Summary. This study examines the effects of pig follicular fluid on the maturation of pig oocytes and on their subsequent fertilizing and developmental capacity in vitro. The addition of pig follicular fluid or its fractions obtained by ultrafiltration, gel filtration and ion-exchange chromatography to maturation medium significantly increased the rates of nuclear maturation, normal fertilization and normal cleavage of pig oocytes after fertilization in vitro: the rates of normal fertilization and cleavage were 2\p=n-\4times higher than those in the control medium. The efficacy of pig follicular fluid was lost after heating at 56\s=deg\Cfor 30 min, whereas no significant decrease in activity was observed after defatting. In addition, the effective component(s) was partially purified by ultrafiltration, gel filtration and ion-exchange chromatography: the activity was observed in the fraction (UF2; Mr 10 000\p=n-\20000) obtained by ultrafiltration. Activity was found in the first fraction (G1) obtained by gel filtration of UF2. Among three fractions obtained by ion-exchange chromatography of Gl, only the third fraction had the activity. The results indicate that pig follicular fluid contains an acidic substance(s) (Mr 10 000\p=n-\200 000) that promotes oocyte maturation.

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Ejaculates from 10 mature fertile large white Yorkshire boars were used to examine the correlation between immunoreactive relaxin levels in seminal plasma and sperm motility characteristics. Seminal plasma levels of immunoreactive relaxin were measured by a time-resolved fluoroimmunoassay (TR-FIA). Motility characteristics were assessed using a CellSoft computer-assisted digital image analysis system. The mean +/- SD level of immunoreactive relaxin in seminal plasma was 2.61 +/- 0.62 ng/mL. When the correlation between seminal plasma levels of immunoreactive relaxin and parameters of sperm movement was examined, it was found that relaxin levels were significantly correlated with the percentage of motile spermatozoa (r=0.687, p < 0.05), curvilinear velocity (r=0.745, p < 0.05), straight line velocity (r=0.651, p < 0.05), mean amplitude of lateral head displacement (mean ALH) (r=0.844, p < 0.01) and the maximum amplitude of lateral head displacement (max ALH) (r=0.830, p < 0.01), but not with linearity, beat-cross frequency, or percentage of circular cells. Among these parameters, seminal plasma levels of immunoreactive relaxin showed the strongest correlation with the ALH parameter related to fertilizing ability. These results indicate that immunoreactive relaxin in boar semen may be necessary not only for normal sperm motility but also for normal fertility, suggesting that determination of the profile of immunoreactive relaxin in ejaculates may have value as a potential marker for predicting sperm fertilizing ability of boars.

Nine antibiotics were tested for the control of 11 bacterial genera isolated from boar semen. Of the antibiotics tested, the aminoglycosides dibekacin, amikacin and gentamicin proved fairly effective. Minimum inhibitory concentrations of those antibiotics were low (less than 6.25 micrograms/ml) compared to those of antibiotics commonly used for semen diluents. Seventy-four semen samples were stored at 15 degrees C by means of dialysis in the presence of dibekacin (100 micrograms/ml). After seven days' storage, about 80 per cent of the samples showed no bacterial growth and the mean values for sperm motility an normal acrosomes were 75.4 per cent and 82.7 per cent respectively. Twenty sows which were inseminated with semen stored for up to 14 days produced 16 litters and the average litter size was 9.9.

To clarify the details of the anti-obesity effect of theanine, g -glutamylethylamide, female ICR mice were fed diets containing theanine at the concentrations of 0.01, 0.02, 0.04, 0.08 and 0.16% for 16 weeks. Bodyweight and food intake in the mice were measured every 4 weeks, and several organs and intraperitoneal adipose tissues (IPAT) were weighed after the feeding. In addition, lipid levels in the serum and liver were analyzed. As a result, the bodyweight increase and weight of IPAT were significantly reduced in mice fed 0.04% theanine compared with controls, but not in mice fed other diets. The levels of triglycerides (TG) and non-esterified fatty acids in the serum and TG level in the liver in mice fed the 0.04% theanine diet were remarkably decreased. These results indicated that bodyweight increase and fat accumulation were suppressed by a limited concentration of 0.04% theanine in mice.