34 Cellular effects of antifreeze proteins type I and III in extender for sheep semen cryopreservation

Antifreeze proteins (AFP) have been included in extenders for sperm cryopreservation to prevent ice crystal formation. Thus, this study assessed the effects of supplementing semen extender with two concentrations of AFP types I and III on the quality of frozen–thawed ram sperm. The hypothesis is that various types and concentrations of AFP enhance cryopreservation of ram sperm. Semen was collected from 4 rams, pooled in 6 replicates, and allocated into 1 of 5 treatments: Control (CONT, without AFP); AFP type I [0.1 (AFPI-0.1) or 0.5 (AFPI-0.5) µg±mL−1]; or AFP type III [0.1 (AFPIII-0.1) or 0.5 (AFPIII-0.5) µg±mL−1]. Straws were placed on a metal wire net frame at 37°C and placed in a refrigerator for 2h to cool them to 5°C (−0.25°C/min). After 2h for stabilisation, straws were cooled in liquid nitrogen vapor (−15.3°C/min) and subsequently immersed (−196°C). After thawing, samples from each treatment were evaluated microscopically (sperm kinetics, plasma membrane integrity, capacitation, hypoosmotic test, acrosome status and mitochondrial activity, chromatin condensation, morphology, binding to egg perivitelline membrane, and lipoperoxidation quantification). The normal distribution of residuals was determined by Shapiro-Wilk test and homoscedasticity by Levene’s test. Normally distributed variables were analysed with one-way analysis of variance (ANOVA), followed by Tukey’s test. The non-normally distributed were analysed by Kruskal–Wallis and Dunn’s test. The repeated-measures ANOVA in general linear model (GLM) was used to effects of concentration for each AFP type in paired samples. The Greenhouse-Geisser test was applied when sphericity was not considered, followed by the Sidak test. Values of P<0.05 were considered significant. Treatments affected (P<0.05) kinetic parameters, plasma membrane integrity, and morphology. Linearity was greater in AFPI-0.1 (56.6±3.1%, mean±s.e.m.), AFPI-0.5 (56.9±2.2%), and AFPIII-0.5 (64.7±6.2%) than in CONT (36.8±3.0%). Straightness was greater in all AFP-supplemented extenders (overall mean, 78.6±2.8%) than in CONT (63.2±0.8%). Plasma membrane integrity was greater in AFPI-0.1 (49.1±4.6%) and AFPI-0.5 (36.6±7.3%) compared with CONT (13.0±4.4%). All AFP groups had a greater percentage of normal sperm (overall mean: 74.3±1.3%) than CONT (65.3±1.9%). There were no significant differences in percentage of sperm with functional membrane (overall mean: 16.1±3.3%), normal acrosome (11.5±4.5%), mitochondrial activity (24.5±6.5%), chromatin condensation (98.8±0.4%), perivitelline membrane binding rate (194.0±44.5 sperm/mm2), and lipoperoxidation (556.7±20.5 TBARS ng±mL−1). In conclusion, the use of AFP, predominantly type I, had potential as a cryoprotectant for ram sperm, increasing sperm cell protection, with no adverse effects on potential fertilization capacity and did not increase reactive oxygen species. This research was funded by FAPERJ, CNPq, and CAPES (Finance Code 001).

114 Short-term hormonal protocol efficiency either with or without equine chorionic gonadotrophin to promote oestrous synchronization in cyclic dairy goats

The use of equine chorionic gonadotrophin (eCG) in oestrous induction protocols is associated with antibody production against eCG. Moreover, there are important equine welfare issues involved in its production and the development of viable protocols without eCG in dairy goats is essential. The aim of this study was to assess oestrus and ovulatory responses of short-term oestrous synchronization protocol with or without eCG in nulliparous (NUL) and multiparous (MUL) dairy goats during the breeding season. On a random day of oestrous cycle (Day 0), Alpine (n=10 NUL and 10 MUL), Nubian (n=10 NUL and 10 MUL), and Saanen (n=10 NUL and 6 MUL) goats received 30μg of d-cloprostenol intramuscularly (IM) and an intravaginal sponge containing 60mg of medroxyprogesterone acetate, which was maintained for 6 days (Day 6). At 24h before sponge removal (Day 5), goats received IM 200IU of Novormon 5000 (G-eCG) or saline solution (G-Control). NUL and MUL goats of each breed were assigned equally into one of the two treatments. Transrectal ultrasonography was used to assess ovarian parameters, and teaser goats detected oestrus every 12h from sponge removal to ovulation or until 96h after sponge removal. The results are described as mean±s.e.m., and categorical results are presented as percentages. The normal distribution of the residues of all variables was determined by the Shapiro-Wilk test and for homoscedastic by Levene test. To evaluate interaction between treatments and parity order, the general linear model (GLM) was applied. Parametric variables were subjected to Student’s t-test. Nonparametric variables were analysed by Mann–Whitney test, Chi-squared test, and Fisher’s exact test. Values of P<0.05 were considered significant. According to the breed and parity order, Nubian and Saanen goats showed no difference (P>0.05) in reproductive parameters. Alpine goats had a longer (P<0.05) interval from sponge removal to onset of oestrus (SROE) in MUL (61±14.0h) than NUL (38.5±12.7h), longer interval from onset of oestrus to ovulation (IEOV) in NUL (33.5±11.9h) than MUL (19.5±13.4h), and the number of ovulations was greater (P<0.05) in MUL (2.2±0.9) than in NUL (1.3±0.5). In goats either receiving eCG or not, Alpine and Nubian goats had no difference (P>0.05) in SROE, IEOV, interval from sponge removal to ovulation (SROV), percentage of animals that ovulated, diameter of the ovulatory follicle, and number of ovulations. Saanen goats had a higher (P<0.05) percentage of animals that ovulated in G-eCG (87.5%) than G-control (25.0%). Regardless of parity order and breed, SROV was longer (P<0.05) in G-control (73.2±9.8h) than in G-eCG (65.1±10.2h), and the percentage of animals that ovulated was greater (P<0.05) in G-eCG (96.4%) than in G-control (67.9%). In summary, in short-term protocols for oestrous synchronization in cyclic dairy goats, the addition of eCG led to a shorter interval from sponge removal to ovulation and increased number of animals that ovulated. This research was supported by CNPq (310166/2012-8) and Embrapa (20.19.01.004.00.03.001).

Exogenous progestogen does not affect first-wave follicle populations and oocyte quality during ovarian stimulation with FSH in sheep

The effect of short-term administration of medroxyprogesterone acetate (MPA) or natural progesterone (P₄) during ovarian stimulation with FSH on oocyte recovery was investigated in Santa Inês ewes. Ewes were treated with an intravaginal sponge containing MPA for 6 d; GnRH was applied 36 h after sponge removal and FSH was given in 3 injections (40, 24, and 16 mg, respectively) every 12 h after (D0, approximate ovulation time). At the first FSH dose, the ewes received either a new MPA sponge (n = 10) or a controlled device for internal release impregnated with P₄ (n = 10) or did not receive any device (n = 10). Ovarian dynamics were assessed every 12 h by transrectal ultrasonography from D-3 to D2. Oocytes were recovered by laparoscopic ovum pick-up (LOPU) on D2 and graded by morphologic quality. The number of small, medium, and large follicles at D0 and D2 (ultrasound examinations), number of both follicles aspirated and oocytes recovered at LOPU, recovery rate, and oocyte grade did not differ (P > 0.05) among treatments. Thus, the short-term use of MPA or P₄ during ovarian stimulation did not affect the first-wave follicle population or morphologic quality of oocytes. We would suggest that, in this protocol, the use of exogenous progestin is unnecessary.