EFFECTS OF SPRAY-DRIED PORCINE PLASMA-PROTEIN ON GROWTH TRAITS AND NITROGEN AND ENERGY-BALANCE IN MICE

Energy and nitrogen balances of mice receiving a dried skim milk-based control diet were compared to a similar group of mice receiving a die t containing 8% spray-dried plasma protein (SDPP). Mice were housed in pairs in metabolism cages with feed and water available for ad Libitu m intake. Five cages were assigned to each diet for a 21-d feeding per iod. Mice fed SDPP gained more weight (P <.01), consumed more feed (P <.01), and had higher gain: feed ratios (G:F) (P <.01) than mice fed t he control diet during wk 1, No significant differences in growth, fee d intake, or G:F were detected during wk 2. During wk 3, mice receivin g the control diet tended to gain more (P <.10) and had a higher G:F ( P <.01). Nitrogen intake and retention were greater for mice fed SDPP (P <.02). Energy intake was greater for mice fed SDPP (P <.01); howeve r, energy retention was not different between treatment groups due to greater (P <.01) metabolic energy losses (urinary energy + heat produc tion). Empty gut weight was greater for control mice on an absolute ba sis (P <.05) and when expressed as a percentage of BW (P <.02). Liver weights of mice fed SDPP were greater on an absolute basis (P <.02) an d as a percentage of BW ( P <.01). Feed intake, growth rate, and G:F w ere increased by dietary addition of SDPP. Mice fed plasma protein fai led to retain more energy than mice fed the control diet in spite of a greater energy intake, perhaps due to an increase in basal metabolic rate.