Active immunization of heifers against a synthetic fragment of bovine inhibin
in ReproductionSearch for other papers by A. R. Scanlon in
Current site
Google Scholar
PubMed
Search for other papers by S. J. Sunderland in
Current site
Google Scholar
PubMed
Search for other papers by T. L. Martin in
Current site
Google Scholar
PubMed
Search for other papers by D. Goulding in
Current site
Google Scholar
PubMed
Search for other papers by D. O'Callaghan in
Current site
Google Scholar
PubMed
Search for other papers by D. H. Williams in
Current site
Google Scholar
PubMed
Search for other papers by D. R. Headon in
Current site
Google Scholar
PubMed
Search for other papers by M. P. Boland in
Current site
Google Scholar
PubMed
Search for other papers by J. J. Ireland in
Current site
Google Scholar
PubMed
Search for other papers by J. F. Roche in
Current site
Google Scholar
PubMed
Two experiments were conducted in cyclic beef heifers to determine whether active immunization against bovine inhibin α 1–26 Gly-Tyr (bINH) affected follicular dynamics, hormone concentration or ovulation rate. In Expt 1, heifers (n = 9) were actively immunized against bINH conjugated to human α globulins (HAG) using bisdiazotized benzidine in non-ulcerative Freund's adjuvant (NUFA; primary on day 0; booster injections on days 53, 84 and 116 using conjugated bINH and on days 176 and 366 using unconjugated bINH; ten heifers were used as controls). Ovaries were examined daily using ultrasound scanning (days 70–155 and 384–391) and corresponding blood samples were collected for bINH antibody titre, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and oestradiol determinations. Four treated and four control heifers were injected with 10 μg gonadotrophin-releasing hormone (GnRH) on day 386 (day 2 of the oestrous cycle). Although bINH-immunized heifers had variable antibody titres ranging from 4 to 50% I125-labelled bINH bound to serum diluted 1:2000, ovulation rate was unaffected. In oestrous cycles with three dominant follicles, the ovulatory follicles grew faster (2.5 ± 0.2 versus 1.6 ± 0.3 mm day−1; mean ± sem), had shorter durations of growth (5.7 ± 0.8 versus 9.6 ± 1.6 days) and duration of detection (7.5 ± 0.8 versus 12.0 ± 2.4 days) in immunized heifers. Mean concentrations of FSH, LH and oestradiol were unaltered in most cases during oestrous cycles in bINH-immunized compared with control heifers. There was no significant difference in the percentage increase in FSH or LH, after GnRH injection, between control and immunized heifers. As ovulation rate was unaltered in the first experiment, a second similar study was designed using a different immunization protocol. In Expt 2, heifers were immunized with bINH conjugated to human serum albumin using glutaraldehyde with the following doses: 0.0 (control; n = 7), 0.33 (n = 7), 1.0 (n = 8) and 3.0 (n = 7) mg. Three booster immunizations were given 33, 66 and 209 days after primary immunization. Immunization increased the number of oestrous cycles with multiple ovulations (42 of 132 (32%) oestrous cycles examined) compared with controls (1 of 30 (3.3%) oestrous cycles examined). Neither titre nor ovulation rate was affected by dose of bINH used. In summary, following bINH immunization, ovulation rate was not increased despite changes in follicular dynamics in Expt 1, but was increased in 32% of oestrous cycles in Expt 2. We conclude that immunization protocols can affect responsiveness of heifers to bINH immunization, and that immunization against inhibin can increase ovulation rate.
Reproduction is committed to supporting researchers in demonstrating the impact of their articles published in the journal.
The two types of article metrics we measure are (i) more traditional full-text views and pdf downloads, and (ii) Altmetric data, which shows the wider impact of articles in a range of non-traditional sources, such as social media.
More information is on the Reasons to publish page.
| Sept 2018 onwards | Past Year | Past 30 Days | |
|---|---|---|---|
| Full Text Views | 1562 | 1331 | 3 |
| PDF Downloads | 100 | 32 | 0 |
Online ISSN: 1741-7899
Print ISSN: 1470-1626
Strengthening biomedical communities
to advance science and health
CONTACT US
Bioscientifica Ltd | Starling House | 1600 Bristol Parkway North | Bristol BS34 8YU | UK
Bioscientifica Ltd | Registered in England no 3190519