The effect of duration of severe feed restriction on growth performance, carcass traits and meat quality of growing rabbits

Abstract

The effects of age and duration of severe restricted feeding on growth performance, carcass traits and meat quality of fattening rabbits were studied. Forty male California  rabbits of 6 weeks old were divided into four treatments with five replicates each. The  duration of severe restricted feeding (6 hours eating/day) lasted for zero, two, three  and four weeks for treatments 1, 2, 3 and 4 respectively, followed by ad-libitum  feeding up to the end of the experiment at age of 18 weeks. Body weight and daily gain were not statistically influenced by increasing the duration of restricted feeding, but daily feed intake was reduced (p<0.01) by 3.79 to 19.81% and zero to 16.19% at 14 and  18 weeks of age respectively. No significant effect in feed conversion or mortality rate were observed with increasing the duration of restricted feeding. Carcass traits and  meat quality were not affected by increasing the duration of restricted feeding. Age of rabbits at slaughter influenced nearly all carcass traits. Starved body weight, carcass  weight, dressing percentage, loin percentage and abdominal fat percentage were increased (p<0.01) while giblets percentage and head percentage were decreased (p<0.01)  with increasing slaughter age. Hind- and forequarter percentage were not statistically  influenced with increasing slaughter age. A positive linear relationship was found among live body weight, carcass weight, dressing percentage and loin percentage.  Dressing percentage was positively correlated with abdominal fat percentage, but negatively correlated with giblets percentage and head percentage. Meat quality was not negatively influenced by increasing the duration of restricted feeding and the meat had  normal meat properties. Heavier rabbits had darker meat (p<0.05) and higher cooking loss percentage (p<0.01)  in hindquarter and also higher pH value after storage of loin region in comparison to  lighter ones. A positive linear relationship existed between pH value taken after 24  hours from bleeding out and pH value after storage. Cooking loss percentage decreased with increasing pH value taken after 24 hours from slaughtering. Nearly all the  physical properties of loin meat were positively correlated (r=0.43 to 0.80) with the  corresponding characteristics of hindquarter meat.