Correlation coefficients (r) among physical characteristics, chemical constituents, and the SID of the first four limiting amino acids of the 10 rapeseed cake samples. * means significant difference (p < 0.05); ** means extremely significant difference (p < 0.01). SIDCP, SIDLys, SIDMet, SIDThr, SIDTrp, and SIDVal indicate the SID of CP, Lys, Met, Thr, Trp, and Val, respectively. DM, dry matter; GE, gross energy; CP, crude protein; EE, ether extract; Ash, crude ash; CF, crude fiber; NDF, neutral detergent fiber; ADF, acid detergent fiber; Ca, calcium; TP, total phosphorus; TGS, total glucosinolate; HT, heating temperature.