In situ starch and crude protein degradation in the rumen and in vitro gas production kinetics of wheat genotypes

et al. 2017

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Rations for dairy cows are comprised of high proportions of cereal grains. Thus, despite their low crude protein (CP) content, grains can contribute considerably to the CP intake of dairy cows. This study was conducted to describe and compare ruminal CP degradation of a broad range of barley, rye and triticale genotypes in situ and in vitro and different methods to estimate the utilisable CP at the duodenum (uCP). Twenty samples each of rye, barley and triticale were incubated in situ and in vitro. Exponential regression analyses were used to estimate in situ degradation parameters. Further, the effective degradability (ED), ruminal undegraded CP (UDP) and uCP for ruminal passage rates of 5% and 8% per hr were estimated. The uCP was estimated in vitro and based on two different approaches using in situ UDP data and estimates of microbial synthesised protein (based on fermented organic matter [fOM] or equations of the Gesellschaft für Ernährungsphysiologie). The degradation rate declined from rye (43% per hr) to triticale (27% per hr) to barley (20% per hr), and it exhibited remarkable variation between the genotypes of a single species. The maximal degradable CP fraction also differed between the species, but was overall very high (94%-99%). The lowest washout fraction (26%) and the highest variation in ED (77%-86% and 69%-80% for a passage rate of 5% and 8% per hr, respectively) were found in barley. The in situ uCP content (estimated using fOM) was lower for barley than for rye and triticale at ruminal passage rates of 5% and 8% per hr (barley: 157 g/kg DM at both passage rates; rye and triticale: 168 (at 5% per hr) and 169 (at 8% per hr) g/kg DM). In vitro estimations of uCP did not differ between the grain species and uCP estimated according to GfE was higher for triticale than for barley and rye, which did not differ. The low variation within a single grain species and the weak correlations between ruminal CP degradation and nutrient concentrations suggested that differentiation of ED and uCP between the genotypes of a single grain species is not necessary.

Section: In Situ Degradation Characteristicssupporting

confidence: 90%

Section: Discussionsupporting

confidence: 61%

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In situ and in vitro evaluation of crude protein degradation and utilisable crude protein content of barley, rye and triticale grains for ruminants

Krieg

Seifried

et al. 2017

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“…The negative relationship between starch and CP, which has also been shown for several cereal grains by Krieg et al (2018) For spelt kernels, the rate of GP was on average 11.4%. This is equal or close to the mean rate of GP determined with the same method for varieties of wheat (11.4%), triticale (11.5%) and barley (11.1%), and lower than that of rye (12.5%) but higher than that of maize (7.1%) (Krieg et al, 2017;Seifried, Steingass, Hoffmann, & Rodehutscord, 2016;Seifried, Steingass, Schipprack, et al, 2016). Thus, ruminal starch degradation characteristics and effects on pH in the rumen may be very similar to those known for wheat and barley, meaning that high amounts of spelt kernels in a ration of dairy cows have the risk of causing an undesirable drop of ruminal pH value.…”

Section: Spelt Kernelssupporting

confidence: 77%

Investigation on the variation of chemical composition and in vitro nutritive value of spelt (Triticum aestivum ssp. spelta) for ruminants

Sommerfeld

Longin

et al. 2020

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Spelt has gained growing interest in Europe in human and animal nutrition. Data on the chemical composition of spelt and its variations, especially their nutritional value for ruminants, are scarce. Therefore, hulled kernels, dehulled kernels and hulls of six spelt cultivars grown on three different locations were analysed for their chemical composition and nutritive value for ruminants using the Hohenheim Gas Test. Most of the analysed constituents varied considerably and were significantly affected by the cultivars or location, or both. Hulled spelt and spelt kernels of more recent cultivars had higher starch and energy concentrations and lower concentrations of crude protein and fibre fractions than those of traditional cultivars. Significant differences between cultivars were found in the energy values for ruminants for hulled spelt but not for fractionated kernels. Spelt hulls of different cultivars and locations showed a high variation in chemical composition with overall high concentrations of fibre fractions and crude ash. The nutritive values for ruminants of hulled spelt and spelt kernels were similar to those of oats and wheat respectively. Pure spelt hulls cannot be recommended for use in ruminant feeding because of their high concentrations of fibre fractions and crude ash. However, when some part of the kernel (~20%) or small kernels remain with the hull in the dehulling process, the resulting hull fraction has a metabolizable energy value for ruminants that is similar to that of wheat straw.

“…The c value of ST, and the mean CP concentration of grains, decreased from location L1 to location L3, which was also reflected in a positive correlation between CP concentration and the c value of ST. Contrary to this, CP concentration was reported to be negatively correlated with ruminal ST degradation in maize and soft wheat grains (Seifried, Steingass, Hoffmann, & Rodehutscord, 2017; Seifried et al., 2016). Seifried et al.…”

Section: Discussionmentioning

confidence: 95%

Ruminal degradation and estimated energy and protein values for ruminants of Durum wheat varieties grown in three locations

Krieg

Titze

et al. 2020

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Durum wheat is mainly used in pasta production, but may also be used as animal feed, for example as concentrate for dairy cows. Data on the ruminal degradation of Durum grains are scarce. Hence, the objective of the present study was to describe ruminal in situ crude protein (CP) and starch (ST) degradation, to investigate in vitro gas production kinetics, and to estimate utilisable CP at the duodenum (uCP) in vitro of five Durum varieties from three growing locations. Metabolisable energy (ME) and digestibility of organic matter (dOM) were also estimated using in vitro data. In situ incubations were conducted in three lactating jersey cows over defined timespans from 1 to 72 hr. Ruminal degradation parameters were estimated using exponential regression, and effective ruminal degradation was predicted for a ruminal passage rate of 8%/hr (ED8). In situ CP (a = 11%–19%; b = 80%–88%; c = 23%–33%/hr) and ST (a = 22%–39%; b = 60%–78%; c = 61%–123%/hr) degradation kinetics varied among samples and were influenced by location. Some samples showed a remarkably high ST degradation rate of up to 123%/h, which can significantly influence rumen pH and health when high amounts are incorporated into dairy rations. However, the ED of CP (77%–82%) and ST (91%–95%), and the in vitro estimates of ME (13.6–14.1 MJ/kg DM), dOM (92%–96%), and uCP (183–195 k/g DM) varied within a relatively small range. Hence, it may be adequate to use the mean values of these Durum grain characteristics when rations for ruminants are calculated and a differentiation depending on variety and location may not be necessary.