Baked cod consumption delayed the development of kidney and liver dysfunction and affected plasma amino acid concentrations, but did not affect blood pressure, blood glucose or liver triacylglycerol concentrations in obese fa/fa Zucker rats.

A diet containing cod backbone proteins attenuated the development of mesangial sclerosis and tubular dysfunction in male obese BTBR ob/ob mice

“…The Cod-BB diet had only minor effects on serum concentrations of kynurenines, both in the obese and in the lean BTBR mice. This is in contrast with findings in diabetic patients with coronary artery disease where lean fish intake affected kynurenine metabolite concentrations [ 14 ], but is in line with our previous studies showing that cod muscle intake did not affect circulating concentrations of kynurenines in obese Zucker fa/fa rats [ 24 ] or in non-diabetic adults with overweight or obesity [ 15 ]. The effects of fish intake on circulating concentrations of indoles have not formerly been explored; however, since lean fish intake modulated gut microbiota in a recent clinical trial [ 54 ], and since fish is a valuable dietary source for tryptophan, intake of fish could be expected to affect gut microbe indole production and hence the concentrations of indoles in circulation.…”

“…The effects of fish protein intake on glomerular abnormalities and albuminuria have never before been investigated in obese BTBR ob/ob mice, and in the present study, we chose to test a cod protein powder since cod is a commercially available and commonly consumed fish. Previous studies from our research group have shown that diets containing cod proteins improved postprandial glucose regulation [ 19 ], delayed the development of kidney dysfunction [ 24 ] and lowered concentrations of markers of kidney dysfunction and reduced urinary loss of amino acids [ 26 ] in obese Zucker fa/fa rats. Moreover, strong findings from other research groups show that dietary cod proteins also improve glucose tolerance and insulin sensitivity in Wistar rats [ 47 – 49 ].…”

“…These rats are leptin-resistant and spontaneously develop metabolic complications of obesity resembling the human metabolic syndrome, including insulin resistance, mild glucose intolerance, hyperinsulinemia, dyslipidemia and high blood pressure, in addition to proteinuria and focal segmental glomerulosclerosis leading to renal failure [ 16 , 17 ]. When obese Zucker fa/fa rats were fed diets containing lyophilised fish muscle or a protein powder produced from fish residuals, we observed improved postprandial glucose regulation [ 18 , 19 ], attenuated development of high blood pressure [ 20 – 23 ], and delayed development of kidney dysfunction [ 20 , 24 – 26 ].…”

Intake of residuals from Atlantic cod attenuated blood pressure increase but did not delay development of kidney damage in obese Zucker fa/fa rats

“…It was recently shown that diets containing fillet from Atlantic salmon (a fatty fish) (11), press cake protein powder with high gut content from Atlantic cod (12), or hydrolysed press cake protein powder from headed and gutted blue whiting (a cod-fish) (13) delayed the development of high blood pressure in obese Zucker fa/fa rats. In contrast, diets containing muscle from Atlantic cod (a lean fish) did not affect the blood pressure development in obese Zucker fa/fa rats (12,14), and the consumption of hydrolysates of muscles from cod, haddock or salmon did not affect blood pressure development in spontaneously hypertensive rats (15). These findings indicate that potent components affecting blood pressure development may be found in lean fish residuals such as skin, viscera, heads and frames.…”

“…Angiotensinogen is cleaved by renin to the biologically inactive angiotensin I, which is then converted to the active vasoconstrictor angiotensin II by angiotensin-converting enzyme (ACE) (16). Motifs with ACE inhibiting activity in vitro have been identified in fish fillet and residuals including skin and backbone (171 [8][9][10][11][12][13][14][15][16][17][18][19][20]. Other nutrients found in fish may also affect blood pressure.…”