Article

Developmental instability in japanese quail genetically selected for contrasting adrenocortical responsiveness.

Department of Poultry Science, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Louisiana State University, Baton Rouge 70803, USA.
Poultry Science (Impact Factor: 1.54). 12/2000; 79(12):1710-4. DOI: 10.1093/ps/79.12.1710
Source: PubMed

ABSTRACT Differences in developmental instability were assessed with Japanese quail of two lines that had been genetically selected over several generations for reduced (low stress, LS) or exaggerated (high stress, HS) plasma corticosterone response to brief mechanical restraint. At 32 wk of age, three bilateral traits were selected for study in each quail line. The characteristics chosen were length of the metatarsus (shank length, SHL), diameter of the shank (SHD) perpendicular to the spur, and distance between the auditory canal and the nares (face length, FL). Significantly greater bilateral trait size variances were associated with the measurement of SHL (P < 0.0088) and FL (P < 0.0016) in the HS line than in the LS line. SHD variances did not differ (P = 0.22) in quail of the HS and LS lines. These findings suggest that developmental instability (i.e., fluctuating asymmetry, FA) is more pronounced in HS quail than in LS quail. Previous studies have shown that not only do quail of the HS line show greater adrenocortical responsiveness to a wide range of stressors but that they are also more easily frightened than LS birds. Therefore, the line differences in FA found here may reflect the birds' differential responsiveness to chronic social and physical environmental stressors. The present findings also support previous suggestions that measuring asymmetries in bilateral traits could be an additional and valid method of assessing stress and of comparing phenotypic stability in selected populations.

0 Followers
 · 
86 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Providing light during incubation has been shown to decrease bilateral physical asymmetry of broilers posthatch, which may indicate that early light stimulation reduces later stress susceptibility. This experiment evaluated the effects of lighting during embryogenesis on other measures of stress responsiveness in broilers. Cobb 500 eggs (n = 1,404) were incubated under 0L:24D, 1L:23D, 6L:18D, or 12L:12D; the light level was 550 lx. The broilers were then raised in floor pens under a 12L:12D lighting regimen, and various stress parameters were measured during wk 3 to 6 of age. There was an effect of incubation lighting regimen on posthatch stress responses. Following 1 h of crating, the change in corticosterone (CORT) concentration was less in the 12L:12D (-0.06 ng/mL, P < 0.05) treatment than all other treatments (pooled mean = 0.24 ng/mL); however, there were no treatment differences in CORT response to adrenocorticotropic hormone administration (pooled mean pre- vs. 1 h postadministration = 17.5 ng/mL, P > 0.05). Anti-keyhole limpet hemocyanin titers were higher in the 12L:12D birds (92,395 units/mL; P < 0.05) than all other treatments (pooled mean = 68,407 units/mL) on d 1 postcrating. Additionally, composite asymmetry scores were lower in the 12L:12D treatment (0.92 mm) than all other treatments (pooled mean = 1.14 mm, P < 0.05). These results demonstrate that providing 12 h of light per day during incubation can reduce the stress susceptibility of broilers posthatch.
    Poultry Science 12/2013; 92(12):3103-8. DOI:10.3382/ps.2013-03434 · 1.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Differences in developmental instability were assessed in female offspring of Japanese quail hens selected for reduced (low stress, LS) or exaggerated (high stress, HS) plasma corticosterone (B) response to stress and treated with a placebo or B during egg formation. Hens of each line were implanted (s.c.) with either a silastic tube containing no B (controls) or one filled with B. Female chicks hatched from each of the 4 line x implant treatment combinations were retained for examination of 3 bilateral traits at 130 d of age: length of the tibiotarsus, middle toe length, and distance between the auditory canal and the nares (face length, FL). Greater bilateral trait size variances were associated with measurement of tibiotarsus length (P < 0.04) and middle toe length (P < 0.06) in the HS line, supporting our previous findings in the opposite sex that developmental instability (i.e., fluctuating asymmetry, FA) of certain morphological traits is more pronounced in HS than LS adult quail. The HS quail are also known to exhibit greater adrenocortical responsiveness to a wide range of stressors, and they are more easily frightened than LS birds. Therefore, the line differences in FA (HS > LS) found previously in males and herein in females may simply reflect the differential responsiveness of the birds to chronic social and physical environmental stressors. In addition, the present study detected more (albeit marginally so, P < 0.06) bilateral variability (i.e., heightened FA) in FL of quail hatched from mothers treated with B, a finding entirely due to the very high FL variance observed in the female offspring of B-treated HS hens. Because others have found in ovo B treatment to be associated with heightened FA in chick tarsus bone length and because we have also demonstrated that greater yolk B deposition occurs in eggs from both unstressed and stressed HS quail hens than their LS counterparts, the present maternal B treatment may be acting independently, or in combination with HS genomic effects, to adversely affect developmental stability.
    Poultry Science 08/2008; 87(8):1504-9. DOI:10.3382/ps.2007-00519 · 1.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The effects of environmental stress on the physiology and behaviour of higher vertebrates has become an important avenue of research in recent years. Evidence from recent studies has suggested that the avian stress-related hormone corticosterone (CORT) may play a role in immunocompetence and sexual selection. We tested whether CORT is immunosuppressive by studying humoral and cell-mediated immune responses in populations of captive zebra finches selected for divergent peak levels of CORT. We also investigated whether selection for peak CORT has an effect on the quality of several sexually selected regions of the male zebra finch; in addition we compared morphometric parameters and the dominance ranking in males from the different selection lines. We also tested whether different components of the immune system compete for limited resources. We found that selection for divergent levels of peak CORT had little effect on humoral immunity, male sexual signal quality or dominance ranking. However, contrary to expectations, we did find a positive relationship between CORT titre and cell-mediated immunity, as well as a greater cell-mediated response in the birds selected for high CORT titre than those selected for low CORT titre. Consistent with predictions, significant negative relationships were found between both testosterone and CORT titre on humoral immunity. Birds from the low CORT lines were significantly larger in terms of skeletal size than those from the high CORT lines. Overall, our results suggest that the cell-mediated immune response is associated with a reduction in the humoral response, but only in males, and that there is no simple relationship between peak CORT levels and immune function.
    Journal of Experimental Biology 01/2008; 210(Pt 24):4368-78. DOI:10.1242/jeb.007104 · 3.00 Impact Factor

Preview

Download
1 Download
Available from