Changes of haematological and biochemical indices with age in rabbits with ad libitum and limited feed intake

The aim of this study was to examine the effects of a one-week feed restriction of different intensities on haematological and biochemical blood indices at the end of the feed restriction and during the realimentation period in growing rabbits. Hyplus rabbits weaned at 35 days of age (n = 195) were divided into three groups: rabbits fed ad libitum (AL) and groups with reduced feed of 50 g (R50) or 65 g (R65) per rabbit per day from 42 to 49 days of age. At the end of the feed restriction and in the following period, haematological and biochemical blood indices were measured at weekly intervals. The live weight at 70 days of age was lower (P ≤ 0.001) in restricted rabbits (–14.5% and –15.5% for group R50 and R65, respectively, compared to AL). Feed restriction significantly (P ≤ 0.011) decreased the number of erythrocytes (–6.2% and –7.4% for group R50 and R65, respectively, compared to AL) and haemoglobin content (P ≤ 0.008). The mean corpuscular volume increased (P ≤ 0.033) in restricted rabbits. Interaction of the feeding regime and age (P ≤ 0.007) was observed in cholesterol with the highest concentration in R50 at 56 days (4.41 mmol/l) and the lowest in R65 at 70 days and in AL at 63 days of age (1.30 mmol/l). The concentration of non-esterified fatty acids (P ≤ 0.003) and triacylglycerides (P ≤ 0.048) were significantly lower in restricted rabbits. It could be concluded that feed restriction influenced mainly erythrocytes and haemoglobin. The changes in biochemical blood characteristics suggest the restriction did not affect protein metabolism, however, results indicate lipid depletion in restricted rabbits.