Bio-nutritional evaluations of three tropical leaf vegetables ( Telfairia occidentalis, Amaranthus cruentus and Talinum triangulare) as sole dietary protein sources in rat assay

The bio-nutritional potentials of three tropical vegetable leaf meals ( Telfairia occidentalis leaf meal, TOLM; Talinum triangulare leaf meal, TTLM and Amaranthus cruentus leaf meal, ACLM) were investigated using albino rat as the test animal. Some protein quality evaluation indices were measured when the three vegetable leaf meals (VLMs) were used as sole protein sources in diets fed to the experimental animals and results were compared with data obtained for a basal nitrogen free diet (diet 1) and another reference diet (diet 2) in which the protein was solely supplied by nutritional casein (pure protein). The weight gain value recorded over a 10 day experimental period for the test animals on the reference (casein) diet 2 was consistently higher ( P < 0.05) than the weight gain value obtained for the animals on the 3 VLMs diets (diets 3–5). Feed intake values recorded for the rats on the VLMs were similar ( P > 0.05) and significantly higher ( P < 0.05) than the value obtained for rats on the reference (casein) diet. Nitrogen excreted in faeces (feacal nitrogen) was lowest ( P < 0.05) for the animals in reference diet 2. However, the nitrogen excreted in urine (urinary nitrogen) was highest ( P < 0.05) for the animals on reference diet 2 and lowest for animals on diet 3 (TOLM diet) ( P < 0.05). The nitrogen retention (NR) value obtained for the test animals on the reference diet 2 was similar ( P > 0.05) to the value obtained for animals on diet 3 (TOLM). These values were significantly higher ( P > 0.05) than NR values obtained for animals on diets 4 (TTLM) and 5 (ACLM). Expectedly, the apparent nitrogen digestibility (AND), protein efficiency ratio (PER), net protein ratio (NPR), true digestibility (TD), biological value (BV) and net protein utilization (NPU) all indicated higher and better values ( P < 0.05) than the corresponding values obtained for the 3 VLMs diets (diets 3–5).