Evaluation of Protein Concentration and Limiting Amino Acids Including Lysine and Met + Cys in Prestarter Diet on Performance of Broilers

Table 4

Effect of feeding diets containing various levels of crude protein (CP) and methionine + cystine (Met + Cys) on body weight gain, feed intake, and feed conversion ratio of broiler chicks (Experiment 1-2).

Treatments			BWG (gr)		FI (gr)		FCR (gr/gr)
Number	CP (%)	Met + Cys (%)	1–7 d	1–10 d	1–7 d	1–10 d	1–7 d	1–10 d
1	23.2	0.85	214.5	332.2^a	188.8	351.3^a	0.880^a	1.057^ab
2	23.2	0.90	217.8	341.8^a	184.4	352.1^a	0.847^ab	1.030^bc
3	23.2	0.95	215.4	340.4^a	177.2	333.0^b	0.823^bc	0.978^c
4	23.2	1.00	222.0	346.7^a	178.5	337.5^b	0.804^c	0.973^c
5	21	0.85	216.3	337.4^a	182.6	343.4^ab	0.844^ab	1.018^bc
6	21	0.90	213.3	330.8^a	185.0	345.0^ab	0.867^a	1.043^ab
7	21	0.95	208.8	312.5^b	180.6	337.0^b	0.865^a	1.078^a
8	21	1.00	214.0	333.6^a	183.5	340.6^ab	0.857^ab	1.021^bc
Pooled SEM			2.45	4.43	2.89	4.71	0.011	0.011
Probability
Protein × (Met + Cys)			NS	*	NS	*	**	*
Protein			NS	NS	NS	NS	NS	NS
Met + Cys			NS	NS	NS	NS	NS	NS

^a–dMeans in each column without common superscripts are significantly different.
*Data are means of four replicates having 20 birds in each replicate. BWG: body weight gain, FI: feed intake, FCR: feed conversion ratio, CP: crude protein, Met + Cys: methionine + cystine, SEM: standard error of mean, NS: not statistically significant; *𝑃<0.05; **𝑃<0.01.