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The Japanese quail is a powerful model to characterize behavioral, physiological, and neurobiological processes in Galliformes. Behavioral tests have already been adapted for quail to assess memory systems, but despite the pivotal role of the hippocampus in this cognitive process, its involvement in spatial memory has not been demonstrated in this species. In this study, lesions were created in the hippocampus of Japanese quail, and both lesioned and control quail were tested for spatial and cue-based learning performances. These hippocampal lesions specifically impacted spatial learning performance, but spared learning performance when birds could solve the task using their cue-based memory. These findings, thus, highlight that the hippocampus plays a crucial role and is essential for spatial declarative memory. Future studies could aim to elucidate the cellular or molecular mechanisms involved in this form of memory.

In order to find out whether a reduction in load-bearing on chicken legs would modify the activity and leg bone tissue, an original suspension device was developed in order to alleviate half of the weight-load on the legs. Thirty-six 5 d-old male meat-type chicks were assigned to 12 groups, each of 3 birds: a control bird (C), a bird equipped with a harness (H) and one equipped with a harness and suspended from a balance (S). The counterweights of the balance reduced the load on the legs by 50%. Behaviour in the birds was recorded twice for a 22-hour period. The birds were slaughtered at 19 d of age. Their legs were then weighed and the humeri, tibiotarsi and femurs were used for computation of length, biomechanical stiffness and composition. Tibiotarsi were also used for histomorphometry. Body weight at 19 d of age was significantly higher in the C birds (642 g vs. 586 g in the H and S groups, $P < 0.05$). The distance travelled as measured in the second week of the experiment was greater in S birds (338 m per 22 h vs. 246 in the C group and 252 in the H group, $P < 0.05$). The length of the tibiotarsi and femora was greater in the S birds when corrected for body weight ($P < 0.05$). Bone stiffness, composition and histological parameters were not significantly different in the 3 groups. We thus concluded that a reduction in load-bearing on the legs of young chicks enhances locomotor activity and longitudinal growth of leg bones. Bone quality was not affected, probably due to the contradictory effects of increased exercise and reduced weight.

Leg deformities were investigated in three flocks of broilers (n = 600, n = 817, n = 361). Two types of twisted legs were characterized: varus of the tarsal joint (1 to 3% of birds) and valgus of the tarsal joint (30 to 40% of birds) with mild, intermediate and severe valgus angulation. Varus angulation appeared suddenly, between 5 and 15 days of age, was unilateral in 80% of cases and affected mainly the right limb. Medial tendinous displacement was always present and led to severe locomotor handicap and, as a consequence, decreased 7-week body weights. In the right legs, a marked inward rotation of the femora, medial angulation of the tibiotarsi and metatarsi, and a shallow distal groove in the tibiotarsus were observed. By contrast, the load bearing limbs showed anteroposterior curvature of the tibiotarsus.Valgus angulation appeared progressively between 2 and 7 weeks of age and became severe in 5% of cases. This disorder was often bilateral. In 60% of birds affected with severe valgus, there was lateral displacement of the gastrocnemius tendon. Mild locomotor disturbance was observed in broilers with intermediate angulation, while severe valgus was associated with lameness, antero-posterior curvature of tibiotarsi and lateral deviations of metatarsi and in some birds a reduction in growth rate. Absence of other bone deformity in birds with mild and intermediate valgus suggests that valgus angulation does not originate from bone abnormalities. Clinical, epidemiological and anatomical differences between both types of angulations suggest that they may be of a different aetio-pathogenesis. Varus could originate from early displacement of the gastrocnemius tendon, which seemed secondary to leg deformation in birds affected with valgus angulation.

•Early hypoxia does not impact trout behavioural repertoire observed later in life.•Fear-related responses after an acute stressor are not impaired by early hypoxia.•Hypoxia resulted in enhanced growth rate 3.5 months after the return to normoxia.•Rainbow trout display a lasting adaptive response to early hypoxia exposure.

Broilers are challenged by metabolical, immunological, and skeletal disorders during a short lifespan. Faster-growing stocks may be frequently feed restricted via various management practices including dietary dilution. Information on the early posthatch nutrition of chicks, however, is limited. Hypothetically, one way to stimulate digestive tract development while slowing down body growth is to dilute the starter diet. In this experiment, wheat bran, usually well tolerated by chickens, was used in the formulation of a low energy and high fiber starter regimen until 11 days after hatch. Evaluated was its effect on food intake, digestive tract, and body development to 41 days of age in males of two stocks differing greatly in growth. Growth and tissue development were evaluated between 11 and 41 days of age when all chickens received the same concentrated diet. Gut development was nearly maintained even under very low nutritional status, but the initial delayed growth of the body could not be compensated for afterward in either stock. These results demonstrate that nutritional status during early life has long lasting effects on both fast- and slow-growing broilers.