Feed efficiency components at fattening in rabbit lines selected for different objectives

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Pascual, Mariam | Piles, Miriam | Pascual, Juan Jose | Ródenas, Luis | Velasco, M. | Herrera, W. | Rafel, O. | Savietto, Davi | Sanchez, J.P.

Edité par CCSD ; Academic Publishers -

International audience. Feed efficiency (FE) for maintenance and for growth in two rabbit lines with different productive aptitude was studied. A total of 29 rabbits from Prat line (P; selected for litter size at weaning) and 29 rabbits from Caldes line (C; selected for growth rate at fattening), equally distributed between males (M) and females (F) were used. Kits weaned at 30 days of age were kept from 53 to 60 days of age fed ad libitum in individual cages. From 60 to 64 days of age (AdLib), animals were also fed ad libitum. Maintenance requirements were calculated for each line as 430 KJ kg-0.75 day-1 multiplied by its mean metabolic weight. At day 64, animals from both lines were distributed in groups R90, R80 or R70, feeding at 90, 80 or 70% maintenance requirements, respectively, from 64 to 67 days of age (Re). For each line and sex individual daily gain and individual daily feed intake were related fitting a linear spline regression with a single knot set at (DFIm,0), being DFIm the daily feed intake when animals do not modify live weight. The knot was set at the point yielding the lowest residual variance after a grid search. DFIm was higher in C (110.3 and 109.9 g/day in M and F, respectively) than in P line (82.8 and 77.5 g/day in M and F). FE for growth (slopes at AdLib) was higher in C (0.51 and 0.63 g/g in M and F) than in P line (0.45 and 0.47 g/g in M and F). During Re FE to cover maintenance requirements was higher in F than M, especially in P line (1.46 and 2.77 g/g in M and F for P line vs 1.40 and 1.63 g/g in M and F for C line). Results indicate that growing rabbits of line C have higher maintenance requirements than those from line P, however the formers are more efficient for growth. Moreover, F from line P are more efficient to cover their maintenance requirements than M from the same line or both M and F from line C. These differences could be consequence of the different selection processes conducted in each line.

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