NUTRITIONAL UTILIZATION BY RATS OF CHICKPEA (CICER-ARIETINUM) MEAL AND ITS ISOLATED GLOBULIN PROTEINS IS POORER THAN THAT OF DEFATTED SOYBEAN OR LACTALBUMIN

The effects on performance, digestibility, N utilization and plasma am ino acid concentrations of dietary chickpea (Cicer arietinum, var. Kab uli) seed meal, globulin proteins or buffer-insoluble residue [starch + non-starch polysaccharides (NSP) + lignin] were studied in growing r ats. Chickpea meal, defatted soybean meal, chickpea globulins and lact albumin were each incorporated into diets as the sole source of dietar y protein (100 g/kg). In addition, chickpea insoluble residue was incl uded in a control diet in the same proportion found in the chickpea me al. Rats were killed while under halothane anesthesia after 10 d of co nsuming the diets, and ileal contents were washed out and freeze-dried for digestibility measurements. Weight gains and gain:feed ratios of rats fed chickpea diets for 10 d did not differ from those of rats fed defatted soybean but were significantly lower than those of rats give n the control (lactalbumin) diet. However, ileal and fecal Id digestib ilities and N retention by rats fed the chickpea diet were significant ly lower than those obtained with the lactalbumin or soybean diet. The inclusion of both chickpea meal or its globulin proteins in the diet significantly increased the amount of N excreted, primarily as urea, t hrough the urine. However, although ileal id digestibility values for chickpea meal were significantly lower, those for its constituent glob ulins did not differ from control values. Urea levels in plasma in rat s fed diets containing chickpea meal, globulins or soybean meal were s ignificantly higher than in those fed lactalbumin. Furthermore, the co ncentrations of glycine, phenylalanine, histidine, arginine and ornith ine in the plasma of rats fed chickpea meal, its globulins or defatted soybean were significantly higher, whereas those of threonine, leucin e, lysine and tryptophan were significantly lower than lactalbumin-fed controls. The chickpea insoluble residue had no adverse effects on pe rformance or N utilization by rats. We conclude that the low nutrition al value of chickpea meal is likely to be due mainly to adverse effect s of its globulin proteins on growth and N metabolism rather than to t he action of any known antinutritional factor present in the diet.