Peptides ranging in size from a mean number of 30 residues down to dipeptides supported growth of a leucine auxotroph when used as both a nitrogen and leucine source. Under nitrogen-limiting conditions, the peptides induced extracellular peptidohydrolytic activity, hydrolyzing peptides to monomer amino acids. Growth of a leu-2 mutant of Neurospora crassa on those peptides transportable by the o...

The objective of this study was to evaluate the effects of replacing protein sources that are commonly used in North America with triticale dried distillers grains with solubles (TDDGS) as a source of dietary N on the productivity of lactating dairy cows. Experimental diets contained 17.1% TDDGS, 17.5% Corn DDGS (CDDGS), 13.1% canola meal (CM), or 10.2% soybean meal (SBM) on a DM basis so that ...

spp.) showed that forage DM intake was positively correlated with N fertilization rate. Fertilization may also Because native, shortgrass prairies are not typically fertilized and increase forage preference by livestock. Cook and Jeffotherwise extensively managed, little information is available on their response to nitrogen (N) fertilization. An experiment was conducted eries (1963) showed tha...

Six genotypes of winter wheat (Triticum aestivum L.) differing in grain protein concentration were grown on a nutrient solution containing low concentrations of NO(3) (-) (2 millimolar). Total NO(3) (-) uptake varied between genotypes but was not related to grain protein content. An in vivo nitrate reductase assay was used to determine the affinity of the enzyme for NO(3) (-), and large phenoty...

T WO experiments involving 296 pigs from gilts fed diets containing low (2%) or adequate (17%) protein during gestation followed by 5% or 17% during lactation were conducted to determine the effect of maternal dietary protein level on performance of the progeny. Blood hematocrit, hemoglobin and plasma protein levels were not affected by the dietary treatments imposed on the dam during gestation...

The objective of this paper was to review recent studies on nutrient synchrony and the effects of synchronization of energy and N supply in the rumen on nitrogen utilization and animal performance. Theoretically, synchronization of energy and N supply in the rumen should allow more efficient use of nutrients by rumen microbes, increase microbial protein and fermentation end products, and thus i...

Efrotomycin, a modified polyketide antibiotic with utility as a growth permittant in the animal industry, is produced by Nocardia lactamdurans. A resting cell system has been developed to facilitate biosynthetic studies. Washed cells harvested from oil-based medium at 64 hours and resuspended in buffer produce up to 700 mg/ml efrotomycin in 60 hours when supplemented with a carbon source, optim...

Soybean meal (SBM) was treated with acid or alkali to determine effects on N solubility, in vitro NH3-N accumulation, in situ N degradability, and N digestion and retention in growing lambs. The following SBM treatments resulted in decreased (P less than .05) N solubility and in vitro NH3-N accumulation compared with control SBM: spraying with 2.5 or 5% acetic or propionic acid, soaking in .5 N...

Four rumen fistulated swamp buffaloes were randomly assigned according to a 4×4 Latin square design to investigate the effects of Eucalyptus (E. Camaldulensis) leaf meal (ELM) supplementation as a rumen enhancer on feed intake and rumen fermentation characteristics. The dietary treatments were as follows: T1 = 0 g ELM/hd/d; T2 = 40 g ELM/hd/d; T3 = 80 g ELM/hd/d; T4 = 120 g ELM/hd/d, respective...

As the limiting substrate is altered, a microorganism’s internal structure is also altered by invoking different metabolic pathways for the utilization of the limiting substrate. Transitions between pathways are moderated by the processes of metabolic regulation and are observed under steady-state and transient conditions. Under nitrogen-limited steady-state conditions, the effects of overflow ...