Water-Soluble Fish Protein Intake Led to Lower Serum and Liver Cholesterol Concentrations in Obese Zucker fa/fa Rats

Abstract

Proteins from different fish species and different raw materials such as fish fillets and by-products have shown promising cardioprotective effects in rodents and humans, including effects on cholesterol metabolism. Blue whiting is used mainly to produce fish meal for the feed industry and during this production, a water-soluble protein fraction, containing small peptides that are easily absorbed and may hold bioactive properties, is isolated. The effects of water-soluble fish protein on cholesterol metabolism were investigated in twelve male obese Zucker fa/fa rats. Rats were fed diets with water-soluble protein from blue whiting (BWW) as 1/3 of the total protein and the remaining 2/3 as casein (BWW group) or with casein as the sole protein source (control group). After 5 weeks intervention, the BWW group had lower serum total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol concentrations and lower cholesteryl ester concentration compared to controls. Hepatic concentrations of cholesterol, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, and LDL receptors were also lower in the BWW group. The groups had a similar concentration of serum total bile acids and similar fecal excretions of cholesterol and bile acids. To conclude, the BWW diet led to lower concentrations of serum and liver cholesterol in obese Zucker fa/fa rats, probably due to lower hepatic cholesterol synthesis.

Dietary Alaska pollock protein alters insulin sensitivity and gut microbiota composition in rats

“…Highly nutritious lean fish protein is abundantly present in fish and consumed worldwide including in processed foods such as artificial crab, kamaboko (fish cakes), and fish sausages. Previously, studies from our laboratory and others showed that fish proteins from Alaska pollock, tuna, and tuna dark muscle, ameliorate hypercholesterolemia and nonalcoholic fatty liver disease (Hosomi et al., 2015, 2017; Maeda et al., 2017) and prevent obesity, hypercholesterolemia, and hypertension (Drotningsvik et al., 2018; Oishi & Dohmoto, 2009; Yathisha, Bhat, Karunasagar, & Mamatha, 2019). In addition, cod protein reduced fasting and postprandial glucose levels and increased peripheral insulin sensitivity compared to casein, in rats fed a high‐sucrose diet (Lavigne, Marette, & Jacques, 2000).…”

Effects of intact and hydrolysed blue whiting proteins on blood pressure and markers of kidney function in obese Zucker fa/fa rats

“…The market for blue whiting as whole fish or fillet for human intake is limited by factors such as small size and discoloration [ 21 ], and blue whiting products based on fish meal or protein hydrolysates may be one option to improve the utilization of this fish species. We have recently shown that a water-soluble protein meal from blue whiting has a hypocholesterolemic effect in obese Zucker fa/fa rats [ 22 ], but more knowledge on the potential health effects of proteins from blue whiting is warranted to expand its usability in new products for human consumption. Enzymatic hydrolysis enables efficient recovery of proteins from fish and fish by-products and produces protein fractions with higher content of small peptides that may exert effects as bioactive compounds.…”

Marine Bioactive Peptides—An Overview of Generation, Structure and Application with a Focus on Food Sources

“…Marine peptides and hydrolyzates can be utilized in two principal ways: as food/feed supplements and as drugs [2,41,82,84,[177][178][179][180][181][182][183][184][185][186][187]. Whole hydrolyzates of marine-derived proteins are usually applied in food/feed preparations, where they serve different functions, as antioxidants [178], hypolipidemic agents [181,182], enhancing physical performance in elderly people [177], and preventing hair loss [180]. Although all these activities have been verified by clinical trials, there are several problems with using whole protein hydrolyzates.…”

“…In all of these cases, one important point has not received the attention it deserves. A large number of in vivo studies are still performed on rats and mice [36,62,84,126,169,171,181]. Given the clear differences in anatomy and physiology, correlation between animal models and humans is questionable [195,196].…”