Table 5.

Summary of estimated optimal digestible amino acid ratios for broiler chicks.

		Model1						Mean
Amino acid	Response	L	Q	95% Quad	LRP	LRP/Quad	QBL	ratio2
Phe + Tyr	Body weight gain	–	113	107	107	110	112
	Breast weight	118	–	–	–	–	–	112
	Breast fillet weight	118	–	–	–	–	–
His	Body weight gain	40	–	–	–	–	–
	Feed conversion ratio	–	36	34	31	34	32
	Breast weight	–	39	37	36	38	40	38
	Breast fillet weight	–	41	39	36	39	40
	Breast yield	–	41	39	37	39	41
	Breast fillet yield	–	39	40	37	38	42
Leu	Body weight gain	–	111	106	102	106	105
	Breast weight	–	110	105	99	104	101
	Breast fillet weight	–	110	105	99	104	101	104
	Breast yield	–	110	105	99	105	100
	Breast fillet yield	–	109	104	99	105	100

¹Optimal digestible ratio estimates shown for each response in which at least one model was significant. Abbreviations: L, linear; Q, quadratic; 95% Quad, 95% of the asymptotic parameter of the quadratic model; LRP, linear response plateau; LRP/Quad, LRP-to-quadratic regression ratio; QBL, quadratic broken line.

²Overall-mean estimated optimal digestible ratio across all significant response variables per amino acid.