Effect of different concentrations of soybean lecithin and virgin coconut oil in Tris-based extender on the quality of chilled and frozen-thawed bull semen.

AIM: The objective of this study was to evaluate the effects of different concentrations of soybean lecithin (SL) and virgin coconut oil (VCO) in Tris-based extender on chilled and frozen-thawed bull semen quality parameters. MATERIALS AND METHODS: A total of 24 ejaculates were collected from four bulls via an electroejaculator. Semen samples were diluted with 2% VCO in Tris-based extender which consists of various concentrations of SL (1, 1.25, 1.5, and 1.75%). A 20% egg yolk in Tris used as a positive control (C+). The diluted semen samples were divided into two fractions; one for chilling which were stored at 4°C for 24, 72, and 144 h before evaluated for semen quality parameters. The second fraction used for freezing was chilled for 3 h at 4°C, packed into 0.25 mL straws and then cryopreserved in liquid nitrogen. The samples were then evaluated after 7 and 14 days. Chilled and frozen semen samples were thawed at 37°C and assessed for general motility using computer-assisted semen analysis, viability, acrosome integrity and morphology (eosin-nigrosin stain), membrane integrity, and lipid peroxidation using thiobarbituric acid reaction test. RESULTS: The results showed that all the quality parameters assessed were significantly (p<0.05) improved at 1.5% SL concentration in chilled semen. Treatment groups of 1, 1.25, 1.5, and 1.75% SL were higher in quality parameters than the control group (C+) in chilled semen. However, all the quality parameters in frozen-thawed semen were significantly higher in the C+ than the treated groups. CONCLUSION: In conclusion, supplementation of 1.5% SL in 2% VCO Tris-based extender enhanced the chilled bull semen. However, there was no marked improvement in the frozen-thawed quality parameters after treatment.

Effect of different concentrations of egg yolk and virgin coconut oil in Tris-based extenders on chilled and frozen-thawed bull semen.

The aim of this study was to evaluate the effects of 8% virgin coconut oil (VCO) combined with different percentages of egg yolk in Tris extender on the quality of chilled and frozen-thawed bull semen. A total of 24 ejaculates from four bulls were collected using an electroejaculator. Semen samples were diluted with 8% VCO in Tris extender which contained different concentrations 0% (control), 4%, 8%, 12%, 16% and 20% egg yolk. The diluted semen samples were divided into two fractions: one was chilled and stored at 4°C until evaluation after 24, 72, and 144h; the second fraction was processed by chilling for 3h at 4°C to equilibrate, then packaged in 0.25ml straws and frozen and stored in liquid nitrogen at -196°C until evaluation after 7 and 14 days. Both chilled and frozen semen samples were then thawed at 37°C and assessed for general motility using computer-assisted semen analysis (CASA), viability, acrosome integrity, and morphology (eosin-nigrosin), membrane integrity (hypo-osmotic swelling test) and lipid peroxidation (thiobarbituric acid-reactive substances (TBARS)). The results indicate treatments with 8%, 12%, 16% and 20% egg yolk with 8% VCO had greater sperm quality (P<0.05) as compared with the control. The treatment with 20% egg yolk had the greatest sperm quality (P<0.05) among the treated groups for both chilled and frozen-thawed semen. In conclusion, the use of 8% VCO combined with 20% egg yolk in a Tris-based extender enhanced the values for chilled and frozen-thawed quality variables of bull sperm.

Plasma progesterone changes and length of oestrous cycle in Rusa Deer (Rusa timorensis).

A study was conducted to profile the plasma progesterone (P4) concentrations and establish the length of oestrous cycle in the Rusa timorensis during the breeding season. Five healthy hinds were selected for peripheral blood sampling twice weekly to gauge the P4 levels by radioimmunoassay, at the start of the breeding season indicated by rutting behaviours of sexually active males. The hinds were polyestrous as proven by the cyclic trend of P4 levels. After the presumptive oestrus indicated by the lowest P4 concentrations (0.20±0.09ng/ml), this ovarian hormone was markedly elevated on day 7 of the cycle (0.78±0.20ng/ml), reached its peak (2.61±0.23ng/ml, P<0.05) on day 14, and then declined to the basal level in the subsequent oestrus. The mean oestrous cycle length in R. timorensis during the breeding season was 19.2 days with a range of 18-21 days, and the pattern of circulating progesterone during the oestrous cycle of the R. timorensis is similar to those of other deer species. It was also observed that the length of oestrous cycle of R. timorensis determined by gauging the progesterone levels and observation of the oestrous behaviours as well as changes in the cellular pattern of vaginal epithelial cells are highly consistent.

Effect of antioxidants on post thaw microscopic, oxidative stress parameter and fertility of Boer goat spermatozoa in Tris egg yolk glycerol extender.

This study was conducted to determine the effect of antioxidants on standard semen parameters, lipid peroxidation and fertility of Boer goat semen after cryopreservation. Ejaculates from four bucks were collected, evaluated and pooled at 37°C. The pooled semen was diluted with Tris citric acid fructose for washing. Semen samples, which were diluted with a Tris-based extender containing the antioxidant ascorbic acid (8.5mg/ml), butylated hydroxytoluene (2mM), cysteine (5mM) and hypotaurine (10mM) and an extender without antioxidant supplementation were cooled to 4°C and frozen in 0.25 straws with programmable freezer and finally stored in liquid nitrogen. Data (10 replicates) were analyzed by one-way analysis of variance. Mean (±SEM) progressive motility was significantly higher in ascorbic acid than other supplement groups and control samples (P>0.05). Best values were observed in ascorbic acid followed by BHT, cysteine, and hypotaurine. Antioxidant supplementation in extender showed significant (P<0.05) better values than the control group for sperm membrane integrity, acrosome integrity and viability. The ability of antioxidants to reduce the lipid peroxidation (LPO) after freeze thawing was measured by the formation of malondialdehyde (MDA) using the thiobarbituric acid method. Results showed that addition of antioxidants significantly reduced the rate of LPO in comparison to control (P<0.05). Ascorbic acid exhibited better values (1.27±0.28), than butylated hydroxytoluene, cysteine and hypotaurine 1.32±0.42, 2.27±0.16 and 2.38±0.17 respectively, which are significantly better than control (3.52±0.54). Higher pregnancy rate was observed with ascorbic acid followed by butylated hydroxtolune, hypotaurine and cysteine. However, differences in the fertility rate were non-significant with hypotaurine, cysteine and control groups.

Cryotop no desenvolvimento de oócitos bovinos imaturos vitrificados / Cryotop and development of vitrified immature bovine oocytes

The effectiveness of different cryodevices (open-pulled straw (OPS), electron microscopy grid (EMG), and Cryotop was evaluated for vitrification of immature bovine oocytes. Polar body, metaphase II stage (MII), survivability, and subsequent developmental rates were determined. Only oocytes with four or five layers of cumulus cells were used. Oocytes were equilibrated in two vitrification solutions - 1: 10 percent DMSO + 10 percent ethylene glycol (EG) for 30-45sec and 2: 20 percent DMSO + 20 percent EG +0.5M sucrose for 25sec -, mounted on one of the cryodevices and directly plunged into liquid nitrogen for 10 days. Immature vitrified oocytes using Cryotop showed the highest rates of polar body extrusion (PB) and nuclear maturity (MII); 41 and 58 percent respectively. Vitrified oocytes using OPS and EMG showed 26 and 32 percent; and 35 and 46 percent of PB and MII rates, respectively. The highest survivability resulted from Cryotop and EMG groups and no significant difference was found between them. Vitrified oocytes using Cryotop had the highest cleavage and blastocyst rates. All of the mean rates for vitrified immature oocytes were significantly lower than that of control group (P<0.05). The results of this study showed the superiority of Cryotop device for vitrification of immature bovine oocytes.

Avaliou-se a eficácia de diferentes dispositivos de congelamento (envasamento em palhetas (EP), microscopia eletrônica de grade (MEG) e Cryotop) para vitrificação de ovócitos imaturos de bovinos. Para tal, foram determinados o corpo polar, a metáfase II (MII), a viabilidade e as subsequentes taxas de desenvolvimento. Foram utilizados somente ovócitos com quatro ou cinco camadas de células do cumulus. Os ovócitos foram equilibrados em duas soluções de vitrificação - 1: DMSO (10 por cento) + etilenoglicol (EG; 10 por cento) por 30 a 45 segundos e 2: DMSO (20 por cento) + EG (20 por cento) + sacarose (0,5M) por 25 segundos -, transferidos para os dispositivos de congelamento e mantidos, por 10 dias, em nitrogênio líquido. Imediatamente após serem retirados do nitrogênio, os ovócitos foram removidos dos dispositivos e processados para maturação, fertilização e cultivo in vitro. Os ovócitos vitrificados com o Cryotop apresentaram as maiores taxas de extrusão do corpo polar (CP) e de maturidade nuclear (MII), 41 e 58 por cento, respectivamente. Para os ovócitos vitrificados com EP e MEG, as taxas de CP e as de MII foram, respectivamente, de 26 e 32 por cento e de 35 e 46 por cento. As taxas de viabilidade não diferiram entre os grupos Cryotop e EMG. Os ovócitos vitrificados com Cryotop apresentaram as maiores taxas de clivagem e de blastocisto. Para todas as variáveis estudadas, as taxas para os ovócitos vitrificados foram significativamente menores do que as do grupo-controle (P<0,05). Os resultados deste estudo mostraram a superioridade do dispositivo Cryotop para vitrificação de ovócitos imaturos de bovinos.

Ovarian activity in beef and dairy cows with prolonged postpartum period and heifers that fail to conceive.

The primary objectives of this study were to investigate incidence of abnormal ovarian cyclicity (AOC) and its type in dairy and beef cows with prolonged postpartum period (>90 days) and in heifers that fail to conceive. A total of 53 animals were included in the study: 17 Friesian crosses, 16 Braford crosses, eight Brangus crosses, and 12 local Kedah-Kelantan (KKX) crosses. These animals were initially checked for absence of pregnancy via palpation per rectum. Blood samples for progesterone analysis were obtained twice a week for 2 to 3 months following their spontaneous oestrous cycle, and all animals were rechecked for pregnancy at the end of the study. Progesterone analysis indicated that 33.9% of the total animals were having AOC: 18.9% with cessation of ovarian cyclicity, 9.4% with prolonged luteal phases (PLP), and 5.7% short luteal phases. The highest incidence was observed in Brangus crosses (62.5%), followed by Braford crosses (43.8%), and Friesian crosses (35.3%). In contrast, no AOC was observed in the local KKX breeds, and all of them were found to be pregnant at the end of the study. A significant difference (p < 0.05) in the incidence of AOC and its type was observed between Kedah-Kelantan crosses and the other breeds. Although not significant (p > 0.05), Friesian crosses showed a higher percentage incidence of AOC than beef cows (40% vs 36.4%), with major types being PLP (26.7%) in dairy and cessation of ovarian cycle (27.3%) in beef cows. Compared with beef heifers, beef cows showed a higher percentage of AOC (36.4% vs 28.6%) where again, cessation of cyclicity was the predominant abnormality. In conclusion, AOC reflected by abnormal endocrine pattern is a possible cause of reduction in fertility for dairy and beef cows beyond 90 days postpartum and heifers that fail to conceive.

Superovulation and egg recovery in goats in the tropics.

The superovulatory response to gonadotrophin treatment during different months of the year was investigated in Kambing kacang goats, a tropical breed, in Malaysia. Sixty-three cycling does, fitted with progesterone impregnated intravaginal sponges for 17 days, received two days before sponge withdrawal, an intramuscular injection of either 10, 15 or 20 mg of follicle stimulating hormone (FSH) or 500, 1000 or 1500 iu of equine chorionic gonadotrophin (eCG). The dose of FSH was divided into four decreasing daily doses and each daily dose was subdivided into two and administered at 07.00 and 19.00. Fifty-four does detected in oestrus were mated with fertile bucks. The ovarian response was determined by laparoscopy and eggs were recovered surgically five or six days after oestrus. The ovulatory response (mean +/- standard deviation) based on corpora lutea was higher in the FSH (13.4 +/- 8.4 corpora lutea per doe, n = 20) than the eCG-treated groups (6.4 +/- 5.1 corpora lutea per doe, n = 25) but the difference was not significant (P greater than 0.05). Does responded to gonadotrophins throughout the year with more than 50 per cent of does responding during the rainy months compared with less than 35 per cent responding during the dry months. This difference was statistically significant (P less than 0.05). Egg recovery was better in the FSH (6.8 +/- 5.3 per doe, n = 20) than the eCG groups (3.0 +/- 3.8 per doe, n = 21) but the difference was not significant (P greater than 0.05).