The estimation of protein degradability in the rumen from incubation measurements weighted according to rate of passage

The protection of sunflower meal (SFM) proteins by treatments with solutions of malic acid (1 M) or orthophosphoric acid (0.67 M) and heat was studied in a 3 3 3 Latin-square design using three diets and three rumen and duodenum cannulated wethers. Acid solutions were applied to SFM at a rate of 400 ml/kg under continuous mixing. Subsequently, treated meals were dried in an oven at 1508C for 6 h. Diets (ingested at 75 g/kg BW 0.75 ) were isoproteic and included 40% Italian ryegrass hay and 60% concentrate. The ratio of untreated to treated SFM in the concentrate was 100 : 0 in the control diet and around 40 : 60 in diets including acid-treated meals. The use of acid-treated meals did not alter either ruminal fermentation or composition of rumen contents and led to moderate reductions of the rumen outflow rates of untreated SFM particles, whereas it did not affect their comminution and mixing rate. In situ effective estimates of by-pass (BP) and its intestinal effective digestibility (IED) of dry matter (DM), CP and amino acids (AAs) were obtained considering both rates and correcting the particle microbial contamination in the rumen using 15 N infusion techniques. Estimates of BP and IED decreased applying microbial correction, but these variations were low in agreement with the small contamination level. Protective treatments increased on average the BP of DM (48.5%) and CP (267%), mainly decreasing both the soluble fraction and the degradation rate but also increasing the undegradable fraction, which was higher using orthophosphoric acid. Protective treatments increased the IED of DM (108%) and CP, but this increase was lower using orthophosphoric acid (11.8%) than malic acid (20.7%). Concentrations of AA were similar among all meals, except for a reduction in lysine concentrations using malic acid (16.3%) or orthophosphoric acid (20.5%). Protective treatments also increased on average the BP of all AA, as well as the IED of most of them. Evidence of higher increases for those AA showing a high resistance to degradation in the untreated meal were also observed. The total supply of metabolisable AA was increased by 3.87 times for sulphur-containing AA, whereas that of lysine was increased by 2.5 times, mainly because of lysine losses with heat treatments. These treatments and especially that with malic acid would be useful to increase the protein value of these meals but their combined use with lysine-rich protein concentrates would improve the metabolisable protein profile.

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“…Calculations Degradation kinetics of DM or CP were fitted for each animal with the exponential model of Ørskov and McDonald (1979):…”

Section: Methodsmentioning

confidence: 99%

Malic acid or orthophosphoric acid-heat treatments for protecting sunflower (Helianthus annuus) meal proteins against ruminal degradation and increasing intestinal amino acid supply

Arroyo

González

Ouarti

et al. 2013

Animal

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“…Calculations and statistical analysis Degradability coefficients were calculated by fitting the data obtained for N to the first order model of Ørskov and McDonald (1979):…”

Section: Protected Urea and Milk Performancementioning

confidence: 99%

The partial replacement of soyabean meal and rapeseed meal with feed grade urea or a slow-release urea and its effect on the performance, metabolism and digestibility in dairy cows

Sinclair

Blake

Griffin

et al. 2012

Animal

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The objectives of the study were to determine the effect of the partial replacement of soyabean meal and rapeseed meal with feed grade urea or a slow-release urea on the performance, metabolism and whole-tract digestibility in mid-lactation dairy cows. Forty-two Holstein-Friesian dairy cows were allocated to one of three dietary treatments in each of three periods of 5 weeks duration in a Latin square design. Control (C) cows were offered a total mixed ration based on grass and maize silages and straight feeds that included 93 g/kg dry matter (DM) soyabean meal and 61 g/kg DM rapeseed meal. Cows that received either of the other two treatments were offered the same basal ration with the replacement of 28 g/kg DM soyabean and 19 g/kg DM rapeseed meal with either 5 g/kg DM feed grade urea (U) or 5.5 g/kg DM of the slow-release urea (S; Optigen R ; Alltech Inc., Kentucky, USA), with the content of maize silage increasing. There was no effect (P . 0.05) of dietary treatment on DM intake, which averaged 22.5 kg/day. Similarly, there was no effect (P . 0.05) of treatment on daily milk or milk fat yield but there was a trend (P 5 0.09) for cows offered either of the diets containing urea to have a higher milk fat content (average of 40.1 g/kg for U and S v. 38.9 g/kg for C). Milk true protein concentration and yield were not affected by treatment (P . 0.05). Milk yield from forage and N efficiency (g milk N output/g N intake) were highest (P , 0.01) in cows when offered S and lowest in C, with cows receiving U having intermediate values. Cows offered S also tended to have the highest live weight gain (0.38 kg/day) followed by U (0.23 kg/day) and C (0.01 kg/day; P 5 0.07). Plasma urea concentrations were higher (P , 0.05) at 2 and 4 h post feeding in cows when offered U and lowest in C, with animals receiving S having intermediate values. There was no effect (P . 0.05) of treatment on whole-tract digestibility. In conclusion, the partial replacement of soyabean meal and rapeseed meal with feed grade urea or a slow-release urea can be achieved without affecting milk performance or diet digestibility, with the efficiency of conversion of dietary N into milk being improved when the slow-release urea was fed.

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“…The in situ rumen DM and N disappearance curves obtained from the silage samples were fitted to the model of Ørskov and McDonald (1979) using a non-linear regression procedure (Statistical Analysis Systems Institute (SAS), 2000). The proportion of N degraded at time t was calculated using the equation: N degraded 5 a 1 b (12e 2ct ), where 'a' is the rapidly degraded fraction, 'b' is the slowly degraded fraction and 'c' is the degradation rate of the slowly degradable fraction, whereas (100 -a -b) was considered the undegradable fraction.…”

Section: Calculationsmentioning

confidence: 99%

Effects of condensed tannins in wrapped silage bales of sainfoin (Onobrychis viciifolia) on in vivo and in situ digestion in sheep

Theodoridou

Aufrere

Andueza

et al. 2012

Animal

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The objective of this study was to characterize the condensed tannins (CTs) in wrapped silage bales of sainfoin (Onobrychis viciifolia) and examine their potential action on in vivo and in situ digestive characteristics in sheep. Silage was made from sainfoin, cut at two phenological stages. The first phenological stage, at which silage was made, was from the first vegetation cycle at the end of flowering and the second stage silage was made from regrowth, 5 weeks after the first cut, but before flowering. The silages made from the two phenological stages were fed to 12 rumen-fistulated sheep in a crossover design. Of the 12 sheep, six received polyethylene glycol (PEG) to bind with and remove the effects of CT, whereas the other six were dosed with water. Organic matter digestibility, total-tract N digestibility and N (N) balance were measured over 6 days. Kinetic studies were performed on total N, ammonia N (NH 3 -N) and volatile fatty acids (VFAs) in rumen fluid before and 1.5, 3 and 6 h after feeding. The kinetics of degradation of dry matter and N from Dacron bags suspended in the rumen were also determined. Biological activity of CT (protein-binding capacity) and CT concentration were greater for the silage made from sainfoin at the early flowering stage. Total-tract N digestibility was increased by the addition of PEG (P , 0.001) to the sainfoin silage before flowering (P , 0.001). CTs decreased N excretion in urine (P , 0.05) and increased faecal N excretion (P , 0.001), but had no effect on body N retention, which is beneficial for the animal. Ruminal N degradability was smaller in the presence of active CT ( P , 0.001) at both phenological stages; however, soluble N (P 5 0.2060) and NH 3 -N (P 5 0.5225) concentrations in rumen fluid remained unchanged. The results of this experiment indicate that CT in the sainfoin retain their ability to affect the nutritive value of preserved forage legumes.Keywords: feed value, in vivo measurements, tannins, polyethylene glycol, sainfoin silage ImplicationsSilage allows the use of good-quality forage throughout the year. Although numerous papers have focused on the effect of condensed tannins (CTs) on the nutritive value of fresh forages, only few reports give data on preserved tanniniferous forages. The potential of tannins in legumes has not been fully exploited in temperate regions where livestock production occurs, largely because the CT-containing fodder legumes have poorer agronomic characteristics than tannin-free legumes. This study assessed the nutritive value of sainfoinwrapped silage bales. The effect of CT on in vivo and on in situ rumen degradability of sainfoin, which had been ensiled at two stages of maturity, was investigated in sheep. In order to investigate the effects of CT, measurements were recorded with and without polyethylene glycol, which inactivates CT throughout the digestive tract.

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The estimation of protein degradability in the rumen from incubation measurements weighted according to rate of passage

Cited by 3,748 publications

References 5 publications

Malic acid or orthophosphoric acid-heat treatments for protecting sunflower (Helianthus annuus) meal proteins against ruminal degradation and increasing intestinal amino acid supply

Malic acid or orthophosphoric acid-heat treatments for protecting sunflower (Helianthus annuus) meal proteins against ruminal degradation and increasing intestinal amino acid supply

The partial replacement of soyabean meal and rapeseed meal with feed grade urea or a slow-release urea and its effect on the performance, metabolism and digestibility in dairy cows

Effects of condensed tannins in wrapped silage bales of sainfoin (Onobrychis viciifolia) on in vivo and in situ digestion in sheep

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