[Chemical-nutritional evaluation of Sorghum saccharatum var. sugar drip. A supplementation study with lactoserum...

The chemical-nutritional composition and some indexes of biological quality of sorghum (Sorghum saccharum, var. sugar drip) unwashed whole flour were studied. The culture and selection of sorghum were assayed in the "San Roque" Experimental Station of the Agriculture Department, Undersecretary of Agricultural Affairs, San Luis, Argentina. The obtained protein content was 7.5% (Nx6.25). The values for net protein utilization (NPU); true digestibility (tD); net protein ratio (NPR) and and relative net protein ratio (RNPR) were 12.4 +/- 0.6, 22.0 +/- 0.2, 0.8 +/- 0.1 and 24%, respectively. Deficient nitrogen utilization constitutes a limitation for the use of sorghum. However, considering its abundance and low cost, sorghum could become a profitable feeding resource if conveniently supplemented without increasing costs. Sorghum flour was supplemented with protein recovered from ricotta serum (50:50), discarded as industrial waste, in order to compensate for lysine and threonine deficiency in this cereal. Studies performed on this mixture gave RNPR values of 85.7%. This might permit us to infer that despite its low biological value, sorghum can be used as food resource, potentially for poultry, with adequate supplementation.