Fig 1.
Diagrammatic summary of the different gilthead sea bream feeding trials (T) showing their timing, the main features of diet composition and the analyses performed at the end of each of them.
Table 1.
Gilthead sea bream genes included in real-time PCR by six functional categories.
1 Cell differentiation and proliferation; 2 Intestinal architecture and permeability; 3 Enterocyte mass and epithelial damage; 4 Immune surveillance; 5 Pattern recognition receptors; 6 Mitochondria function and biogenesis.
Table 2.
Dose dependent effects of sodium butyrate (BP-70 ®Norel) on growth performance and blood parameters of gilthead sea ream in trial 1 (T1).
Fish were fed four diets: T1-D1 (control), T1-D2 (0.2% BP-70), T1-D3 (0.4% BP-70) and T1-D4 (0.8% BP-70). Data on body weight, feed intake, and growth indices are the mean ± SEM of triplicate tanks. Data on viscera and liver weight are the mean ± SEM of 24 fish. Data on plasma parameters are the mean ± SEM of 12 fish. Different superscript letters in each row indicate significant differences among dietary treatments (P < 0.05; Student-Newman-Keuls).
Fig 2.
Effect of sodium butyrate (BP-70 ®Norel) on gilthead sea bream histological traits in trial 1 (T1).
A, D: Representative images of fish fed the control diet without BP-70 (T1-D1); B, C and E: fish fed the diet with 0.8% BP-70 supplementation (T1-D4). Note the lymphocytic infiltration in the epithelial base and the eosinophilic granular cell abundance in insert C. Stainings = haematoxylin-eosin in posterior (A) and anterior (B, C) intestine (A, B, C) and periodic acid-Schiff in liver (D, E). Scale bars = 50 μm.
Table 3.
Gene expression of the anterior and posterior intestine segments in gilthead sea bream fed the control diet (T1-D1) and the 0.8% sodium butyrate (BP-70 ®Norel) supplemented diet (T1-D4).
Values are the mean ± SEM (n = 8). Different superscript letters in the same row indicate significant differences (P < 0.05; Student-Newman-Keuls).
Fig 3.
Differentially expressed genes at the anterior intestine (AI) of gilthead sea bream fed the three experimental substitution diets in trial 2 (T2).
Fold changes are related to the control diet T2-D1. Bars above 1 stand for up-regulated genes and bars below 1 for down-regulated ones. Gene markers are grouped into 5 functional categories: 1 = cell differentiation and proliferation; 2 = intestinal architecture and permeability; 3 = enterocyte mass and epithelial damage; 4 = interleukins and cytokines; 5 = pattern recognition receptors. (*P < 0.05).
Fig 4.
Differentially expressed genes at the posterior intestine (PI) of gilthead sea bream fed the three experimental substitution diets in trial 2 (T2).
Fold changes are related to the control diet T2-D1. Bars above 1 stand for up-regulated genes and bars below 1 for down-regulated ones. Gene markers correspond to three functional categories: 1 = cell differentiation and proliferation; 2 = intestinal architecture and permeability; 5 = pattern recognition receptors. (*P < 0.05).
Fig 5.
Trans-epithelial electrical resistance (Rt) of the anterior intestine of gilthead sea bream from trial 3 (T3).
A: fish from T3-A (mean weight 1,420 g): B: fish from T3-B (mean weight 249 g). Data are given as the mean ± SEM of the tissue resistance along the 120 min of in vitro experiments with Ussing chamber. Groups displaying different letters are significantly different (P < 0.05).
Table 4.
Summary of the most important changes induced by the experimental diets in the three gilthead sea bream trials.