Rabbit Lines Divergently Selected for Total Body Fat Content: Correlated Responses on Growth Performance and Carcass Traits

Abstract

The aim of this experiment was to study the effect of divergently selected rabbits for total body fat content (fat index) on growth performance and carcass traits. The fat index was determined at 10 weeks of age by computed tomography and lasted for four consecutive generations. The rabbits with the lowest fat index belonged to the lean line and those of the highest values belonged to the fat line. At generation four, 60 rabbits/line were housed in wire-mesh cages and fed with commercial pellet ad libitum from weaning (5 w of age) to slaughtering (11 w of age). Growth performance, dressing out percentage and carcass adiposity were measured. The lean line showed a better feed conversion ratio (p < 0.001) than the fat line. Furthermore, the carcass of the lean rabbits had the highest proportion of fore (p < 0.020) and hind (p < 0.006) parts. On the contrary, rabbits of the fat line had the highest carcass adiposity (p < 0.001). The divergent selection for total body fat content showed to be effective for both lean and fat lines. Selection for lower total body fat content could be useful for terminal male lines, while the selection for higher total body fat content could be an advantage for rabbit does in providing fat (energy) reserves.

Rabbits Divergently Selected for Total Body Fat Content: Changes in Proximate Composition and Fatty Acids of Different Meat Portions

“…In general, the results confirm that the effectiveness of divergent selection in developing Lean and Fat lines based on total body fat content [ 11 ] was also reflected in the lipid content of the studied meat cuts.…”

“…This was observed for the fat content of the LTL, which is the leanest meat cut of the rabbit carcass [ 8 ], and fat reduction cannot exceed a physiological threshold. The first results of the present experiment showed that after four generations of selection, the Lean and Fat lines diverged in the growth performance traits (feed conversion ratio), dressing-out percentage (different fore and hind part proportions) and carcass adiposity [ 11 ]. To the best of the authors’ knowledge, in the literature there are no other studies that tried to exploit the divergent selection for total body fat content to create two rabbit populations with different meat quality attributes by using CT.…”

“…The Pannon Ka rabbit (selected on the number of kits born alive; [ 11 ]) was involved in the divergent selection program for total body fat content. Selection was based on the fat index calculated in 10-week-old live rabbits by means of CT.…”

“…The experiment of Kasza et al [ 11 ] proved that it is possible to successfully select for increasing and decreasing fat depots, thus offering the opportunity (1) to provide energy reserves that rabbit does can mobilize when needed, and (2) to increase productive efficiency and reduce slaughter waste in terminal lines. The purpose of the present experiment is to investigate how the divergent selection for the total fat content of the body affects the fat content and fatty acid composition of different meat cuts.…”

A general technique for the estimation of farm animal body part weights from CT scans and its applications in a rabbit breeding program

“…It is important for market leaders to meet consumer needs as much as possible. Therefore the selection and research programs are targeting the genetic growth of the reproduction, carcass and meat quality which have great impact on the production level and the efficiency [7,22,4,10]. The quantitative characteristics of live animals collected by CT image analysis are essential for a successful and effective selection program.…”