Effect of β-lactoglobulin on plasma retinol and triglyceride concentrations, and fatty acid composition in calves

Abstract

β-Lactoglobulin (β-lg) is the main protein of ruminant milk whey. Although β-lg can bind in vitro to a variety of hydrophobic substrates, mainly retinol and long-chain fatty acids, its physiological function is still unknown. In Exp. 1, we investigated the effect of β-lg on the plasma retinol concentration in preruminant calves. Holstein male calves (n = 20) were fed Holstein whole milk at 40 g/kg body weight (BW) plus vitamin A acetate (500,000 i.u.) with or without β-lg (0·4 g/kg BW). The plasma retinol concentration of 10-d-old calves was greater (P<0·05) in the β-lg-fed group than in the control group during the period from 8 to 12 h and at 24 h after the feeding. The postprandial change of plasma retinol in 40-d-old calves fed milk with β-lg was higher (P<0·05) than that in the control calves only at 12 h after the feeding. In Exp. 2, Holstein male calves (n = 18) were used to investigate the effect of β-lg on plasma triglyceride concentration and fatty acid composition. Calves were fed Holstein whole milk at 40 g/kg BW plus milk fat prepared from whole milk at 2 g/kg BW with or without β-lg (0·4 g/kg BW). Plasma triglyceride concentration at age 10 d was higher (P<0·05) in the β-lg-fed group than in the controls during the periods from 1 to 2 h and from 7 to 11 h after the feeding. At age 40 d, plasma triglyceride in the β-lg-fed group was higher (P<0·05) than in the control group only at 9 h. Ratios of palmitic, stearic, and oleic acids to total plasma lipids were higher (P<0·05) in the calves fed β-lg milk than in the control calves at age 10 d. These results suggest that β-lg enhances the intestinal uptake of retinol, triglyceride, and long-chain fatty acids in preruminant calves.

β-Lactoglobulin-linoleate complexes: In vitro digestion and the role of protein in fatty acid uptake

“…Recent studies suggest that LCFA are taken up by intestinal epithelial cells by both active transport via specific FA transporters, and by passive diffusion (Stremmel, 1988, Trotter et al, 1996, Abumrad et al, 1998. However, uptake and bioavailability of FA may be altered depending on the food matrix (Kushibiki et al, 2001, Mu, 2008, Singh et al, 2009. We observed that linoleate, the salt form of LA, bound to βlg was less bioaccessible compared to free linoleate (Le Maux et al, 2012).…”

Crystal structure of a secondary vitamin D3 binding site of milk β‐lactoglobulin

“…During the past 40 years, β‐LG has been extensively studied for its biochemical properties, and an abundance of literature exists about its physicochemical nature 9. Although the exact physiological functions of β‐LG are not fully explored, one of its roles is to transport hydrophobic molecules, such as retinol, fatty acids, and vitamin D 49, 50. The active form of vitamin D is 1α, 25(OH) 2 vitamin D 3 , which maintains calcium homeostasis and plays important roles on the immune system and prevents the growth and differentiation of cancer cells.…”

Dietary whey protein lowers serum C-peptide concentration and duodenal SREBP-1c mRNA abundance, and reduces occurrence of duodenal tumors and colon aberrant crypt foci in azoxymethane-treated male rats

“…When compared with CAS, whey proteins and peptides have faster transit times within the gastrointestinal tract and increased digestion rates [48][49][50][51]. Whey peptides may differentially affect small intestine uptake and transfer of macromolecules and nutrients as well as functioning of the enteroendocrine system [39,52,53]. In a seminal study, Bounous et al [15] reported reduced tumor multiplicity and tumor size in A/J mice fed WPC when compared with CAS-based diet.…”