1. The endogenous nitrogen losses of men of different ethnic, ecological and socio-economic backgrounds are similar when calculated per unit body-weight or per unit basal energy consumption. The hypothesis that endogenous N losses, adjusted upwards by a factor of 0-30 to equate them with N equilibrium, can be used to derive man's physiological requirements for proteins of high quality, e.g. tho...

Dairy cows utilize feed crude protein (CP; N x 6.25) with much greater efficiency than other ruminant livestock but still excrete about 2-3 times more N in manure than in milk. This contributes to increased costs of milk production and to environmental N pollution. The function of dietary CP is to supply the cow with metabolizable protein (MP) as absorbed amino acids (AA) but any extra dietary ...

1. In Expt 1 three male goat kids of the Swedish Landrace breed were bottle-fed on isoenergetic liquid diets composed of goat's milk alone or substituted with 200, 400, 600 and 800 ml of a nitrogen-free liquid diet/l. The goat kids were 3 weeks old at the start of the experiment and weighed on average 5.3 (SD 0.22) kg. The experiment lasted for 45 d divided into nine 5 d periods. The goat kids ...

Interest in the production of carbon commodities from photosynthetically fixed CO2 has focused attention on cyanobacteria as a target for metabolic engineering and pathway investigation. We investigated the redirection of carbon flux in the model cyanobacterial species, Synechococcus elongatus PCC 7942, under nitrogen deprivation, for optimized production of the industrially desirable compound,...

The objectives of this study were to assess the relationship between urinary nitrogen excretion (UN, g/d) and milk urea nitrogen concentration (MUN, mg/dl) and whether the types of carbohydrates fed interacts with the dietary CP and the breed (size) of cows to affect this relationship. Eight multiparous cows (four Holstein and four Jersey) were fed four different diets in a 2 × 2 factorial arra...

Because dietary nitrogen intake affects nitrogen content in manure, diet management has been recognized as a means to reduce ammonia emissions from poultry operations. The objectives of the present research were 1) to determine the extent to which the CP content of laying diets can be reduced, based on performance criteria, and 2) to determine how ash:nitrogen ratios of manure, eggs, and hens a...

Two swine feeding trials were conducted (initial body weight = 47 +/- 2 and 41 +/- 3 kg for Trials 1 and 2, respectively) to evaluate reduced crude protein (CP) and yucca (Yucca schidigera Roezl ex Ortgies) extract-supplemented diets on NH3 emissions. In Trial 1, nine pigs were offered a corn-soybean meal diet (C, 174 g kg(-1) CP), a Lys-supplemented diet (L, 170 g kg(-1) CP), or a 145 g kg(-1)...

After obstruction of the cardiac end of the stomach and after obstruction and release of the pylorus there is a marked increase in non-protein nitrogen excretion. This increase is due to accelerated protein destruction, which may result from the great fluid loss, or to the action of some toxic body.

Reliable estimates of N excretion in the urine and feces of beef cattle are essential for developing cost-effective and environmentally sound nutrient management plans. A meta-analysis dataset was compiled that included data for starting live BW, DMI, N intake, dietary CP and RDP concentrations, urine N excretion, and feces N excretion. The data were taken from 12 individual feeding trials that...

MUCH evidence has accumulated to show that ammonia and urea excretion is characteristic of aquatic and amphibian life, and uric acid of terrestrial life [Needham, 1930; Delauney, 1935]. An ontogenetic sequence similar to the above has been shown to occur during the development of the chick [Needham, 1925]. During ontogenesis, at one stage 900 of the N excretion is present as NH3. On the other h...