A response of growth performance, nutrient digestibility and nitrogen retention of growing female rabbits to levels of Psophocarpus scandens vines in diets
A study was implemented to determine the optimum levels of Psophocarpus scandens (PS) vine in diets of female rabbits (New Zealand x local breed) based on growth performance, nutrient intake and digestibility. It was a complete randomized design with five treatments and three replicates. Sixty female rabbits at 60 days of age (799 g on average) were allocated in the experiment for 70 days. The treatments were levels of 0, 15, 30, 45 and 60% (DM basis) of Psophocarpus scandens replacing Para grass (PG) in the diets. They were corresponding to the treatments named PS0, PS15, PS30, PS45 and PS60, respectively. PS protein content was higher than that of PG (23.1 vs. 9.9% of DM) and NDF content was lower (41.8 vs. 61.6% of DM). The results showed that dry matter intake was significantly reduced for the highest PS proportions (P<0.01) with 93.5 – 93.0 – 92.7 – 85.0 and 84.5 g/d for the PS0 to PS60 diets respectively. Crude protein intake of rabbits significantly (P<0.01) increased with the increase of the PS proportion. The daily weight gain of the rabbits was higher in the diets with PS replacement (15.1, 17.3, 18.2, 16.3 and 17.5 g/d for diets PS0 to PS60 respectively). However, only the daily weight gain of the PS30 treatment was significantly higher than that of the PS0 one. The nutrient digestibility (dry matter and crude protein) and nitrogen retention of rabbits were also significantly (P<0.01) improved with increasing the level of PS in the diets. It was concluded that the use of Psophocarpus scandens vine to replace Para grass improved nutrient utilization, daily weight gain and profits, and replacing Para grass by Psophocarpus scandens at a level of 30% (DM) could be recommended for producers’ application.
