Response of the Weanling Rat to Alpha- or Beta-Lactose With or Without an Excess of Dietary Phosphorus

Open Access
Publisher Website
Google Scholar
Abstract
One hundred twenty weanling male albino rats (Sprague-Dawley) were employed in two 3x2 factorial experiments designed to compare effects of substituting [alpha]-lactose and [beta]-lactose for the glucose component of diets containing either adequate or excess P. Rats receiving glucose had no diarrhea and gained faster than rats receiving lactose. Also, glucose-fed rats had more carcass fat but less carcass water and Ca than lactose-fed rats. Pair-gain studies indicated that these carcass effects were independent of gain and final body weight. Rats fed lactose had much larger ceca than those fed glucose. Blood samples taken just prior to sacrifice revealed higher hematocrits for rats receiving lactose than for those receiving glucose. [alpha]-Lactose effected a greater weight gain than [beta]-lactose when fed with adequate P or with excess P as H3PO4. Conversely, with excess P as Na2HPO4, [beta]-lactose supported a faster rate of gain than [alpha]-lactose. Excess P provided as H3PO4 uniformly depressed rate and efficiency of gain.