جستجوی مقالات مرتبط با کلیدواژه « بز خلخالی » در نشریات گروه « علوم دام »

 Selenium (Se), as an antioxidant element, is a neutralizing mineral for oxidative stress and urging apoptosis in stressed biological systems. Selenium is a necessary trace element for ruminants that participates in varied biological processes like antioxidant defense, production of thyroid hormone, and response of immune system. In recent years, researches have focused on the best supplementary sources of selenium to maximize biological performance. The studies about reproductive performance, such as that of Gabryszuk and Klewiec (2002), showed that injecting ewes with Se four weeks before breeding and again during the last four weeks of gestation caused a 32% increase in lambing percentage compared with Se-deficient ewes. Furthermore, adequate Se status of the newborn lambs not only ensures prevention of nutritional myopathy, but also decreases losses in lamb productivity. Lambs from Se-supplemented ewes showed faster progression to stand and nurse compared with lambs from unsupplemented ewes and leading to an overall decrease in lamb mortality (Muñoz et al. 2009). It has been observed that selenium mineral supplements, such as sodium selenite and sodium selenate, have the same bioavailability. However, organic selenium supplements such as yeast selenium more effectively increase the concentration of selenium in blood and milk and may have a better bioavailability. However, the recently developed red elemental selenium has promising uses in the environmental protection from the pollution of the excessive selenium (Zhang et al. 2007). Zhang et al. (2007) synthesized nano red elemental selenium (nano-Se) with the size of 5 – 100 nm and observed that nano-Se had a similar bioavailability in rat and much less acute toxicity in mice compared with selenite. Recently, Wang et al. (2007) showed that nano-Se (20 – 60 nm) possesses equal efficacy in increasing the activities of GSH-Px in plasma and liver from male Kunming mice compared with selenomethionine. The periparturient period is the foremost necessary stage in farm animals about health standing and production. The objective of this study was to determine the effect of different sources of selenium on blood and serum selenium concentration of Khalkhali goats during late pregnancy, as well as the effect of these sources on the concentration of selenium in their kids up to four weeks and serum and colostrum immunoglobulin concentration (IgG) of mothers and kids (immediately after birth).

The experiment was conducted using 40 Khalkhali goats in a completely randomized design devided into four groups with 10 goats per each group. The goats were randomly allocated to four treatments to receive supplementations of 0 (control), 0.6 mg Se head−1</sup> day−1</sup> of seleno-methionine (SM), 0.6 mg Se head−1</sup> day−1</sup> of nano-selenium (SN), and 0.6 mg Se head−1</sup> day−1</sup> of sodium selenite (SS) from four weeks before the expected day of delivery. Their blood samples were taken at that time and on the kidding day. In addition, colostrums were collected in pre-cleaned polyethylene bottles from the goats as immediately as possible after kidding. Instantly after delivery, newborn kids were taken apart from their dams. The control group did not receive any supplement and received only the basal ration containing 0.1 mg Se kg-1</sup> DM. Blood samples were collected from goats three weeks before the expected kidding. Blood samples of kids were taken from the jugular vein on the day of birth and 7 days after birth. Blood samples were centrifuged at 3000 rpm for 15 minutes to prepare the serum. The ELISA method was used to determine the concentration of IgG and selenium concentration was measured using the ICP-OES device. The weight of kids at the birth and up to four weeks, colostrum production in the first three days and milk production of goats for four weeks were recorded and analyzed.

 There were no significant differences in birth weight, weight of kids up to four weeks, colostrum production in the first three days, and milk production until the fourth week in goats. There was a significant difference between the groups in serum IgG concentration, colostrum IgG, and blood IgG concentration of kids (P<0.05). No significant differences were observed between mineral selenium, nano-selenium, and control group. However, seleno-methionine had a significantly better performance than nano-selenium and sodium selenite. Serum and blood selenium concentrations were similar before kiding, but the concentration of selenium in serum and blood of supplemented goats was significantly higher than the control ones (P> 0.05). The results of this experiment showed that serum and blood selenium concentrations in nano-selenium recieved goats were significantly higher compared with other groups (P<0.05). Serum and blood selenium concentrations of kids at birth and colostral selenium concentration in the experimental groups were significantly higher than the control group (P <0.05), except for the goats supplemented with selenium nanoparticles, which significantly decreased compared to the control goats. The serum selenium and blood levels of selenomethionine recieved group showed the highest selenium levels in comparison with other groups. Selenium blood levels increased significantly in the first week of life of the kids only in the organic supplementation treatment (P <0.05).

Organic selenium supplementation in late pregnancy was effective in transferring blood immunity from the goats to the kids and led to changes in serum and colostrum IgG levels of goats. The supplementation of different Se forms (sodium selenite, selenomethionine and elemental nano-Se) into pregnant goats’ diet increased Se status in the whole blood and serum compared with controls. Among Se sources, nano-selenium exhibited an excellent increasing Se status in pregnant goats. Current results showed differences in the transplacental Se transfer capacities of sodium selenite, selenium nanoparticles, and selenomethionine. When comparing these three Se sources, the results of the study clearly demonstrated that kids from goats receiving selenomethionine had higher whole-blood and serum-Se concentrations compared with kids from goats receiving sodium selenite and selenium nanoparticles. There was a failure of nano-selenium to increase newborn Se concentrations as compared with control. Seleno-methionine had higher transplacental transfer of Se and also resulted in higher Se concentrations in colostrum. Goats supplemented with seleno-methionine had greater colostral Se concentrations than goats supplemented with sodium selenite and selenium nanoparticles.

Due to a crucial role in transferring of Prolactin hormone signals to milk protein gene promoter, Prolactin receptor (PRLR) gene has been detected as the most important candidate gene. The present study investigated the genetic variation of exon 9 of PRLR gene and bioinformatics analysis of this gene in farm animals. For bioinformatics analysis, 37 samples of different farm animal species genomic sequences were obtained. A mutation was detected in exon 9 of Khalkhali goat PRLR gene that causes to the substitution of A to G nucleotide and, led to change ATG codon to GTG codon with the substitution of Metioning amino acid with Valin. The results of analyzing of Exon 9 led to identify 28 polymorphic sites in the PRLR gene that causes 10 haplotypes with 0.8408 haplotype diversity in studied species. Nucleotide diversity and average nucleotide differences among species were 0.04439 and 10.655 respectively. Analysis of genetic diversity showed that ovine species have the more diversity compared with other species. Also, analysis of species distance and network analyses showed that ovine is most closed species to Capra than other species, and Khalkhali goat belongs to the same phylum as Capra Hircus.

Increment of ovulation rate in farm animals improves reproductive performance through increasing in litter size and fecundity rate. Estrus synchronization or the induction of estrus is a valuable management tool for increasing the pregnancy rate in goats. Stimulation of ovulation using different methods can improves reproduction performance by increasing the proportion of goats having twin ovulations and thereby increase kidding percentage (Khaldari 2008; Rahman et al. 2008). It has been suggested to use new reproductive approaches such as controlling and synchronizing of estrus and using hormones by applied Artificial Insemination (AI) to increase prolificacy leading to gain practical and economical advantages. Recently, Progesterone or its analogues is generally used to synchronize estrous during the breeding and non-breeding season. Administration of gonadotropins such as equine Chorionic Gonadotropin (eCG) after stopping progesterone treatment, causes an increase in rate of ovulation (Lopez-Sebastian et al. 2007). Also using Gonadotropin Releasing Hormone (GnRH) with eCG leads to a raise in ovulation rate and litter size in different goats breed (Akifcam and Kuran 2003). The objective of this study was to improve the reproductive performance using GnRH and eCG administration in breeding season.
Material and The experiment was carried out on 150 mature (2–5 years of age), non-lactating does with a body weight varying between 37 and 39 kg. The current study was performed in the natural breeding season under natural photoperiod environment. Synchronization of estrus was done by inserting intravaginal sponges containing 40 mg flugestone acetate (FGA, Chrono-Gest, Intervet International B.V., Holland) for 16 days. Goats were randomly assigned to three groups. The control group (T1) exposed to Khalkhali bucks without any treatments for mating after sponge removal. Goats in second (T2) and Third (T3) groups were injected intramuscularly 400 IU eCG (Serogonadotropin®, Biowet S.A., Poland) and 400 IU eCG with 50 mg GnRH (Vetocept®, Aboureyhan Co., Karaj, Iran) respectively in sponge removal time. Then the does were mated naturally with Khalkhali bucks. Five fertile Khalkhali bucks were introduced to each group twice a day, starting about 24 h after CIDR withdrawal, and left with them for estrus detection and natural mating. Does were observed continuously for 3 h when bucks were introduced to them and their mating were recorded. The date of birth, numbers of kids born per does and weight of each kid were recorded at kidding time. Reproductive parameters, including pregnancy rate, kidding rate, fecundity rate, twinning rate was determined as well. Blood was sampled from the external jugular vein into heparinized test tubes. The first blood samples were collected before inserting intravaginal sponges, the second, 7 days after inserting sponges and the third, one day after intravaginal sponge withdrawal. Samples were immediately transferred to the lab and centrifuged in the tubes for 15 min at 1000 ×g to separate the plasma. Plasma samples were stored at −20 ◦C for less than 2 months until analyzed for estrogen and progesterone concentrations. All assays were carried out in duplicate. The reproductive parameters were analyzed by ProcGenmod using SAS 9.2 in completelyrandomized design. The means of all reproductive traits were compared by using Chi-Square test. Born weight of kids and hormone concentration data were analyzed using the General Linear Models procedure of SAS and P 0.05) in breeding season. Control group had lower fecundity rate (106%) than the treatment groups (158% and 188 % in second and third groups respectively). Lambing rate in 1 to 3 treatments were calculated 113, 175 and 177% respectively that the treatment groups had higher (P 0.05). There was no significant difference in plasma estrogen and progesterone concentrations between treatments as well (P>0.05). eCG has biological activity of FSH and LH hormones and luteinizing effect of eCG promotes the maturation of follicle that lead to increase the production of estrogen hormone. Estrogen is effective in causing the estrous cycle (Godfery et al. 1997). Results of the current study showed that the injection of 400 IU eCG after sponge removal had no effect on kidding rate and pregnancy rate. But Zaiem et al (1996) observed that the goats treated with eCG had a higher pregnancy rate compared to the control group. Although some studies have reported that administration of eCG can improve the kidding rate and pregnancy rate in breeding season (Kermani Moakhar et al. 2012) as well as non-breeding season (Husein and Ababneh 2008). On the other hand, some studies reported that eCG has negative effects on pregnancy rate (Zeleke et al. 2005; Menchaca and Rubianes 2004). In the current study, treatment with eCG and eCGᩴ increased twinning rate. This result agrees with those reported by Ali et al (2007). Zarkawi et al (1999) reported that using eCG at CIDR withdrawal increased twinning rate from 7% in control group to 30% in treatment group. Also they observed no significant difference in twinning rates for high eCG doses. In another study using eCG in breeding season led to significant increase in twinning rate (61.9% vs 29.2%), lambing rate (86.2% vs 68.6%) and fecundity rate (127.6% vs 71.4%) compared with the control group (Koyuncu and Ozis Altıcekic 2010). These results were similar to the findings in the present study. There was no significant difference in weight of kids at kidding between treatments groups and control and this result shows that weight of kids was not affected by hormones treatments.
In conclusion, using of synthetic hormone caused improvement of reproductive efficiency of Khalkhali goat in breeding season.