Utilisation of field beans by growing rabbits. 1-Effects of supplementations aimed at improving the sulfur amino acid supply.

Abstract

One hundred New Zealand White rabbits distributed into five dietary groups were fattened between 35 and 77 days in individual cages. The diets were SOJ (soybean control), FEV (26.5 % f1eld beans), FEVM (FEV diet supplemented with di methionine), F'EVF (FEV diet supplemented with field beans up to a total of 37 %) and FEVT (FEV diet supplemented with sunflower cake) provided ad libitum. The mean protein content was 14.5 % in the SOJ, FEV and FEVM diets and 16.3 % in the FEVF and FEVT diets. The digestible energy content varied little between diets (2256 to 2324 kcal DE/ kg). The fibre content of each diet was 14.5 %. Apparent digestibility of dry matter was comparable in all five diets (58.9 to 60.3 %). Apparent digestibilitv of crude proteins was lower in the FEVF diet (66.2 %) than in the SOJ (70.8 %), FEVM (70.0 %) and FEVT (73.3 %) diets. The daily growth rate of rabbits fed the FEV diet (38.9 g / d) was lower than that in the other groups (40. 7 to 44.5 g / d) but their feed conversion ratio was similar. The diet did not affect dressing percentage (mean: 57 %) or the relativa weiQht of the skin and of the full gastrointestinal tract. However, 1t did affect several carcass composition parameters: the muscle to bone ratio was highest under the FEVM diet (5.29) and lowest under the FEV diet (4.34) and relativa liver we1ght was lowest under FEVT and highest under FEVF. Finally, there was no difference in the sensory guality of meat between SOJ and FEVF diets. In conclusion, field beans were a good source of proteins for rabbits that could totally replace soybean meal but did require supplementation with sulfur amino acids (d/methionine or another plant source) in order for performance to be adequate.