Effect of ruminal ammonia supply on lysine utilization by growing steers

Citation: Hussein, A. H., Batista, E. D., Miesner, M. D., & Titgemeyer, E. C. (2016). Effect of ruminal ammonia supply on lysine utilization by growing steers. Journal of Animal Science, 94(2), 656-664. doi:10.2527/jas2015-9717Six ruminally cannulated Holstein steers (202 +/- 15 kg) were used to study the effects of ruminal ammonia loading on whole-body lysine (Lys) utilization. Steers were housed in metabolism crates and used in a 6 x 6 Latin square design. All steers received 2.52 kg DM/d of a diet (10.1% CP) containing 82% soybean hulls, 8% wheat straw, 5% cane molasses, and 5% vitamins and minerals, and 10 g/d of urea (considered to be part of the basal diet) was ruminally infused continuously to ensure adequate ruminal ammonia concentrations. All steers were ruminally infused continuously with 200 g/d of acetic acid, 200 g/d of propionic acid, and 50 g/d of butyric acid and abomasally infused with 300 g/d of glucose continuously to increase energy supply without increasing microbial protein supply. Steers were also abomasally infused continuously with an excess of all essential AA except Lys to ensure that Lys was the only limiting AA. Treatments were arranged as a 3 x 2 factorial with 3 levels of urea (0, 40, or 80 g/d) continuously infused ruminally to induce ammonia loading and 2 levels of Lys (0 or 6 g/d) continuously infused abomasally. Treatments did not affect fecal N output (P = 0.37). Lysine supplementation decreased (P < 0.01) urinary N excretion from 51.9 g/d to 44.3 g/d, increased (P < 0.01) retained N from 24.8 to 33.8 g/d, increased (P < 0.01) plasma Lys, and decreased (P <= 0.05) plasma serine, tyrosine, valine, leucine, and phenylalanine. Lysine supplementation also tended (P = 0.09) to reduce plasma urea-N. Urea infusions linearly increased (P = 0.05) retained N (27.1, 29.3, and 31.5 g/d) and also linearly increased (P < 0.01) urinary N excretion (31.8, 48.1, and 64.4 g/d), urinary urea (21.9, 37.7, and 54.3 g/d), urinary ammonia (1.1, 1.4, and 1.9 g/d), and plasma urea (2.7, 4.0, and 5.1 mM), and linearly decreased plasma alanine (P = 0.04) and plasma glycine (P < 0.01). Assuming that retained protein is 6.25 x retained N and contains 6.4% Lys, the incremental efficiencies of infused Lys utilization were 51%, 59%, and 69% for steers receiving 0, 40, and 80 g/d of urea, respectively, indicating that ruminal ammonia loads may improve the efficiency of Lys utilization. This is supported by observed increases in whole body-protein deposition in response to ammonia loading of our steers that were, by design, Lys deficient

Effects of Guanidinoacetic Acid on Lean Growth and Methionine Flux in Cattle

Objective: To evaluate the effect of supplementing guanidinoacetic acid in the presence or absence of L-methionine on nitrogen retention (lean tissue growth) when cattle were purposefully maintained under conditions of a methionine deficiency. Study Description: Seven ruminally-cannulated Holstein steers (355 lb) were used in an experiment where each steer received each of six treatments. Treatments were abomasal infusion of 0 or 6 g/day methionine, and 0, 7.5, or 15 g/day guanidinoacetic acid, with all combinations represented. Energy was supplied by ruminal infusion of volatile fatty acids and abomasal infusion of glucose. All essential amino acids except methionine were infused abomasally to make methionine the most limiting amino acid. The Bottom Line: Supplementation with 15 g/day of guanidinoacetic acid tended to increase lean tissue growth when steers received supplemental methionine, probably by increasing creatine synthesis by the steers

О необходимости прослеживания Балейско-Дарасунского разлома в пределах Борщевочного кряжа

In this paper we present the development of a compact, thermo-optically stable and vibration and mechanical shock resistant mounting technique by soldering of optical components. Based on this technique a new generation of laser sources for aerospace applications is designed. In these laser systems solder technique replaces the glued and bolted connections between optical component, mount and base plate. Alignment precision in the arc second range and realization of long term stability of every single part in the laser system is the main challenge. At the Fraunhofer Institute for Laser Technology ILT a soldering and mounting technique has been developed for high precision packaging. The specified environmental boundary conditions (e.g. a temperature range of -40 °C to +50 °C) and the required degrees of freedom for the alignment of the components have been taken into account for this technique. In general the advantage of soldering compared to gluing is that there is no outgassing. In addition no flux is needed in our special process. The joining process allows multiple alignments by remelting the solder. The alignment is done in the liquid phase of the solder by a 6 axis manipulator with a step width in the nm range and a tilt in the arc second range. In a next step the optical components have to pass the environmental tests. The total misalignment of the component to its adapter after the thermal cycle tests is less than 10 arc seconds. The mechanical stability tests regarding shear, vibration and shock behavior are well within the requirements

Некоторые результаты применения метода геометрического анализа дизъюнктов для поисков смещенного крыла пласта в Прокопьевском районе Кузбасса

In this paper we present the development of a compact, thermo-optically stable and vibration and mechanical shock resistant mounting technique by soldering of optical components. Based on this technique, new generations of laser pump sources for aerospace applications are designed. In these laser systems the used soldering technique replaces the glued connection between the optical component and its join partner. The main challenges are the alignment accuracy in the arc second range and the realization of the long term stability of every single part in the laser system (e.g. resonator mirrors)

Exact Eigenstates and Magnetic Response of Spin-1 and Spin-2 Vectorial Bose-Einstein Condensates

The exact eigenspectra and eigenstates of spin-1 and spin-2 vectorial Bose-Einstein condensates (BECs) are found, and their response to a weak magnetic field is studied and compared with their mean-field counterparts. Whereas mean-field theory predicts the vanishing population of the zero magnetic-quantum-number component of a spin-1 antiferromagnetic BEC, the component is found to become populated as the magnetic field decreases. The spin-2 BEC exhibits an even richer magnetic response due to quantum correlation between 3 bosons.Comment: 5 pages, no figures. LaTeX20

Effects of Guanidinoacetic Acid, Creatine, and Choline on Protein Deposition and Creatine Status in Growing Cattle

Objective: This study was conducted to evaluate effects of guanidinoacetic acid and creatine supplementation in the presence or absence of supplemental choline on body creatine status and lean tissue growth. Study Description: Six ruminally-cannulated Holstein steers (321 lb) were utilized in an experiment consisting of six 10-day periods, where each steer received one of six treatments in each period. Treatments were abomasal infusion of a saline solution (control), 15 g/day guanidinoacetic acid, or 16.8 g/day creatine, in combination with 0 or 5 g/day choline, with all treatment combinations represented. Complete collection of urine and feces was conducted to calculate nitrogen retention as a measure of protein deposition. Steers were fed a corn-based diet. Bottom line: Supplementing 15 g/day guanidinoacetic acid increased lean tissue growth in growing steers fed corn-based diets

Quantum tunneling across spin domains in a Bose-Einstein condensate

Quantum tunneling was observed in the decay of metastable spin domains in gaseous Bose-Einstein condensates. A mean-field description of the tunneling was developed and compared with measurement. The tunneling rates are a sensitive probe of the boundary between spin domains, and indicate a spin structure in the boundary between spin domains which is prohibited in the bulk fluid. These experiments were performed with optically trapped F=1 spinor Bose-Einstein condensates of sodium.Comment: 5 pages, 4 figure