Bioavailability of nutrients in rats fed on edible seaweeds, Nori (Porphyra tenera) and Wakame (Undaria pinnatifida), as a source of dietary fibre

A comparative study of the influence of two edible seaweeds, Nori (Porphyra tenera) and Wakame (Undaria pinnatifida), on dietary nutritive utilization was performed. Male adult Wistar rats were fed, for 2 weeks, diets containing Nori, Wakame or cellulose as source of dietary fibre. All diets contained similar amounts of dietary fibre (5%), protein (14%) and ash (5%). Intake, body weight gain, food efficiency (weight gain/food intake), apparent digestibility and retention coefficients for protein, fat, and minerals (calcium, iron, magnesium, zinc, sodium, and potassium) were evaluated. The addition of Wakame or Nori did not affect the gain in body weight of rats or food efficiency. Fresh and dry stool weights were higher in rats fed seaweeds than in the control group. Seaweed-fed animals showed significantly lower apparent digestibilities of protein and fat but absorbed nitrogen was more effectively used by animals. Apparent digestibility and retention coefficients for calcium, magnesium, zinc, iron, sodium and potassium were lower for seaweed-fed rats, and showed lower values for Wakame than Nori. The seaweeds could be a good source of dietary fibre in diet but they may modify digestibility of dietary protein and minerals.