Lipid Metabolism and Comparative Genomics

Unilever asked the Study Group to focus on two problems. The first concerned dysregulated lipid metabolism which is a feature of many diseases including metabolic syndrome, obesity and coronary heart disease. The Study Group was asked to develop a model of the kinetics of lipoprotein metabolism between healthy and obese states incorporating the activities of key enzymes. The second concerned the use of comparative genomics in understanding and comparing metabolic networks in bacterium. Comparative genomics is a method to make inferences on the genome of a new organism using information of a previously charaterised organism. The first mathematical question is how one would quantify such a metabolic map in a statistical sense, in particular, where there are different levels of confidence for presense of different parts of the map. The next and most important question is how one can design a measurement strategy to maximise the confidence in the accuracy of the metabolic map

Cardiopulmonary parameters and arterial blood gases during etorphine-medetomidine-midazolam immobilization in free-ranging black rhinoceroses (Diceros bicornis) undergoing electro-ejaculation : a preliminary study

Conservation management interventions for the critically endangered black rhinoceros (Diceros bicornis) require immobilization, which offer opportunities for semen collection and cryopreservation to establish genetic reservoirs. In free-ranging rhinoceroses, a combination of the potent opioid etorphine and the tranquilizer azaperone is routinely used for chemical immobilization but is associated with muscle rigidity and severe cardiopulmonary changes. Additionally, azaperone inhibits semen emission. Seven free-ranging, male, sexually mature black rhinoceroses were immobilized with an alternative protocol consisting of 4.5mg etorphine, 5mg medetomidine, 50mg midazolam and 2,500 IU hyaluronidase delivered remotely by darting from a helicopter. During the immobilization, electro-ejaculation was performed with a portable electro-ejaculator, and a species-specific rectal probe. Animals were observed for muscle tremors. Longitudinal changes in respiratory rate, heart rate and peripheral oxyhemoglobin saturation, measured at 5min intervals, were assessed using a general mixed model. Non-invasive oscillometric blood pressure and arterial blood gas variables were measured at first handling and before reversal and compared using the Wilcoxon rank sum test. All animals were successfully immobilized, showed no muscle tremors, presented with normal heart rates and lactate concentration (<5 mmol/L), recovered uneventfully, but experienced acidemia, hypoxemia and hypercapnia. Induction time and total time in recumbency were 4.2 ± 0.41 and 38.4 ± 6.9min, respectively. Electro-stimulation commenced after 11.7 ± 3.98min and completed after 24.3 ± 6.65min. Semen-rich fractions were successfully collected from six animals. Our observations indicate that etorphinemedetomidine- midazolam provides a promising immobilization protocol for free-ranging black rhinoceroses, that allows for successful electro-ejaculation.Rhino Force SA NPChttps://www.frontiersin.org/journals/veterinary-science#am2022Production Animal Studie

Arterial blood gases and cardiorespiratory parameters in etorphine-medetomidine-midazolam immobilized free-ranging and game-farmed Southern white Rhinoceroses (Ceratotherium simum simum) undergoing electro-ejaculation

With the rapid loss of individuals in the wild, semen cryopreservation has gained importance to safeguard the genetic diversity of white rhinoceroses (Ceratotherium simum). For semen collection via electro-ejaculation, immobilization of free-ranging individuals requires the potent opioid etorphine, which is routinely combined with azaperone, but causes hypoxemia, hypercarbia, acidemia, muscle rigidity, tachycardia, and systemic hypertension. In this study, the suitability of two alternative immobilization protocols including etorphine, medetomidine, and midazolam at different doses (high vs. low etorphine) was evaluated in adult white rhinoceros bulls in two different management systems (free-ranging vs. game-farmed) and undergoing electro-ejaculation. Fourteen free-ranging (Group 1) and 28 game-farmed rhinoceroses (Group 2) were immobilized with ≈2.5 µg/kg etorphine (high dose), ≈2.5 µg/kg medetomidine, ≈25 µg/kg midazolam and 1,500–1,700 IU hyaluronidase and received ≈2.5 µg/kg of butorphanol intravenously at first handling. Twenty game-farmed animals (Group 3) received ≈1 µg/kg etorphine (low dose), ≈5 µg/kg medetomidine, ≈25 µg/kg midazolam and 1,700 IU hyaluronidase. Respiratory rate, heart rate and peripheral hemoglobin oxygen saturation (SpO2) were measured at 5-min intervals; non-invasive oscillometric blood pressures and arterial blood gases at first handling and before reversal of the immobilization; serum clinical chemistry analytes and hematocrit at first handling. Generalized mixed models (fixed factors: group, time, recumbency; random factor: individual rhinoceros) were applied to compare longitudinal changes between free-ranging and game-farmed rhinoceroses immobilized with the higher etorphine dose (Groups 1 and 2), and between the two protocols tested in the game-farmed rhinoceroses (Groups 2 and 3). All animals were successfully immobilized, presented with normal lactate concentrations (<5 mmol/L), experienced no muscle tremors and recovered uneventfully. Hypoxemia and hypertension persisted throughout the immobilization in all groups. Acidemia and hypercarbia were absent in Group 1, but present in the game-farmed animals. The lower etorphine dose in Group 3 resulted in significantly longer induction times, however, tachycardia was not observed. SpO2 was higher for sternal vs. lateral recumbency. Semen-rich fractions were recovered following electro-stimulation in 46 out of the 62 animals. Our findings suggest that etorphine-medetomidine-midazolam provides effective immobilization with fewer side effects compared to previous reports in white rhinoceroses and is suitable for successful electro-ejaculation.Rhino Force SA NPChttps://www.frontiersin.org/journals/veterinary-sciencedm2022Mammal Research InstituteProduction Animal Studie

Effects of GnRH vaccination in wild and captive African Elephant bulls (Loxodonta africana) on reproductive organs and semen quality

OBJECTIVES: Although the African elephant (Loxodonta africana) is classified as endangered by the International Union for Conservation of Nature (IUCN), in some isolated habitats in southern Africa, contraception is of major interest due to local overpopulation. GnRH vaccination has been promoted as a non-invasive contraceptive measure for population management of overabundant wildlife. We tested the efficacy of this treatment for fertility control in elephant bulls. METHODS: In total, 17 male African elephants that were treated with a GnRH vaccine were examined in two groups. In the prospective study group 1 (n = 11 bulls, ages: 8±36 years), semen quality, the testes, seminal vesicles, ampullae and prostate, which were all measured by means of transrectal ultrasound, and faecal androgen metabolite concentrations were monitored over a three-year period. Each bull in the prospective study received 5 ml of Improvac® (1000 μg GnRH conjugate) intramuscularly after the first examination, followed by a booster six weeks later and thereafter every 5±7 months. In a retrospective study group (group 2, n = 6, ages: 19±33 years), one examination was performed on bulls which had been treated with GnRH vaccine for 5±11 years. RESULTS: In all bulls of group 1, testicular and accessory sex gland sizes decreased significantly after the third vaccination. In six males examined prior to vaccination and again after more than five vaccinations, the testis size was reduced by 57.5%. Mean testicular height and length decreased from 13.3 ± 2.6 cm x 15.2 ± 2.8 cm at the beginning to 7.6 ± 2.1 cm x 10.2 ± 1.8 cm at the end of the study. Post pubertal bulls (>9 years, n = 6) examined prior to vaccination produced ejaculates with viable spermatozoa (volume: 8±175 ml, sperm concentration: 410-4000x106/ml, total motility: 0±90%), while after 5±8 injections, only 50% of these bulls produced ejaculates with a small number of immotile spermatozoa. The ejaculates of group 2 bulls (vaccinated >8 times) were devoid of spermatozoa. Faecal androgen metabolite concentrations measured in captive males decreased significantly after the fourth vaccination. None of the males entered musth during the treatment period. CONCLUSIONS: Our results showed a marked decrease in semen quality, testicle and secondary sex gland sizes following repeated GnRH vaccinations. After 2±4 years of continuous treatment every 5±7 months, the effects were similar to surgical castration.ISIScopu

Effects of GnRH vaccination in wild and captive African elephant bulls (Loxodonta africana) on reproductive organs and semen quality

OBJECTIVES : Although the African elephant (Loxodonta africana) is classified as endangered by the International Union for Conservation of Nature (IUCN), in some isolated habitats in southern Africa, contraception is of major interest due to local overpopulation. GnRH vaccination has been promoted as a non-invasive contraceptive measure for population management of overabundant wildlife. We tested the efficacy of this treatment for fertility control in elephant bulls. METHODS : In total, 17 male African elephants that were treated with a GnRH vaccine were examined in two groups. In the prospective study group 1 (n = 11 bulls, ages: 8±36 years), semen quality, the testes, seminal vesicles, ampullae and prostate, which were all measured by means of transrectal ultrasound, and faecal androgen metabolite concentrations were monitored over a three-year period. Each bull in the prospective study received 5 ml of Improvac® (1000 μg GnRH conjugate) intramuscularly after the first examination, followed by a booster six weeks later and thereafter every 5±7 months. In a retrospective study group (group 2, n = 6, ages: 19±33 years), one examination was performed on bulls which had been treated with GnRH vaccine for 5±11 years. RESULTS : In all bulls of group 1, testicular and accessory sex gland sizes decreased significantly after the third vaccination. In six males examined prior to vaccination and again after more than five vaccinations, the testis size was reduced by 57.5%. Mean testicular height and length decreased from 13.3 ± 2.6 cm x 15.2 ± 2.8 cm at the beginning to 7.6 ± 2.1 cm x 10.2 ± 1.8 cm at the end of the study. Post pubertal bulls (>9 years, n = 6) examined prior to vaccination produced ejaculates with viable spermatozoa (volume: 8±175 ml, sperm concentration: 410-4000x106/ml, total motility: 0±90%), while after 5±8 injections, only 50% of these bulls produced ejaculates with a small number of immotile spermatozoa. The ejaculates of group 2 bulls (vaccinated >8 times) were devoid of spermatozoa. Faecal androgen metabolite concentrations measured in captive males decreased significantly after the fourth vaccination. None of the males entered musth during the treatment period. CONCLUSIONS : Our results showed a marked decrease in semen quality, testicle and secondary sex gland sizes following repeated GnRH vaccinations. After 2±4 years of continuous treatment every 5±7 months, the effects were similar to surgical castration.I. Lueders and GvDH received a grant from the U.S. Fish and Wildlife Service- African elephant Fund #AFE 0705; I. Lueders received funding through the German Academic Exchange Service (DAAD) within the Postdoctoral Fellowship Program, Grant #D/11/45084; I. Lueders received project funding through the International Elephant Foundation and the Birmingham Zoo, USA; HJB received additional funding through the Technology Innovation Agency (Pretoria, South Africa).http://www.plosone.orgam2017Anatomy and PhysiologyProduction Animal Studie

Photograph of an elephant hindleg showing swelling (circle line) one day after GnRH vaccine booster.

<p>Photograph of an elephant hindleg showing swelling (circle line) one day after GnRH vaccine booster.</p

Univariate associations between reproductive organ size and quantitative predictor variables in 17 bull elephants.

<p>Univariate associations between reproductive organ size and quantitative predictor variables in 17 bull elephants.</p

Microscopic image of stained elephant spermatozoa 8.5 months after the first GnRH vaccination (= 3 injections: Primer, 1^st and 2^nd booster), showing the example of tail and head separation, stain: SpermBlue®, magnification: x1000.

<p>Microscopic image of stained elephant spermatozoa 8.5 months after the first GnRH vaccination (= 3 injections: Primer, 1^st and 2^nd booster), showing the example of tail and head separation, stain: SpermBlue®, magnification: x1000.</p

Overview and details of all elephants treated and examined during the course of the study.

<p>Overview and details of all elephants treated and examined during the course of the study.</p

Convex ultrasound probe and steel extension used for transrectal examination of intra-abdominally situated testicles in elephant bulls.

<p>Convex ultrasound probe and steel extension used for transrectal examination of intra-abdominally situated testicles in elephant bulls.</p