Reference ranges for biochemical and haematological values in farmed saltwater crocodile (Crocodylus porosus) yearlings

Objective To determine reference ranges for healthy yearling farmed saltwater crocodiles by performing routine biochemical and haematological laboratory tests on blood samples.
Design A clinico-pathological study.
Procedure Blood samples were collected from 120 healthy yearlings from four Northern Territory crocodile farms and body weight and length were measured. All animals had been fasted for 2 days before sample collection. Routine biochemical analytes were determined on 120 samples and haematological values determined on 30 samples (from one farm).
Results Reference ranges for biochemical and haemato-logical values were determined for farmed yearling saltwater crocodiles in the Northern Territory.
Conclusion The results were comparable with published reference ranges for other crocodilian species. Other published results of haematological values from saltwater crocodiles were from very young (6-week-old) hatchlings and older (2- to 4-year-old) crocodiles. Differences in values were presumed to be caused by age-related factors.     

The effects of decreased body temperature on the onset,duration and action of medetomidine and its antagonist atipamezole in juvenile farmed estuarine crocodiles (Crocodylus porosus)

ObjectiveTo determine the efficacy of medetomidine for immobilisation of captive juvenile crocodiles over a range of temperatures, and its reversibility with atipamezole.Study designProspective experimental study.AnimalsForty male estuarine crocodiles (body weight 2.0 to 4.8 kg).MethodsEach crocodile was randomly assigned to one of four temperature groups: Group 1:32 °C; Group 2:27 °C; Group 3:22 °C; and Group 4:17 °C (n = 10 for each group). Medetomidine (0.5 mg kg^?1) was administered intramuscularly (IM) into the thoracic limb of all crocodiles. After 50 minutes, all animals from each group received 2.5 mg kg^?1 atipamezole IM in the opposite thoracic limb and time to recovery was documented. Heart and respiratory rates and the degree of immobilisation were monitored every 5 minutes until recovery, and behaviour monitored for 7 subsequent days.ResultsOnset of immobilisation occurred at 15 ± 10 minutes in Group 1, and at 30 ± 10 minutes in Groups 2 and 3. In Group 4, animals were not immobilised. Recovery following atipamezole was 10 ± 5 minutes at all temperatures. One-way analysis of variance (anova) demonstrated a significant difference in induction times between groups (p < 0.01) but not in recovery times following atipamezole administration (p < 0.25). Heart and respiratory rates decreased markedly following medetomidine administration and increased markedly following atipamezole reversal.Conclusions and clinical relevanceMedetomidine administered in the thoracic limb of juvenile captive estuarine crocodiles provides profound sedation or immobilisation at temperatures of 22 °C and above. Atipamezole administered in the contralateral thoracic limb results in consistent reversal of the effects of medetomidine and a return to normal behaviour within 15–20 minutes regardless of temperature. Even though immobilisation is not induced at 17 °C, profound reversible sedation does occur reliably and repeatably.     

Effect of air velocity on deep body temperature and weight gain in the broiler chicken

Tunnel ventilation has been adopted as an effective approach to combatting heat stress in poultry. Setting tunnel air velocity to levels that ensure bird comfort, while optimizing performance is an important goal. In recent years, biotelemetry has provided a way to effectively evaluate the impact of management practices on poultry physiology. In this study, we present an approach for evaluating the effects of heat stress and tunnel ventilation on poultry deep body temperature (DBT) using biotelemetry. Three consecutive experiments were conducted using 6 broilers, each at the ages of 8.6, 9.0, and 9.4 wk. Experiments spanned approximately 12 h each and led to 18 data sets. DBT responses of birds under no ventilation rose by as much as 3°C as a result of step increases in ambient temperature. Birds exposed to tunnel ventilation maintained a lower DBT by as much as 0.9°C. During experiment days, birds exposed to tunnel ventilation consistently gained weight with a percentage weight gain ranging from 1% to 11%. Birds not exposed to tunnel ventilation behaved less consistently with some gaining as much as 14% while others lost as much as 9%. Although further studies are required to derive more comprehensive and more statistically significant results, this study provided preliminary data that is needed to warrant such studies, and a stepping stone for making optimal management and risk assessment decisions that are based on physiological needs of the birds.     

Relationships between body weight,fasting blood glucose concentration,sex and age in tree shrews (Tupaia belangeri chinensis)

The tree shrew (Tupaia belangeri chinensis) is a squirrel‐like lower primate or a close relative of primates, commonly used as an animal model in biomedical research. Despite more than three decades of usage in research, the clear relationships between body weight, fasting blood glucose concentration, sex and age among tree shrews remain unclear. Based on an investigation of 992 tree shrews (454 males and 538 females) aged between 4 months and 4 years old, we found that male tree shrews have significantly higher body weight and fasting blood glucose concentration than female tree shrews (p < 0.001). The concentration of fasting blood glucose slightly increased with body weight in males (r = 0.152, p < 0.001). Meanwhile, in females, the body weight, concentration of fasting blood glucose and waist circumference positively increased with age (p < 0.001). Additionally, 17 tree shrews with Lee index [body weight (g)*0.33*1000/body length (cm)] above 290 had significantly higher body weight, waist circumference and glycated haemoglobin A1c (HbA1c) than non‐obese tree shrews with a Lee index score below 290 (p < 0.001). Interestingly, 6 of 992 tree shrews (three males and three females, 2–4 years old) displayed impaired plasma triglycerides, HbA1c, low‐density lipoprotein and oral glucose tolerance test, suggestive of the early symptoms of metabolic syndrome. This study provides the first clear relationships between body weight, fasting blood glucose concentration, sex and age in tree shrews, further improving our understanding of this relationship in metabolic syndrome (MetS). Given the similarity of tree shrews to humans and non‐human primates, this finding supports their potential use as an animal model in the research of MetS.