Endokrinologische Untersuchung männlicher Papageienvögel zur Beurteilung ihres Reproduktionsstatus

Zusammenfassung

Gegenstand und Ziel: Etablierung von Methoden zur Hormonbestimmung in verschiedenen Medien bei männlichen Papageienvögeln mit dem Ziel, deren Reproduktionsstatus und Stressachse zu ermitteln. Material und Methoden: Als Vertreter der Papageienartigen (Psittaciformes) wurden Nymphen- und Halsbandsittiche endokrinologisch untersucht. Vorversuche dienten der Etablierung geeigneter Methoden zur Bestimmung von Testosteron in Plasma, Speichel und Kot. Zur Extraktion der Blut- und Kotproben erwies sich Diethylether als Mittel der Wahl, während der Speichel direkt ohne Extraktion in den Testosteron-Enzymimmunoassay eingesetzt werden konnte. Da Papageien hauptsächlich konjugierte Testosteronmetaboliten im Kot ausscheiden, wurden die Kotproben vor der Etherextraktion mithilfe der β-Glucuronidase/Arylsulfatase hydrolysiert. Neben Testosteron wurde das Stresshormon Kortikosteron im Blut untersucht. Die Kortikosteronanalyse erfolgte durch Fällung der Proteine mittels absolutem Alkohol und Einsatz der Plasmaextrakte im Radioimmunoassay. Ergebnisse: Die untersuchten Papageienspezies zeigten sowohl für Testosteron als auch für Kortikosteron unterschiedliche jahreszeitlich bedingte Sekretionsmuster. Die Nymphensittiche erreichten im Februar und die Halsbandsittiche im November maximale Testosteronspiegel im Blut. Bedingt durch die kumulative Ausscheidung lagen die Testosteronkonzentrationen im Kot wesentlich höher als im Blut. Bezüglich der Stresshormonspiegel wiesen die Halsbandsittiche insgesamt deutlich höhere Werte auf als die Nymphensittiche. Schlussfolgerung: Durch diese Studie ließen sich geeignete Methoden zur Testosteronanalyse in Blut und Kot beim Nymphen- und Halsbandsittich etablieren, mit deren Hilfe eine Einordnung ihres Reproduktionsstatus möglich ist. Die Hormonanalyse im Speichel stellt zum jetzigen Zeitpunkt keine zuverlässige Methode dar und bedarf weiterer Untersuchungen. Klinische Relevanz: Durch Verlaufsuntersuchungen können ein Anstieg der Testosteronkonzentration und/oder pathologische Veränderungen ermittelt und bei der Zuchtplanung berücksichtigt werden.

Summary

Objective: Evaluating methods of hormone measurement in different specimens of male parrots in order to assess their reproductive status and stress axis. Material and methods: Cockatiels and rose-ringed parakeets were chosen as psittaciforme representatives and their endocrine profiles were examined. In various pre-experiments, suitable techniques for the determination of testosterone in plasma, saliva and faeces of male parrots were established. Before analysing the samples by enzyme immunoassay, blood and faeces were extracted using diethyl ether, while saliva could be tested without extraction. Based on the excretion of mainly conjugated testosterone metabolites, parrots’ faecal samples were also hydrolysed with β-glucuronidase/arylsulfatase before extraction. In addition, the levels of the stress hormone corticosterone were determined by radioimmunoassay in order to assess possible relationships between stress and the secretion of testosterone. Results: The examined psittacine species displayed different seasonal secretion patterns for both testosterone and corticosterone. Cockatiels had maximum plasma testosterone levels in February, in contrast, rose-ringed parakeets showed highest concentrations in November. As a consequence of cumulative excretion, both species showed much higher faecal than plasma testosterone concentrations. In rose-ringed parakeets, the levels of corticosterone in plasma were exceptionally high compared to the cockatiels. Conclusion: According to this study, we have been able to establish suitable methods for testosterone analysis in blood and faeces of cockatiels and rose-ringed parakeets, supporting the assessment of their reproductive status. At present saliva does not appear to be an ideal medium for reliable hormone level measurement, thus further investigations are required concerning this subject. Clinical relevance: By means of process analysis, it will be possible to detect increasing testosterone levels and/or pathological alterations, which could be considered in breeding programmes.

Schlüsselwörter

Psittaziden - Testosteron - Kortikosteron - Reproduktion - Stress

Key words

Psittacines - testosterone - corticosterone - reproduction - stress

• Literatur

• 1 Bacon WL, Proudman JA, Foster DN, Renner PA. Pattern of secretion of luteinizing hormone and testosterone in the sexually mature male turkey. Gen Comp Endocrinol 1991; 84 (03) 447-460.
• 2 Bélanger C, Hould FS, Lebel S, Biron S, Brochu G, Tchernof A. Omental and subcutaneous adipose tissue steroid levels in obese men. Steroids 2006; 71 (08) 674-682.
• 3 BirdLife International 2009. BirdLife International announces more critically endangered birds than ever before vom 14.05.2009. 1-5. http://www.birdlifeorg/news/pr/2009/05/red_listhtml
• 4 Blas J, Lopez L, Tanferna A, Sergio F, Hiraldo F. Reproductive endocrinology of wild, long-lived raptors. Gen Comp Endocrinol 2010; 168 (01) 22-28.
• 5 Bowles HL. Evaluating and treating the reproductive system. In: Clinical Avian Medicine. Volume II. Harrison GJ, Lightfoot TL. eds. Florida: Spix Publishing; 2006: 519-539.
• 6 Brown JL, Wasser SK, Wildt DE, Graham LH. Comparative aspects of steroid hormone metabolism and ovarian activity in felids, measured noninvasively in feces. Biol Reprod 1994; 51 (04) 776-786.
• 7 Carsia RV, Harvey S. Adrenals. In: Sturkie’s Avian Physiology. 5th ed. Whittow GC. ed. London: Academic Press; 2000: 489-537.
• 8 Cockrem JF, Rounce JR. Fecal measurements of oestradiol and testosterone allow the non-invasive estimation of plasma steroid concentrations in the domestic fowl. Brit Poultry Sci 1994; 35 (03) 433-443.
• 9 Dawson A. Seasonal reproduction, birds. In: Encyclopedia of Reproduction. Volume 4. Knobil E, Neill JD. eds. New York, San Francisco: Academic Press; 1999: 321-328.
• 10 Dawson A, King VM, Bentley GE, Ball GF. Photoperiodic control of seasonality in birds. J Biol Rhythm 2001; 16 (04) 365-380.
• 11 Erickson CJ. Induction of ovarian activity in female ring doves by androgen treatment of castrated males. J Comp Physiol Psychol 1970; 71 (02) 210-215.
• 12 Erickson CJ, Hutchison JB. Induction of nest-material collecting in male Barbary doves by intracerebral androgen. J Reprod Fertil 1977; 50 (01) 9-16.
• 13 Feder HH, Storey A, Goodwin D, Reboulleau C, Silver R. Testosterone and “5alpha-dihydrotestosterone” levels in peripheral plasma of male and female ring doves (Streptopelia risoria) during the reproductive cycle. Biol Reprod 1977; 16 (05) 666-677.
• 14 Goymann W. Noninvasive monitoring of hormones in bird droppings: Physiological validation, sampling, extraction, sex differences, and the influence of diet on hormone metabolite levels. Ann NY Acad Sci 2005; 1046 (01) 35-53.
• 15 Goymann W, Moore IT, Scheuerlein A, Hirschenhauser K, Grafen A, Wingfield JC. Testosterone in tropical birds: Effects of environmental and social factors. Am Nat 2004; 164 (03) 327-334.
• 16 Goymann W, Möstl E, Gwinner E. Non-invasive methods to measure androgen metabolites in excrements of European stonechats, Saxicola torquata rubicola . Gen Comp Endocrinol 2002; 129 (02) 80-87.
• 17 Haense M, Schmidt V, Schneider S, DellaVolpe A, Krautwald-Junghanns ME. Comparative examination of testicular biopsy samples and influence on semen characteristics in budgerigars (Melopsittacus undulatus). J Avian Med Surg 2008; 22 (04) 300-309.
• 18 Hanke W. Interrenal gland, stress response and reproduction. In: Encyclopedia of Reproduction. Volume 2. Knobil E, Neill JD. eds. New York, San Francisco: Academic Press; 1999: 866-869.
• 19 Harvey S, Phillips JG, Rees A, Hall TR. Stress and adrenal function. J Exp Zool 1984; 232 (03) 633-645.
• 20 Hau M, Wikelski M, Soma KK, Wingfield JC. Testosterone and year-round territorial aggression in a tropical bird. Gen Comp Endocrinol 2000; 117 (01) 20-33.
• 21 Hayward LS, Booth RK, Wasser SK. Eliminating the artificial effect of sample mass on avian fecal hormone metabolite concentration. Gen Comp Endocrinol 2010; 169 (02) 117-122.
• 22 Hochleithner M, Nowotny P. Kortisol- und Kortikosteron-Plasmaspiegel bei verschiedenen Psittaciformes . Tierärztl Prax 1992; 20 (06) 605-607.
• 23 Kenton B, Millam JR. Photostimulation and serum steroids of orangewinged amazon parrots. Main Conference Proceedings – Association of Avian Veterinarians; Reno, USA: 1994: 437.
• 24 Kim IS, Yang HH. Seasonal changes of testicular weight, sperm production, serum testosterone, and in vitro testosterone release in Korean ring-necked pheasants (Phasianus colchicus karpowi). J Vet Med Sci 2001; 63 (02) 151-156.
• 25 Klasing KC. Potential impact of nutritional strategy on noninvasive measurements of hormones in birds. Ann NY Acad Sci 2005; 1046: 5-16.
• 26 Krishnaprasadan TN, Kotak VC, Sharp PJ, Schmedemann R, Haase E. Environmental and hormonal factors in seasonal breeding in free-living male indian rose-ringed parakeets (Psittacula krameri). Horm Behav 1988; 22 (04) 488-496.
• 27 Lantermann W. Papageienkunde: Biologie – Verhalten – Haltung – Artenauswahl der Sittiche und Papageien. Berlin: Parey; 1999
• 28 Lee J, Tell L, Lasley B. A comparison of sex steroid hormone excretion and metabolism by psittacine species. Zoo Biol 1999; 18: 247-260.
• 29 Lovas EM, Johnston SD, Filippich LJ. Using a GnRH agonist to obtain an index of testosterone secretory capacity in the cockatiel (Nymphicus hollandicus) and sulphur-crested cockatoo (Cacatua galerita). Aust Vet J 2010; 88 (1–2): 52-56.
• 30 Maitra SK, Dey M. Importance of photoperiods in determining temporal pattern of annual testicular events in rose-ringed parakeet (Psittacula krameri). J Biol Rhythm 1992; 07 (01) 13-25.
• 31 Maitra SK, Mitra A. Testicular functions and serum titers of LH and testosterone in methyl parathion-fed rose-ringed parakeets. Ecotoxicol Environ Saf 2008; 71 (01) 236-244.
• 32 Millam JR. Reproductive Physiology. In: Avian Medicine and Surgery. Altman RB, Clubb SL, Dorrestein GM, Quesenberry K. eds. London: Saunders; 1997: 12-26.
• 33 Millam JR, Roudybush TE, Grau CR. Influence of environmental manipulation and nest-box availability on reproductive success of captive cockatiels (Nymphicus hollandicus). Zoo Biol 1988; 07 (01) 25-34.
• 34 Millspaugh JJ, Washburn BE. Use of fecal glucocorticoid metabolite measures in conservation biology research: considerations for application and interpretation. Gen Comp Endocrinol 2004; 138 (03) 189-99.
• 35 Nakamura T, Tanabe Y. In vitro steroidogenesis by testes of the chicken (Gallus domesticus). Gen Comp Endocrinol 1972; 19 (03) 432-40.
• 36 Ninnes CE, Waas JR, Ling N, Nakagawa S, Banks JC, Bell DG. et al. Comparing plasma and faecal measures of steroid hormones in Adelie penguins Pygoscelis adeliae . J Comp Physiol B 2010; 180 (01) 83-94.
• 37 Parisot M, Tanvez A, Lacroix A, Vallet E, Beguin N, Leboucher G. Social competition and plasma testosterone profile in domesticated canaries: An experimental test of the challenge hypothesis. Horm Behav 2005; 48 (02) 225-232.
• 38 Pollock CG, Orosz SE. Avian reproductive anatomy, physiology and endocrinology. Vet Clin North Am Exot Anim Pract 2002; 05 (03) 441-474.
• 39 Popp LG, Serafini PP, Reghelin ALS, Spercoski KM, Roper JJ, Morais RN. Annual pattern of fecal corticoid excretion in captive Red-tailed parrots (Amazona brasiliensis). J Comp Physiol B 2008; 178: 487-493.
• 40 Quissell DO. Steroid hormone analysis in human saliva. Ann NY Acad Sci 1993; 694: 143-145.
• 41 Scanes CG. Introduction to endocrinology: Pituitary gland. In: Sturkie’s Avian Physiology. 5th ed. Whittow GC. ed. London: Academic Press; 2000: 437-452.
• 42 Searcy WA, Wingfield JC. The effects of androgen and antiandrogen on dominance and aggressiveness in male red-winged blackbirds. Horm Behav 1980; 14 (02) 126-135.
• 43 Silver R, Reboulleau C, Lehrman DS, Feder HH. Radioimmunoassay of plasma progesterone during the reproductive cycle of male and female ring doves (Streptopelia risoria). Endocrinology 1974; 94 (06) 1547-1554.
• 44 Tell LA. Excretion and metabolic fate of radiolabeled estradiol and testosterone in the cockatiel (Nymphicus hollandicus). Zoo Biol 1997; 16 (06) 505-518.
• 45 Vizcarra JA, Kreider DL, Kirby JD. Episodic gonadotropin secretion in the mature fowl: serial blood sampling from unrestrained male broiler breeders (Gallus domesticus). Biol Reprod 2004; 70 (06) 1798-1805.
• 46 Wada H, Moore IT, Breuner CW, Wingfield JC. Stress responses in tropical sparrows: comparing tropical and temperate Zonotrichia . Physiol Biochem Zool 2006; 79 (04) 784-792.
• 47 Wingfield JC, Hegner RE, Dufty J, Ball GF. The “challenge hypothesis”: Theoretical implications for patterns of testosterone secretion, mating systems, and breeding strategies. Am Nat 1990; 136 (06) 829-846.