No abstract

Biobanking refers to the systematic collection, storage, and distribution of pre- or post-mortem biological samples derived from volunteer donors. The demand for high-quality human specimens is clearly demonstrated by the number of newly emerging biobanking facilities and large international collaborative networks. Several animal species are relevant today in medical research; therefore, similar initiatives in comparative physiology could be fruitful. Dogs, in particular, are gaining increasing attention in translational research on complex phenomena, like aging, cancer, and neurodegenerative diseases. Therefore, biobanks gathering and storing dog biological materials together with related data could play a vital role in translational and veterinary research projects. To achieve these aims, a canine biobank should meet the same standards in sample quality and data management as human biobanks and should rely on well-designed collaborative networks between different professionals and dog owners. While efforts to create dog biobanks could face similar financial and technical challenges as their human counterparts, they can widen the spectrum of successful collaborative initiatives towards a better picture of dogs’ physiology, disease, evolution, and translational potential. In this review, we provide an overview about the current state of dog biobanking and introduce the “Canine Brain and Tissue Bank” (CBTB)—a new, large-scale collaborative endeavor in the field.

Herein we examined the effects of yolk size and ovulation order on the fertilisation of yolks within double-yolked (DY) duck eggs. Single-yolked (SY) duck eggs had high fertility (89.98%), whereas in DY duck eggs fertility was low (51.9% yolks). The yolks closer to the airspace (Yolk 1) in DY eggs had higher fertility (68.82% vs 34.98% for Yolk 2; P<0.001). When only one of the two yolks was fertilised, Yolk 1 was fertilised in 99.12% of those eggs. Yolk 1 is presumed to be the first ovulated. The higher fertility of Yolk 1 is consistent with a primacy effect where the first ovulation has a higher probability of achieving fertilisation. Small DY eggs within the normal SY egg weight range (75-104.9g) had significantly lower yolk fertility (47.91%; n=550) compared with large (≥105g) DY eggs (54.56%; n=768; P<0.001). Yolk 1 fertility was lower in small compared with large DY eggs (64.18% vs 72.14%, respectively; P=0.003). Although Yolk 2 fertility was low, it was not affected by egg size. DY eggs with zero fertilised yolks were significantly lighter than DY eggs with one (P=0.007) or two (P<0.001) fertilised yolks (i.e. larger DY eggs were more likely to have fertilised yolks). Larger eggs (≥105g) have larger yolks and the evidence here shows that an optimal yolk size is a significant positive factor in achieving fertilization by dislodging spermatozoa, after ovulation, from their storage sites.

Dogs have been claimed to engage in social referencing by responding in a way that corresponded with their owners' reaction in some contexts. We aimed to assess how owners' actions affect family dogs' behaviour in two ambiguous lifelike situations. In Experiment 1, two groups were tested; in the suspicious owner (SO) group, owners behaved suspiciously (N = 25), in the reassuring owner (RO) group, owners behaved in a reassuring manner (N = 28) facing a 'threatening stranger'. The sitting owners provided voice intonation and body posture changes as cues for the dogs when the stranger entered the room. Dogs looked longer at the owners and stayed longer near them in the SO group but their tendency to approach the stranger did not differ between the groups. Although the owners' behaviours seemed to have relevant effects on dogs' responses, we note that these looking and proximity seeking behaviours might also be explained by reactions to the owners' behaviour alone. In Experiment 2, all dogs (N = 19) were tested in both the SO and RO conditions in a slightly different procedure. Depending on the condition, owners took one step forward/backward and spoke happily/worryingly. The procedural differences and the larger distance between the stranger and the owner allowed the dog more time to perceive the behaviour of both the stranger and the owner, which made the distinction between alternative explanations for the dogs' behaviour easier to interpret. Dogs spent more time behind their owners in the SO condition and more dogs approached the stranger in the RO condition. Dogs' avoidance of the stranger when the owner behaved suspiciously and their tendency to approach the stranger only when the owner displayed positive emotions, can be best explained by social referencing.