Advertisement

Polar Biology

, Volume 27, Issue 12, pp 801–809 | Cite as

Comparison of mass-transfer and isotopic dilution methods for estimating milk intake in Antarctic fur seal pups

  • Simon D. GoldsworthyEmail author
  • Mary-Anne Lea
  • Christophe Guinet
Original Paper

Abstract

The efficacy of a new mass-transfer method for estimating milk intake was examined in Antarctic fur seals (Arctocephalus gazella) at Iles Kerguelen. Our method differed from previous mass-transfer approaches in that we estimated milk-mass transfer as the maternal mass lost (MML; kg) during an attendance bout, less the mass lost to metabolic maintenance (MMLE) over that time. MML was significantly related to pup mass-gain (PMG) and attendance bout duration (d days) as follows: MML=1.106PMG+1.002d (r2=0.998). Based on this and previous studies, we estimated that the MMLE was 0.0285 kg kg−1 day−1 for lactating females; and we developed the following milk-mass transfer equation: MMLM=1.106PMG+1.002d−0.0285MMd (where MM is maternal mass). Milk-mass intake was also estimated in an additional 21 pups, using the isotopic dilution method. These values were then compared with estimates based on the milk mass-transfer equation for the same individual pups. A pair-wise comparison indicated that milk-mass transfer estimated using tritium dilution methods were significantly lower than those based on mass-transfer (MMLM). Furthermore, the absolute PMG exceeded tritium dilution estimates of milk-mass transfer in 35% of cases. In contrast, all milk-mass transfer estimates using the mass transfer method were greater than PMG. Overestimation of metabolic water production (MWP), leading to a smaller proportion of the total water intake being attributed to milk ingestion, is believed to be the most likely cause for significant underestimation of milk-mass transfer using the tritium dilution method. Consumption of exogenous water by pups is the most likely reason for the overestimation of MWP, although errors in estimated milk water content may have also contributed to underestimates. We conclude that, in our study, the mass-transfer method provided a more reliable estimate of milk-mass transfer than the isotopic dilution method; and we argue that, under certain conditions, it provides a practical alternative method where the assumptions of isotopic dilution methodology (e.g., all exogenous water from maternal milk) and quantitative parameters (e.g., maternal milk water content) may either be violated or impractical to measure.

Keywords

Assimilation Efficiency Milk Intake Lactate Female Isotopic Dilution Method Maternal Mass 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

We sincerely thank the Institut Français pour la Recherche et Technologie Polaires (IFRTP) and les Terres Australes et Antarctiques Françiases (TAAF) for financial and logistical support. Funding for this project was also provided by the Antarctic Science Advisory Committee (ASAC project 2128) and the SeaWorld Research and Rescue Foundation. We also thank expeditioners at Iles Kerguelen for their support and Bristol–Myers Squibb for providing Clairol bleaching products. The study was conducted under scientific and animal ethics permits issued by the IFRTP. We thank John Arnould, Paddy Pomeroy and two anonymous referees for commenting on the manuscript.

References

  1. Anderson S, Fedak M (1987) Grey seal energetics: females invest more in male offspring. J Zool 211:667–679Google Scholar
  2. Arnould JPY, Boyd IL (1995) Temporal patterns of milk production in Antarctic fur seals (Arctocephalus gazella). J Zool 237:1–12Google Scholar
  3. Arnould JPY, Hindell MA (2002) Milk consumption, body composition and pre-weaning growth rates of Australian fur seal (Arctocephalus pusillus doriferus) pups. J Zool 256:351–359CrossRefGoogle Scholar
  4. Arnould JPY, Boyd IL, Socha DG (1996a) Milk consumption and growth efficiency in Antarctic fur seal (Arctocephalus gazella) pups. Can J Zool 74:254–266Google Scholar
  5. Arnould JPY, Boyd IL, Speakman JR (1996b) Measuring the body composition of Antarctic fur seals (Arctocephalus gazella): validation of hydrogen isotope dilution. Physiol Zool 69:93–116Google Scholar
  6. Arnould JPY, Boyd IL, Rawlins DR, Hindell MA (2001a) Variation in maternal provisioning by lactating Antarctic fur seals (Arctocephalus gazella): response to experimental manipulation in pup demand. Behav Ecol Sociobiol 50:461–466CrossRefGoogle Scholar
  7. Arnould JPY, Green JA, Rawlins DR (2001b) Fasting metabolism in Antarctic fur seal (Arctocephalus gazella) pups. Comp Biochem Physiol A 129:829–841CrossRefGoogle Scholar
  8. Bowen WD, Iverson SJ, Boness DJ, Oftedal OT (2001) Foraging effort, food intake and lactation performance depend on maternal mass in a small phocid seal. Funct Ecol 15:325–334CrossRefGoogle Scholar
  9. Costa DP (1987) Isotopic methods for quantifying material and energy intake of free-ranging marine mammals. In: Huntley AC, Costa DP, Worthy AJ, Castellini MA (eds) Approaches to marine mammal energetics. Society for Marine Mammalogy, Lawrence, pp 43–66Google Scholar
  10. Costa DP (1991) Reproductive and foraging energetics of pinniped: implications for life history patterns. In: Renouf D (ed) Behaviour of pinnipeds. Chapman and Hall, Cambridge, pp 300–344Google Scholar
  11. Costa DP, Gentry RL (1986) Free-ranging energetics of Northern fur seals. In: Gentry RL, Kooyman GL (eds) Fur seals: maternal strategies on land and at sea. Princeton University Press, New Jersey, pp 79–101Google Scholar
  12. Costa DP, Trillmich F (1988) Mass changes and metabolism during the perinatal fast: a comparison between Antarctic (Arctocephalus gazella) and Galapagos fur seals (A. galapagoensis). Physiol Zool 61:160–169Google Scholar
  13. Costa DP, Le Boeuf BJ, Ortiz CL, Huntley AC (1986) The energetics of lactation in the Northern elephant seal, Mirounga angustirostris. J Zool 209:21–33Google Scholar
  14. Donohue MJ, Costa DP, Goebel ME, Baker JD (2000) The ontogeny of metabolic rate and thermoregulatory capabilities of Northern fur seal, Callorhinus ursinus, pups in air and water. J Exp Biol 203:1003–1016PubMedGoogle Scholar
  15. Donohue MJ, Costa DP, Goebel ME, Antonelis GA, Baker JD (2002) Milk intake and energy expenditure of free-ranging Northern fur seals, Callorhinus ursinus pups. Physiol Biochem Zool 75:3–18CrossRefPubMedGoogle Scholar
  16. Fedak M, Anderson S (1987) Estimating the energy requirments of seals from weight changes. In: Huntley AC, Costa DP, Worthy AJ, Castellini MA (eds) Approaches to marine mammal energetics. Society for Marine Mammalogy, Lawrence, pp 205–226Google Scholar
  17. Gales NJ, Costa DP, Kretzmann M (1996) Proximate composition of Australian sea lion milk throughout the entire supra-annual lactation period. Aus J Zool 44:651–657Google Scholar
  18. Gentry RL (1981) Seawater drinking in eared seals. Comp Biochem Physiol 68:81–86CrossRefGoogle Scholar
  19. Georges JY, Guinet C (2000) Maternal provisioning strategy and pup growth in subantarctic fur seals on Amsterdam Island. Ecology 81:295–308Google Scholar
  20. Georges JY, Groscolas R, Guinet C, Robin J-P (2001) Milking strategy in subantarctic fur seals Arctocephalus tropicalis breeding on Amsterdam Island: evidence from changes in milk composition. Physiol Biochem Zool 74:548–559CrossRefPubMedGoogle Scholar
  21. Goldsworthy SD (1995) Differential expenditure of maternal resources in Antarctic fur seals, Arctocephalus gazella, at Heard Island, southern Indian Ocean. Behav Ecol 6:218–228Google Scholar
  22. Goldsworthy SD, Crowley HM (1999) The composition of the milk of antarctic (Arctocephalus gazella) and subantarctic (A. tropicalis) fur seal at Macquarie Island. Aust J Zool 47:593–603Google Scholar
  23. Guinet C, Georges JY (2000) Growth in pups of the subantarctic fur seal (Arctocephalus tropicalis) on Amsterdam Island. J Zool 251:289–296CrossRefGoogle Scholar
  24. Guinet C, Goldsworthy SD, Robinson S (1999) Sex differences in mass loss rate and growth efficiency in Antarctic fur seal (Arctocephalus gazella) pups at Macquarie Island. Behav Ecol Sociobiol 46:157–163CrossRefGoogle Scholar
  25. Guinet C, Lea M-A, Goldsworthy S (2000) Mass change in Antarctic fur seal (Arctocephalus gazella) pups in relation to maternal characteristics at Kerguelen Islands. Can J Zool 78:476–483CrossRefGoogle Scholar
  26. Higgins LV, Costa DP, Huntley AC, Le Boeuf BJ (1988) Behavioral and physiological measurements of maternal investment in the Steller sea lion, Eumetopias jubatus. Mar Mamm Sci 4:44–58Google Scholar
  27. Holleman DF, White RG, Luick JR (1975) New isotope method for estimating milk intake and yield. J Dairy Sci 58:1814–1821 Google Scholar
  28. Holleman DF, White RG, Lambert P (1988) Analytical procedures for estimating milk intake and yield in steady state and non-steady state systems. J Dairy Sci 71:1189–1197PubMedGoogle Scholar
  29. Lea MA, Bonadonna F, Hindell MA, Guinet C, Goldsworthy SD (2002) Drinking behaviour and water turnover rates of Antarctic fur seal pups: implications for the estimation of milk intake by isotopic dilution. Comp Biochem Physiol A 132:321–331CrossRefGoogle Scholar
  30. Nagy KA, Costa DP (1980) Water flux in animals: analysis of potential errors in the tritiated water method. Am J Physiol 238:454–465Google Scholar
  31. Oftedal OT (1985) Pregnancy and lactation. In: Hudson RJ, White G (eds) The Bioenergetics of Wild Herbivores. CRC Press, Boca Raton, Florida, pp 215–238Google Scholar
  32. Oftedal OT, Gittleman JL (1989) Energy output during reproduction in carnivores. In: Gittleman JL (ed) Carnivores: behavior, ecology and evolution. Chapman and Hall, London, pp 355–381Google Scholar
  33. Oftedal OT, Iverson SJ (1987) Hydrogen isotope methodology for measurement of milk intake and energetics of growth in suckling young. In: Huntley AC, Costa DP, Worthy AJ, Castellini MA (eds) Approaches to marine mammal energetics. Society for Marine Mammalogy, Lawrence, pp 29–42Google Scholar
  34. Oftedal OT, Iverson SJ, Boness DJ (1987) Milk and energy intakes of suckling California sea lion, Zalophus californianus pups in relations to sex, growth and predicted maintenance requirements. Physiol Zool 60:560–575Google Scholar
  35. Ortiz CL, Costa DP, Le Boeuf BJ (1978) Water and energy flux in elephant seal pups fasting under natural conditions. Physiol Zool 51:166–178Google Scholar
  36. Ortiz CL, Le Boeuf BJ, Costa DP (1984) Milk intake of elephant seal pups: an index of parental investment. Am Nat 124:416–421CrossRefGoogle Scholar
  37. Robinson SA (2002) The foraging ecology and provisioning strategies of sympatric fur seals Arctocephalus gazella and Arctocephalus tropicalis at Macquarie Island. PhD thesis, University of Tasmania, HobartGoogle Scholar
  38. Stewart REA, Lavigne DM (1984) Energy transfer and female condition in nursing harp seals Phoca groenlandica. Holarct Ecol 7:182–194Google Scholar
  39. Tedman R, Green B (1987) Water and sodium fluxes and lactational energetics in suckling pups of Weddell seals (Leptonychotes weddelli). J Zool 212:29–42Google Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Simon D. Goldsworthy
    • 1
    • 4
    Email author
  • Mary-Anne Lea
    • 2
    • 5
  • Christophe Guinet
    • 3
  1. 1.Sea Mammal Ecology Group, Zoology DepartmentLa Trobe UniversityAustralia
  2. 2.Antarctic Wildlife Research Unit, School of ZoologyUniversity of TasmaniaHobartAustralia
  3. 3.Centre d’Etudes Biologiques de Chizé – CNRSBeauvoir-sur-NiortFrance
  4. 4.South Australian Research and Development Institute (SARDI) Aquatic SciencesHenley BeachAustralia
  5. 5.Marine Mammal Research UnitUniversity of British ColumbiaVancouverCanada

Personalised recommendations