The effects of age, size, and cage complexity on the behaviour of farmed female chinchillas (Chinchilla lanigera).

Even though chinchillas have been farmed for a century, there are not many studies concerning their behaviour in captivity or their optimal housing conditions, both of which are important factors in the assessment of their welfare. This study aimed to evaluate the effect of different cage types on chinchillas' behaviour and their reactions towards humans. Female chinchillas (n = 12) were kept in three types of cages: standard with a wire floor (S); standard with a deep litter floor of shavings (SR); and enlarged with a deep litter floor of shavings (LR). Animals spent 11 weeks in each type of cage. The chinchillas' reactions toward humans were observed via intruder test. Ethograms were prepared based on round-the-clock video recordings. The activity of the chinchillas was compared, taking into account the different cage types and the animals' varying responses to the hand test. The generalized ordered logistic regression model was used to ascertain whether cage type has an effect on a chinchilla's behaviour towards humans. To compare the time distribution of various activity between chinchillas, the non-parametric Scheirer-Ray-Hare test was used. Animals kept in LR cages presented significantly less timid reactions in comparison to those kept in S and SR cages. The chinchillas spent most of their time resting (68% of the day), in locomotion (23%), and eating or drinking (8%); they spent only 1% on grooming behaviour. Cage enrichment generally reduced the fear of humans. However, the average chinchilla response to the hand test was classified in each type of cage as "cautious". Analyses of the ethograms indicated that the chinchillas were active mostly during the dark stage of the day. In conclusion, the larger cage size and its enrichment (particularly litter) reduced the fearfulness and passivity of the animals, which could be evidence of better welfare conditions.

Effects of embryonic cadmium exposure on erythrocyte indices and morphology in newly hatched Gallus gallus domesticus chicks.

The aim of the current study was to assess the influence of embryonic exposure to cadmium on basic and derived erythrocyte indices, the morphology and morphometric properties of erythrocytes, as well as erythrocyte spectrin distribution in newly hatched Gallus gallus domesticus chicks. The eggs were injected with cadmium (Cd) at a dose of 2 µg, 4 µg, 6 µg, or 8 µg per egg on the sixth day of incubation. Blood samples were collected on the first day after hatching. Exposure to cadmium resulted in higher levels of red blood cell count, hemoglobin concentration, and hematocrit value, while derived erythrocyte indices were lower (mean corpuscular volume) or higher (mean corpuscular hemoglobin concentration) in comparison to the control. These changes occurred in animals exposed to higher doses of this toxic agent. In cadmium-treated individuals (2 and 8 µg of Cd), the percentage of erythrocytes which exhibited changed shape increased. Increases in the length (6 and 8 µg) and width (2, 6, and 8 µg) of erythrocytes and the length and width of the nucleus (2-8 µg) of red blood cells were observed. Changes in spectrin distribution were also observed, which indicate alterations at structural and molecular levels.

Infrared Thermography as an Indicator of Heat Loss in Fur-Chewing Chinchillas (Chinchilla Lanigera).

Fur-chewing is a common problem in chinchilla (Chinchilla lanigera). It may affect the welfare of animals due to heat loss, thereby possibly impacting food and water intake to maintain body temperature. In this context, infrared thermography seems to be a suitable method of measuring heat emissions from the surface of objects. Sexually mature male domestic chinchillas were divided into two groups: "non-fur chewers", exhibiting normal behaviour (n = 25), and "fur chewers" displaying fur-chewing behaviour (n = 23). Food and water intake (mean ± SD) measured in the control animals amounted to 20.7 ± 4.52 g and 15.9 ± 3.45 mL, while in fur-chewing chinchillas were 25% and 33% higher, respectively. Metabolic energy intake, were calculated 2.2 and 2.8 W for the control and fur-chewing animals, respectively. Heat flux through chewed areas was 6.06 mW cm-2, which is 2.8 times higher than through undamaged chinchilla fur. To sum up, thermal imagingexplicitly shows that fur-chewing causes increased heat loss. Disturbances in the maintenance of thermal homeostasis may be an additional factor that reduces the welfare of these animals.

Cross Species Amplification of Coat Colour Genes in Nutria (Myocastor coypus Mol).

In this study, nutria-specific DNA fragments were amplified with cross-species primers for parts of coat colour genes (MC1R, ASIP, TYRP-1, c-KIT) conserved across a number of species. Twenty-three nutria-specific DNA fragments were generated using cross-species PCR (26.7% amplification success rate). Certain limitations of this approach were encountered, including strong mismatching in the primer binding sites. Sequences of 12 nutria-specific PCR products aligned in the BLASTx option showed homology with known protein sequences. Obtained sequences were submitted to GenBank with accession number KC758969 for MC1R, KF511655 for ASIP, KF511656 for TYPR-1 and KU831489 for c-KIT. The highest homology for all translated queries was obtained with protein sequences belonging to species of the rodent family. Sequences of proteins encoded by genes involved in environmental adaptation (coat colour genes in rodents) were found to be strongly conserved among species.

Biochemical adaptations to dive-derived hypoxia/reoxygenation in semiaquatic rodents.

To meet the challenges presented by dive-derived hypoxia/reoxygenation transition, the aquatic mammals possess multi-level adaptations. However, the adjustments of the semiaquatic animals as modern analogs of evolutionary intermediates between ancestral terrestrial mammals and their fully aquatic descendants are still not fully elucidated. The aim of this study was to analyze the total lactate dehydrogenase (LDH) activity (in the lactate to pyruvate direction), the LDH patterns and the antioxidant defense in the tissues (heart, kidney, liver, lung, muscle, spleen) of semiaquatic rodents such as Eurasian beaver (Castor fiber), muskrat (Ondatra zibethicus) and nutria (Myocastor coypus). Samples from Wistar rat were used for comparison. Semiaquatic rodents had higher catalase activity compared to rats. The superoxide dismutase activity was higher and the catalase activity was lower in almost all tissues of muskrat than of both beaver and nutria. Comparing beaver and nutria, no significant differences in the antioxidant enzyme activities were found for the heart, kidney and liver. In beaver, most of the examined tissues (heart, kidney, lung and spleen) use lactate as preference to glucose as a substrate but in muskrat the heart, liver and skeletal muscle showed the increased LDH activity. Nutria had the unusual LDH properties that are needed to be further investigated. Our results suggest that beaver, nutria and muskrat have distinct mechanisms of adaptation to diving hypoxia/reoxygenation and support the hypothesis that semiaquatic mammals are the intermediate animals that help to define which potential selection factors and mechanical constraints may have directed the evolution of the aquatic forms.