Effects of dietary supplementation of different sources and levels of selenium on the semen quality and reproductive performance in aged broiler breeder roosters.

Fertility has a great impact on economic outcome in poultry sector. However, several physiological stressors such as aging adversely affected fertilization capacity and hatching quantity and quality. This study investigated the effect of dietary supplementation of different sources and levels of inorganic and organic selenium on the semen quality and reproductive performance of aged broiler breeder roosters. A total of thirty-six 50-wk-old Ross 308 roosters were randomly allocated to 6 groups and fed with different levels of organic and inorganic selenium. Treatments were included in the basal diet (control: CG), dietary supplementation of 0.15 (SeY0.15), 0.30 (SeY0.30), and 0.45 (SeY0.45) mg/kg selenium-enriched yeast (SeY), dietary supplementation of 0.30 mg/kg commercial organic selenium (Selemax), and dietary supplementation of 0.30 mg/kg sodium selenite (SS) as an inorganic source during 12 consecutive weeks. Ejaculated volume, semen quality attributes of the collected semen samples were evaluated every week. To assess fertility, hatchability and the hatched chick quality, the semen samples collected during last 2 wk of the trial were used to artificial insemination of hens. In order to measure seminiferous tube diameter and seminiferous epithelium thickness, testicular histology was also performed at the end of the experiment. Sperm motility, plasma membrane functionality and integrity, and ejaculation volume were higher in the SeY0.45 group compared to the other groups (P < 0.05). Fertility and hatchability rate as well as seminiferous epithelium thickness and seminiferous tube diameter were improved in the SeY0.45 compared with CG, SeY0.15 and SS groups (P < 0.05). Also hatchelling quality from roosters with SeY0.45 was higher than CG and SS groups (P < 0.05). No significant differences were noted in embryonic mortality between groups (P > 0.05). In conclusion, dietary supplementation of 0.45 mg SeY improved sperm quality and reproductive performance of aged broiler breeder roosters.

Addition of MitoTEMPO to the maturation medium improves in vitro maturation competence of bovine oocytes.

The effects of MitoTEMPO, a mitochondria-targeted antioxidant, and its non-targeted parent, TEMPO, on bovine oocyte maturation competence have not been determined so far. Hence, our study was aimed to investigate the effects of supplementing maturation medium with different concentrations of MitoTEMPO (0.00, 0.10, 1.00 and 10.00 µM) or TEMPO (0.00, 5.00, 10.00 and 15.00 mM) on in vitro maturation (IVM) and fertilization (IVF) of bovine oocytes. The oocytes after IVM and IVF were evaluated for the signs of nuclear maturation and normal fertilization. The average number of spermatozoa penetrated per oocyte and the level of intracellular reactive oxygen species (ROS) were also evaluated. The results showed that percentages of bovine oocytes reached the metaphase II stage of meiosis were significantly higher in the 1.00 µM MitoTEMPO group compared to the control group (without antioxidant supplementation). The normal fertilization rate also tended to be greater in this group than the control group. In comparison with the control group, the medium supplementation with 1.00 µM MitoTEMPO led to a significant decrease in the intracellular ROS level. The average number of spermatozoa penetrated per oocyte was not significantly different among the antioxidant-treated and the non-treated groups. The TEMPO addition to the maturation medium affected neither the rate of maturation/fertilization nor the level of intracellular ROS in bovine oocytes. Based on these results, we concluded that MitoTEMPO at a concentration of 1.00 µM had beneficial effects on the quality and fertilization potential of bovine oocytes.

Pro-and anti-inflammatory effects of glucocorticoid Fluticasone on ovarian and immune functions in commercial-aged laying hens.

Ovarian chronic inflammation has been created and extended in the laying hen mainly via increasing laying frequency and microbial infection, especially during the late stage of production period. This study was aimed to evaluate glucocorticoid (GC) Fluticasone as an anti-inflammatory agent on the gene expression of the ovarian pro-and anti-inflammatory mediators (follicular cyclooxygenases COX 1, 2, and cytokines), inflammatory responses of the immune system, ovarian functions (ovulation rate and follicular growths), and hormones in the commercial-aged laying hens. White Leghorn hens aged 92-weeks were used for four weeks to be supplemented by 2 ppm Fluticasone as an optimum dose obtained in a pre-trial base on ovulation rate. As compared to control, Fluticasone resulted in a significant decrease in the mRNA expression of COX-1 and pro-and anti-inflammatory cytokines, and increase in COX-2 mRNA expression and heterophil to lymphocyte ratio (P < 0.001). A significant reduction was observed in the ovulation rate, follicular size (P < 0.001), ovarian hormones, immunoglobulins, body weight, and food consummation (P ≤ 0.05) by administering GC Fluticasone. Although a relative anti-inflammatory improvement was created by Fluticasone in the ovarian condition, the administration of this glucocorticoid resulted in a considerable reduction in ovarian hormones and functions of commercial aged laying hens.

The stimulation and inhibition of beta-2 adrenergic receptor on the inflammatory responses of ovary and immune system in the aged laying hens.

BACKGROUND: Ovarian chronic inflammation has been known to incidence in the laying hen mainly via increasing laying frequency and microbial infection, especially during late stage of production period. This study was aimed to evaluate beta-2 adrenergic agonist (Beta-2 Adrenergic Agonist, BAA) Salmeterol and beta blocker (Beta Blocker, BB) Propranolol on the gene expression of the ovarian pro- and anti-inflammatory mediators, inflammatory responses of immune system, ovarian functions and, hormones in the laying hens on the late stage of production period. Forty-eight White Leghorn hens aged 92 weeks were used for 4 weeks to be supplemented by Salmeterol and Propranolol. Ovulation rate and follicular growth were determined based on laying frequency and ovarian visual evaluation, respectively; the mRNA expressions of follicular beta-2 adrenergic receptor (Beta-2 Adrenergic Receptor, ß2ADR), cyclooxygenases (Cyclooxygenases, COX) 1 and 2, and cytokines were measured by real-time PCR. The plasma concentration of ovarian hormones, cellular, and humoral immune responses were measured via ELISA, heterophil to lymphocyte ratio (Heterophil to Lymphocyte ratio, H:L), and sheep red blood cell (Sheep Red Blood Cell, SRBC) test, respectively. RESULTS: As compared to control, both of BAA Salmeterol and BB Propranolol resulted in a significant decrease in the mRNA expression of ß2ADR, cyclooxygenases, and pro- and anti-inflammatory cytokines (P < 0.01). A significant elevation was observed in the ovulation rate (P < 0.05), plasma estradiol content on both treated groups (P < 0.05), and the content of progesterone and was just significantly (P < 0.05) increased in Salmeterol group. H:L was reduced in BAA group (P < 0.05), and immunoglobulin (Ig) M was elevated in both treated hens, when compared to control. The results indicated that Salmeterol significantly increases body weight (P < 0.05). CONCLUSION: The stimulation and inhibition of beta-2 adrenergic signaling could reduce ovarian inflammatory condition in addition to enhancing laying efficiency in the aged laying hens.

Determination of optimum carcass weight for meat quality and fatty acid composition in fat-tailed male and female Chall lambs.

The aim of this study was to determine the optimum carcass weight for meat quality and fatty acid composition in fat-tailed Chall lambs. Thirty lambs (15 male and 15 female) were allotted to three carcass weight groups: (1) light carcass weight (LCW 10-15 kg), (2) moderate carcass weight (MCW 15-20 kg), and (3) heavy carcass weight (HCW 20-25 kg). Back fat thickness and intramuscular fat (IMF) content were greater (P < 0.05) for HCW and female groups than their counterparts, respectively. Drip loss was lower (P < 0.05) for female and HCW lamb groups than male and LCW group, respectively. Female and LCW lambs had lower (P < 0.05) shear force compared with their corresponding male and HCW groups. Meat from LCW and MCW lambs had higher lightness (L* value; 43.6, 43.5 vs. 39.9), while redness (a* value; 13.6, 13.9 vs. 15.4) was greater for HCW and female (13.7 vs. 14.9) lambs compared with their counterparts (P < 0.05). The MCW lambs produced meat with higher overall acceptability compared with other two groups (P < 0.05). The HCW lambs contained lower polyunsaturated fatty acids (PUFA), polyunsaturated fatty acids to saturated fatty acids (P:S) ratio, and n-3 PUFA compared with LCW group (P < 0.05). Results show that as the animal grow faster and achieved HCW, the IMF content also increased mainly as storage triglyceride, while functional fats consisting long-chain omega-3 did not increase proportionately. In addition, the study also demonstrates that using IMF for predicting or assessing meat quality aspects such as juiciness and flavor or the nutritional value of meat relating to health claimable fatty acids would not be appropriate.

An improvement in productive and reproductive performance of aged broiler breeder hens by dietary supplementation of organic selenium.

This study was conducted to determine the optimum level of home-made selenium-enriched yeast (SeY) in the diet of broiler breeder hens and to compare the effects of this product with sodium selenite (SS) or Selemax (SM) on their productive and reproductive performance. A total of 150 broiler breeder hens were divided to six groups and hens in each group were received a basal diet containing no selenium (CG), 0.15, 0.30, 0.45 mg SeY/kg diet (SeY-0.15, SeY-0.30 and SeY-0.45, respectively), 0.30 mg SM/kg diet or 0.30 mg SS/kg diet for 15 successive weeks. The results showed that egg weight and production and hatchability rate were higher in SeY-0.45 compared to other groups (P < 0.05). Also, SeY-0.45 group led to lower embryonic mortality rate compared to CG and SS groups. Fertility rate and chick quality parameters were not affected by selenium supplementation during this period (P > 0.05). In conclusion, the dietary supplementation of home-made selenium, as an organic selenium source, can be used to improve the productive and reproductive performance in aged broiler breeder hens at 0.45 mg/kg feed.

Supplementation of extender with coenzyme Q10 improves the function and fertility potential of rooster spermatozoa after cryopreservation.

The effects of coenzyme Q10 (CoQ10) has not yet been assessed for cryopreservation of rooster semen. The aim of this study was to evaluate the effect of different concentrations of CoQ10 in Lake extender for cryopreservation of rooster semen. The viability and apoptosis status, DNA fragmentation, abnormal morphology, motion parameters, membrane functionality, mitochondrial activity, acrosome integrity, lipid peroxidation, and fertility potential were evaluated after the freeze-thaw process. Semen samples were collected from ten roosters, twice a week, and then diluted in extender contained different concentrations of CoQ10 as follows: Lake without CoQ10 (control, Q 0), Lake containing 1 µM (Q 1), 2 µM (Q 2), 5 µM (Q 5), and 10 µM (Q 10) CoQ10. Supplementation of Lake with 1 and 2 µM CoQ10 resulted in greater sperm viability, total motility, progressive motility, membrane functionality, mitochondrial activity, acrosome integrity, and fertility rate. Furthermore, the extent of lipid peroxidation in thawed spermatozoa treated with 1 and 2 µM CoQ10 was less than with the other groups. Different concentrations of CoQ10 had no effect on DNA fragmentation and sperm morphology. Results of the present study indicate that supplementation of Lake extender with 1 and 2 µM CoQ10 enhances the quality of rooster sperm after the freeze-thaw process.

Attenuation of cryopreservation-induced oxidative stress by antioxidant: Impact of Coenzyme Q10 on the quality of post-thawed buck spermatozoa.

The aim of this study was to determine the quality of post-thawed buck spermatozoa by attenuation of cryopreservation-induced oxidative stress using CoQ10, a lipophilic antioxidant. Ejaculates at every sampling period were collected from four Mahabadi bucks, pooled and diluted in soybean lecithin-based extenders containing 0 (negative control, NC), 0.5 (CQ0.05), 1 (CQ1), and 1.5 (CQ1.5) µM CoQ10 and 0.9% (v/v) DMSO (positive control, PC). The diluted semen was gradually cooled to 4 °C, then frozen and stored in liquid nitrogen. After thawing, total motility although was significantly higher in CQ1 (53.40 ±â€¯1.83) than control groups (43.60 ±â€¯1.83% and 42.20 ±â€¯1.83%; P < 0.05), but this parameter did not differ between CQ1 and CQ1.5. Sperm viability was significantly higher in CQ1 (54.20 ±â€¯2.03%) than that of control and CQ0.5. The CQ1 and CQ1.5 led to significantly higher the plasma membrane functionality compared to control groups. Sperm abnormality was significantly lower in CQ1 than that of NC. The results also showed that MDA level was significantly lower in CQ1 and CQ1.5 compared with control and CQ0.5. The CQ1 (59.43 ±â€¯3.93%) was significantly increased mitochondrial activity compared to control groups. Although a greater value for %DFI was found in NC (10.24 ±â€¯0.48%) and PC (9.77 ±â€¯0.48%) groups compared to others, it was lower in CQ1 group (4.26 ±â€¯0.48%). In conclusion, based on our research results, 1 µM CoQ10 could protect buck spermatozoa from cryoinjury.

Effect of melatonin supplementation in the long-term preservation of the sheep ovaries at different temperatures and subsequent in vitro embryo production.

Investigations in the past decades have shown that oocytes developmental competence following in vitro fertilization is greatly influenced by an interval between isolation of the ovaries immediately after death/slaughter and oocytes recovery from the visible follicles. In order to determine the optimal conditions for long-term preservation of ovaries, an experiment was conducted with adding different doses of melatonin (0 (C), 500 (M1), 600 (M2), 700 (M3) and 800 (M4) µM) as an antioxidant to sheep ovaries preservation medium (PBS) maintained at 4 and 20 °C for 24 h. The effects on in vitro embryo production (IVEP) parameters including maturation, fertilization, cleavage, and blastocyst rates and the total number of blastomere were evaluated after the ovaries preservation. Melatonin reduced the decline in fertilization rate as an indicator of success in vitro maturation (P ≤ 0.05). Furthermore, ovarian storage time had significant negative effect (P ≤ 0.05) on IVEP parameters. Supplementation with melatonin increased the total cell number of blastocysts as an indicator of embryo quality (i.e. mean blastomeric cells in 4°C groups: 86.00 ± 3.00, 98.50 ± 3.5, 111.5 ± 1.5, 125.5 ± 2.00 and 126.50 ± 5.5 for C, M1, M2, M3 and M4. respectively). Overall, the results showed that the use of melatonin antioxidant in the ovaries storage medium had beneficial effects on sheep oocytes development and embryos quality.

The effect of conspecific ampulla oviductal epithelial cells during in vitro maturation on oocyte developmental competence and maturation-promoting factor (MPF) activity in sheep.

The acquisition of fertilization ability by oocytes is one of the prerequisites for successful in vitro embryo production. In the present study, we examined the influence of conspecific ampulla oviductal epithelial cells incubated with cumulus-oocyte complexes (COCs) throughout the IVM phase on the developmental competence and maturation-promoting factor (MPF) activity of sheep oocytes. There were six experimental groups in this study, namely four groups with and two groups without oviductal epithelial cells added to IVM media: adult COCs matured in vitro with the ampulla oviductal epithelial cells obtained from adult (AAE; G1) or prepubertal donors (prepubertal sheep ampulla oviductal epithelial cells [PAE]; G4), COCs obtained from prepubertal animals cocultured with AAE (G2) or PAE (G3), and adult (C1) and prepubertal sheep COCs (C2) matured without oviductal epithelial cells. Coincubation of oocytes retrieved from both adult and sexually immature donors with AAE (G1 and G2) resulted in significantly improved rates of metaphase-II (M-II) attainment (G1: 85.1 ± 2.0 and G2: 40.2 ± 1.3) and blastocyst formation (G1: 42.2 ± 1.1 and G2: 21.2 ± 1.0) as well as blastocyst development (total cell count; G1: 130.3 ± 7.8, G2: 70.2 ± 3.5) compared with their respective controls (C1: 94.3 ± 4.1 and C2: 49.7 ± 2.0). Prior to IVM, the activity of MPF was greater (P < 0.05) for oocytes obtained from ewes (G1, G4, and C1) compared with those from ewe lambs (G2, G3, and C2). The greatest increment in MPF activity was recorded in G2 (MPF activity before IVM/MPF activity after IVM = 3.62) followed by C2 and G3 (2.22 and 2.20, respectively), and then all remaining groups of oocytes (C1: 1.89, G1: 1.87, and G4: 1.86). In summary, coincubation with AAE during the 24-hour IVM had a positive impact on ovine oocyte competence and ensuing in vitro embryo production efficiency. A significant increase in MPF activity following IVM of G2 oocytes could be responsible, at least partly, for the improved rate of blastocyst formation after IVF of prepubertal sheep oocytes.

Fertility response of artificial insemination methods in sheep with fresh and frozen-thawed semen.

The aim of this study was to evaluate the fertility response of artificial insemination (AI) methods with fresh and frozen sperm in sheep. In experiment 1, one hundred and fifty fat tailed Zandi ewes were assigned into 3 equal groups and inseminated with three AI methods consisting of vaginal, laparoscopic and trans-cervical AI with fresh semen. In experiment 2, a factorial study (3 AI methods × 2 extenders) was used to analyze the effects of three AI methods and two freezing extenders containing soybean lecithin (SL) or Egg yolk (EY) on reproductive performance of 300 fat tailed Zandi ewes. Also, total motility, progressive motility, viability and lipid peroxidation of semen were evaluated after freeze-thawing in two extenders. In result, there was no significant difference among three AI methods when fresh semen was used. In experiment 2, the highest percentage of pregnancy rate, parturition rate and lambing rate were obtained in laparoscopic AI group (P < 0.05). Although pregnancy rate, parturition rate and lambing rate in trans-cervical group were higher (P < 0.05) than vaginal group, the results were not as high as laparoscopic group. No difference was observed between SL and EY extenders and their performance was close to each other. It can be concluded that although no difference was observed on reproductive performance for fresh semen, trans-cervical AI was more efficient than vaginal method when frozen-thawed semen was used, but its efficiency was not as high as laparoscopic method. Also, SL extender can be an efficient alternative extender to preserve ram sperm during cryopreservation procedure without adverse effects of EY.

Differential influence of ampullary and isthmic derived epithelial cells on zona pellucida hardening and in vitro fertilization in ovine.

The central role of the oviduct, as the site of zona pellucida (ZP) maturation, fertilization and early embryogenesis, has been recognized. The objective of this study was to investigate whether ampullary and isthmic derived epithelial cells have different effects on in vitro ZP hardening, in vitro fertilization (IVF) and in vitro culture (IVC) of the resulting embryos. Cumulus oocyte complexes (COCs) were matured in a coculture system with ampullary/isthmic epithelial cells, TCM199 supplemented with insulin-like growth factor I (IGF-I) and epithelial derived growth factor (EGF) (GF treated group), conditioned media produced using ampullary (ACM), isthmic (ICM), COCs+ampullary, and COCs+isthmic epithelial cells, contactless culture system, oviductal fluid, GF+ACM/ICM, and drops of TCM199 (control), for 24h. The matured oocytes were randomly divided into two groups: Group I was subjected to ZP digestion; Group II underwent IVF. The duration of the ZP digestion, in a coculture system with ampullary epithelial cells (AE) was significantly increased (p<0.05), compared with other groups. Penetrated oocytes and monospermic fertilization were significantly increased (p<0.05) in the AE group. The mean number of spermatozoa per penetrated oocyte was reduced dramatically for the AE group (p<0.05). A significant increase (p<0.05) in the embryo development was observed in all treated groups, compared to the control. Results revealed that epithelial cells harvested from the ampullary segment of the oviduct had in vitro specialized role in ZP hardening and have subsequent IVF and IVC outcomes.

Effects of dietary supplementation of pioglitazone on metabolism, milk yield, and reproductive performance in transition dairy cows.

The objective of this study was to investigate the effect of dietary supplementation of pioglitazone (PGT), a specific ligand for PPARγ, on metabolic dynamics, milk production, and reproductive performance of transition dairy cows. Eighty multiparous Holstein cows in their second or more lactations were blocked by the calving date and parity and assigned randomly to four dietary groups (n = 20 cow/treatment) including control (no PGT-/-), supplemented with PGT (6-mg PGT/kg body weight) from Day -14 to +21 relative to parturition (PGT+/+) or only during prepartum (PGT+/-) or postpartum periods (PGT-/+). Postpartum body condition score and body weight loss decreased (P < 0.05) in all PGT-supplemented groups. Milk yield was not affected by PGT supplementation (P > 0.05). Percentage of milk fat decreased (P < 0.05) in all PGT-treated groups; however, milk fat yield was lower (P < 0.05) in PGT (+/+) and PGT (+/-) groups compared with PGT (-/-). Peripartum (Day -7 to +7) concentrations of plasma nonesterified fatty acids and ß-Hydroxybutyrate decreased in PGT (+/+) but not in the PGT (-/-) group (P < 0.05). During the postpartum period, PGT reduced (P > 0.05) plasma concentrations of nonesterified fatty acids in all PGT-treated groups but did not affect ß-Hydroxybutyrate level. Plasma concentrations of triglycerides decreased in all PGT-supplemented groups. Supplementation of PGT increased the peripartum concentrations of plasma glucose in PGT (+/+) and PGT (+/-) groups compared with control. Plasma concentrations of insulin-like growth factor 1 were higher in PGT (+/+) compared with the control group during both the peripartum and postpartum periods. Plasma concentrations of growth hormone and insulin were not affected by PGT treatment (P > 0.05). Mean days to ovulation were lower in PGT (+/+) and PGT (-/+), and the proportion of cows ovulating by Day 14 postpartum was higher in PGT (+/+) compared with control. Days open were shorter in PGT (+/+), PGT (+/-), and PGT (-/+) groups compared with control. However, the proportion of pregnant cows at 120 days in milk were higher in all PGT-supplemented groups. The results showed positive effects of dietary supplementation of PGT, especially supplementation during both the prepartum and postpartum periods, on metabolic dynamics, ovarian function, and reproductive performance in transition dairy cows.

Dietary n-3 PUFAs improve fresh and post-thaw semen quality in Holstein bulls via alteration of sperm fatty acid composition.

The goal of this study was to investigate the effect of fish oil-supplemented diet on fresh and post-thaw semen quality and sperm lipid composition in bulls. Bulls were randomly assigned to two groups (n = 6). Six bulls were used as the control group and six received the fish oil (1.2% dry matter of total diet) for 11 weeks. Semen was individually collected from each bull and frozen biweekly. Semen volume, sperm concentration, viability, progressive motility, and fatty acid profile of sperm were measured in 1st, 3rd, 5th, 7th, 9th, and 11th week of experiment. Viability, progressive motility, and fatty acid profile of post-thaw sperm were also measured in 3rd, 5th, 9th, and 11th week of experiment. Data were analyzed with using Proc GLM or MIXED (for repeated measurement data) in SAS program. The fish oil-supplemented diet increased the semen volume and sperm concentration. The fish oil-supplemented diet also altered the viability, progressive motility, and fatty acid profile of fresh and post-thaw sperm. In conclusion, feeding a fish oil-enriched diet via alteration of fatty acid profile of sperm lipid could improve in vitro quality of fresh and post-thaw sperm in Holstein bulls.

In vitro ovine embryo production: the study of seasonal and oocyte recovery method effects.

BACKGROUND: To current knowledge, different oocyte's recovery method and various seasons have profound impact on in vitro embryo production (IVEP). OBJECTIVES: The aim of this study was to define an efficient recovery method for oocytes harvesting from slaughterhouse material in different seasons, and their effects on IVEP yield. MATERIALS AND METHODS: Ovaries from slaughtered ewes in breeding season (BS) and non-breeding season (NBS) were collected from a local abattoir. The oocytes were recovered through aspiration, centrifugation (ORC), puncture and slicing, and categorized into three classes (I, oocytes with more than three layers of cumulus cells; II, less than three layers with damaged cumulus cells; III, denuded oocytes). After cultivation in TCM 199 for 24 hours, matured oocytes were subjected to in vitro fertilization (IVF) and in vitro culture (IVC). The oocyte recovery using ORC in BS and NBS was significantly higher (P < 0.05) compared with other recovery methods. RESULTS: No significant dissimilarities in the proportion of oocytes reaching M-II stage were recorded when using different oocyte recovery methods in different seasons. Aspiration resulted in lower (P < 0.05) proportion of class I (BS, 60.0 ± 2.1; NBS, 51.1 ± 2.1) compared to ORC (BS, 82.0 ± 1.2; NBS, 70.0 ± 1.2), slicing (BS, 80.0 ± 2.1; NBS, 71.0 ± 1.4) and puncture (BS, 80.0 ± 1.5; NBS, 72.0 ± 2.0). Monospermy and blastocyst development rates were significantly higher using ORC than other recovery techniques in both BS and NBS. More oocytes with high quality, greater blastocyst development and oocyte recovery rates were achieved in BS. CONCLUSIONS: The results revealed that oocytes harvesting technique and season are effective in the rate of cleavage and blastocysts' development, and suggest that despite same meiotic resumption rate in all treatments, it would be better to use ORC.

Comparison of the meat quality and fatty acid composition of traditional fat-tailed (Chall) and tailed (Zel) Iranian sheep breeds.

The aim of this study was to compare the meat quality of a traditional fat-tailed breed, Chall, to a tailed Iranian sheep breed, Zel. Lambs were grazed on pasture until weaning, and then were finished until slaughter at 10-12 months. Meat quality traits were measured on the longissimus dorsi (LD) muscle. Zel lambs accumulated more intramuscular fat (IMF) (p<0.01) and had lower shear force and drip loss than Chall lambs (p<0.05). The meat color of Zel lambs was higher for both a* (p<0.001) and b* (p<0.01) compared to Chall lambs. Meat from Zel lambs was more tender (p<0.01) and more juicy (p<0.05) than Chall lambs. The PUFA:SFA fatty acid ratio (P:S) was higher (p<0.05) and the n-6:n-3 PUFA ratio was lower in Chall compared to Zel lambs (p<0.05). Overall, these results show that the eating quality of Zel lambs was better, but that this was at the cost of less favorable fatty acid profiles and poorer meat color.

Unexpected detrimental effect of Insulin like growth factor-1 on bovine oocyte developmental competence under heat stress.

PURPOSE: To investigate the effects of Insulin like growth factor-1 (IGF-1) on bovine oocyte developmental competence under heat stress. METHODS: In Experiment 1, bovine cumulus-oocyte complexes (COCs) were cultured at 38.5 or 41 degrees C for the first 12 h of maturation in the presence of either 100 ng/ml human recombinant (hr)-IGF-1 or acetic acid. In Experiment 2, COCs were cultured in 38.5 or 41 degrees C for the first 12 h of maturation in the presence either of 100 ng/ml hr-IGF-1 or acetic acid. After fertilization, putative zygotes were cultured for 8 days. RESULTS: In experiment 1, addition of rh-IGF-1 to maturation medium at 38.5 degrees C significantly increased the proportion of M II oocytes and decreased the percentage of TUNEL-positive oocytes compared to the other groups. However, addition of rh-IGF-1 to maturation medium under heat stress increased the percentage of TUNEL-positive oocytes. In experiment 2, addition of rh-IGF-1 under heat sress did not affect cleavage rate, whereas, blastocyst formation rate decreased in heat-stressed and heat-stressed plus rh-IGF-1 groups. Similarly, The number of trophectoderm cells and total cell number were decreased in heat-stressed and heat-stressed plus rh-IGF-1 groups and the percentage of TUNEL-positive nuclei were increased in heat-stressed and heat-stressed plus rh-IGF-1 groups compared to the other groups. CONCLUSION: The results of the present study demonstrate that IGF-1 decreases oocyte developmental competence and total cell number and increases TUNEL-positive nuclei at heat stress condition. These unexpected results of IGF-1 during maturation period under heat stress condition warrant further optimizations and investigations.