Table 6.

Head kidney and spleen morphological changes in different groups of grown-up grass carp fed diets containing different levels of lysine for 60 d after infection with the Aeromonas hydrophila for 6 d.¹

Item	Dietary lysine levels, g/kg diet
	5.6	14.4	20.7
Head kidney
Macrophage numbers	1	0.33	0.67
Blood vessel wall incrassating	1.3	0	1.33
Endothelial cell swelling and defluxion	0.67	0	0.67
Haemorrhage	0.67	0	0.33
Extravasated blood	0.67	0	0.67
Vacuolization	0.33	0.33	1
Column totals	4.64b	0.66a	4.67b
Spleen
Macrophage numbers	1.67	0	1
Blood vessel wall incrassating	0.33	0.33	0.67
Endothelial cell swelling and defluxion	1	0.33	0.67
Haemorrhage	1.33	0.33	1.67
Extravasated blood	1	0.67	0.67
Vacuolization	0.67	0.33	1
Column totals	6b	1.99a	5.68b

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

¹Values are means (n = 3).