Dietary inclusion of marama bean (Tylosema esculentum) in broiler chicken diets compromises feed utilization, growth performance, and carcass traits

Abstract

Orphan legumes that are native to semi-arid areas of southern Africa, such as marama (Tylosema esculentum) bean, hold promise as sustainable nutrient sources in conventional broiler diets. Yet, their nutritive value remains largely unexplored, and the presence of antinutrients could potentially compromise their nutritional quality. Therefore, this study evaluated the effect of full-fat marama bean meal (MBM) on growth performance and physiological and meat quality parameters of growing broiler chickens. Fourteen-day-old male Ross 308 broilers (n = 385; 359.7 ± 25.48 g live-weight) were randomly assigned to five experimental diets formulated by including MBM in a standard broiler grower diet at 0 (MBM0), 16.25 (MBM16), 32.49 (MBM32), 48.74 (MBM49), and 64.98 g/kg (MBM65). Each diet was randomly allocated to 7 replicate pens (experimental units). Diets had no effect on feed intake, but body weight gain and final body weight showed negative linear responses, while feed conversion ratio showed linear and positive quadratic responses (P < 0.05) to increasing MBM levels. There were negative quadratic effects (P < 0.05) for eosinophils, lymphocytes, and alanine transaminase, whereas linear and quadratic responses (P < 0.05) were recorded for alkaline phosphatase. Hemoglobin, neutrophils, monocytes, and albumin:globulin ratio linearly decreased (P < 0.05), whereas red blood cells, symmetric dimethylarginine, cholesterol, and lipase increased linearly with MBM levels. Linear increases (P < 0.05) were recorded for shear force and proventriculus, gizzard, pancreas, duodenum, jejunum, and ileum sizes. In contrast, linear decreases were observed for carcass weights, breast weight, and breast meat pH. In conclusion, higher levels of MBM resulted in poor growth performance, low carcass weights, and heavier visceral organs, possibly due to anti-nutritional compounds in MBM.