Energetic chronometabolism in New Zealand white rabbits

The temporal organization of some physiological parameters in rabbits by evaluating the circatrigintan rhythms of some haematochemical and haematological parameters, and of rectal temperature, in New Zealand white rabbits was studied. For 30 days before the study the animals all followed the same pattern of daily activity with the natural photoperiod for that season, and were fed on hay ad libitum. Subsequently, the same animals followed another pattern of daily activity for a further 30-day period with a natural photoperiod and were fed on commercial pellets. At the end of each experimental period, blood samples were taken and rectal temperature was measured every 5 days for 30 days. Spectrophotometry in UV was used to calculate the concentration in each sample of: glucose, NEFA, triglycerides, total cholesterol, total proteins, uric acid, urea, albumin, creatinine, calcium, phosphorus and magnesium. The following values were measured on samples rendered unclottable: haematocrit, haemoglobin, RBC, MCV, WBC and VES. A periodic statistical model was used to elaborate the data, on average values of the two sets of samples. Intra-group variance was not significant. Glucose, triglycerides, RBC, Hb, PCV and rectal temperature showed a circatrigintan rhythm in both the experimental periods, but with different acrophases; creatinine, magnesium and phosphorus showed periodicity only when the subjects were fed on hay, while total proteins, urea, albumin and calcium were periodic only when they were fed with commercial pellets. The results obtained showed that the type of ration synchronizes the circatrigintan rhythm of some haematochemical and haematological parameters in the rabbit.