Presentation on theme: "Mary Ann Ottinger IPA, LEG/NIA Department of Animal and Avian Sciences, University of Maryland, College Park, MD Avian Models for the Comparative Biology."— Presentation transcript:
Mary Ann Ottinger IPA, LEG/NIA Department of Animal and Avian Sciences, University of Maryland, College Park, MD Avian Models for the Comparative Biology of Aging and Evaluating Effects of Calorie Restriction
Why is an avian system of interest and is there relevance for other species/phyla? Understand basic biological processes, especially aging Calorie restriction and has been used to optimize health and reproduction in domestic species for many years. Domestic poultry include genetic strains selected for growth, disease resistance, reproductive and metabolic endocrine characteristics. Some birds age rapidly (Japanese quail and domestic poultry); others have long lifespans and do not show classic signs of aging (terns and other sea birds, cranes, kestrals, humming birds).
Do Avian Species Have Similar Lifetime Reproductive Patterns? Within classes patterns of aging appear similar Some species with a relatively long life- span show little sign of aging
CHOOSING APPROPRIATE MEASURES LIFESPAN What are the constraints? REPRODUCTION Fertility Number of viable young Years of productivity Reproductive success of offspring METABOLIC ENDOCRINE IGF-1, thyroid hormone, GH AGING Post reproductive lifespan? Biomarkers of aging (skin, etc) ?
What Needs to be Considered? COMPARISON WITHIN A SPECIES Individual variability Environmental factors (nutrition, stress, housing, photoperiod) Captive versus wild (seasonal factors, disease, predation, etc) COMPARISONS BETWEEN SPECIES Lifetime strategies in reproduction (# young/year, precocial vs altricial) Environmental factors (season, migratory, nutrition, etc)
COMPARING JAPANESE QUAIL AND KESTRELS (Work in Collaboration with Dr. John French, USGS-Patuxent Wildlife Research Center JAPANESE QUAIL Short lived; terrestrial; migratory; omnivore Rapidly aging Large clutches; precocial chicks; coveys Sex difference in senescence Reproductive, metabolic, and sensory systems aging all decline Neuroplasticity KESTRELS Long lived; terrestrial; carnivore Slow maturation and aging Small clutches; altricial; small groups Pair bond
Yea r Male Age Female Age Start Date - Days off Mean # Eggs Layed # Fertile # Hatched # Fledged Comments 199 3 2205555 199 4 3315555 199 5 44044331 egg died 199 6 5514---eggs euthanized 199 7 66055332 eggs euthanized 199 8 77053+212 eggs lost; 1 hatchling died before fledge 199 9 88054--eggs euthanized 200 0 99053+001 egg lost; 3 eggs dead; 1 egg infertile 200 1 10 152+212 eggs lost; I egg infertile; 1 hatchling died 200 2 11 none0000never laid
Current data for American kestrels Cross sectional: Blood chemistry, cell counts [..years?] WNV antibody titer Longitudinal Body weight Reproduction: date 1 st egg, clutch size, fertility, egg weight, proportions hatch & fledge
A MERICAN K ESTREL Life Table PATUXENT WILDLIFE RESEARCH CENTER 1993 - 2000 Note: - estimate of S 0 from fledging - missing 1y information - includes all birds (partial LH) - birds from 1991 on: earlier? - all 11, 12y birds still alive - evidence of aging?
Studies in Broiler Breeders hatch maturation adult (peak reprod, health, metabolism) aging Age 0-3 or…8wks 18-24 wks 28-55 wks 56-64 wks diet ad lib skip a dayrestricted daily feeding Diet Group 1: ad lib weeks 1-3; 15% CR Group 2: ad lib weeks 1-8; 15% CR
Females initiating CR at 3 weeks matured slower; egg production continued at a higher level than birds full fed for 8 weeks and then restricted.
(Robinson et al., 20002) As the hen ages, the number of eggs laid in a sequence declines, due to increasing irregular ovulation. CR AL L CR hens lay regularly as they age, with less signs of aging. Eggs are produced in a hierarchy with daily ovoposition; yolk accumulation occurs over several days.
Studies in Broiler Breeders hatch maturation adult (peak reprod, health, metabolism) aging Age 0-3 wks 18-24 wks 28-55 wks 56-64 wks Diet: ad lib skip a dayrestricted daily feeding Diet Group 1: ad lib weeks 1-3; then 15% CR Group 2: ad lib weeks 1-3; 15% CR until mature (24 wks); then 37% CR Group 3: low protein diet weeks 1-10; then 15% CR
The Japanese Quail as a Model System for Studying Aging Natural history Characteristics of aging in male quail l sexual behavior as an index of reproductive status l circulating hormone levels l phases in reproductive aging
The Hypothalamic-Pituitary-Gonadal Axis in Japanese Quail Hypothalamus GnRH-I Pituitary Gland LH, FSH Gonads androgens, estrogens, progestins + + NE DA Opioid peptides OT AVT GABA - + - Neuroendocrine systems regulate endocrine and behavioral components of reproduction.
Effects of Calorie Restriction in Japanese Quail (% difference between 20 or 40% CR with pair fed ad lib control; data expressed as % difference) (230%) from Mobarak, Abdelnabi, and Ottinger, 1995
Saline treatment LHRH challenge TreatmentPreinjectionPost inj (15 min) PreinjectionPost inj (15 min) 0% CR6.5 a 5.6 a 6.8 a 9.8 b 20% CR4.8 c 4.0 c 4.6 c 9.4 b 40% CR2.4 d 1.9 d 1.8 d 6.8 a Effects of LHRH challenge (20 g/kg body weight) in castrated CR males on serum LH ( ng/ml plasma ; different letters denote significant (p<0.05) differences in rows).
Acknowledgements This work has been supported by the Maryland Agriculture Experiment Station, University of Maryland, College Park, NRI #92-37203 and NSF #9817024 (MAO). Dr. Joseph Soares Dr. Mohammed Mobarak Dr. Estelle Russek-Cohen Dr. Mahmoud Abdelnabi Nichola Thompson Dr. Robert Clarke Dr. Qichang Li Our animal care crew!