +/- 0.04 ng mL(-1)) for Mehraban and Sanjabi ewes, respectively (p<0.01). In the present study, positive relationship has been shown between plasma Leptin and FSH concentrations (p<0.01) in Mehraban and Sanjabi sheep. Ovulation rate had a significant difference between Mehraban (1.20 +/- 0.33) and Sanjabi (1.07 +/- 0.1) ewes. Significant differences were not observed between concentrations of FSH and leptin with ovulation rate in both breeds (p < or = 0.01).