Nutritional and genetic adaptation of galliform birds: implications for hand-rearing and restocking

Tuija Liukkonen-Anttila

Department of Biology, University of Oulu, P.O.Box 3000, FIN-90014 University of Oulu, Finland

Abstract

The impact of hand-rearing on the morphology and physiology of captive and wild grey partridges (Perdix perdix) and capercaillies (Perdix perdix) was studied in three feeding trials conducted under laboratory conditions, and two comparative studies between wild and captive birds. Finally, wild and hand-reared grey partridges from several localities in Europe were sampled and the control region 1 of mitochondrial DNA was sequenced to reveal genetic variation between populations, as well as to compare wild and captive stocks.

Wild capercaillies had heavier pectoral muscles, hearts, livers and gizzards, longer small intestines than hand-reared ones, and a higher cytochrome-c oxidase activity in muscle and heart. Invertebrates were essential to the growth, primary and temperature regulation development in grey partridge chicks. Fish was not sufficient to replace invertebrates in the diet. A change in diet from commercial to natural decreased the assimilation efficiency in the grey partridge. It also increased the mass of gizzard reflecting the need for greater grinding ability. Of hepatic P450 enzymes used in this study 7-ethoxyresorufin-0-deethylase and 7-pentoxyresorufin-0-deethylase differed between wild and hand-reared birds. Coumarin-7-hydroxylase activity was higher in grey partridges than capercaillies. Diet differences may have caused these differences. Quebracho tannin added to the diet lowered caecal nitrogen, and elevated tannin excreted in feces. Otherwise its effects were slight.

Mitochondrial control region revealed 14 variable sites between two main lineages detected. Nucleotide and haplotype diversities varied greatly between populations. The markedly deep divergence between the two lineages indicated most probably post-glacial recolonisations from geographically isolated refuges. In Finland, wild birds represented the eastern lineage, while the farmstock represented the western lineage. Surprisingly little trace, contrary to expectations, from the large-scale releasing of imported partridges could be seen in the European populations.

Table of Contents

Acknowledgements

Abbreviations

List of original papers

1. Introduction: Gamebird management

1.1. Hand-rearing of gamebirds for release

1.2. Factors affecting the survival of hand-reared birds after release

1.2.1. Nutritive constraints
1.2.2. Gastrointestinal tract adjustments to variable diets
1.2.3. Temperature regulation in chicks
1.2.4. Plumage and primary growth
1.2.5. Energy reserves and flight ability
1.2.6. Genetic adaptation

1.3. The gamebird species studied

1.3.1. The grey partridge
1.3.2. The capercaillie

2. Aims of the study

3. Material and methods

3.1. The birds studied
3.2. Morphological features
3.3. Blood sampling
3.4. Temperature regulation
3.5. Nutritional status
3.6. Power production
3.7. Detoxication mechanisms
3.8. Mitochondrial DNA

4.1. Body mass and morphological characteristics of organs
4.2. Primaries
4.3. Plasma analysis
4.4. Cooling rate
4.5. Food consumption, excretion, and assimilation efficiency
4.6. Biochemical tissue analysis
4.7. Hepatic enzyme activity
4.8. Variation in the CR1 sequence
4.9. Population structuring and gene flow
4.10. Changes in the population size
4.11. Patterns of phylogeography

5. Discussion

5.1. Body mass reflected the diet and changes in it
5.2. Gut dimensions may reflect the diet
5.3. Nutritional status affected the blood parameters only slightly
5.4. Food consumption and MEC responded to the change in diet
5.5. Added dietary tannin expressed in excreted nitrogen and tannin content
5.6. Energy reserves and power production vs. morphology and biochemistry of tissues
5.7. Primary growth and temperature regulation
5.8. The main detoxication route in galliforms may not be the liver
5.9. A deep divergence between the two lineages of the grey partridge
5.10. Past and present populations
5.11. The impact of ice ages can be seen in present day grey partridge populations
5.12. Morphology and genetic variation may go hand in hand
5.13. Introductions – work for hunting or conservation?
5.14. Practical gamebird management in light of this study

6. Conclusions and further study visions

List of Tables
1. Origins and numbers of birds used in this study.
2. Pairwise φ_ST values between expected subspecies in grey partridge. NS = non-significant, otherwise P < 0.001.

List of Figures
1. Gastrointestinal tract of the rock dove Columba livia (modified from Proctor & Lynch 1993) and long paired caeca typical for galliform birds.
2. The wing feathers (primaries and secondaries) of the grey partridge. Numbering of primaries starts from the innermost feather, i.e. closest to body is the P1 primary.
3. Feather samples could be received like these from Kazakhstan – fastened in a notebook.
4. The primaries of a seven-week-old grey partridge. P1-P3 are postjuvenile primaries, P4 has been moulted, and P5-P10 are juvenile primaries (Thompson & Taber 1948).

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