The aim of this study was to combine QTL and NGS information to characterize regions affecting adiposity in chicken. This led to the identification of 216 missense SNPs, 5 nonsense SNPs and 3 coding indels occurring in 77 genes that underlay two QTLs. Using conservation- and functionality-based filters aiming at prioritizing polymorphisms, this number was reduced to 76 functional polymorphisms in 41 genes including 21 functional polymorphisms in 10 genes related to energetic metabolism. How single BAY-60-7550 housing affects mice and the associated studies is however far from fully understood. Mice clearly opt for social contact when presented with a choice – even male mice on the receiving end of male-male aggression will do so – but whether they suffer from the lack of it has been disputed. It has been speculated that the lone mouse may be less capable of coping with external stressors than is its group-housed counterpart, but single housing appears, in itself, not to induce an acute stress response. Male mice often respond with aggression to other, unfamiliar males; stable malemale groups are thus preferentially established at weaning, often consisting of littermates.

Additionally, if isolated for as little as 12–24 h, it has been shown that male mice may become aggressive and territorial, even if re-housed with their littermates. Some studies argue that single-housed mice are no more stressed than group-housed mice, effectively suggesting that social isolation may carry no impact on the wellbeing of the mice and the associated studies. There has even been outright advocacy – albeit in the past – of single housing of male mice in the laboratory animal science community. Still, both American and European guidelines today stress the importance of social housing of laboratory mice and there is indirect evidence that single-housed mice experience some form of sub-acute stress. The effect of single housing on laboratory mice is clearly an issue that despite extensive study has yet to be fully understood. The biggest hurdle that must be negotiated is how to identify and quantify the impact brought on by single housing. 8-OH-DPAT is a potent serotonin receptor agonist, preferentially acting on the 5-HT1A receptor. The 5-HT1A receptor is highly implicated as playing an important role in depressive states – from mild anxiety and lowered mood to major depression in many animal species and even suicidal tendencies in humans. Numerous studies into the altered affinities and expression patterns of 5-HT1A in relation to negative stimuli have been carried out.

As a simple but crude method for gauging serotonergic signaling integrity, the hypothermic state brought on by 5-HT1A agonists has been studied. The degree of hypothermia has been demonstrated as a well-consolidated indirect measure of affectedness. We propose that hydroxy-dipropylamino-tetralin–induced hypothermia constitutes a simple, but powerful, tool capable of manifesting the effect of social deprivation in laboratory mice. Drawing on previous findings where we noted that single-housed mice belonging to a control group would alter their HIH response over time, seemingly from the circumstances of their housing alone, we set out to investigate whether the HIH challenge can be applied in a novel context, evaluating the impact of single housing on male laboratory mice. In addition to a controlled proof-of-concept study we investigated, in a larger opportunistic study, whether single housing of males during routine operations in a mouse breeding unit would also impact serotonergic signaling integrity as evaluated through HIH.