Table 5. Intestinal histomorphology of fish exposed to different experimental treatments for 60 days.

Variable	CG	SB1	SB2	SB3	p value
Anterior part
Villi length (μm)	151.487 ± 15.48a	227.611 ± 17.604b	376.646 ± 28.711c	286.525 ± 11.085d	<0.0001
Villi width (μm)	112.108 ± 20.842a	114.84 ± 7.845a	86.42 ± 30.315a	100.855 ± 3.95a	0.3114
Goblet cell/mm2	32 ± 3.606a	40 ± 3.606a	70.333 ± 5.508b	54.667 ± 6.506c	<0.0001
The inter-villi space (μm)	104.943 ± 14.55a	80.878 ± 6.64ac	42.490 ± 9.29b	52.941 ± 13.692bc	0.0029
Middle part
Villi length (μm)	373.497 ±24.584a	491.627 ±43.98ac	738.84 ±39.57b	593.617 ± 133.102bc	0.0018
Villi width (μm)	88.165 ±8.685a	95.728 ±7.280a	65.887 ±9.523b	81.340 ±7.387ab	0.0122
Goblet cell/mm2	50.667 ±3.055a	64.334 ±3.215b	90.00 ±4.001c	77.00 ±7.00d	<0.0001
The inter-villi space (μm)	33.357 ±3.571a	23.160 ±5.784b	8.823 ±0.577c	12.093 ±2.303c	0.0001
Posterior part
Villi length (μm)	69.780 ±11.628a	89.27 ±8.552a	197.925 ±10.616b	123.389 ±5.384c	<0.0001
Villi width (μm)	125.567 ±45.946a	87.454 ±10.912a	87.972 ±10.454a	106.678 ±19.90a	0.3013
Goblet cell/mm2	17.33 ±3.055a	25.33 ±2.516ac	39.33 ±3.511b	33.667 ±3.785bc	0.0002
The inter-villi space (μm)	123.111 ±33.495a	99.507 ±22.469ac	37.59 ±10.55b	56.294 ±17.649bc	0.0061

Note: Means ± SD within the same row with different superscripts are significantly different (p< 0.05). Different superscript letters (a, b, c, d) indicate significant differences between different groups: CG, the fish received basal diet; Syrena Boost group 1 (SB1), fish received basal diet containing 0.1 g kg–1 Syrena Boost; Syrena Boost group 2 (SB2), fish received basal diet containing 0.2 g kg–1 Syrena Boost; Syrena Boost group 3 (SB3), fish received basal diet containing 0.4 g kg–1 Syrena Boost.