Glucomannan and Glucomannan plus Spirulina-enriched Squid-surimi Added to High Saturated Diet Affect Glycemia, Plasma and Adipose Leptin and Adiponectin Levels in Growing Fa/fa Rats.

Type 2 diabetes is a very prevalent chronic disease. Among dietary factors for its prevention and treatment, interest has grown in satiating fibre (konjac glucomannan) and spirulina. Our previous studies suggest that glucomannan itself and/or in conjunction to spirulina displayed hypolipemic and antioxidant effects when incorporated to squid surimi as functional ingredients. The present study aims to determine whether glucomannan- enriched or glucomannan plus spirulina-enriched squid-surimi improve plasma glucose and insulin levels in Zucker fa/fa rats fed a high saturated fat diet. Twenty four growing rats, divided into three groups, were given modified AIN-93M diets for seven weeks: 30% squid-surimi control diet (C), 30% glucomannan-enriched squid-surimi diet (G) and 30% glucomannan plus spirulina-enriched squid-surimi diet (GS). All rats became hyperglycemics and hyperinsulinemics, but G and GS diets induced significantly lower glucose levels (20%; p < 0.05) but did not modify insulinemia with respect to C diet. GS animals showed higher HOMA-D (p < 0.05) than C ones suggesting increased insulin availability. Plasma leptin and adiponectin decreased in G and GS vs. C group (p < 0.05). Adipose adiponectin increased significantly in G and GS vs. C rats (16-20 times, p < 0.01). Leptin in adipose tissue was higher in GS vs. G group (p < 0.05). In conclusion, both glucomannan-diets were able to reduce hyperglycemia and increase adipose tissue adiponectin levels in fa/fa rats, suggesting an anti-hypertrophic and insulin-sensitizing adipokine effect in this tissue. Spirulina inclusion increased insulin availability. Although results are promising, the utility of consuming glucomannan surimis as part of usual diets demands future studies.