EFFECTS OF A ONE WEEK INTENSIVE FEED RESTRICTION IN THE GROWING RABBIT: Part 1 - PERFORMANCE AND BLOOD BIOCHEMICAL PARAMETERS

A total of 192 Hyplus rabbits (male and female ratio 1:1) of weaning age 35 d were randomly divided into three experimental groups (n=64 each), group 1 was fed ad libitum (control), group 2 (R50) was restricted from 42 to 49 d of age (50 g/d/rabbit), and group 3 (R65) was restricted from 42 to 49 d of age (65 g/d/rabbit). After the restriction time, all the groups were back to ad libitum feeding till the end of the experiment (70 d of age). Growth was recorded weekly. After restriction period, haematological and biochemical parameters were measured in a week interval. During the restricted period, the values of daily weight gain in restricted rabbits were lower than in full-fed rabbits, but after restriction, when animals were again fed ad libitum, a compensatory growth was found. Final body weight (at 70 d of age) tended to be lower in restricted groups (-9%, P=0.08). Blood plasma glucose, total protein and urea concentrations were not significantly affected by feed restriction in growing rabbits. However, feed restriction reduced blood plasma triacylglycerols (-23% in R50 and -16% in R65 vs control, P<0.05), and non-esterified fatty acids (NEFA, 19 % in R50 and 23% in R65) while increased cholesterol (+27 % in R50 and +29% in R65 vs control, P<0.01). Feed restriction reduced the erythrocyte number by 6 and 7% in R50 and 3 resp. (P<0.05) and haemoglobin concentration by 7 and 5% in R50 and R65, resp.(P< 0.01), meanwhile mean cell volume (MCV) was increased by 1.5 and 2.7% in R50 and R65, resp. (P<0.05). Feed restriction had no significant effect on leukocyte number and haematocrit value. It could be concluded that short-term limitation of the feed intake improved feed conversion ratio, had a limited negative effect on final body weight, reduced blood plasma TAG and NEFA, and seemed to produce normal blood picture in fattening rabbits.