The effects of recombinant LHRH fusion proteins on testicular development and histology in ram lambs.

Two recombinant luteinizing hormone releasing hormone (LHRH) fusion proteins were evaluated for their effectiveness in suppression of testicular development and histology by injecting together. Recombinant fusion proteins, ovalbumin-LHRH-7 and thioredoxin-LHRH-7, were generated using recombinant DNA technology and expressed in E. Coli. Eleven ram lambs ranked by age and body weight were randomly assigned to receive either ovalbumin and thioredoxin recombinant protein mixture (control group, n = 5) or ovalbumin-LHRH-7 and thioredoxin-LHRH-7 recombinant fusion protein mixture, anti-LHRH vaccine, (immunization group, n = 6). Animals in each group were weaned at 17 wk of age and were injected (primary immunization) with either mixture at 18 wk of age. Both groups received a booster immunization 8 wks later (26 wk of age). Scrotal circumference, scrotal length, testicular diameter and testicular length were measured in both groups every other week. All animals were slaughtered at 36 wk of age. Immediately after slaughter, a small testicular tissue was taken and processed for histological examination. In the ram lambs in immunization group scrotal circumference and testicular diameter increased steadily until second booster and then remained as a plateau until the end of the experiment. The differences in scrotal circumferences and testicular diameter were significant between the two groups during the last three weeks of the study (p < 0.05). There were no differences in testicular and scrotal length throughout the study (p > 0.05). Seminiferous tubules lost their regular shape and were decreased in diameter in immunization group. Although a few spermatozoa were seen in some tubules, in general, there were atrophy of the seminiferous tubules and loss of spermatogenesis, nevertheless, it seemed that animals in this group were potentially fertile.

Umbilical artery doppler sonography in Saanen goat fetuses during singleton and multiple pregnancies.

The objective of this study was to evaluate the blood flow from the umbilical artery (UA) in healthy pregnant goats. Doppler sonography examinations were performed every two weeks in Saanen goats with a singleton (n = 5) or multiple (n = 4) pregnancy from 40 to 145 days of gestation. Fetal heart rates (FHR), pulsatility index (PI), and resistance index (RI) were recorded from the mid-cord site of the free-floating umbilical cord. FHR decreased gradually as the pregnancy progressed and significantly decreased during the last two examinations of all fetuses (P < 0.05). The mean PI level was dramatically different (P < 0.05) until 85 days of gestation, after which it reached a plateau level until parturition. Similar to PI, RI decreased by 85 days of gestation (P < 0.05), and decreased again by 130s gestation. No reverse or absent end-diastolic flow were observed in fetuses during any examinations. When comparing singleton and multiple pregnancies, there were no significant differences in UA pulsatility or resistance in fetuses seen. The middle of the second trimester was observed to be a threshold stage for indices in the pattern of caprine pregnancy. In conclusion, this work provides additional values that might be useful when evaluating singleton and multiple pregnancies, and may be evaluated in further studies regarding fetal monitoring.

GnRH or eCG treatment fails to restore reproductive function in GnRH immunized ewes.

This study was designed to evaluate the potential of using eCG or GnRH in restoring reproductive functions in GnRH immunized ewes. Thirty-three multiparous Kivircik ewes were randomly assigned into either control group (n=11) or immunization group (n=22). Ewes were immunized against GnRH by injecting with a cocktail of ovalbumin-LHRH-7 (ovalbumin-GnRH-7) and thioredoxin-LHRH-7 (thioredoxin-GnRH-7) fusion proteins generated by recombinant DNA technology in April. 500 IU eCG or 0.008 mg GnRH analogue was used to induce ovulations. Serum GnRH antibodies were present in animals of the immunized group beginning the second week after the first immunization and maintained throughout the study (14 months). Immunization caused anestrus in immunized ewes. eCG or GnRH analogue administration given after 14 days progestagen (20 mg fluorogestone acetate, FGA) treatment during breeding season (mid July) did not induce ovulation in these ewes. Two more attempts with single or multiple eCG injections failed to induce ovulation in this group as well. It appears that the gonadotropin stimulation was not of adequate time since neither eCG nor GnRH administration was able to restore reproductive function in immunized animals. The immunization effect lasted more than a year. These results suggest that GnRH immunization exerts its effect via the hypothalamo-pituitary axis and that more than such stimulation is required to overcome the reproductive suppression.