Protein energy malnutrition and taurine supplementation: effects on vitamin A nutritional status and electroretinogram of young rats.
The effect of protein energy malnutrition (PEM) on retinal function was investigated in weanling Long-Evans rats fed a low protein (4.2%) diet. After 8 wk, plasma retinol levels were lower in low protein (LP) and growth-restricted (GR) groups than in ad libitum controls (P less than 0.05); however, ocular vitamin A concentration remained normal. Plasma taurine concentration was lower only in the LP group, while retinal taurine was lower in both LP and GR groups than in control groups. The dark-adapted electroretinogram (ERG) became abnormal (e.g., depressed a and b waves, P less than 0.05) in both LP and GR groups but was corrected by ad libitum feeding of the control diet for an additional 8 wk. In a second study, weanling LP rats were supplemented with 0.4% taurine, 0.4% methionine or 0.4% glycine. Although taurine supplementation maintained plasma and retinal taurine stores, ERGs remained abnormal with retinal sensitivity significantly lower than in unsupplemented LP rats. Thus, PEM produced abnormal ERGs independent of ocular vitamin A concentration and retinal taurine levels. The high dietary taurine fed to protein-malnourished rats caused further impairment of visual function but was not detrimental to control or pair-fed rats.
D000818:Animals; D004044:Dietary Proteins / Q000008:administration & dosage*; D004596:Electroretinography; D006128:Growth; D008297:Male; D009752:Nutritional Status; D011502:Protein-Energy Malnutrition / Q000378:metabolism / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains; D012160:Retina / Q000378:metabolism / Q000503:physiopathology*; D013654:Taurine / Q000008:administration & dosage* / Q000378:metabolism; D014801:Vitamin A / Q000378:metabolism*
D004044:Dietary Proteins; D014801:Vitamin A; D013654:Taurine