EN
The aim of study was to determine the effect of grain aphid (Sitobion avenae /F./) on nutritive value of soluble protein isolated from ears of spring triticale cultivars. Nutritive value of protein was estimated by the limiting amino acid index (CS) calculated in according with to Mitchel and Block (1946), and by the integrated index of essential amino acids (EAA) calculated in with according to Oser (1951). Obtained results showed that feeding of the grain aphid on the ears of tested spring triticale cultivars caused the decrease in the content of essential amino acids. This resulted in the decrease of CS and EAA values and in the reduction of nutritive value of soluble protein.