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 Bookmarks
 · 
77 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The growing realisation that selective breeding may offer rapid solutions to certain animal welfare problems and the associated production losses lends urgency to the search for suitable selection criteria. We have already shown that genetic selection of Japanese quail for a reduced (low stress, LS) rather than an exaggerated (high stress, HS) adrenocortical response to brief mechanical restraint was associated with marked reductions in underlying fearfulness, non-specific stress responsiveness and developmental instability. However, since genetic selection for one trait can also modify others, monitoring of other important characteristics is imperative before we can make any recommendations. Inappropriate levels of sociality (motivation to be near conspecifics) could cause pronounced social stress. The present study compared underlying sociality in LS and HS quail in two ways. In experiment 1, when undisturbed, same-line groups of six chicks were observed at 4 days of age we found that LS quail stayed closer together than HS ones. When naive, individually tested chicks were tested in a runway at 11–12 days of age in experiment 2, LS quail spent longer near a goal box containing cagemates than did the HS birds. Social proximity in the home cage and reinstatement responses in runway tests of social affiliation are positively related to underlying sociality. Therefore, these findings strongly suggest that underlying sociality is greater in quail of the LS than the HS line. Enhanced sociality could be regarded as an additional advantage of this type of selection programme, particularly if the phenomenon generalised to include commercially important species that are often housed at high stocking densities, like chickens or turkeys.
    Applied Animal Behaviour Science 02/2002; 75(4):337-346. · 1.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: It has been suggested that the time taken by an individually tested domestic chick to begin pecking at pebbles on the floor of a novel arena might be used as a test of fear and anxiety, with low latencies to peck indicating low fear and vice versa, and as a potential selection criterion ‘to choose fowls with the best performance later in life’ [Appl. Anim. Behav. Sci. 73 (2001) 102]. The present study tested the above hypotheses by comparing the responses of 1-day-old Japanese quail chicks from genetic lines known to show high (HS) or low (LS) levels of fearfulness when they were exposed individually to a similar test situation. Since social separation is a stressful event the quail were housed either individually (IND) or in groups (SOC) before test to establish whether the prior social environment influenced behaviour in the pebble test. The LS chicks walked sooner and more than HS ones but there were no line effects on pecking at the pebbles. Chicks that had been housed individually walked and pecked at the pebbles sooner than did those that were housed in a group prior to test, indicating that sudden isolation elicited greater fear in SOC than in IND quail. The higher levels of activity then shown by SOC than IND quail probably reflected greater social reinstatement motivation in socially housed birds. Although the inconsistency between the present results and those of Salvatierra and Arce [Appl. Anim. Behav. Sci. 73 (2001) 102] might simply reflect species differences, our findings sound a cautionary note and point to the need for further study before a pebble test could be confidently used to assess fearfulness.
    Applied Animal Behaviour Science 08/2004; 87(3):285-291. · 1.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Selection of Japanese quail for a reduced (low stress, LS) rather than exaggerated (high stress, HS) adrenocortical response to brief restraint is associated with a non-specific reduction in stress responsiveness, decreased fearfulness, greater sociality, and enhanced male reproductive function, e.g. greater cloacal gland size, foam production, and testes weight. Because sexual behaviour has components that may be affected by all of these traits, the copulatory behaviour of male LS and HS adults was compared herein. In experiment 1, males from each line were individually tested in a runway (novel environment) in two consecutive steps. First, the approach (social proximity) of a test male (LS or HS) to a compartment containing two females (one LS+one HS) that he could see but not reach was examined. Second, after allowing the test male and both females to mingle, the male’s latency to first grab and the numbers of grabs, mounts and cloacal contacts were recorded. A tendency for LS males to spend a longer (P=0.08) amount of time near the females before the sexes were mingled was observed. When the birds were allowed contact, LS males showed a significantly higher (P
    Applied Animal Behaviour Science 09/2003; 83(3):187-199. · 1.63 Impact Factor

Preview

Download
1 Download
Available from