Quantitation of the flow of soluble non-ammonia nitrogen entering the omasal canal of dairy cows fed grass silage based diets

Homolka

et al. 2018

IJAR

The objective of this study was to evaluate the nutritional value of different feeds using chemical analysis and procedures to determine the nitrogen fractions expressed in g/kg of crude protein (CP) using a Cornell system. The experiment includes samples of common feeds used for ruminants in the Czech Republic. Fraction A is most commonly available from silages (average 468.2 g/kg CP) and least available in soybean (83.9 g/kg CP). In contrast, rapidly degradable protein (fraction B1) showed the lowest values in silages (average 31.5 g/kg CP) and the highest values in rapeseed cakes (average 195.7 g/kg CP) and lupines (average 308.7 g/kg CP). The intermediately degradable protein fraction B2 had a high value in almost all of the samples and especially in lupines (average B2 fraction 384.7 g/kg CP). The remaining fractions (B3 and C) represent slowly degraded proteins and unavailable proteins and represented a very small part of CP (average 18.9 and 34.9 g/kg CP, respectively). A strong relationship was found between fraction A and soluble protein (SOLP) and fraction B1 and SOLP. Other strong correlations were found between fraction B2 and CP, B2 and insoluble protein (IP), B3 and IP and B3 and neutral detergent insoluble nitrogen (NDIN).

Section: Resultssupporting

confidence: 92%

Evaluation of ruminal crude protein degradation of common feeds used in temperate climates

Homolka

et al. 2018

IJAR

“…The proportion of NAN dietary flow (% of ingested N) that escaped rumen degradation was small (on average 10.6%) and ranged from 5.8 to 10.1% for perennial ryegrass and 10.9 to 15% for cocksfoot. As in the results of Peltekova and Broderick [32], Choi et al [11], some soluble N escaped rumen degradation and flowed to the duodenum in the liquid phase of the digesta. However, in this study, dietary NAN flow may have been overestimated.…”

Section: The Various Nitrogen Fractions In Rumen Fluidmentioning

confidence: 70%

“…However, in this study, dietary NAN flow may have been overestimated. This fraction may contain other N forms such as nucleic acids [33] that are found in low quantities [39] and other nitrogen forms (saliva N, endogenous N, microbial nitrogen) as observed by Choi et al [11]. On the contrary to the results for in situ degradation of N (DegN) obtained on the same samples, and to previously reported results [8,16,24,25], the effects of maturity stage or conservation method were not observed, but the NAN flow was relative to ingested N in this study.…”

Section: The Various Nitrogen Fractions In Rumen Fluidmentioning

confidence: 99%

Ruminal degradation of protein of cocksfoot and perennial ryegrass as affected by various stages of growth and conservation methods

2003

-The behaviour of nitrogenous fractions in the rumen of sheep fed grasses at different vegetation stages and preserved by different methods was examined in this study. The measurements were made on four sheep fed forages. In Experiment 1, we used fresh cocksfoot cut at three stages of vegetation in the first growth stage (heading, first flower and full flower), two silages (one made with formic acid and the other without a preservative) and a first flower hay. In Experiment 2, we used fresh perennial ryegrass cut in the first growth stage (end of heading) and in the second growth stage at 7 week regrowth. A silage made with formic acid, two wrapped big bales harvested at 42% and 58% dry matter and a hay cut at the first growth stage (end of heading) were compared. The effective degradability of crude protein (DegN) estimated using the in situ method was lower (P < 0.05) with the latter vegetation stage for cocksfoot: 0.693 for the heading, 0.667 for the first flower, 0.597 for the full flower. For cocksfoot, the DegN of the silages was higher (P < 0.05) for silage without additive (0.770) than for silage with formic acid (0.705) and higher than that of the fresh forage at first flower (0.667). The DegN of hay was markedly lower (0.537, P < 0.05) than that of the original fresh forage. The DegN of silage of perennial ryegrass (0.760) and wrapped big bales harvested at 42% DM (0.739) were higher (P < 0.05) than that of fresh forage harvested at the end of heading (0.705). The DegN of wrapped big bales of perennial ryegrass harvested at 58% DM (0.667) and hay (0.536) were lower than those of the other forages (P < 0.05). Whatever the forage studied, the concentration of total nitrogen (tN), ammonia nitrogen (NH 3 -N) and non-ammonia nitrogen (NAN) were high 1 or 2 h after feeding and diminished rapidly up to 7 h after feeding. Some of the solubilised nitrogen remained as proteins 1 to 2 h after feeding for fresh forage harvested at various growth stages, but no protein was found in the rumen fluid after sheep were fed the silage (with or without preservative), wrapped big bales or hay. The proportion of dietary NAN flow (relative to ingested nitrogen) escaping rumen degradation was 5.8% to 10.1% for perennial ryegrass and 10.9% to 15% for cocksfoot. Quel que soit le fourrage étudié, les teneurs en azote total, en azote ammoniacal, et en azote non ammoniacal dans le rumen sont maximales 1 ou 2 h après le repas et diminuent jusqu'à 7 h après le repas. Une partie des matières azotées solubilisées reste sous forme de protéines 1 ou 2 h après le repas pour les fourrages verts tandis qu'on ne retrouve pas de protéines solubilisées dans le rumen des moutons recevant des fourrages conservés (ensilages, balles rondes, foin). Le flux d'azote alimentaire non ammoniacal (exprimé par rapport à l'azote ingéré) qui échappe à la dégradation dans le rumen et transite avec le liquide ruminal représente de 5,8 % à 10,1 % pour le ray-grass anglais et de 10,9 % à 15 % pour le dactyle.dactyle / ray-grass anglais / mode de conse...

“…(3) The presence of the enzyme polyphenol oxidase, decreased proteolysis and non protein nitrogen content (NPN). Forage NPN consists of oligopeptides, free amino acids, ammonium compounds and other small molecules that rapidly contribute to the ruminal ammonia pool [12].…”

Section: Discussionmentioning

confidence: 99%

Protein degradation in the rumen of red clover forage at various stages of growth and conserved as silage or wrapped big bales

2002

-In order to study the extent to which rumen soluble nitrogen can contribute to the intestinal flow, a study was carried out to simultaneously assess the dynamics of protein disappearance from dacron bags placed in the rumen and the amount of various N products in the rumen fluid (total nitrogen (tN), ammonia nitrogen (NH3-N), non-ammonia nitrogen (NAN)). The measurements were carried out on 4 sheep fed successively various red clover forages. These forages included the initial growth of fresh red clover (50% bud, first flower, and full flower). In addition, one silage and one wrapped big bale at the first flower stage and two wrapped big bales (harvested at 51% and 71% dry matter) at the full flower stage were given. The effective degradability of nitrogen (DegN) for a fresh forage estimated from the nylon bag procedure did not vary (p > 0.05) with the vegetation stage (0.727 for the bud stage, 0.694 at the first flower, 0.706 at the full flower). The DegN of the silage was higher (p < 0.05; 0.735) and the DegN of the wrapped big bale was markedly lower (p < 0.05; 0.660), than the original fresh forage at the first flower. The DegN of the wrapped big bales made at 51 and 71% DM, respectively, were 0.625 and 0.604 against 0.706 for fresh forage at the full flower stage. The concentrations of tN and NAN in the rumen fluid were low, highest 1 h to 2 h after feeding, and then decreasing up to 7 h after feeding whatever the growth stage and conservation mode. A part of the solubilised nitrogen remained as protein 1 h after feeding for fresh red clover harvested at various growth stages, while minimal protein could be seen in the rumen fluid after the sheep were fed silage or wrapped big bales. The part of NAN escaping rumen degradation and transiting with the rumen fluid was between 7 and 13% of the nitrogen disappearing from the nylon bags (NAN/CP D egN) placed in the rumen. There was only a small difference for forages at different stages of growth, or modes of conservation. This fraction was higher for wrapped big bales and particularly for the late stage forage (wrapped big bale, 71% DM, harvested at the full flower stage). red clover / vegetation stage / conservation method / protein degradation / rumen fluid composition Reprod. Nutr. Dev. 42 (2002) [559][560][561][562][563][564][565][566][567][568][569][570][571][572] 559