Note:

To investigate the physiological action of follistatin in the swine ovary a recombinant porcine follistatin (rpFS) with apparent molecular weights of 39, 46, 48, and 50 kDa was expressed and characterized. The rpFS crossreacted with antibodies against native porcine follistatin and with activin A. One rpFS isotype was purified by monoclonal antibody affinity chromatography (rp-305 a.a. FS). In porcine granulosa cell cultures, rp-305 a.a. FS suppressed estradiol-17<math> <f> <g>b</g></f> </math> accumulation (ED50 = 0.9 <math> <f> <g>m</g></f> </math>g/ml) independent of activin. Gilts were vaccinated against rpFS to determine the effect of follistatin immunoneutralization on litter size or ovulation rate. In Experiment 1, forty-seven gilts were vaccinated four times with rpFS (FS n = 23) or with a control vaccine (CTL n = 24). The naturally matured, cycling gilts were bred and piglet numbers were recorded at farrowing. FS vaccination did not increase total litter size. However, grouping by low (<math> <f> <=</f> </math>1:400 n = 16) or high anti-follistatin antibody titer (>1:400 n = 7) responses showed an increased litter size in gilts with a high titer (total piglets: FS high titer = 13.0 ± 0.8; FS low titer = 10.8 ± 0.6; CTL 11.4 ± 0.5; p = 0.08). In Experiment 2, sixty-nine gilts were vaccinated three times with rpFS (n = 35) or CTL (n = 34) vaccines. The gilts were induced and synchronized into estrus using PG600, <math> <f> <rm>PGF<inf>2<g>a</g></inf></rm></f> </math> and boar exposure; cycling gilts received a fourth vaccination. Reproductive tracts were collected two weeks after the second observed estrus (FS n = 14, CTL n = 15). FS vaccination did not increase the number of corpora lutea (FS = 13.2 ± 0.5, CTL = 14.5 ± 0.7) or corpora albicantia (FS = 12.1 ± 1.9, CTL = 12.3 ± 2.0), but appeared to effect normal ovarian morphology increasing the number of blood-filled follicles and corpora lutea. In conclusion, rp-305 a.a. FS appears to negatively affect estradiol accumulation 'in vitro'. Vaccination against follistatin in naturally cycling gilts enhanced litter size. Follistatin vaccination of pharmacologically induced gilts did not increase ovulation rate, but biological effects were apparent suggesting that pharmacological induction of estrus may have confounded the follistatin vaccination treatment.

Thesis (MTech. degree in Agriculture)--Tshwane University of Technology, 2011. / There is a lack of research on the characterization and cryopreservation of Kolbroek boar semen. This study evaluated Kolbroek boar semen characteristics, extenders and cryoprotectants for cryopreservation, and its subsequent assessment of fertility by in vitro fertilization.

Thesis (M. Tech. Agriculture) -- Central University of Technology, Free state, 2012 / Frozen-thawed boar sperm has the potential to impact the future of the swine industry. The objectives of the study were to characterise semen of Kolbroek and Large White boars, find a suitable holding temperature and extender, determine the effect of breed and pregnancy rate following artificial insemination by frozen-thawed boar semen. A total of eight boars and 33 sows were used in this study. The 120 ejaculates were collected from each individual Kolbroek and Large White boars with the gloved-hand technique. Macroscopic and microscopic sperm characteristics were recorded. The bodyweight of Kolbroek (154.7 kg) was significantly lower compared to Large White (189.9 kg) boar. However, no significant differences were observed in Kolbroek and Large White boar semen volume (140 and 170 ml), sperm concentration (0.727 and 0.761 x 109 sperm/ml), and total sperm motility (95 and 91%). A positive correlation existed between bodyweight and semen volume of Kolbroek (r= 0.22) and Large White (r= 0.26). Conversely, the bodyweight of Large White was positively correlated to sperm concentration of Large White (r= 0.37) but negatively correlated to Kolbroek (r= -0.66). Storage time and temperature did not affect Large White boar sperm motility rate. However, Kolbroek sperm total motility rate (61.0%) was affected at 25°C after 24 hours. The highest total sperm motility rate was observed for semen diluted with Tris-based extender (74.1%) in Kolbroek boars at 48 hours of storage. Large White boar semen diluted with BTS (62.9%), Kobidil+ (69.3%) and Tris (65.1%) showed significantly higher sperm motility rate at 48 hours of storage, compared to Citrate (27.6%) extender. Cryopreservation significantly reduced sperm motility rate for Kolbroek (30.2%) and Large White (24.0%) boars. However, a high pregnancy rate was recorded in both sows of inseminated with raw diluted (100% vs. 81.3%) and frozen-thawed (50% vs. 50%) semen of Kolbroek and Large White boars. In conclusion, the bodyweight of Kolbroek and Large White boar was positively correlated with ejaculated semen volume. Kolbroek and Large White boar sperm stored at 18°C for 24 hours maintained the acceptable sperm motility rate. Kolbroek boar semen diluted with Tris-based extender maintained high sperm motility rate. Cryopreservation significantly reduced sperm motility rate regardless of breed; however, pregnancy rate from frozen-thawed semen was high for Kolbroek (50%) and Large White (50%) even though the frozen-thawed fertility was low.