A Mixture of Cod and Scallop Protein Reduces Adiposity and Improves Glucose Tolerance in High-Fat Fed Male C57BL/6J Mice

Abstract

Low-protein and high-protein diets regulate energy metabolism in animals and humans. To evaluate whether different dietary protein sources modulate energy balance when ingested at average levels obesity-prone male C57BL/6J mice were pair-fed high-fat diets (67 energy percent fat, 18 energy percent sucrose and 15 energy percent protein) with either casein, chicken filet or a mixture of cod and scallop (1∶1 on amino acid content) as protein sources. At equal energy intake, casein and cod/scallop fed mice had lower feed efficiency than chicken fed mice, which translated into reduced adipose tissue masses after seven weeks of feeding. Chicken fed mice had elevated hepatic triglyceride relative to casein and cod/scallop fed mice and elevated 4 h fasted plasma cholesterol concentrations compared to low-fat and casein fed mice. In casein fed mice the reduced adiposity was likely related to the observed three percent lower apparent fat digestibility compared to low-fat, chicken and cod/scallop fed mice. After six weeks of feeding an oral glucose tolerance test revealed that despite their lean phenotype, casein fed mice had reduced glucose tolerance compared to low-fat, chicken and cod/scallop fed mice. In a separate set of mice, effects on metabolism were evaluated by indirect calorimetry before onset of diet-induced obesity. Spontaneous locomotor activity decreased in casein and chicken fed mice when shifting from low-fat to high-fat diets, but cod/scallop feeding tended (P = 0.06) to attenuate this decrease. Moreover, at this shift, energy expenditure decreased in all groups, but was decreased to a greater extent in casein fed than in cod/scallop fed mice, indicating that protein sources regulated energy expenditure differently. In conclusion, protein from different sources modulates energy balance in C57BL/6J mice when given at normal levels. Ingestion of a cod/scallop-mixture prevented diet-induced obesity compared to intake of chicken filet and preserved glucose tolerance compared to casein intake.

Lean‐seafood intake decreases urinary markers of mitochondrial lipid and energy metabolism in healthy subjects: Metabolomics results from a randomized crossover intervention study

“…Samples were hydrolyzed (6 M HCl, 110 ± 2°C, 22 h), before acid removal by evaporation at 60°C under vacuum and sample derivatization (AccQTag Ultra Derivatization Kit, Waters, MA, USA). Amino acids were separated and detected on the ACQUITY UPLC System (Waters) as previously described . For determination of 3MH, norleucine was added to the samples as internal standard, samples were hydrolyzed (6 M HCl, 110 ± 2°C, 22 h) to liberate protein‐bound 3MH, before acid removal as described above.…”

The protein source determines the potential of high protein diets to attenuate obesity development in C57BL/6J mice

“…The cod fillet was freeze dried and pulverized by the provider (Seagarden AS), whereas beef, chicken and pork filets were freeze-dried and pulverized at NIFES. All protein sources were subsequently analyzed for amino acid composition, nitrogen and total fat content (Table 1) as described previously 11 in order to balance the diets with respect to total protein and fat content. The diets (Table 2) were mixed using a Crypto Peerless EF20 blender, kept at -20 C, and analyzed for gross energy (Table 2) by bomb calometry (Parr Instruments, Moline, IL, USA) and fatty acid composition (Table 3) using a capillary gas chromatograph (GLC Trance GC 200, Thermo Scientific, USA) with a flame ionization detector (Thermo Scientific) as described.…”

“…The diets (Table 2) were mixed using a Crypto Peerless EF20 blender, kept at -20 C, and analyzed for gross energy (Table 2) by bomb calometry (Parr Instruments, Moline, IL, USA) and fatty acid composition (Table 3) using a capillary gas chromatograph (GLC Trance GC 200, Thermo Scientific, USA) with a flame ionization detector (Thermo Scientific) as described. 11 In addition, a standard very high fat (VHF) diet obtained from Ssniff (acc. D12492 Ssniff, Spezialdi€ aten, Soest, Germany) was used to induce obesity in experiment 4, see below.…”

“…5 However, a few studies where rodents were fed diets with standard levels (i.e 18-20 energy %) of proteins indicated that different protein sources have different obesogenic potential. [6][7][8][9][10][11][12] Nevertheless, the general notion that high protein diets attenuate obesity in rodents is almost exclusively based on studies where milk proteins are used as protein sources. [13][14][15][16][17][18][19][20][21][22] However, protein sources for human consumption would normally comprise fish and meat.…”

Preclinical and Clinical Studies on Antioxidative, Antihypertensive and Cardioprotective Effect of Marine Proteins and Peptides—A Review

“…Cod and scallop were compared to chicken and casein as protein sources to assess their effect on blood lipids in a high fat diet and in a Western diet [25,53]. The level of triglycerides was reduced after seven weeks on the high fat diet with cod and scallop, whereas no effects on total cholesterol or HDL-cholesterol were observed.…”