Individuals reared in captivity are exposed to distinct selection pressures and evolutionary processes causing genetic and phenotypic divergence from wild populations. Consequently, restocking with farmed individuals may represent a considerable risk for the fitness of free-living populations. Supportive breeding on a massive scale has been established in many European countries to increase hunting opportunities for the most common duck species, the mallard (Anas platyrhynchos). It has previously been shown that mallards from breeding facilities differ genetically from wild populations and there is some indication of morphological differences. Using a common-garden experiment, we tested for differences in growth parameters between free-living populations and individuals from breeding facilities during the first 20 days of post-hatching development, a critical phase for survival in free-living populations. In addition, we compared their immune function by assessing two haematological parameters, H/L ratio and immature erythrocyte frequency, and plasma complement activity. Our data show that farmed ducklings exhibit larger morphological parameters, a higher growth rates, and higher complement activity. In haematological parameters, we observed high dynamic changes in duckling ontogeny in relation to their morphological parameters. In conclusion, our data demonstrate pronounced phenotype divergence between farmed and wild mallard populations that can be genetically determined. We argue that this divergence can directly or indirectly affect fitness of farmed individuals introduced to the breeding population as well as fitness of farmed x wild hybrids.

• MeSH
• chov MeSH
• divoká zvířata růst a vývoj   imunologie   MeSH
• farmy MeSH
• fenotyp MeSH
• kachny růst a vývoj   imunologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

Avidin is a key egg white antimicrobial protein with strong binding capacity for biotin, an essential growth and immune cell precursor. As such, it is assumed to have a pronounced, though still poorly explored, effect on hatchling phenotype. We tested the effect of experimentally increased egg white avidin concentration (AVIDIN+) on hatching success, chick morphology, post-hatching growth performance and innate immune function in a model bird, Japanese quail (Coturnix japonica). Probability of embryo survival in the late embryonic phase increased with increasing egg weight in control eggs, but not in AVIDIN+ eggs. Chicks hatching from lighter AVIDIN+ eggs had a shorter tarsus than chicks hatching from heavier AVIDIN+ eggs. This suggests that an increase in egg white avidin favours embryo survival in lighter eggs during late embryogenesis, but at the expense of reduced structural body size. Plasma complement activity in 6-day-old AVIDIN+ chicks decreased with increasing body mass and tarsus length; the opposite was observed in control chicks, implying that the later post-hatching innate immune function of larger chicks was compromised by an increase in egg white avidin concentration. Here, we document an important role of egg white antimicrobials in maintenance of embryo viability, avian hatchling morphology and immune phenotype.

• Klíčová slova
• Albumen, Antimicrobials, Avidin-biotin complex, Embryogenesis, Maternal effects, Plasma complement,
• Publikační typ
• časopisecké články MeSH

Avian eggshell color seems to fulfill multiple functions, some of them being structural and others signaling. In this study, we tested whether or not eggshell coloration may play a role in sexual selection of Tree Sparrows (Passer montanus). According to the "Sexually selected eggshell coloration" hypothesis, eggshell coloration signals female, egg or chick quality and males adjust parental investment according to this signal. Eggs of this species are covered with brown spots and patches, and variation between clutches is high. We found that eggshell coloration correlates with both protoporphyrin and biliverdin, but protoporphyrin concentrations are ten times higher. Eggshell coloration reflects egg and offspring quality, but not female quality. Thus, eggshell coloration may signal female postmating investment in offspring rather than female quality. Furthermore, differential allocation in terms of maternal investment is supported by the fact that females lay more pigmented clutches when mated to males with bigger melanin-based ornaments relative to their own. Moreover, males invested proportionally more to chicks that hatched from more pigmented clutches. Our correlative results thus seem to support a role of sexual selection in the evolution of eggshell coloration in birds laying brown eggs, pigmented mainly by protoporphyrin.

• Klíčová slova
• Tree Sparrow, differential allocation, eggshell coloration, female quality, paternal investment, sexual selection,
• Publikační typ
• časopisecké články MeSH