. 2021 Mar 7;7(2):556–568. doi: 10.1016/j.aninu.2020.07.009

Table 3.

Growth performance, head kidney and spleen weight, index of grown-up grass carp (Ctenopharyn-godon idellus) fed diets containing graded levels of lysine for 60 d.

Item	Dietary lysine level, g/kg diet
Item	5.6	8.5	11.6	14.4	17.5	20.7
IBW¹, g/fish	164.33 ± 0.33^a	164.89 ± 1.07^a	165.00 ± 0.88^a	165.44 ± 0.38^a	164.89 ± 1.02^a	164.56 ± 1.02^a
FBW¹, g/fish	403.33 ± 3.53^a	485.33 ± 3.72^c	581.33 ± 4.00^f	549.78 ± 13.23^e	515.33 ± 5.92^d	442.22 ± 10.12^b
PWG¹, %	144.20 ± 2.11^a	192.62 ± 3.36^c	250.01 ± 2.80^f	230.21 ± 8.24^e	210.59 ± 4.13^d	167.22 ± 5.56^b
SGR¹, %/d	1.49 ± 0.01^a	1.79 ± 0.02^c	2.09 ± 0.01^f	1.99 ± 0.04^e	1.89 ± 0.02^d	1.64 ± 0.03^b
FI¹, g/fish	454.47 ± 0.30^a	527.02 ± 0.28^c	606.50 ± 0.25^f	579.18 ± 0.30^e	541.55 ± 0.26^d	471.06 ± 0.30^b
FE¹, %	0.52 ± 0.01^a	0.61 ± 0.01^b	0.68 ± 0.01^d	0.66 ± 0.02^cd	0.65 ± 0.01^c	0.59 ± 0.02^b
HKW², g	0.71 ± 0.01^a	0.96 ± 0.05^b	1.29 ± 0.06^d	1.23 ± 0.02^d	1.05 ± 0.04^c	0.88 ± 0.06^b
HKI², %	0.18 ± 0.00^a	0.20 ± 0.01^ab	0.22 ± 0.02^cd	0.23 ± 0.00^d	0.21 ± 0.01^bc	0.20 ± 0.01^ab
SW², g	0.55 ± 0.03^a	0.80 ± 0.03^b	1.00 ± 0.02^c	0.99 ± 0.08^c	0.82 ± 0.03^b	0.63 ± 0.01^a
SI², %	0.14 ± 0.01^a	0.17 ± 0.01^cd	0.17 ± 0.02^cd	0.18 ± 0.01^d	0.16 ± 0.00^bc	0.14 ± 0.00^ab
Regressions
Y_PWG = −1.495X² + 40.617X – 36.919					R² = 0.970	P < 0.05
Y_SGR = −0.008X² + 0.231X + 0.463					R² = 0.956	P < 0.01
Y_FE = −0.211X² + 5.916X + 26.061					R² = 0.957	P < 0.01
Y_HKI = -0.001X² + 0.018X + 0.096					R² = 0.909	P < 0.05
Y_SI = −0.001X² + 0.019X + 0.055					R² = 0.933	P < 0.05

IBW = Initial body weight; FBW = final body weight; PWG = percent weight gain; SGR = specific growth rate; FI = feed intake; FE = feed efficiency; HKW = head kidney weight; HKI = head kidney index; SW = spleen weight; SI = spleen index.

^{a to f} Values with different letter superscripts are significantly different (P < 0.05).

Values are means ± SD for 3 replicate groups, with 30 fish in each group.

Values are means ± SD (n = 12).