Ferda Karakuş

LHRH Fusion Protein Immunization Alters Testicular Development, Ultrasonographic and Histological Appearance of Ram Testis

This study was designed to evaluate the effectiveness of a luteinizing hormone releasing hormone (LHRH) fusion protein immunization on reproductive traits in ram lambs including the changes in histology and ultrasonographic appearance of testis. Thirty native ram lambs at 19 weeks of age were divided into control (C, n = 10), immunization (I, n = 10) and castration (E, n = 10) groups. Animals in immunization group were immunized against LHRH using ovalbumin-LHRH-7 (OL) protein generated by recombinant DNA technology as a primary and a booster injection at 19 and 23 weeks of age respectively. Animals were bled via jugular venepuncture at 2-week intervals to determine LHRH antibody and testosterone concentrations. Bi-weekly ultrasonographic examination of the testes was performed to determine the changes in ultrasonographic appearance as the age increased. Biopsied testicular tissues taken at 19, 29 and 41 weeks age were also evaluated. At 41 weeks of age, animals were slaughtered. Semen and epididymis were evaluated for the presence of sperm cells. Testicular development and sperm production were suppressed in the immunized animals. Semineferous tubule diameters decreased, basal membrane of the tubule was thickened and hyalinized in immunized ram lambs. While testes of control animals gained their normal ultrasonographic appearance as the age increased, immunized animals had uniform hypoechogenic testicular structure as observed at 19 weeks of age until slaughter. Simultaneous histological and ultrasonographic evaluations indicated that the changes in testicular histology could partly be monitored via ultrasonographic imaging. Nevertheless, it is difficult to claim that ultrasonographic image reflects the exact changes in such instances. In conclusion, these results indicate that recombinant OL fusion protein is effective in immunocastration in ram lambs and has a potential to be used as an alternative to physical castration. Further research studies should be conducted to help assess reproductive status of testes from ultrasound images.

Feedlot performance and carcass characteristics of ram lambs immunized against recombinant LHRH fusion proteins at 10 weeks of age

Body growth, feedlot performance and carcass characteristics of ram lambs (n = 16) immunized against luteinizing hormone-releasing hormone (LHRH) at 10 weeks of age with recombinant LHRH fusion proteins were investigated. Recombinant fusion proteins, ovalbumin–LHRH-7 and thioredoxin–LHRH-7 were produced using recombinant DNA technology. Animals were immunized (n = 8) against LHRH with ovalbumin–LHRH-7 and thioredoxin–LHRH-7 recombinant protein mixture in the Freund’s complete adjuvant. The immunization group received two booster injections 4 and 8 weeks later, with Freund’s incomplete adjuvant. Animals in control group (n = 8) were not treated. Animals were kept at relatively poor pasture until 27 weeks of age. This was followed by a 70 days finishing period that involved housing in groups and ad libitum feeding with concentrate. Carcasses were evaluated after chilling for 24 h at +4 ◦ C. Live weights, finishing weight, weight gain and average daily weight gain were similar between groups (P > 0.05). Carcass measurements, loin eye muscle area and back fat thickness were not affected from immunization. Immunization did not affect hot and cold carcass weights, dressing percentage, offal items and wholesale cuts weights. Immunized animals had smaller testis, chop and bone weights than control animals (P < 0.05). It was concluded that immunological castration could be achieved at 10 weeks of age in ram lambs using new recombinant LHRH fusion proteins and used in finishing programs without adverse effect on growth rate, feedlot performance and carcass characteristics. Nevertheless, the effectiveness of these proteins should be further evaluated with more animals.

The Effectiveness of recombinant OL fusion protein (ovalbumin-LHRH-7) in suppressing reproductive functions when injected in single-dose vaccination protocols with different adjuvants

The objective of this study was to evaluate the effectiveness of recombinant LHRH fusion protein, Ovalbumin-LHRH-7 (OL), using a single-dose vaccination protocol in combination with different adjuvants in suppressing reproductive functions in buck kids. For this purpose, either a mixture of free OL antigen and encapsulated OL antigen, or encapsulated OL antigen was used. Thirty-nine native buck kids at 12 weeks of age were divided into control (n=7) and treatment groups (n=8 bucks/group). The four treatment groups were formed according to the different vaccine formulations: Group CpG received 0.5mg free OL protein together with 1.0mg of encapsulated protein with CpG adjuvant. Group mFCA received 0.5mg free OL protein together with 1.0mg of encapsulated protein with modified Freunds complete adjuvant. Group IS received 1.5mg encapsulated OL protein with a mix of inulin and saponin adjuvants. Group ISmFCA received 1.5mg encapsulated OL protein with a mix of inulin, saponin and modified Freunds complete adjuvants. Scrotal circumference in CpG and mFCA groups were significantly smaller than that of Control, IS and ISmFCA groups (P<0.05). Numbers and percentage of bucks having spermatozoa in their ejaculate were significantly lower in CpG and mFCA groups (P<0.05). OL immunization completely suppressed sperm production, except one buck, in CpG and mFCA groups (P<0.05). These results imply that it is possible to use OL protein in a single injection protocol for the purpose of immunocastration. Further investigation with a larger number of animals should be carried out to determine the longevity of response to a single injection.