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 diet containing 8% spray-dried plasma protein (SDPP). Mice were housed in pairs in metabolism cages with feed and water available for ad libitum intake. Five cages were assigned to each diet for a 21-d feeding period. Mice fed SDPP gained more weight (P 0.01), consumed more feed (P 0.01), and had higher gain: feed ratios (G:F) (P 0.01 ) than mice fed the control diet during wk 1. No significant differences in growth, feed intake, or G:F were detected during wk 2. During wk 3, mice receiving the control diet tended to gain more (P 0.10) and had a higher G:F (P 0.01). Nitrogen intake and retention were greater for mice fed SDPP (P 0.02). Energy intake was greater for mice fed SDPP (P 0.01); however, energy retention was not different between treatment groups due to greater (P 0.01) metabolic energy losses (urinary energy + heat production). Empty gut weight was greater for control mice on an absolute basis (P 0.05) and when expressed as a percentage of BW (P 0.02). Liver weights of mice fed SDPP were greater on an absolute basis (P 0.02) and as a percentage of BW (P 0.01 ). Feed intake, growth rate, and G:F were increased by dietary addition of SDPP. Mice fed plasma protein failed 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