Browsing by Author "Reeves, JJ"

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The Effect of Immunization Against Lhrh on Body Growth and Carcass Characteristics in Karakas Ram Lambs
(Elsevier, 2002) Ülker, H; Gökdal, Ö; Temur, C; Budag, C; Oto, M; deAvila, DM; Reeves, JJ
The effects of immunization against luteinizing hormone releasing hormone (LHRH) on body growth and carcass characteristics in Karaka ram lambs were investigated using recombinant LHRH fusion proteins. Recombinant fusion proteins, ovalbumin-LHRH-7 and thioredoxin-LHRH-7, were produced using recombinant DNA technology and expressed in E. coli. The control group (C, n = 5) was injected with ovalbumin and thioredoxin recombinant protein mixture, the immunization group (1, n = 6) was injected with a ovalbumin-LHRH-7 and thioredoxin-LHRH-7 recombinant fusion protein mixture (anti-LHRH vaccine) and, ram lambs in the elastrator group (E, n = 5) were castrated using elastrator bands. Animals in each group were weaned at 17 weeks of age and injected (primary immunization) with either mixture at 18 weeks of age or castrated. The C and I groups received a booster immunization 8 weeks later (26 weeks of age). Animals were housed in groups, weighed every 2 weeks and slaughtered at 36 weeks of age. Carcass of slaughtered lambs were chilled for 24 h at +4 degreesC and evaluated for carcass characteristics. Immunization did not reduce growth rate and live body weights. Immunization and castration had no effect on carcass measurements and loin eye muscle area, hot and cold carcass weights, dressing percentage and wholesale cuts. Immunization against LHRH reduced testis weight and immunized animals had leaner carcasses than castrates. It was concluded that immunizing ram lambs against LHRH using new recombinant LHRH fusion proteins could be an alternative to physical castration to improve carcass quality in ram lamb production; however, further research is required to determine the effective immunization and slaughter age to improve carcass traits. Published by Elsevier Science B.V.
The Effects of Recombinant Lhrh Fusion Proteins on Testicular Development and Histology in Ram Lambs
(M H Schaper Gmbh Co Kg, 2001) Ülker, H; Kanter, M; Gökdal, Ö; De Avila, D; Reeves, JJ
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 throught the study (p >0.05). Semineferous 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 semineferous, tubules and loss of spermatogenesis, nevertheless, it seemed that animals in this group were potentially fertile.
Feedlot Performance and Carcass Characteristics of Ram Lambs Immunized Against Recombinant Lhrh Fusion Proteins at 10 Weeks of Age
(Elsevier Science Bv, 2003) Ülker, H; Gökdal, Ö; Aygün, T; Karakus, F; DeAvila, DM; Reeves, JJ
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 degreesC. 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. (C) 2003 Elsevier B.V. All rights reserved.
Testicular Development, Ultrasonographic and Histological Appearance of the Testis in Ram Lambs Immunized Against Recombinant Lhrh Fusion Proteins
(Elsevier Science Bv, 2005) Ülker, H; Kanter, M; Gökdal, Ö; Aygün, T; Karakus, F; Sakarya, ME; Reeves, JJ
Sixteen native ram lambs weaned at 10 wk of age were divided into two groups. Eight animals were immunized against LHRH with a mixture of two fusion proteins: ovalbumin-LHRH-7 and thioredoxin-LHRH-7. The immunized lambs received a primary immunization plus two booster immunizations at 4 and 12 wks. Animals in the control group (n = 8) were not treated. Scrotal measurements and blood samples were taken at 2-week intervals. Beginning at 25 wk of age, semen was collected and sexual behaviour was evaluated on a weekly basis. At 35 and 37 wk of age testes and accessory glands of all animals were subjected to ultrasound scanning. At 37 wk of age animals were slaughtered and testes were evaluated histologically. Serum LHRH antibodies (P < 0.01) were detected in animals of the immunized group which had reduced serum testosterone concentrations (P < 0.01). Testicular development was suppressed in the immunized animals (P < 0.01). Immunized animals exhibited mounting activity 5 wks later than control animals. No mature spermatozoa containing ejaculates were collected from immunized animals. Control animals had moderately echogenic ultrasonographic appearance at 37 wk age, whereas immunized animals had hypoechogenic images. Mean seminiferous tubule diameter in immunized lambs was significantly smaller than that in control lambs. Basal membrane was thickened and hyalinized; there was an increase in peritubular connective tissue. No proliferating spermatogonia or mature spermatozoa were present in the tubules in these animals. There were no differences in the ultrasonographic appearance of prostate and vesicular gland between control and immunized animals. The LHRH recombinant fusion proteins were effective in immunological castration in ram lambs when started at 10 wk of age as noted by differences in serum testosterone, testicular histology and ultrasonographic appearance of testis and weight of accessory sex glands. Determining the effects of immunization on ultrasonographic appearance of the testis related to time after immunization requires further investigations. (c) 2004 Elsevier B.V. All rights reserved.