Evaluation of marine algae Undaria pinnatifida and Porphyra purpurea as a food supplement: composition, nutritional value and effect of intake on intestinal, hepatic and renal enzyme activities in rats.

BACKGROUND: There is a long tradition in Eastern countries of consuming seaweeds, although demand for these organisms has also increased in Western countries. However, knowledge of the effects of consumption of algae is limited. In this study the proximate composition and amino acid profile of Undaria pinnatifida (Harvey) Suringar (wakame) and Porphyra purpurea (Olivi) De Toni (nori) were determined. The effects of feeding diets containing 100 g kg(-1) of wakami or nori for 4 weeks on food intake, growth, protein efficiency ratio, diet conversion ratio and some organ weights in growing rats were evaluated. The effects on intestinal, hepatic and renal enzyme activities were also studied. RESULTS: Both algae are a good source of protein, particularly nori, and contain essential amino acids. There was no effect of alga consumption on trophic balance. Intestinal disaccharidase and hepatic and renal γ-glutamyl transpeptidase activities were lower in alga-fed rats than in the control group, while intestinal leucine aminopeptidase activity was higher in rats fed algae. CONCLUSION: Both seaweeds are a good source of protein and carbohydrates and contain all essential amino acids. The effects of the two algae on enzyme activities were similar. The inhibition of intestinal disaccharidase activity by seaweed ingestion could be interesting in patients with altered glucose homeostasis.

Evaluation of the marine alga Ulva rigida as a food supplement: effect of intake on intestinal, hepatic, and renal enzyme activities in rats.

The use of seaweeds as a food is more widespread in Eastern than in Western countries, although demand for these plants has increased in the West because their possible usefulness as dietary supplements. However, very little is known about the effects of regular consumption of algae. The aim of the present study was to determine the composition of Ulva rigida and to evaluate the effects of dietary supplementation of the diet with 10% alga for 4 weeks on dietary intake, growth, protein efficiency ratio, diet conversion ratio, and some organ weights in growing male rats. We also studied the effect of inclusion of the alga in the diet on intestinal, hepatic, and renal enzymatic activities. U. rigida was found to be a good source of protein and carbohydrates. Food intake was higher in the U. rigida group than in the control group, but ingestion of alga did not have any effect on the other trophic parameters. The intestinal disaccharidase and leucine aminopeptidase activities were lower in rats fed with alga than in control rats, but γ-glutamyl transpeptidase activity was higher in the kidneys of alga-fed rats than in control rats. U. rigida contains high amounts of protein, carbohydrates, vitamins, and minerals and low amounts of lipids. Analysis of the amino acid composition revealed good-quality protein. The addition of alga to the diet inhibited disaccharidase activities, which suggested that alga consumption could be useful in some chronic disorders associated with pertubations of glucose homeostasis caused by carbohydrate absorption.

Composition, nutritional aspects and effect on serum parameters of marine algae Ulva rigida.

BACKGROUND: Algae are commonly consumed in Asia and have also gained popularity in Europe. However, data on the bioavailability of their components are limited. The present study was designed to determine the composition of Ulva rigida and the effects of inclusion of 10% of the algae in a standard diet for 4 weeks on nutritive value and serum parameters in order to consider the usefulness of Ulva as a dietary supplement. RESULTS: Ulva rigida is rich in protein, carbohydrates, fibre, vitamins and minerals and has a low lipid content. Analysis of the amino acid composition revealed good-quality protein. The algae were well accepted by experimental animals and did not significantly change nutritional parameters but reduced LDL cholesterol. CONCLUSIONS: Ulva rigida is an excellent source of nutrients and could improve a balanced diet. Further studies are required to research the potential of the seaweed as a natural source of bioactive compounds.

Somatodendritic action of pindolol to attenuate the paroxetine-induced decrease in serotonin release from the rat ventral hippocampus: a microdialysis study.

We used intracerebral microdialysis to study the role of raphe and presynaptic serotonin (5-HT) autoreceptors in the effect of the selective 5-HT reuptake inhibitor, paroxetine, on 5-HT release from ventral hippocampus of anaesthetised rats. In addition, we have tested the ability of pindolol, a non-selective beta-adrenergic/5-HT(1A) receptor antagonist, to alter the response of hippocampal 5-HT to paroxetine. Doses of paroxetine with maximal effects were near to three-fold less effective when administered systemically than after local infusion at increasing extracellular 5-HT in ventral hippocampus. Moreover, systemic paroxetine treatment resulted in a marked decrease of the extracellular 5-HT in the hippocampus when 5-HT reuptake was blocked with paroxetine 3 microM applied locally, thereby evidencing that systemic treatment induced a decrease of 5-HT release in the neuronal terminal. A similar drop was observed when paroxetine 3 microM was perfused into the median raphe, a region that contains the cell bodies of the neurons innervating the ventral hippocampus. Racemic (+/-)-pindolol (10 mg/kg, s.c.) completely blocked the paroxetine-induced decrease in 5-HT release from rat hippocampus. In addition, the infusion into median raphe of (-)-pindolol, the isoform with highest antagonist activity, at concentrations of 10 microM and 100 microM was able to partially block the decrease of hippocampal 5-HT release after systemic paroxetine. However, perfusion of (-)-pindolol into the hippocampus was without effect on local 5-HT release. These data suggest that pindolol acts preferentially through the blockade of somatodendritic 5-HT(1A) autoreceptors to restore the decline in 5-HT outflow in rat forebrain following systemic administration of selective 5-HT reuptake inhibitors.