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

Background: Documentation of health effects of residuals after fish filleting may motivate both consumers and producers to increase the use of this under-utilised protein source.Objectives: The primary objective of the present study was to investigate the effects of a diet containing resid-uals from Atlantic cod (Gadus morhua) filleting on the development of high blood pressure in obese Zucker fa/fa rats, which spontaneously develop hypertension and proteinuria. The secondary objectives were to inves-tigate any changes in kidney morphology, kidney function and organ damage, and to determine the potential inhibition of cod residuals on renin and angiotensin-converting enzyme (ACE) activities in vitro.Methods: Male rats were fed diets containing protein powder prepared from head, backbone and skin frac-tion (HBS, n = 6) from Atlantic cod as 25% of total protein with the remaining 75% as casein, or casein as the sole protein source (Control group, n = 6) for 4 weeks. Blood pressure was measured on day 0, 14 and 26. Kidneys were analysed morphologically, and markers for renal function and organ damage were analysed biochemically.Results: The HBS diet attenuated the blood pressure increase compared to the Control group, but kidney damage and dysfunction were similar between the two groups.Conclusion: A diet containing a protein powder consisting of HBS fraction from cod attenuated the blood pressure increase in obese Zucker fa/fa rats, without preventing kidney damage.