THE INFLUENCE OF BREED, AGE OF BOARS AND EXPLOITATION SEASON ON THEIR LIBIDO IN CONDITIONS OF THE INSEMINATION STATION
In this study it was defined the influence of breed, age and season on libido of boars exploited in insemination station. It was found that libido of hybrids (Duroc x Pietrain), (Pietrain x Duroc) and PIC is indeed higher than that of pure breed boars Pietrain, Duroc, wbp and pbz. Boars of Pietrain and pbz breed showed changes of sexual activity according to the exploitation season. Libido of boars was significantly higher in summer and autumn. The reaction of breeders to phantom in mention seasons was 2,75 min. The fastest reaction to phantom (2,4 min.) and the indeed shortest time to start ejaculation (4,6 min.) comparing to remaining age groups was shown by boars in ages above 36 months. Specimen in this age group didn’t shown any significant changes in sexual activity in each exploitation season. Received results can find use in practice. The acquaintance of boar’s libido will permit on his rational exploitation and improvement of organization of collecting the semen.
Measurement of semen production rates of boars.
Frequency of semen collection was used to determine methods of stabilising epididymal sperm reserves in young boars in order to measure daily sperm output which then allows estimation of daily sperm production. By collecting from boars 3 times a week (Monday, Wednesday and Friday) most boars reached epididymal stabilisation within 4 weeks and the daily sperm output could be calculated from the following 6 collections. A more rapid method of measuring daily sperm output was achieved by collecting from boars 4 or 5 times during one day and daily for the following 4 days. Daily sperm output measured by this method was not found to be significantly different from the method requiring collections over a 6-week period. Frequency of collection had a significant effect on semen characteristics. Collecting 3 times a week resulted in significantly greater volumes, sperm concentration, total number of sperm in the ejaculate and daily sperm output compared with collecting at intervals of 48 h. A collecting frequency of 48 h resulted in significantly greater volumes, sperm concentration and total number of sperm in the ejaculate but not daily sperm output when compared with collecting every 24 h.
Inhibition of Root Growth and Polyamine Metabolism in Sunflower (Helianthus annuus) Seedlings Under Cadmium and Copper Stress
Although sunflower is usually regarded as a highly tolerant crop, impairment of root growth at initial stages of plant development may result in poor crop establishment and higher susceptibility to pathogen attack. In order to evaluate if Cd2+ and Cu2+ may impact on sunflower germination and initial root development, a pot experiment under controlled conditions was carried out. Possible involvement of polyamine metabolism in sunflower response to these stressors was also investigated. Although Cd2+ and Cu2+ treatments affect neither seed germination nor radicle emergence, sunflower seedlings grown in the presence of these heavy metals showed significant inhibition of root growth, being this inhibition greater for Cd2+. Both metals caused significant increases in proline contents at the highest concentrations tested (0.5 and 1 mM), and these increments were more pronounced for Cd2+ treatments, especially between days 3 and 10. Metals also increased putrescine (Put) contents at all concentrations assayed from the seventh day onward, causing no variations on this polyamine time-course pattern. Spermine and spermidine contents, however, were increased only by 1 mM Cd2+. Arginine decarboxylase seems to have been the enzyme responsible for Put increases under both metal treatments. This work demonstrates that initial root growth of sunflower seedlings may be significantly impaired in Cd2+ or Cu2+ contaminated soils. It also shows that polyamines are key biological compounds, which are probably involved in signaling pathways triggered under stress environmental conditions.