فهرست مطالب mohammad javad zamiri

Lighting is one of the important management factors affecting the health and welfare of birds. The objective of this study was to assess the effects of light-emitting diodes (LEDs) on production, reproduction, blood metabolites, immunology, and hepatic sterol regulatory element binding protein-1 (SREBP1) gene expression in broiler breeders. One-day-old Ross 308 female breeder chicks (n=100) were randomly assigned to 20 light-proof pens and reared under five lighting regimens, including green (GL) or white (WL) LED at two exposure photophases (8 or 12 hours) as a 2 ´ 2 factorial experiment plus a control group (incandescent lamp at 8L:16D duration; CON). The LED color affected the feed intake during the rearing period, being higher in white than in green light; however, green light resulted in more medium and large white follicles on the ovaries, higher mean corpuscular hemoglobin concentration, and plasma cholesterol level. In WL8 lighting, the relative weight of the bursa of Fabricius was higher (P≤0.05) than in CON birds. Plasma cholesterol level in GL12 was higher compared to CON. Conventional and WL12 regimens resulted in lower plasma alkaline phosphatase activity. Twelve hours of GL lighting resulted in higher eggshell weight and strength while it caused a small but significant decrease in egg shape index. Greater numbers of medium white (MWF) and large white (LWF) follicles were recorded in GL12 birds, and there were more small white follicles (SWF) in GL8 group (P≤0.05). The GL12 and CON lighting resulted in higher concentrations of WBC and Hb compared with WL. Hepatic expression of SREBP1 was higher in WL8 birds. The results indicated that green LED improved egg quality while white LED caused higher relative weight of bursa and hepatic SREBP1 expression, indicating the LED light may be beneficial to broiler breeder productivity. However, more studies are required to substantiate these findings.

 Intrauterine endocrine abnormalities have profound effects on the development of physiological disorders.

 This study aimed to assess the effects of in utero exposure to letrozole (an aromatase inhibitor) and its late consequences on the reproductive and metabolic performance of an adult male offspring.

 15 pregnant Sprague-Dawley rats (8 wk, 155 gr) were randomly assigned into 5 experimental groups (n = 3/each) and orally received either letrozole at doses of 0.25, 0.75, 1.00, and 1.25 mg/kg body weight (BW) or vehicle (control) on the gestation days of 16, 17, and 18. Pregnancy outcome, sexual behaviors on postnatal day 60, serum biochemical features, and the histopathology of testes were assessed in male offspring.

 Compared to control group, delayed labor (21.83 vs. 24.25, p < 0.0001) and reduced litter size (n = 12.25 vs. n = 2, p < 0.0001) were recorded in 1.25 mg/kg BW group. A reduction in high-density lipoprotein level and the elevation of testes weight, BW gain, anogenital distance, as well as the serum concentrations of testosterone, triglycerides, cholesterol, and glucose were observed in 1.25 mg/kg BW (p < 0.0001) and 1.00 mg/kg BW (p < 0.0001) groups in comparison to control. A larger number of anogenital female sniffing, pursuit, and mounting behaviors were also observed in 1.25 mg/kg BW group in comparison to control (p < 0.0001). Severe testicular defects including necrosis and disruption of the epithelium of seminiferous tubules, sloughing of epithelial cells, and spermatogenesis arrest were observed in letrozole-treated groups, in a dose-dependent manner.

 Maternal exposure to letrozole can adversely affect the reproductive and metabolic performance of male offspring rats, suggesting an incomplete sex differentiation.

Despite prevalence of polycystic ovary syndrome (PCOS) among childbearing women and development of many animal models for this syndrome, information on its etiology is still scarce. The intrauterine hyperandrogenic environment may underlie changes at the level of hypothalamus, pituitary, ovary organization in female offspring, and PCOS later in life. Letrozole has been shown to mimic reproductive and metabolic characteristics of PCOS in adult rodent models. Therefore, this research aimed to assess the condition in a prenatal letrozole-treated rat model. 

Twenty-eight female rats dams receiving letrozole at certain doses during late pregnancy were used in the trial.  Pregnant Sprague-Dawley rats (n=21) received letrozole treatment on gestation days 16–18 at doses of 1.25, 1.0, 0.75, 0.5, and 0.25 mg/kg body weight (BW).    

Prenatal letrozole treatment delayed parturition time and reduced the litter size in pregnant dams (P<0.0001). Late puberty onset, irregular ovarian cyclicity, increased anogenital distance (AGD), body weight gain, serum testosterone concentration, and reduced estradiol levels (P<0.0001) were observed in the female offspring of dams receiving 1.25 and 1 mg/kg BW letrozole. Furthermore, letrozole at 1.25 and 1 mg/kg BW showed increased RFRP and decreased GnRH mRNA expression (P<0.0001). Letrozole treatment at doses of 1 mg/kg BW and lower was not fetotoxic. 

It was concluded that 1 mg/kg BW letrozole may be suggested for prenatal PCOS induction.

This study was conducted to compare the effect of a cellulosic (wheat straw; WS) and non-cellulosic (beet pulp; BP) forage source on high producingdairy cows during the transition period (three weeks before to six weeks after calving). Multiparous Holstein cows (n=36) with mean body weight of697±59.6 kg and body condition score of 3.3±0.22 were used in the experiment. Before calving, the cows received diets containing 7.17% WS (n=18)or BP (n=18). After calving, the cows in each group were divided into two subgroups (n=9), and received the diets containing 5% BP or WS.Prepartum dry matter intake (DMI) was similar between dietary treatments but prepartum digestibility of DM (P=0.05) and neutral detergent fiber (P=0.06) was lower in cows feeding on the WS diet. The yield of energy-corrected milk, 4% fat-corrected milk and milk fat percentage tended to behigher in the cows fed with the BP diet during the prepartum period (P = 0.09). In conclusion, the results showed that feeding non-cellulosic foragesduring the transition period may improve the performance in dairy cows.

This study compared six non-linear equations [Exponential growth (4 parameters), Exponential growth (Stirling), Polynomial (Cubic), Quadratic, Brody, and Sinusoidal] for prediction of pre-weaning body weights at different ages in Holstein calves. Thirty-two calves (16 males and 16 females) were randomly divided into two treatment groups and fed with starter diets containing either corn or barley as the grain source. Starter feeding began on the third day of life, and high quality alfalfa hay and fresh cow milk were fed according to the farm schedule. The calves were weighed at birth and weekly thereafter until weaning. In this manner, ten weight records, including the birth and weaning weights, constituted the data set. The results of experiment revealed the fact that all functions mentioned earlier showed good fitness to predict weight gain in relation to age in all groups of calves. However, based on the goodness of the fit of various criteria and the statistical performance, the polynomial (cubic) function was considerably superior to other functions for predicting the calf live weight. The flexible growth functions (more parameters) very often give a closer fit to data points and a smaller residual sum of square (RSS) value than the simpler functions such as the Brody functions.

The effects of different levels of fish oil on productive and reproductive performance as well as serum biochemical indices in female Chukar partridges were evaluated. Thirty-six 1.5-year-old laying Chukar partridges and 12 age-matched males (female: male ratio of 3:1) were divided to four experimental groups (three replicates of three birds each) in a completely randomized, to orally receive 0 (control), 0.1, 0.2, or 0.3 mL of fish oil on a daily basis for 21 successive days where the control birds received 0.3 mL normal saline solution only as the sham control group. The birds had a free access to feed and fresh water and were weighed weekly. The eggs (n=271) were collected once per two hours during the photophase (8 times daily) for the last 21 days of the treatment period (from 7 through 28 d of experiment). Blood samples were collected on d 0, 10, and 21 of the trial to analyze selected biochemical attributes. Although administration of 0.2 mL fish oil increased the egg production and fertility rate, the difference was not significant as compared to the control group (p> 0.05). Feed intake, body weight, and daily weight gain were not influenced by the different levels of fish oil. A significant decrease in egg weight was detected in fish oil-fed birds where partridges receiving 0.2 mL fish oil recorded the lowest egg weight among the experimental groups (p< 0.05). Similarly, the birds administered with different levels of fish oil had lower serum total cholesterol and triglyceride levels compared to the control group where the lowest records were found for 0.3 mL fish oil level. The interaction effect of fish oil level and time on serum total cholesterol was significant (p=0.02). The serum levels of LDL and glucose were decreased in partridges receiving 0.3 mL fish oil (p<0.05). No significant changes in the serum concentration of VLDL, HDL, total protein, calcium, and phosphorus were found during the trial. Data suggested that oral exposure of Chukar partridge to 0.2 mL of fish oil had poitive effect on egg production and fertility rate. However, egg weight was decreased. Oral administration of 0.3 mL of fish oil may decrease serum total cholesterol, triglyceride, LDL, and glucose in partridges.

Nowadays, assisted reproduction has become an essential part of the management of horse reproduction in different parts of the world. In vitro production of equine embryos requires established techniques including oocyte collection, in vitro oocyte maturation and intracytoplasmic sperm injection. No report is available on in vitro oocyte maturation of horse oocytes in Iran. Ovaries were immediately collected from newly dead mares of different ages, and transported to the laboratory. The visible follicles were opened using a scalpel blade and the granulosa layers of the follicle wall were scraped from the follicle. Then, the ovaries were cut in 5 mm sections to collect more oocytes from follicles within the ovarian stroma. The oocytes were cultured in TCM-199 medium, supplemented with 10% fetal calf serum and hormones, in a CO2 incubator at 38.5 0C for 30 h. In addition, using a home assembly devised ovum pick-up (OPU) system, five attempts were made to collect oocytes from preovulatory follicles in four mares. After 30 h in culture, the denuded oocytes were fixed and stained with aceto-orcein to determine the nuclear maturation of the oocytes. Out of 29 cultured oocytes from dead mares, 15 (51.7%) oocytes reached the metaphase II. Further, of five OPU operations on live mares, one compact COC suitable for culture and one degenerate COC were collected. The results of this report describe the feasibility of ovum pick-up and oocyte collection from either live mares or immediately after death of the animal and further successful in vitro maturation of the equine oocytes.

Despite the long history of artificial insemination, its widespread use in many species, including the poultry, sheep, and goat, has been faced with many challenges especially when frozen semen is used. The freezing-thawing process results in physical and chemical insults on the sperm which subsequently decrease the fertility of the sperm. The decrease in fertility is much greater in most species compared with the species such as cattle. Many factors affect the fertility of the frozen-thawed sperm, and different procedures, including the use of various extenders, have been investigated to improve the quality of frozen-thawed sperm. Glycerol and egg yolk are traditionally used as the protective components in many extenders. Despite the positive effects of the egg yolk (mainly as a result of its low-density lipoproteins), there have been concerns with the use of animal products in semen extenders. Therefore, attempts have been made to substitute the egg yolk with other sources such as lecithin. There are reports that several additives such as disaccharides, antioxidants, and essential oils may have beneficial effects on the fertility of frozen-thawed sperm. Variable success rates were reported, and a small number of publications contained fertility data. In this paper, I shall review the most recent research findings on frozen-thawed sperm in sheep and goats, supplemented with data on other mammals when appropriate.

The aim of this study was to investigate the effect of replacing alfalfa hay (AH) with corn silage (CS) in the finely ground starter diet on health status and blood biochemical parameters of male Holstein calves during pre-weaning period. Thirty (3-d old) newborn calves (40.2 ± 1.28 kg body weight) were assigned randomly to three experimental groups receiving starter diets containing 10% (on dry matter basis) AH (Control), 5% AH and 5% CS, and 10% CS. The starter diets had the same nutrient composition but dry matter content was highest and lowest in Control and 10% CS groups, respectively. Blood concentration of albumin was higher in calves fed 5% CS diet compared with calves fed Control or 10% CS diets (P ≤ 0.05). Compared with calves on other treatments, calves on Control group were more susceptible to develop diarrhea or pneumonia (P ≤ 0.05) and thereby had lower chance to be treated. No difference was observed among treatment groups for frequency and medication days of diarrhea or pneumonia, but duration of diarrhea was higher in calves on Control group compared with other treatments (P ≤ 0.05). Based on obtained results, feeding CS containing diets (5 or 10%) to male Holstein calves during the preweaning period may have a potential to improve calf health and to decrease costs related to drugs and medication

Heat stress has adverse effects on livestock production, hence reducing benefits of them. With the viewpoint of reducing heat production within cells,an experiment was conducted to investigate the effects of different sources of fat on mitochondrial energetics of broilers in chronic heat-stress condition. The consumed fat included: a)tallow; as a source of long-chain fatty acids, b)coconut oil; as a source of short and medium-length-chain fatty acids, c)olive oil; as a source of monounsaturated fatty acid (MUFA)and d. soy oil; as a source of polyunsaturated fatty acid (PUFA). Broilers were under chronic heat stress (36 oc) from 32 to 42 d of the experiment. Broilers fed with tallow or coconut oil showed higher mitochondrial dehydrogenases activity, membrane potential and ROS production (p˂0.01) and lower glutathione concentration (p˂0.01) than those fed with olive oil or soy oil. The results seggest that in heat stress conditions using saturated fat sources especially those with long-chain fatty acids could help in reducing heat production inbroilers.

An abnormality in pulse amplitude and frequency of gonadotropin releasing hormone (GnRH) secretion is the most characteristics of polycystic ovarian syndrome (PCOS). On the other hand, arginine-phenylalanine-amide (RFamide)-related peptide-3 (RFRP3) inhibits the secretion of GnRH in mammalian hypothalamus. The current study performed in order to investigate the expression of RFRP3 mRNA in the dorsomedial hypothalamic nucleus (DMH) after the induction of PCOS in a rat model of constant light exposure, and the possible role of parity on occurrence of PCOS.
In the experimental study, female nulliparous (n=12) and primiparous (n=12) rats were randomly subdivided into control and PCOS subgroups (n=6). PCOS were induced by 90 days exposure to constant light. After 90 days, blood, brain, and ovaries were sampled. Serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone were evaluated. In addition, six adult female ovariectomized rats as a control of real-time polymerase chain reaction (PCR) tests were prepared and in the DMH of all rats, the relative mRNA expression of RFRP3 was assessed.
Histological evaluation of ovaries represented the polycystic features. In addition, serum concentrations of testosterone in the PCOS subgroups were more than the controls (P Constant light model of the PCOS-induced rats decreased the gene expression of RFRP3 in the DMH that suggests the decrease of RFRP3 may reduce its inhibitory effect on GnRH during the PCOS pathogenesis. This effect was stronger in the nulliparous rats than the primiparous.

Lead (Pb) induced oxidative stress is known to suppress growth performance in broiler chickens. The current study was carried out in an attempt to describe the specific underlying mechanisms of such phenomenon.
The objective of this study was to investigate the effect of Pb-induced oxidative stress on performance, antioxidant status and behavioral responses of broiler chicken.
Eighty day-old broiler chicks were randomly assigned to 2 dietary treatment groups of 4 pen replicates, namely i) basal diet containing no lead supplement (control) and ii) basal diet containing 200 mg Pb/kg of diet.
The results showed that addition of lead decreased body weight gain (p Our data conclude that Pb-induced oxidative stress adversely suppressed feed conversion ratio and growth performance. The proposed underlying mechanism for such phenomenon is Pb-induced oxidative stress by impaired antioxidant status and feeding behavior decreased the growth performance.

Palm date leaves were processed with lime in a processing reactor in a factorial arrangement of treatments (3 × 3) with 3 levels of temperatures (40, 80 and 100°C) and time periods (80, 160, and 240 minutes) in a completely randomized design. Fermentation parameters measured using gas production technique. With increasing pretreatment time and temperature lignin content reduced from 13.0 percent in untreated leaves to 6.0 percent in leaves treated in 100°C for 240 min. Increasing time and temperature of the processing decreased ash content (P

Following the ban on the use of growth stimulant antibiotics in many countries, interest has arisen in finding a suitable alternative for antibiotics in poultry production.
The aim of this study was to investigate the effect of supplementation of two levels of nano-copper (0 and 100 mg/kg) and two levels of mannan oligosaccharide (0 or 1 g/kg) as natural growth stimulants on digestibility of nutrients and performance in broiler chicks.
At the end of the second week of breeding, 160 Cobb-500 broiler chicks were assigned in four treatment groups. For each treatment, four replicates (10 chicks per replicate) were considered. Experiment was conducted as a 2×2 factorial model in a completely randomized design.
No significant differences in digestibility of nutrients and growth performance between birds that ate the supplements with control group were observed (p>0.05).
Mannan oligosaccharides and nano-copper on growth performance and nutrient digestibility in broiler chicks had no significant effect. At the doses used, concomitant supplementation of copper and mannan oligosaccharide did not have a positive effect on traits that were studied in broilers.

Until 2000 it was believed that gonadotropin-releasing hormone (GnRH) was the sole regulator of hypophyseal gonadotropes. In 2000, the discovery of a gonadotropin inhibitory hormone (GnIH) initiated a revolution in the field of reproductive physiology. Identification of GnIH homologues in mammals, the arginine-phenylalanine- amide (RFamide)-related peptides (RFRPs), indicated a similar function. Subsequently, further works conducted in various laboratories worldwide have shown that these neuropeptides inhibit the hypothalamic-hypophyseal axis. This review discusses the role of RFRPs in mammalian reproductive processes.

The aim of the present study was to determine the effect of dietary supplementation of pioglitazone (PGT) during transition period on the ovarian function and the incidence of several diseases after parturition. Eighty Holstein cows were randomly allocatted to four treatment groups (n=20) using a 2×2 factorial design. Pioglitazone was fed for 14 day before the expected parturition time, or for 21 days after parturition, or furing both pre- and post-partum period. The cows received either 0 or 6 mg PGT/kg live weight. Data on the incidence of production diseases (laminitis, mastitis, cystic ovaries, infected uterus and inactive ovaries) and the day of ovulation were recorded and analyzed using the GENMOD and GLM procedures of SAS. Postpartum supplementation of PGT decreased the mean days to ovulation (P<0.02). The percentage of cows which ovulated during 14 DIM was significantly increased when PGT was supplemented postpartum (P<0.03). PGT supplementation during prepartum (p<0.01) and postpartum (P<0.10) periods decreased laminitis. Prepartum PGT supplementation had no significant effect on mastitis incidence. Prepartum (P<0.03) and postpartum (P<0.08) PGT supplementation resulted in decreased uterine infections. Postpartum PGT supplementation significantly decreased the proportion of cystic cows (P<0.04). PGT had no significant effect on the percentage of cows with inactive ovaries (P>0.05). In conclusion, supplementation of PGT during transition period in dairy cows may be beneficial in decreasing the incidence of some postpartum diseases, and may enhance ovarian cyclicity after parturition.

The effect of litter size and suckling intensity on the expression of KiSS-1 mRNA in the arcuate nucleus (ARC) of rats were evaluated. Thirty two pregnant and four non-lactating ovariectomized (as control group) rats were used in this experiment. Lactating rats were allotted to eight equal groups. In three groups, litter size was adjusted to 5, 10, or 15 pups upon parturition and allowed to suckle their pups continuously by 8 days postpartum. In the other three groups, litter size was adjusted to five upon birth; the pups were separated from the dams for 6 hr on day 8 postpartum, after which the pups were allowed to suckle their dams for 2.5, 5, or 7.5 min prior to killing the dams. Two groups of lactating rats with either 10 or 15 pups were separated from their pups for 6 hr on day 8 postpartum, after which the pups were allowed to suckle their dams for 5 min before the dams were killed on day 8 postpartum. The ARC was removed and the expression of KiSS-1 mRNA was evaluated, using real-time PCR. The expression of KiSS-1 mRNA in the ARC was decreased as the litter size and intensity of suckling stimulus were increased. The effect of suckling intensity on the expression of KiSS-1 mRNA was more pronounced than that of litter size. Increased litter size and suckling intensity decreased KiSS-1 mRNA expression in the ARC which may contribute to lactation anestrus in rat.

The effects of different levels (0، 10، 20 and 30 percentage of dry matter) of apple pomace ensiled with urea were investigated on 24 Ghezel male lambs in a completely randomized design with four treatments and six replicates. The average starting weight and age of the lambs were 31. 27 ± 7. 40 and 187 ± 37 days، respectively. After 15 days of adaptation، the lambs were individually fed with experimental diets for 70 days. Daily feed intake was measured individually and the lambs were weighted at the beginning and the end of the experiment after an overnight feed and water withdrawal. Average daily gain and feed intake، and feed conversion ratio were calculated. At the end of the experiment، lambs were slaughtered and the warm and cold carcass and other cuts were weighed. There were no significant differences among treatments in term of average daily gain، dry matter intake، feed conversion ratio، warm and cold dressing percentage. Percentage of internal organs fat was not statistically different among the treatments. The results showed that، including apple pomace ensiled with urea into the diet of fattening Ghezel male lambs is recommendable as a replacement for alfalafa hay.

This study aimed to investigate the effect of different levels of silymarin against lead induced oxidative stress in broiler chickens. Therefore، 240 broiler chickens of Ross 308 allocated to 24 experimental units in a completely randomized design with factorial 2x3 arrangements and four replicates of 10 birds. The experimental diets containing silymarin at 3 levels (0، 100، 200 mg/kg) and 2 levels of lead (0، 200 mg/kg) were fed for 6 weeks. Results of this experiment showed that supplementation of 200 mg/kg silymarin attenuated adverse effect of lead on body weight gain (BWG) and feed conversion ratio (FCR) in 42 d. Also، addition of 200 mg/kg silymarin in lead-induced oxidative stress improved carcass characteristics. In addition، supplementation of silymarin in lead-induced oxidative stress no significantly decreased blood lipid parameters (cholesterol، triglyceride، LDL). Furthermore، supplementation of 200 mg/kg silymarin significantly increased superoxide dismutase (SOD) and decreased malondealdehyde (MDA) and heterophyle /lymphocyte (H/L ratio). These results suggested that supplementation of silymarin in lead induced oxidative stress had a protective role and by improving the antioxidant system improved the performance.

In order to investigate the effect of different levels of silymarin (0، 100 and 200 mg/kg diet) on performance، carcass characteristics، blood parameters and antioxidant status، 120 day old chicks were assigned to 3 treatments with four replicates and 10 birds in each in a completely randomized design. Results showed supplementation of 200 mg silymarin significantly decreased the body weight gain (BWG) in starter (P<0. 05) and whole period of experiment (P<0. 01) and significantly increased feed conversion ratio at starter (P<0. 05)، grower (P<0. 05) and total rearing periods (P 0. 01). Also، addition of 100 mg silymarin significantly increased the carcass relative weight (P<0. 01) and supplementation of 200 mg silymarin significantly increased the breast relative weight (P<0. 05). Furthermore، 200 mg silymarin significantly increased the malondialdehyde and heterophil/ lymphocyte ratio and significantly decreased superoxide dismutase (P<0. 05). These results showed that supplementation of silymarin in diet under normal condition، improved the carcass and breast relative weight، but no had effect on bird’s oxidative status.

Essential oils (EO) are antimicrobial compounds، but may be beneficial under unfavorable nutritional and environmental conditions. Essential oils produced in Iran are of comparable quality to imported ones.

The aim of this study was to compare the effects of Orego-Stim (Essential oil based on Oregano; 0. 5 g/kg; imported) and Anti-Biophin (Essential oil based on Thyme; 1 g/kg; local) essential oils on performance and precaecal digestibility of nutrients in broiler chicks fed barley-corn based diets with and without b-glucanase (0. 05 g/kg).

At the beginning of the second week of rearing period، 192 chicks of mixed sex were allotted into six groups of four replicates with eight chicks per replicate according to a 2×3 factorial experiment arranged as a completely randomized design.

Inclusion of Orego-Stim or Anti-Biophin in barley based diets caused a significant (p<0. 05) improvement in total feed conversion، final body weight and nutrients digestibility، without a significant effect of b-glucanase addition to the diets. The type of essential oils (imported vs. local) did not affect the measured characteristics.

Feeding broiler chicks with barley based diets، supplemented with essential oils، decreased the anti-nutritional effects of barley grains in these diets and improved broiler performance، without the need to supplement the barley-based diets with b-glucanase. Because of the lack of any significant difference between the imported and locally-produced essential oils، and the higher cost and scarcity of the imported EO، domestic products such as Anti-Biophin at recommended levels can replace the imported ones.

RFamide-related peptide (RFRP) is believed to act as an inhibitor of gonadotropin releasing hormone (GnRH) secretion. The aim of the present study was to compare the expression pattern of RFRP neurons in the dorsomedial nucleus of hypothalamus (DMH) at different phases of the rat estrous cycle. The phases of the estrous cycle were determined in 16 adult female Sprague-Dawley rats using vaginal smears. The rats were divided into five groups: proestrus phase (n=4), early estrus phase (n=3), estrus phase (n=3), metestrus phase (n=3) and diestrus phase (n=3). After transcardial perfusion, their brains were removed and fixed. Diencephalon of each rat brain was sectioned, and DMH-containing sections were stained using an immunohistochemical method. The number of RFRP positive neurons in DMH was counted microscopically Almost all of the neurons expressing RFRP in the DMH were bipolar. Mean and standard error of the number of RFRP neurons during diestrus (45.8±12.6) and estrus phases (44.7±3.6) were greater (P<0.05) than early estrus (18.8±0.8) and proestrus phases (16.2±2.0). Results confirm a regulatory role for RFRP in DMH in the control of rat estrous cycle.

Kisspeptin and RFamide-related peptide-3 (RFRP-3) are known to affect GnRH/luteinizing hormone (LH) in several species, including the rat. It has been hypothesized that GnRH/LH changes during the rat estrous cycle may result from changes in the expression of KiSS1 and RFRP-3 genes. Therefore, the present study investigates KiSS1 and RFRP-3 gene expression at the transcriptional level in the rat hypothalamus during the estrous cycle. In the present experimental study, 36 adult female Sprague-Dawley rats (3-4 months old) were used to study the expression of KiSS1 and RFRP-3 mRNA in the hypothalamus during the estrous cycle. Four rats were ovariectomized, whereas the remainder were allotted to four different phases of the estrous cycle (n=8 per estrus phase). Rats were decapitated, and the hypothalami were immediately dissected and frozen in liquid nitrogen. Expressions of KiSS1 and RFRP-3 mRNAs were analyzed by real-time PCR. The expression of KiSS1 mRNA during estrus was lower than other phases of the cycle (p<0.01). Expression of KiSS1 mRNA during the metestrus phase was lower than the proestrus phase (p<0.01). The expression of RFRP-3 mRNA during proestrus was lower than the diestrus phase (p<0.01). Results of the present study showed the role of coordinated expression of KiSS1 and RFRP-3 mRNA in the hypothalamus in the control of the rat estrous cycle.

Seventy four 9-month-old Fars indigenous roosters were randomly divided into three equal groups. The first group was exposed to 14 hours light and 10 hours darkness. The second group was exposed to the same lighting schedule as the first one and supplemented with 3 mg/kg of body weight edible melatonin daily. The third group was finally exposed to 24 hours of constant light. Semen was collected four times at 20 day intervals through abdominal massage the semen samples of every 8 roosters in each group, being pooled. The pooled semen samples of the first group were supplemented with either 4 vs. 8 mg/ml of vitamin E or 3 vs. 6 mM of melatonin, respectively. The pooled semen samples were frozen, and then thawed after 2 weeks past. Semen characteristics including pH, sperm motility, sperm viability, sperm membrane integrity and Malondialdehyde (MDA) concentration were evaluated before freeze and after thawing. The interaction between the treatment and freezing process was significant (P<0.05) only for MDA concentration and sperm viability. Supplementation of semen with melatonin significantly decreased the sperm viability as compared with the control. Vitamin E (at a concentration of 4 mg/ml) increased sperm viability following thawing as compared with the control. Maximum vs. minimum concentrations of MDA were observed at 6 mM melatonin vs. 4 mg /ml) vitamin E supplementation, respectively. In conclusion, it could be said that vitamin E supplementation in indigenous rooster semen, (as compared with melatonin supplementation) decreases lipid peroxidation in frozen sperm, improvig semen quality following thawing.

To evaluate the effects of different dry period lengths on milk yield, milk composition, reproductive performance and energy balance in dairy cows, 30 Holstein breeds (average 270 days pregnant) were made use of in a randomized complete block design. Cows were assigned to three treatments (60, 45 and 30 days of dry period) and two blocks as based on parity (either first lactation or multifarious cows). Milk production and composition as well as somatic cell counts of cows with 45 and 30 days of dry period were not significantly different from cows with 60 days of dry period (P>0.05). Body condition score changes after calving for 60, 45 and 30 days of dry period (1.06, 0.93 and 0.68, respectively) were significantly different. The smallest change in body condition score was observed for 30-day dry period ones, which also had a lower blood concentration of non-esterified fatty acids before calving (364.8 vs 394.9 and 390.9 µEq/l for 45- and 60-day dry periods). Mean days to first postpartum ovulation were 27.9, 27.8 and 22.7 days for dry periods of 60, 45 and 30 days, respectively (P<0.05). Fewer numbers of services per conception was recorded for 30- day dry periods compared with 45- and 60- day dry periods (1.5 vs 2.1 and 3.75, respectively). Cows with 30-day dry periods as experienced fewer number of days in negative energy state in comparison with 60- and 45-day dry periods, which amounts to a better reproductive performance.