Effect of beta-lactoglobulin on plasma retinol and triglyceride concentrations, and fatty acid composition in calves.
Beta-lactoglobulin (beta-lg) is the main protein of ruminant milk whey. Although beta-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 beta-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 beta-lg (0.4 g/kg BW). The plasma retinol concentration of 10-d-old calves was greater (P < 0.05) in the beta-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 beta-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 beta-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 beta-lg (0.4 g/kg BW). Plasma triglyceride concentration at age 10 d was higher (P < 0.05) in the beta-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 beta-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 beta-lg milk than in the control calves at age 10 d. These results suggest that beta-lg enhances the intestinal uptake of retinol, triglyceride, and long-chain fatty acids in preruminant calves.
Kushibiki
S
S
Department of Animal Production, Tohoku National Agricultural Experimental Station, Morioka, Iwate, Japan. mendoza@tnaes.affrc.go.jp
Hodate
K
K
Kurisaki
J
J
Shingu
H
H
Ueda
Y
Y
Watanabe
A
A
Shinoda
M
M
D000818:Animals; D000831:Animals, Newborn / Q000097:blood; D001835:Body Weight; D002417:Cattle / Q000097:blood*; D004032:Diet; D005227:Fatty Acids / Q000097:blood*; D007700:Kinetics; D007782:Lactoglobulins / Q000494:pharmacology*; D008055:Lipids / Q000097:blood; D008297:Male; D008892:Milk; D019301:Oleic Acid / Q000097:blood; D019308:Palmitic Acid / Q000097:blood; D013229:Stearic Acids / Q000097:blood; D014280:Triglycerides / Q000097:blood*; D014801:Vitamin A / Q000097:blood*
D005227:Fatty Acids; D007782:Lactoglobulins; D008055:Lipids; D013229:Stearic Acids; D014280:Triglycerides; D014801:Vitamin A; D019301:Oleic Acid; D019308:Palmitic Acid; C031183:stearic acid