RESUMEN
Production of high quality embryos in vitro needs an efficient in vitro fertilization (IVF). Seminal origin is one of the important factors that affects the success of in vitro embryo production. So our goal was to determine the effect of using fresh and frozen semen in fertilization on developmental competence and cryo-survival of buffalo embryos. Buffalo oocytes were matured and fertilized in vitro by fresh and frozen semen. After embryos evaluation, good quality morula and blastocysts were vitrified using 0.25 ml straws and the post-warmed viability was assessed by further culture for 24 h. There was no significant difference in cleavage rate between embryos derived from fresh and frozen semen, whereas the rate of embryo development to the morula (P<0.05) and blastocysts (P<0.01) stages was significantly decreased in embryos derived from frozen compared to fresh semen. After warming the vitrified embryos, there was no significant difference between embryos derived from fresh and frozen semen in the percentages of morphologically viable embryos. However, 24 h after culture, the rate of morphologically normal and survived embryos was increased (P<0.05) in embryos derived from fresh compared to the frozen semen. In conclusion, in buffalo, the use of fresh semen could improve the rate of embryo development and their crytolerance compared to the frozen semen.
RESUMEN
Egypt is anticipated to be potentially influenced by the global climate warming. Therefore, the current study aimed to evaluate the influence of age on the fertility potential of Arabian stallions during summer breeding months. Arabian horses grouped according to their age into three groups, each involved six stallions: young (5-6 years), middle (11-12 years) and old (15-20 years) age groups, were weekly sampled during the months of July-August. Ejaculates were collected using artificial vagina, Missouri model, and examined for pH, volume, concentration, motility, livability and morphological abnormalities. Serum samples were harvested and assessed for testosterone, total antioxidant capacity (TAC), lipid profile, and copper and zinc levels. Semen pH (P<0.005), spermatozoa motility (P=0.08), sperm morphology (P<0.001), tail abnormalities (P<0.001), and sperm count per ejaculate differed noticeably between stallions' groups. Testosterone (P=0.07) and TAC (P<0.05) concentrations were markedly affected by stallions' age. Cholesterol correlated negatively with sperm normality, but serum copper and zinc levels correlated positively with semen volume, sperm cell count and spermatozoa livability. These results revealed that the fertility of stallions is age-dependent and is prominently influenced by lipid metabolism and oxidative stress during hot summer breeding season. It is highly advisable to provide animals' house (along with feed and drinking water) with the evaporative cooling system and allow morning or late afternoon outdoor activity to bypass the summer hot climates and sustain stallions' fertility.
RESUMEN
The aims of the present study were to assess the effects of cysteamine as an anti-oxidant on the rate of in vitro maturation (IVM) of buffalo oocytes (experiment 1), and their viability and nuclear status following vitrification (experiment 2). Immature oocytes with compact cumulus cells obtained from the ovaries of slaughtered animals were harvested and then cultured in the maturation medium with no cysteamine (control) or 50 µM cysteamine (treated). Oocytes were vitrified in vitrification solution 1 (VS1): 1.5 M ethylene glycol (EG) + 1.5 M dimethyl sulfoxide (DMSO) for 45 s (step one). After this initial exposure, oocytes were transferred to VS2: 3 M EG + 3 M DMSO in a holding medium for 25 s (step two). After warming, oocytes were evaluated morphologically and then cultured for a further 2 h in the cysteamine-supplemented or control maturation media. The oocytes were evaluated morphologically, stained with trypan blue for viability evaluation. The maturation rate of oocytes was higher (P<0.05) for IVM media with cysteamine compared with controls. There was no significant difference in morphology, survivability and maturation rate between the two vitrification groups (cysteamine-treated and untreated groups) but the morphology, survivability and percentages of metaphase-II oocytes in both groups of vitrified oocytes were lower compared with their respective controls. In conclusion, the addition of cysteamine to the maturation medium improved nuclear maturation of buffalo oocytes but had no positive effect on their cryoresistance during vitrification.
RESUMEN
The intensity of heat signs in buffaloes is generally low and the incidence of suboestrus varied from 15 to 73% (Buffalopedia). The objective of this study was to investigate the feasibility of monitoring the changes in some milk constituents, oestradiol levels and electrical conductivity of vaginal mucus during peri-oestrous period in prediction of the timing of oestrus in buffaloes. Twenty-one Egyptian buffaloes aged 3-9 year, 1st-6th lactations, were examined by oestrous detector and ultrasonographically for monitoring the ovarian and uterine activity for 7 days around the time of standing oestrus. Sodium, potassium, chloride and lactose were assayed in aqueous phase of milk; besides, oestradiol was estimated in serum. Current results declared highly significant acute changes in milk constituents at the time of oestrus characterized by peaking of chloride and sodium levels and lowering of potassium and lactose values. The alternation in milk composition when arranged in decreasing order of magnitude, sodium was the highest (77.78 ± 0.69%), followed by chloride (61.60 ± 1.52%) and potassium (-58.14 ± 10.89%). Concomitantly, milk lactose decreased by 26.07 ± 7.97% compared to baseline levels. Synchronously, vaginal electrical resistance (VER) showed a significant (p < 0.01) decrease, but serum oestradiol 17ß levels surged (59.93 ± 7.29 pg/ml) on day of oestrus. Serum oestradiol level was negatively correlated with VER (r = -0.577), potassium (r = -0.661), positively correlated with chloride (r = 0.707) and sodium (r = 0.579) and not correlated with lactose levels. These results for the first time suggested that the changes in constituents of milk during peri-oestrous period may be used as a practical non-invasive indicator for oestrous detection and prediction of ovulation in Egyptian buffaloes.