Retention of nitrogen from ground barley grain supplemented with lucerne or barley leaf juice in long‐term balance experiments conducted with rats

Abstract

The biological value (BV) and true digestibility of lucerne and barley juice protein mixed with ground barley grain were estimated using the Thomas‐Mitchell balance method with rats. The BV with forage barley juice protein was similar to that of barley grain protein alone and was not improved by any of the applied treatments. The BV with lucerne juice protein was lower and was improved by separating the ‘brown juice’ after heat coagulation. Better results were obtained in a group fed diets with lowered levels of potassium and calcium which suggested an imbalance in the mineral content of lucerne juice; there was no difference in water consumption. The haemoglobin content of the blood of rats fed lucerne or barley juice alone was lower than that of animals fed plant juice/barley grain mixtures. No pathological lesions were observed in the guts, kidneys and livers of the rats.

The nutritive value of native and modified lucerne juice for rats

“…In the case of diets with casein, mixtures of minerals in a readily available form were included. On the basis of the results of this work and previous experiments (Hanczakowski 1979;Hanczakowski et a/ 1982) it can be stated that coagulation of protein and its separation from the remaining liquid from the best way of utilising lucerne juice protein. Another promising way to use the juice may be to ferment the whole juice anaerobically.…”

“…The deficiency of sulphur amino acids is a primary reason for the low nutritive value of protein extracted from lucerne (Henry and Ford 1965;Ueda and Ohshima 1982) but in the case of whole juice its poor nutritive value may also result from a mineral imbalance (Barber et a1 1981). It has been observed in previous experiments on rats (Hanczakowski et al 1982) that removing the 'brown juice', ie the liquid remaining after heat coagulation or storing the whole lucerne juice at room temperature for 48 h, improved the nutritive value of lucerne-juice protein.…”