The aim of the experiment was to study the effect of different energy intake on carcass traits and meat quality of rabbits, divergently selected for body fat content. Pannon White rabbits selected for high (HFAT) or low (LFAT) total body fat content were weaned at 4 weeks of age and fed three isocaloric diets (11.72, 11.60 and 11.66 MJ DE/kg diet, respectively). Compared to the ad libitum fed group (H), the daily feed intake was reduced by 10% (M) and 20% (L). Proportional to the reduction of feed intake the nutrient density of diets was increased. Thus, the energy intake was reduced while the protein intake remained similar in the three experimental groups. Effect of genotype on carcass traits was less marked than that of nutrition. Selection for high body fat content significantly improved the dressing out percentage (58.2 and 57.3% in HFAT and LFAT respectively; P<0.01), and reduced the ratio of the full gastrointestinal tract related to liveweight (13.9 and 14.4%, respectively; P<0.01). Reduction of energy intake decreased the body weight and the weight of the body parts significantly (P<0.001), while it had no effect on dressing out percentage. In group H the proportion of fore part to carcass was significantly higher (30.5 vs. 29.5%; P<0.001) while that of the hind part was lower than in group L (37.8 vs. 38.5%). Genotype influenced the overall meat quality traits to a lower extent than energy intake. The L. lumborum muscles from HFAT exhibited a lower (P<0.01) moisture content (76.09 vs. 76.52) and darker (L*, 53.45 vs. 54.41; P<0.05) and less yellow (b*, 0.42 vs. 0.81; P<0.05) colour. Restricted rabbits (L) exhibited higher values of pH (5.87 vs. 5.73; P<0.01) associated with lower values of cooking loss (17.82 vs. 19.06; P<0.01) and a higher moisture content (76.86 vs. 75.68; P<0.01). Moreover, L rabbits also produced lower (P<0.01) values of redness (a*, 2.21 vs. 3.35) and yellowness (b*, 0.23 vs. 0.91). Neither the genotype nor the energy intake affected significantly the lipid content of the meat. Energy intake restriction resulted in a lower (P<0.01) amount of total SFA (L: 32.13 vs. H: 35.75) and total MUFA (L: 20.98 vs. H: 28.64) as well as higher (P<0.01) content of PUFA (L: 45.48 vs. H: 34.85) of the hindleg meat. These results were related to the higher inclusion rate of sunflower oil in the feed L (4.2%) in respect with feed H (2.5%).

Effect of energy restriction in interaction with genotype on the performance of growing rabbits: II. Carcass traits and meat quality

BIANCHI, MAURIZIO;CAVANI, CLAUDIO;PETRACCI, MASSIMILIANO;
2009

Abstract

The aim of the experiment was to study the effect of different energy intake on carcass traits and meat quality of rabbits, divergently selected for body fat content. Pannon White rabbits selected for high (HFAT) or low (LFAT) total body fat content were weaned at 4 weeks of age and fed three isocaloric diets (11.72, 11.60 and 11.66 MJ DE/kg diet, respectively). Compared to the ad libitum fed group (H), the daily feed intake was reduced by 10% (M) and 20% (L). Proportional to the reduction of feed intake the nutrient density of diets was increased. Thus, the energy intake was reduced while the protein intake remained similar in the three experimental groups. Effect of genotype on carcass traits was less marked than that of nutrition. Selection for high body fat content significantly improved the dressing out percentage (58.2 and 57.3% in HFAT and LFAT respectively; P<0.01), and reduced the ratio of the full gastrointestinal tract related to liveweight (13.9 and 14.4%, respectively; P<0.01). Reduction of energy intake decreased the body weight and the weight of the body parts significantly (P<0.001), while it had no effect on dressing out percentage. In group H the proportion of fore part to carcass was significantly higher (30.5 vs. 29.5%; P<0.001) while that of the hind part was lower than in group L (37.8 vs. 38.5%). Genotype influenced the overall meat quality traits to a lower extent than energy intake. The L. lumborum muscles from HFAT exhibited a lower (P<0.01) moisture content (76.09 vs. 76.52) and darker (L*, 53.45 vs. 54.41; P<0.05) and less yellow (b*, 0.42 vs. 0.81; P<0.05) colour. Restricted rabbits (L) exhibited higher values of pH (5.87 vs. 5.73; P<0.01) associated with lower values of cooking loss (17.82 vs. 19.06; P<0.01) and a higher moisture content (76.86 vs. 75.68; P<0.01). Moreover, L rabbits also produced lower (P<0.01) values of redness (a*, 2.21 vs. 3.35) and yellowness (b*, 0.23 vs. 0.91). Neither the genotype nor the energy intake affected significantly the lipid content of the meat. Energy intake restriction resulted in a lower (P<0.01) amount of total SFA (L: 32.13 vs. H: 35.75) and total MUFA (L: 20.98 vs. H: 28.64) as well as higher (P<0.01) content of PUFA (L: 45.48 vs. H: 34.85) of the hindleg meat. These results were related to the higher inclusion rate of sunflower oil in the feed L (4.2%) in respect with feed H (2.5%).
METZGER SZ.; SZENDRŐ ZS.; BIANCHI M.; HULLÁR I.; FÉBEL H.; MAERTENS L.; CAVANI C.; PETRACCI M.; RADNAI I.; BIRÓ-NÉMETH E.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/77514
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