Table 1.
Crude protein and digestible energy contents of the commercial feed (Acqua Fish, SUPRA; São Leopoldo, RS, Brazil) fed to black and red Nile tilapia.
Fig 1.
Histological sections of the skin of (A) black and (B) red Nile tilapia (Oreochromis niloticus) stained with Picrosirius Red and observed under a polarized light microscope (20× magnification). Type I collagen fibers are shown in red-orange (white arrows), and type III collagen fibers are shown in green (yellow arrows). Bar = 100 μm.
Table 2.
Gene sequences used in RT-qPCR reactions.
Fig 2.
Experimental scheme and analyses.
Table 3.
Body biometrics of black and red Nile tilapia (Oreochromis niloticus).
Table 4.
Quality indicators of black and red Nile tilapia (Oreochromis niloticus) fillets.
Table 5.
Antioxidant capacity (DPPH• and ABTS•+) and oxidative metabolites in muscle tissues of black and red Nile tilapia.
Fig 3.
Expression of genes encoding ryanodine receptors 1 (ryr1) and 3 (ryr3) in the muscle of black and red Nile tilapia (Oreochromis niloticus).
Each fish was considered an experimental unit (n = 7 individuals per variety). Results are expressed as arbitrary units (AU) and presented as mean ± standard error.
Table 6.
Skin resistance parameters of black and red Nile tilapia (Oreochromis niloticus).
Fig 4.
Hydroxyproline and collagen content of the skin of black and red Nile tilapia (Oreochromis niloticus).
Each fish was considered an experimental unit (n = 7 individuals per variety). Results are presented as mean ± standard error. a,b Different letters indicate significant differences by Student’s t-test (P < 0.05).
Fig 5.
Determination of the area occupied by type I and type III collagen in the skin of black and red Nile tilapia (Oreochromis niloticus).
Each fish was considered an experimental unit (n = 7 individuals per variety). Results are presented as mean ± standard error.
Fig 6.
Expression of genes encoding collagen type I alpha 1 (col1a1), 2 (col1a2), and 3 (col1a3), vimentin (vim), and DEAH box helicase 9 (dhx9) in the skin of black and red Nile tilapia (Oreochromis niloticus).
Each fish was considered an experimental unit (n = 7 individuals per variety). Results are expressed as arbitrary units (AU) and are presented as mean ± standard error. a,b Different letters indicate significant differences by Student’s t-test (P < 0.05).
Fig 7.
2,2-Diphenyl-1-picrylhydrazyl radical (DPPH•) scavenging activity of the skin of black and red Nile tilapia (Oreochromis niloticus).
Each fish was considered an experimental unit (n = 7 individuals per variety). Results are presented as mean ± standard error. a,b Different letters indicate significant differences by Student’s t-test (P < 0.05).
Fig 8.
In vivo staining of fresh fillets of (A) black and (B) red Nile tilapia (Oreochromis niloticus). Source: Personal archive. The yellow arrow indicates the lateral line.