Effect of Simulated Microgravity on Metabolite Concentrations in the Muscles and Liver of Developing Japanese Quail Chicks

Hypodynamy is the most frequently used ground-based model to study the negative consequences of microgravity on an animal organism. The objective of the current experiment was to examine the influence of hypodynamy on the growth and development of the breast muscle, thigh muscles and liver in female Japanese quail chicks from 3 to 56 d of age. Samples of muscles and liver were obtained at 1, 14, 28, 42 and 56 d; the variables studied were: weight (g), relative weight (%), dry matter (mg/g) and content of total proteins, total lipids and glycogen (mg/g). The actual weight of breast muscle, thigh muscles and liver gradually increased with age of quail in both groups. However, the experimental birds exposed to hypodynamy showed a reduction in growth relative to age-matched control. At the end of testing, the body weight of the hypodynamy group was significantly lesser than that of control (P P < 0.05). On the contrary, the differences in the content of total protein and glycogen in muscles and liver of both groups were not significant at the end of experiment. These results provide further evidence that, although hypodynamy affects the examined variables of selected skeletal muscles and liver, the female Japanese quail is able to develop under conditions of simulated weightlessness

Chicks from a high and low feather pecking line of laying hens differ in apomorphine sensitivity

Proactive rodents show a larger behavioral response to apomorphine (APO) than reactive copers, suggesting a more sensitive DA system in proactive individuals. Previously, chicks from a high feather pecking (HFP) and low feather pecking line (LFP) have been suggested to display a proactive and reactive coping strategy, respectively. Therefore, at approximately 4 weeks of age, the behavior of 48 LFP and 48 HFP chicks in response to an APO injection was studied using an open field. Another objective of the present study was to determine whether behavioral variation (in an open field) between HFP and LFP birds, after APO injection, is also reflected by variation of D1 and D2 receptor densities in the brain. Receptor binding capacities were assessed by measuring specific binding of tritiated D1 and D2 receptor ligands in different regions of the brain of control HFP and LFP chicks. In the present study, it is shown that indeed HFP chicks display a more enhanced behavioral response to acute APO treatment (0.5 mg/kg BW) than LFP birds in an open field. This difference was not reflected by variation of D1 and D2 receptor densities in the brain between both lines.