Production of sexed bovine embryos in vitro can be improved by selection of sperm treatment and co-culture system

The study investigated the effects of sperm sorting, capacitation treatment and co-cultivation on sexed bovine in vitro embryo production. The effect of treatment and co-culture on production of embryos of the preferred sex from unsorted sperm was also studied. Sperm from five breeding bulls was used for fertilization of mature oocytes as follows : Experiment 1, sorted and unsorted sperm (bulls A-E) treated only with heparin in standard co-cultures; Experiment 2, sorted sperm (bulls A-E) treated with heparin-PHE (penicillamine, hypotaurine, and epinephrine) or heparin-caffeine in drop co-cultures; and Experiment 3, unsorted sperm (bull E) treated with either heparin-PHE or heparin-caffeine in both standard and drop co-cultures. In all bulls, treatment with heparin resulted in significantly (p < .05) reduced cleavage and blastocyst rates from sorted sperm, as compared with those from unsorted sperm. In bulls A, B, D and E, treatment of sorted sperm with heparin-PHE in drops significantly increased the blastocyst rate (p < .05). In unsorted sperm of bull E, heparin-PHE treatment in drops resulted in the XX/XY sex ratio inverse to that obtained by heparin-caffeine treatment in standard co-cultures (32.3%/67.7% and 66.7%/33.3%, respectively). In conclusion, the treatment of sorted sperm with heparin-PHE in modified drop co-cultures can be recommended for production of in vitro sexed embryos. The use of unsorted sperm for production of embryos of the preferred sex by selected capacitation treatment and co-culture can be the method of choice in bulls with low IVF yields from sorted sperm.     

Variability in plasma membrane integrity, mitochondrial membrane potential and acrosomal status before and after cryopreservation of bull sperm

In the present study variability of bull sperm concerning percentages of sperm with intact plasma membranes (PMI), high mitochondrial membrane potential (HMMP) and positive acrosomal status (PAS) before and after cryopreservation (vKK; nKK) between bulls and between ejaculates within bulls was examined. Studies were performed on 4 semen samples each of 20 Deutsche Fleckvieh bulls. VKK-Values were 76.5% +/- 9.6% (PMI) 68.3% +/- 8.9% (HMMP) and 9.8 +/- 5.1% (PAS) and nKK-values were 38.1 +/- 14.0% (PMI), 38.2 +/- 14.0% (HMMP) and 30.9 +/- 12.1% (PAS). After freezing, variabilities in sperm parameter values between bulls (nKK: PMI: 49.8%, HMMP 52.1% and PAS: 56.6%) were nearly quite as high or higher than variabilities between ejaculates (nKK: 50.2%, 47.9% and 43.4%). VKK-values of PMI, HMMP and PAS were only fairly to moderately related (0.36 < r < 0.53; P < 0.05) to nKK-values. The results show that PMI, HMMP and PAS did not only vary between bulls, but also between ejaculates within bulls. As there are no high relationships in these sperm parameters between times before and after cryopreservation, each ejaculate should be examined after cryopreservation in order to receive a reliable information about the quality of cryopreserved sperm.     

Effects of aflatoxin B1 on mitochondrial respiration,ROS generation and apoptosis in broiler cardiomyocytes

Aflatoxin B1 (AFB1) develops various toxic effects in the liver by impairing mitochondrial function, inducing cell apoptosis. However, little is focused on its toxicity to broiler cardiomyocytes (BCMs). Here, the mitochondrial membrane potential (MMP), reactive oxygen species (ROS) generation, cardiac troponin T (cTnT) location, apoptosis induced by AFB1, and antioxidative genes were investigated in BCMs. It was found that AFB1 evoked intracellular ROS generation, and induced apoptosis in BCMs. AFB1 treatment resulted in increased percentage of apoptotic cells, increased location range of cTnT in cytoplasm, upregulated messenger RNA (mRNA) expression of nuclear factor erythroid 2‐related factor 2 (Nrf2) and downregulated mRNA expressions of Mn‐superoxide dismutase in BCMs. These findings suggested AFB1 treatment caused significant cardiomyocyte damage and cardiotoxicity, impairment of mitochondrial functions, activated ROS generation, and induced apoptosis, and probably was involved in the Nrf2 signal pathway in BCMs.     

Melatonin reduces apoptotic cells,SOD2 and HSPB1 and improves the in vitro production and quality of bovine blastocysts

Effects of adding different concentrations of melatonin (10^?7, 10^?9 and 10^?11 M) to maturation (Experiment 1; Control, IVM  + 10^?7, IVM  + 10^?9, IVM  + 10^?11) and culture media (Experiment 2; Control, IVC  + 10^?7, IVC  + 10^?9, IVC  + 10^?11) were evaluated on in vitro bovine embryonic development. The optimal concentration of melatonin (10^?9 M) from Experiments 1–2 was tested in both maturation and/or culture media of Experiment 3 (Control, IVM  + 10^?9, IVC  + 10^?9, IVM /IVC  + 10^?9). In Experiment 1, maturated oocytes from Control and IVM  + 10^?9 treatments showed increased glutathione content, mitochondrial membrane potential and percentage of Grade I blastocysts (40.6% and 43%, respectively). In Experiment 2, an increase in the percentage of Grade I blastocysts was detected in IVC  + 10^?7 (43.5%; 56.7%) and IVC  + 10^?9 (47.4%; 57.4%). Moreover, a lower number and percentage of apoptotic cells in blastocysts were observed in the IVC  + 10^?9 group compared to Control (3.8 ± 0.6; 3.6% versus 6.1 ± 0.6; 5.3%). In Experiment 3, the IVC  + 10^?9 treatment increased percentage of Grade I blastocysts with a lower number of apoptotic cells compared to IVM /IVC  + 10^?9 group (52.6%; 3.0 ± 0.5 versus 46.0%; 5.4 ± 1.0). The IVC  + 10^?9 treatment also had a higher mRNA expression of antioxidant gene (SOD 2) compared to the Control, as well as the heat shock protein (HSPB 1) compared to the IVM  + 10^?9. Reactive oxygen species production was greater in the IVM /IVC  + 10^?9 treatment group. In conclusion, the 10^?9 M concentration of melatonin and the in vitro production phase in which it is used directly affected embryonic development and quality.     

Addition of D-penicillamine,hypotaurine, and epinephrine (PHE) mixture to IVF medium maintains motility and longevity of bovine sperm and enhances stable production of blastocysts in vitro

The present study aimed to establish an efficient system for bovine embryo production by in vitro fertilization (IVF) that can achieve stable normal fertilization and blastocyst developmental rates in any bull without optimization of the sperm concentration in IVF medium. We examined the effects of a PHE mixture (20 μM D-penicillamine, 10 μM hypotaurine and 1 μM epinephrine), theophylline (2.5 mM), and sperm concentration (1, 2 or 5 × 10⁶ cells/ml) on fertilization and blastocyst developmental rates. High cleavage rates (78.3 to 92.4%) and blastocyst developmental rates (31.9 to 62.0%) at day 7 were obtained in the presence of PHE and theophylline in IVF medium with a sperm concentration of 2 × 10⁶ cells/ml using sperm from 9 bulls. In addition, the synergistic effect of PHE and theophylline on normal fertilization (2 pronuclei) was clarified at 12 h after IVF with a sperm concentration of 1 × 10⁶ cells/ml. Moreover, high linearity, high flagellar beat cross frequency, and low amplitude of lateral head of motile sperm were found by computer-assisted sperm analysis. In conclusion, the combination of the PHE mixture and theophylline synergistically accelerates sperm motility and sperm penetration of bovine oocytes. Theophylline activates sperm motility with increasing intracellular cAMP. However, PHE prevents an excessive increase of cAMP and maintains sperm motility without hyperactivation. When the combination of PHE and theophylline is added to IVF medium at a sperm concentration of 2 × 10⁶ cells/ml, we can achieve stable normal fertilization and blastocyst development in any bull.