Providing straw to allow exploratory behaviour in a pig experimental system does not modify putative indicators of positive welfare: peripheral oxytocin and serotonin.

Numerous studies have shown that providing straw to pigs can reduce undesirable behaviours such as aggression, tail biting and stereotypy. The measurement of various neuromodulators can be helpful in assessing the development of positive behaviours and overall animal welfare. The oxytocin release is frequently linked to positive emotions and positive welfare. It has been suggested that oxytocin modulates the serotoninergic system. This study aims to investigate the potential effect of straw provision in pigs on peripheral levels of oxytocin and serotonin. In total, 18 mini-pigs were involved in an exploratory study conducted in two parallel groups, Enriched (n=10) and Control (n=8) groups. Pigs were divided by group and housed in pens of two individuals. Straw was provided continuously only in Enriched group and renewed each day for 2 weeks. Two blood samples were drawn from each animal 5 to 10 min before providing the straw, and 15 min after providing straw, during the 1st week, to analyse peripheral changes in oxytocin and serotonin before and after straw provision, and determine the existence of a putative short-term effect. The same procedure was carried out for Control group, without straw provision. Long-term effects of straw provision were also examined using blood samples drawn at the same hour from each animal in the 2nd and 3rd weeks. During this time, animals had the permanent possibility to explore the straw in Enriched group but not in Control group. At the end of each week, one animal-keeper completed two visual analogue scales for each mini-pig regarding the difficulty/ease to work with and handle it and its trust in humans. Results showed peripheral oxytocin increases in both groups after 2 weeks (P=0.02). Results did not demonstrate any effect of providing straw to allow exploratory behaviour on peripheral serotonin. Other results were not significant. This preliminary study explored the relationship between peripheral oxytocin and serotonin and the presence of straw that allow pigs to perform exploratory behaviour, suggesting that there was no relationship between them. Some future studies may include crossing oxytocin and serotonin with other parameters, such as behavioural measures, to obtain more information about the true state of the animal and any possible relationship with pig welfare.

Study of the hooking behaviour of Lepeophtheirus salmonis (Krøyer, 1837) copepodids on Atlantic salmon, Salmo salar L., using a novel in vivo test system.

The screening of putative semiochemicals involved in the interaction between Lepeophtheirus salmonis copepodid and the Atlantic salmon could be used to develop methods to prevent infestation. A bioassay was designed to evaluate the attractiveness of Atlantic salmon for L. salmonis copepodids by counting the number of hooked parasites. A salmon was bathed in a tank with 60 copepodids during 45 min. The salmon was humanely killed and its body was scrubbed above a plastic bag. The content of the bag was filtered to count the number of hooked parasites. This procedure was tested at different water temperatures and for different body mass. The temperature significantly influenced the number of hooked copepodids (p < .05). Smolts presented significantly more hooked copepodids at a higher water temperature (24.6 at 13.8°C) compared to smolts at a lower temperature (18.6 at 6.1°C; p = .011). No correlation was found between the body mass and the number of hooked parasites (p = .65). This bioassay was used to successfully measure the attractiveness of Atlantic salmon for L. salmonis copepodids, making it an interesting tool to screen putative semiochemicals designed to prevent the infestation.

Efficacy of dog-appeasing pheromone in reducing behaviours associated with fear of unfamiliar people and new surroundings in newly adopted puppies.

This study was designed to determine the potential value of dog-appeasing pheromone (DAP) in reducing behaviours associated with fear of unfamiliar people and new surroundings in puppies newly adopted from a pet shop. The study was triple-blinded, randomised and placebo-controlled. It used 66 puppies (32 fitted with a DAP collar and 34 control) and the adoptive owners were contacted by phone three days and 15 days after they had adopted the puppy to question them about its reactions to specific situations eliciting fear. Fifteen days after the treatments significantly fewer of the puppies with the DAP collars showed signs of fear when facing unfamiliar people at home and/or during outings. This difference was irrespective of breed size.

Efficacy of dog-appeasing pheromone in reducing stress associated with social isolation in newly adopted puppies.

This study was designed to determine the potential value of dog-appeasing pheromone (dap) in reducing stress in puppies newly adopted from a pet shop. The trial was triple-blinded and placebo-controlled. After their arrival at the pet shop, 32 puppies were fitted with a dap collar and 34 were fitted with a control collar, according to a randomisation protocol. Adopting owners were contacted by telephone, three and 15 days after they had adopted a puppy, to obtain information about the puppy's integration into the family, and particularly about any signs of distress shown by the puppy when it was socially isolated. All the isolated puppies from the control group vocalised during the first night. Signs of distress, particularly vocalisation, were significantly lower in the dap group on day 3 and throughout the rest of the study, and vocalisation during the night ceased significantly sooner in this group. These differences were observed in puppies of small, medium and large breeds. The dap collars had no effect on the incidence of house soiling.

Are thirty-five days enough to observe the stress-reducing effect of a semiochemical analogue on chickens (Gallus gallus domesticus) housed under high density?

Two similar 400-m2 buildings, each housing 8,400 broilers of a commonly used industrial strain, were used to test the effectiveness of the semiochemical treatment known as mother hen uropygial secretion analogue (MHUSA). The birds in 1 building were exposed to MHUSA continuously during a 35-d growing period, whereas those in the other building received a placebo. The experiment was then repeated using precisely the same conditions but with the building treatment reversed to control for any building effect. The purpose of the trial was to evaluate the effect of MHUSA on growing performances (live weights) and stress indicators observed from blood samples: heterophil-lymphocyte ratio and corticosterone level. Data analysis (ANOVA) showed that MHUSA-treated broilers had a higher mean growth rate, as shown by increased live weights at both d 17 and 35 (P < or = 0.001 and P < or = 0.001, respectively). After the 35-d growing period, we observed both lower heterophil-lymphocyte ratio (P < or = 0.001) and lower corticosterone level (P < or = 0.05) for birds treated with MHUSA compared with placebo, further indicating that the birds were less stressed. We conclude that constant diffusion of MHUSA in buildings used to house broilers might enhance the welfare and growth of the bird by reducing stress.