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Zoo Biology Jul 2021Tigers (Panthera tigris spp.) are endangered in the wild; ensuring sustainable insurance populations requires careful planning within zoological collections. In captive...
Tigers (Panthera tigris spp.) are endangered in the wild; ensuring sustainable insurance populations requires careful planning within zoological collections. In captive situations, contraceptives are often used to control breeding and ensure genetically viable populations that contain manageable numbers of animals; reversible contraceptives are ideal because they offer flexibility for breeding management. Historically, synthetic progestins, such as melengestrol acetate implants, were used in female tigers, but these are associated with an increased risk of reproductive pathology and subsequent infertility. Recent management advice to ex-situ collections has been to transition to the use of gonadotropin-releasing hormone agonists, such as deslorelin acetate implants, which do not appear to have a similar risk of reproductive pathology but are associated with highly variable reversal times in exotic felids. Using data from 917 contraceptive records in female tigers captured by the Association of Zoos and Aquariums Reproductive Management Center and the European Association of Zoos and Aquaria Reproductive Management Group's joint Contraception Database and from supplementary surveys, this study reviews the changing use of contraceptives in captive female tigers. The aim was to describe the historical and current use of contraceptives and provide a comprehensive assessment on the use of deslorelin implants, including data on product protocols, efficacy, pathology, and reversibility. This study determined that current dose, frequency, reversibility, and anatomical placement sites of deslorelin implants are highly variable, indicating that specific, readily available, unified, evidence-based recommendations on the use of deslorelin would be useful for future contraceptive use in managed tiger populations.
Topics: Animals; Animals, Zoo; Contraceptive Agents, Female; Female; Retrospective Studies; Tigers; Triptorelin Pamoate
PubMed: 33724521
DOI: 10.1002/zoo.21601 -
Zoo Biology Mar 2021Melengestrol acetate (MGA) implants are progestin-based reversible contraceptives used to manage fertility in zoo populations. Although it is recommended that MGA...
Melengestrol acetate (MGA) implants are progestin-based reversible contraceptives used to manage fertility in zoo populations. Although it is recommended that MGA implants should be replaced every 2 years, the duration of efficacy has not been systematically evaluated in most species. Anecdotal reports for Old World monkeys indicate that reproduction may be suppressed longer if the implant is not removed. This study uses Guereza colobus monkey (Colobus guereza) as a model Old World monkey species to examine the effects of MGA implants on reproductive potential. In particular, we investigate whether the probability of reproducing (pR) and rates of stillbirth differ among (1) non-implanted females, (2) females who have had MGA implants removed, and (3) females whose implants were left in past expiration. We found no significant difference in pR between non-implanted and implant-removed groups, but when implants were left in past expiration, the pR was significantly lower than in other groups. Both parity and age significantly impacted pR for the non-implanted group (i.e., younger females and those who were parous increased pR), but neither were significant factors for the implant-removed group. Stillbirth rates were significantly higher post-contraception as compared with pre-contraception. These results support similar analyses in other taxa that show a shorter time to reversal after MGA contraception when implants are removed, making this a good contraceptive option for females likely to receive a breeding recommendation, especially when a more predictable time to reversal is important.
Topics: Animals; Animals, Zoo; Colobus; Contraception; Contraceptive Agents, Female; Drug Implants; Female; Melengestrol Acetate; Pregnancy; Reproduction; Stillbirth
PubMed: 33238048
DOI: 10.1002/zoo.21581 -
Environmental Science and Pollution... Jan 2021
PubMed: 33216304
DOI: 10.1007/s11356-020-11617-y -
Journal of Biomolecular Structure &... Apr 2022Growth hormones (GH) have diverse functions like growth promotion, metabolism, appetite, reproduction and social behavior in vertebrates, which is mediated through the...
Growth hormones (GH) have diverse functions like growth promotion, metabolism, appetite, reproduction and social behavior in vertebrates, which is mediated through the growth hormone receptor (GHR). This work was aimed to analyze structural features, homology modeling and molecular docking of GHR protein. A physicochemical characteristic, like molecular weight was 67.2 kDa and hydropathicity was 0.336. Protein modeling and structure confirmation of GHR protein showed 92.7% residues are in the favored region. Selection of ligands and molecular docking shown Melengestrol and Riboflavin ligand showed uppermost binding energy values -7.8 and -7.3 kcal/mol. Molecular interactions describe conventional hydrogen bonding of Melengestrol was observed with VAL94, GLU97, GLU95, TRP57, PHE33, THR34, PRO35, ASP36, PRO37, ARG49, GLY292, LYS291, ILE290, ALA287, LYS289 residues. Riboflavin hydrogen bonds interaction was at PRO37, ASP36, PRO35, THR34, ARG49, SER144, VAL443, GLN442, PRO284, ASP294, ILE285, PRO286, SER408, ALA287, GLY292, LYS291, ILE290, PRO288, LYS287. Molecular dynamics simulation outcomes revealed that complex 2 (Riboflavin and GHR protein) is better than complex1 (Melengestrol and GHR protein). Overall, the results of the present work lead identification of novel molecules that may be agonistic of growth hormone receptor protein and can be used to surge growth in fish. Communicated by Ramaswamy H. Sarma.
Topics: Animals; Cyprinidae; Growth Hormone; Ligands; Melengestrol Acetate; Molecular Docking Simulation; Receptors, Somatotropin; Riboflavin
PubMed: 33179589
DOI: 10.1080/07391102.2020.1844063 -
Bioorganic Chemistry Nov 2020Glomerella fusaroide, and Rhizopus stolonifer were effectively able to transform the steroidal hormone melengestrol acetate (MGA) (1) into four (4) new metabolites,...
Glomerella fusaroide, and Rhizopus stolonifer were effectively able to transform the steroidal hormone melengestrol acetate (MGA) (1) into four (4) new metabolites, 17α-acetoxy-11α-hydroxy-6-methyl-16-methylenepregna-4,6-diene-3,20-dione (2), 17α-acetoxy-11α-hydroxy-6-methyl-16-methylenepregna-1,4,6-triene-3,20-dione (3), 17α-acetoxy-6,7α-epoxy-6β-methyl-16-methylenepregna-4,6-diene-3,20-dione (4), and 17α-acetoxy-11β,15β-dihydroxy-6-methyl-16-methylenepregna-4,6-diene-3,20-dione (5). All these compounds were structurally characterized by different spectroscopic techniques. The objective of the current study was to assess the anti-inflammatory potential of melengestrol acetate (1), and its metabolites 2-5. The metabolites and the substrate were assessed for their inhibitory effects on proliferation of T-cells in vitro. The substrate (IC = 2.77 ± 0.08 µM) and its metabolites 2 (IC = 2.78 ± 0.07 µM), 4 (IC = 2.74 ± 0.1 µM), and 5 (IC = < 2 µM) exhibited potent T- cell proliferation inhibitory activities, while compound 3 (IC = 29.9 ± 0.09 µM) showed a moderate activity in comparison to the standard prednisolone (IC = 9.73 ± 0.08 µM). All the metabolites were found to be non-toxic against 3T3 normal cell line. This study thus identifies some potent compounds active against T-cell proliferation. Their anti-inflammatory potential, therefore, deserves to be further investigated.
Topics: 3T3 Cells; Animals; Biotransformation; Cell Proliferation; Dose-Response Relationship, Drug; Fermentation; Humans; Melengestrol Acetate; Mice; Molecular Structure; Phyllachorales; Rhizopus; Seeds; Structure-Activity Relationship; T-Lymphocytes
PubMed: 33142425
DOI: 10.1016/j.bioorg.2020.104313 -
Environmental Science and Pollution... Nov 2020The toxicity of endocrinologically active pharmaceuticals finasteride (FIN) and melengestrol acetate (MGA) was assessed in freshwater mussels, including acute (48 h)...
The toxicity of endocrinologically active pharmaceuticals finasteride (FIN) and melengestrol acetate (MGA) was assessed in freshwater mussels, including acute (48 h) aqueous tests with glochidia from Lampsilis siliquoidea, sub-chronic (14 days) sediment tests with gravid female Lampsilis fasciola, and chronic (28 days) sediment tests with juvenile L. siliquoidea, and in chronic (42 days) sediment tests with the amphipod Hyalella azteca and the mayfly Hexagenia spp. Finasteride was not toxic in acute aqueous tests with L. siliquoidea glochidia (up to 23 mg/L), whereas significant toxicity to survival and burial ability was detected in chronic sediment tests with juvenile L. siliquoidea (chronic value (ChV, the geometric mean of LOEC and NOEC) = 58 mg/kg (1 mg/L)). Amphipods (survival, growth, reproduction, and sex ratio) and mayflies (growth) were similarly sensitive (ChV = 58 mg/kg (1 mg/L)). Melengestrol acetate was acutely toxic to L. siliquoidea glochidia at 4 mg/L in aqueous tests; in sediment tests, mayflies were the most sensitive species, with significant growth effects observed at 37 mg/kg (0.25 mg/L) (ChV = 21 mg/kg (0.1 mg/L)). Exposure to sublethal concentrations of FIN and MGA had no effect on the (luring and filtering) behaviour of gravid L. fasciola, or the viability of their brooding glochidia. Based on the limited number of measured environmental concentrations of both chemicals, and their projected concentrations, no direct effects are expected by these compounds individually on the invertebrates tested. However, organisms are exposed to contaminant mixtures in the aquatic environment, and thus, the effects of FIN and MGA as components of these mixtures require further investigation.
Topics: Animals; Bivalvia; Ephemeroptera; Female; Finasteride; Invertebrates; Melengestrol Acetate; Pharmaceutical Preparations; Water Pollutants, Chemical
PubMed: 32696412
DOI: 10.1007/s11356-020-10121-7 -
Animal Reproduction Science Jul 2020This experiment was designed to evaluate breeding strategies involving natural service or fixed-time artificial insemination (FTAI) in Bos indicus-influenced beef...
Comparison of long-term progestin-based protocols to synchronize estrus prior to natural service or fixed-time artificial insemination in Bos indicus-influenced beef heifers.
This experiment was designed to evaluate breeding strategies involving natural service or fixed-time artificial insemination (FTAI) in Bos indicus-influenced beef heifers (n = 1456) when there were field-type management conditions. Body weights and reproductive tract scores (RTS; Scale 1-5) were obtained for heifers before assignment to one of five treatments: 1) Non-synchronized control exposed for natural service (NS), n = 299; 2) melengestrol acetate + natural service (MGA + NS; 0.5 mg/heifer/d), n = 295; 3) 14-d controlled internal drug release insert + natural service (CIDR + NS), n = 289; 4) 14-d MGA-prostaglandin F (PG) + FTAI, n = 295; or 5) 14-d CIDR-PG + FTAI, n = 278. Fertile bulls were placed in pastures with heifers of the three NS treatment groups for a 65-day period which began 10 days after progestin treatments (MGA or CIDR) ended. Heifers in FTAI treatment groups were administered PG (25 mg, IM) 16 days after CIDR removal or 19 days following MGA withdrawal, respectively, and FTAI was performed at 66 (CIDR-PG) or 72 h (MGA-PG) after PG. Gonadotropin-releasing hormone (GnRH; 100 μg, i.m.) was administered at FTAI. Pregnancy status was determined at the end of a 65-day breeding period. Pregnancy rates on Days 21 and 65 of the breeding period differed among treatment groups based on pre-treatment pubertal status (P ≤ 0.02) and body weight (P ≤ 0.05) but did not differ by group. These data highlight the need for continued research efforts to improve reproductive management of Bos indicus-influenced females.
Topics: Animals; Cattle; Estrus Synchronization; Female; Insemination, Artificial; Melengestrol Acetate; Ovary; Pregnancy; Pregnancy Rate; Progesterone; Progestins
PubMed: 32507258
DOI: 10.1016/j.anireprosci.2020.106475 -
Theriogenology Jul 2019Fixed-time and split-time AI were compared following the melengestrol acetate (MGA) prostaglandin F (Experiment 1) and 7-d CO-Synch + controlled internal drug release...
Fixed-time and split-time AI were compared following the melengestrol acetate (MGA) prostaglandin F (Experiment 1) and 7-d CO-Synch + controlled internal drug release (CIDR) protocols (Experiment 2). Heifers in Experiments 1 (n = 524) and 2 (n = 456) were assigned within pen to balanced treatments based on weight and reproductive tract score (RTS; Scale 1-5). In Experiment 1, MGA (0.5 mg∙animal∙d) was fed for 14 d, and prostaglandin F (PG; 250 μg im cloprostenol sodium) was administered 19 d after MGA withdrawal. In Experiment 2, gonadotropin-releasing hormone (GnRH; 100 μg gonadorelin acetate) was administered coincident with CIDR (1.38 g progesterone [P]) insertion. Inserts were removed after 7 d, and PG (250 μg im cloprostenol sodium) was administered at CIDR removal. In both experiments, estrus detection aids (Estrotect) were applied at the time of PG administration. Estrous status was recorded at FTAI or STAI. Estrus was defined as removal of ≥ 50% of the grey coating from the Estrotect patch. Heifers assigned to FTAI treatments received GnRH and were artificially inseminated at the standard time for FTAI for each protocol: 72 or 54 h after PG administration for the MGA-PG or 7-d CO-Synch + CIDR protocol, respectively. In the STAI treatments, only heifers that expressed estrus prior to the standard time of FTAI were artificially inseminated at that time. For heifers failing to express estrus, AI was postponed 24 h. Only heifers that failed to exhibit estrus by the delayed time received GnRH concurrent with AI. In both experiments, estrous response prior to the standard time of FTAI did not differ between treatments. Total estrous response was increased (P < 0.01) among heifers assigned to STAI in Experiment 1 (88%, STAI; 72%, FTAI) and 2 (74%, STAI; 47%, FTAI). In Experiment 1, pregnancy rates resulting from AI were greater (P < 0.04) for heifers assigned to STAI compared with FTAI (55% vs 46%, respectively). In Experiment 2, pregnancy rates resulting from AI were similar between treatments (48% and 46%, respectively; P = 0.6). In summary, when compared with FTAI, STAI resulted in greater estrous response following both the MGA-PG and 7-d CO-Synch + CIDR protocols. The increased estrous response through use of STAI was associated with a corresponding increase in pregnancy rates to AI following the MGA-PG protocol; however, a similar improvement in pregnancy rates was not observed following the 7-d CO-Synch + CIDR protocol.
Topics: Animals; Cattle; Estrus Synchronization; Female; Insemination, Artificial; Pregnancy; Pregnancy Rate; Progestins; Time Factors
PubMed: 31125868
DOI: 10.1016/j.theriogenology.2019.04.011 -
The Science of the Total Environment May 2019Animal manure contains various organic contaminants such as steroids. The fate of these steroids during composting is still unknown. Here we investigated the fate of...
Animal manure contains various organic contaminants such as steroids. The fate of these steroids during composting is still unknown. Here we investigated the fate of androgens, progestogens, and glucocorticoids during animal manure composting and evaluated their residues in compost-applied soils. The results showed the presence of 16 steroid hormones in the initial compost with concentrations ranging from 3.26 ng/g dw (Cortisol) to 2520 ng/g dw (5α-dihydroprogesterone). The concentrations of almost all detected hormones increased on the 2nd day of composting, and some of them increased several or even dozens of times. Steroids such as hydroxyprogesterone caproate, melengestrol acetate, and methyltestosterone were not found in the initial compost but later detected during the composting process. After 171 days of composting, only 40.4% of detected steroid hormones was removed, and the total concentration of detected steroids was still as high as 3210 ng/g dw. The removal rates of some target compounds were negative, especially for the natural androgens androsta-1,4-diene-3,17-dione and the synthetic androgen 17β-boldenone whose concentrations significantly increased by the end of composting, indicating conversion from their conjugates or transformation from other steroids. The steroid hormones were mainly eliminated in the first three weeks; prolonged composting time did not obviously promote further removal. The variations in steroid concentration were related to the changes in compost properties such as pH and temperature during the composting process. The dissipation of steroid hormones was also linked to the changes of microbial communities in the compost to some extent. Twelve steroids were detected in the compost-treated soils of a kailyard, while 26 steroid hormones were detected in the roots of Chinese cabbages grown on the soil. The results suggest that the application of manure compost product can lead to soil contamination and plant uptake.
Topics: Androgens; Animals; Composting; Environmental Monitoring; Glucocorticoids; Manure; Progestins; Soil Pollutants
PubMed: 30772582
DOI: 10.1016/j.scitotenv.2019.02.120 -
Zhongguo Zhong Yao Za Zhi = Zhongguo... Jul 2018To investigate the effects of anti-androgen drugs and melengestrol acetate (MGA) on development of regrowth antlers in 6 year old sika deer, twenty healthysika deerwith...
To investigate the effects of anti-androgen drugs and melengestrol acetate (MGA) on development of regrowth antlers in 6 year old sika deer, twenty healthysika deerwith similar body weight and antler weightwere randomly divided into five groups by using single factor test design: flutamide (=4), bicalutamide (=4), progesterone acetate (CPA, =4), melengestrol acetate (MGA, =4), control(=4). All deer were fed with same diets and were housed outside together in an opened fence of 15 m×30 m with free access to water and feed. Treatment groups were injected subcutaneously sustained-release agents of the four drugs respectively when two-branched antlers were harvested. The control group had no special treatment. In the experiment period of 60 d, blood sampleswere collected for 4 times for each deer. The concentration of testosterone in plasma was tested and analyzed to compare the changes between different groups. Development of regrowth antlers was observed. At the end of the experiment, regrowth antlers were weighted and analyzed. The resultsshowed that the weights of regrowth antlers in treatment groups were significantly greater than those from control group and the weight gain (as compared with the control group) was 100.50%, 64.46%, 87.16% and 117.46% respectively in flutamide group, bicalutamide group, progesterone acetate group and melengestrol acetate group. For plasma testosterone concentration, it was not significantly different in the early stage (in the first 35 d), but at the end of the experimen, it was significantly higher than that of earlier stage (<0.01) in various groups. Testosterone concentration of flutamide treated group was significantly lower than that of the other groups (<0.01), while the level inbicalutamide and MGA treated groups was significantly higher than that in other groups (<0.01). The results showed that both anti-androgen drugs and MGA treatment promoted the development of regrowth antlers and increased the weight of regrowth antlers, where the effect was most significant by MGA treatment. From the morphological observation of the antlers, it was found that anti-androgen and MGA treatments prolonged the growth period of regrowth antlers through delaying the ossification of antlers. However, plasma testosterone concentration was not affected by the treatments.
Topics: Animals; Antlers; Deer; Progesterone; Testosterone
PubMed: 30111021
DOI: 10.19540/j.cnki.cjcmm.20180514.010