Dietary Tuna Dark Muscle Protein Attenuates Hepatic Steatosis and Increases Serum High‐Density Lipoprotein Cholesterol in Obese Type‐2 Diabetic/Obese KK‐A^y Mice

Abstract

Tuna muscle consists of light and dark muscle in approximately equal proportions. However, besides for the light muscle of tuna, cod, sardine, and salmon, few researches have assessed the health-promoting functions of fish protein. Therefore, we evaluated the mechanisms underlying the alteration of lipid storage and cholesterol metabolism following the intake of tuna dark muscle protein (TDMP) by obese type-2 diabetic/obese mice. Four-week-old male KK-A mice were separated into 2 dietary groups, with one group receiving a casein-based diet and the other receiving a diet with the substitution of part of the protein (50%, w/w) by TDMP (TDMP diet) for 4 wk. The TDMP diet significantly increased the content of serum high-density lipoprotein cholesterol, partly due to the reduction of the expression of scavenger receptor class B member 1 in epididymal white adipose tissue. In addition, dietary TDMP decreased the content of hepatic triacylglycerol, which could be due to the enhancement of carnitine palmitoyltransferase-2 activity through the activation of the expression of the peroxisome proliferative activated receptor-α in the liver. These results suggest that TDMP could have the potential to prevent the development of obesity-related diseases by suppressing the storage of hepatic triacylglycerol and cholesterol.

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).…”

Dietary Alaska Pollock Protein Attenuates the Experimental Colitis Induced by Dextran Sulfate Sodium via Regulation of Gut Microbiota and Its Metabolites in Mice

“…The loss of BW in the APP + DSS group was significantly lower on Day 8 compared with the CAS + DSS group (Figure 1A). The APP + DSS group had a significantly lower DAI score on Day 10,12,16,22, and 24 than the CAS + DSS group (Figure 1B). The area under the curve (AUC) of the DAI score in the APP + DSS group was significantly lower than that of the CAS + DSS group (Figure 1C).…”

“…In addition to fat, fish is also rich in nutritious protein [15]. Our previous studies have suggested that proteins prepared from several fish species protect against the accumulation of triacylglycerol in the liver [16,17] and reduce the level of serum cholesterol [18]. Other researchers have reported that Alaska pollock protein (APP) exhibits beneficial effects on obesity [19] and muscle hypertrophy [20].…”

Preparation, Characterization, and Cytoprotective Effects on HUVECs of Fourteen Novel Angiotensin-I-Converting Enzyme Inhibitory Peptides From Protein Hydrolysate of Tuna Processing By-Products

“…In addition, Chi et al found that protein hydrolysates of tuna dark muscle presented significant radical scavenging and lipid peroxidation inhibition ability ( 28 ). Maeda et al revealed that the dietary tuna dark muscle could decrease hepatic steatosis and promote serum high-density lipoprotein cholesterol in obese type-2 diabetic/obese KK-A (y) mice ( 29 ).…”