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

Table 7.

Effects of graded levels of lysine on immune related parameters in the spleen, head kidney and skin of grown-up grass carp (Ctenopharyngodon idella).¹

Item	Dietary lysine levels, g/kg diet
Item	5.6	8.5	11.6	14.4	17.5	20.7
Spleen
Lysozyme, U/mg protein	109.21 ± 4.79^a	137.97 ± 7.13^b	173.06 ± 8.93^d	176.40 ± 4.34^d	164.18 ± 9.02^c	144.29 ± 8.65^b
ACP, U/mg protein	184.69 ± 5.96^abc	183.19 ± 17.43^abc	170.46 ± 9.99^a	173.88 ± 13.58^ab	186.35 ± 11.64^bc	191.23 ± 9.20^c
C3, mg/g protein	29.49 ± 2.81^a	33.62 ± 1.46^b	40.38 ± 3.35^de	42.32 ± 2.49^e	37.77 ± 3.59^cd	35.47 ± 2.36^bc
C4, mg/g protein	8.17 ± 0.28^a	10.12 ± 0.79^b	13.45 ± 1.11^de	14.18 ± 1.25^e	12.76 ± 1.20^cd	12.07 ± 0.65^c
IgM, mg/g protein	42.72 ± 3.59^a	57.99 ± 5.38^b	68.56 ± 4.22^cd	72.19 ± 4.26^d	70.09 ± 3.04^cd	65.61 ± 2.64^c
Head kidney
Lysozyme, U/mg protein	106.40 ± 4.78^a	153.10 ± 11.42^b	203.72 ± 5.26^d	213.57 ± 8.55^d	186.95 ± 6.53^c	149.08 ± 11.43^b
ACP, U/mg protein	194.62 ± 9.49^ab	184.40 ± 10.27^a	182.88 ± 6.83^a	179.39 ± 10.59^a	194.54 ± 12.96^ab	203.61 ± 18.14^b
C3, mg/g protein	18.08 ± 1.41^a	19.83 ± 1.81^a	25.80 ± 1.79^cd	26.45 ± 1.70^d	24.00 ± 1.66^c	21.84 ± 1.48^b
C4, mg/g protein	8.33 ± 0.54^a	10.09 ± 0.46^b	12.45 ± 0.80^c	12.63 ± 0.93^c	9.44 ± 0.29^b	8.43 ± 0.51^a
IgM, mg/g protein	46.43 ± 4.15^a	55.01 ± 4.05^b	61.93 ± 4.61^c	62.15 ± 4.78^c	60.57 ± 3.81^c	58.66 ± 4.28^bc
Skin
Lysozyme, U/mg protein	86.54 ± 5.67^a	90.18 ± 8.23^ab	113.09 ± 9.49^c	115.52 ± 8.91^c	95.94 ± 1.98^b	87.32 ± 2.89^a
ACP, U/mg protein	171.88 ± 12.97^b	170.11 ± 13.18^b	152.59 ± 13.26^a	172.65 ± 12.76^b	184.46 ± 16.89^bc	192.99 ± 6.64^c
C3, mg/g protein	21.37 ± 1.14^a	24.62 ± 1.18^c	28.48 ± 2.39^d	28.31 ± 0.95^d	23.41 ± 1.45^bc	21.97 ± 2.12^ab
C4, mg/g protein	4.85 ± 0.41^a	6.12 ± 0.29^b	7.90 ± 0.52^d	8.00 ± 0.26^d	6.61 ± 0.42^c	5.81 ± 0.33^b
IgM, mg/g protein	71.75 ± 7.69^a	92.40 ± 4.32^b	122.93 ± 5.54^d	123.90 ± 7.51^d	104.90 ± 10.03^c	90.19 ± 8.86^b

ACP = acid phosphatase; C = complement; IgM = immunoglobulin M.

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

Values are means ± SD (n = 6).