Nitrogen excretion in rats on a protein-free diet and during starvation.

Nitrogen balances (six days) were determined in male Wistar rats during feeding a diet with sufficient protein or a nearly protein-free diet (n = 2 x 24), and then during three days of starvation (n = 2 x 12). The objective was to evaluate the effect of protein withdrawal on minimum nitrogen excretion in urine (UN), corresponding to endogenous UN, during feeding and subsequent starvation periods. The rats fed the protein free-diet had almost the same excretion of urinary N during feeding and starvation (165 and 157 mg/kg W(0.

Gas exchange, heat production and oxidation of fat in chicken embryos from a fast or slow growing line.

The experiment comprised 48 chicken (Gallus gallus) embryos from a modern, fast growing line, Ross 308 (RO) and 48 from a slow growing line, Labresse (LA). The O(2) consumption and CO(2) production were measured in an open-air-circuit respiration unit, and heat production (HE) from embryos was calculated at an age of 10, 13, 16 and 19 days. Gas exchange was below 10 ml/h for RO and LA by an age of 10-13 days, increasing steeply to a "peak" on day 16 and then slowing down between 16 and 19 days.

Energy metabolism and nutrient oxidation in young pigs and rats during feeding, starvation and re-feeding.

The investigation included individual measurements of energy metabolism and oxidation of nutrients in 12 castrated male pigs (Sus scrofa) (20-40 kg) and 12 male rats (Rattus norvegicus) (65-105 g). Measurements were carried out in 5-6 days balance periods with ad libitum feeding, followed by 3-4 days of starvation and 4 days of re-feeding. O2 consumption and CO2 production were measured by open-air-circuit respiration units.

Diurnal rhythm in heat production and oxidation of carbohydrate and fat in pigs during feeding, starvation and re-feeding.

Diurnal rhythm in heat production (HE), oxidation of carbohydrate (OXCHO) and fat (OXF) was calculated from daily measurements of gas exchange in 12 pigs [20-40 kg live weight, (LW)] during 6 days of near ad libitum feeding, followed by 4 days of starvation and 4 days of re-feeding. All measurements, divided in five times intervals from 12.00 to 8.