Digestibility Of Rumen Undegradable Protein Research Articles

Effect of processing with ozone on in vitro and in situ ruminal degradability and intestinal digestibility of feather meal protein

This study aimed to investigate the effect of processing feather meal (FM) with ozone (O3) gas on nutrient content, ruminal degradability, and intestinal digestion of crude protein (CP) using in vitro and in situ techniques. Experimental treatments were designed as control (not-processed), O3-processed FM for 12 h (h; treat 1), O3-processed FM for 24 h (treat 2), and O3-processed FM for 48 h (treat 3). Five Ghezel sheep equipped with ruminal cannulas were used to measure the nutrient degradability and to obtain ruminal fluid for in vitro gas production. Processing with O3 gas significantly decreased dry matter (DM), ether extract (EE), and Ash content of the FM compared to the control (P < 0.05). Processing FM by O3 increased the volume of in vitro gas production (P < 0.05). The soluble and potentially degradable fractions of the DM and CP showed a significant increase with increasing processing time (P < 0.05). Processing with O3 gas increased quickly degradable protein (QDP), rumen degradable protein (RDP), effective rumen degradable protein (ERDP), and digestible undegradable protein (DUP) content as a proportion of feather meal CP. Still, undegradable dietary protein (UDP) decreased significantly. Intestinal digestibility of rumen undegradable protein (RUP) and Metabolize Protein (MP) content of the FM was also significantly increased with increased processing time and the highest values were achieved after 48 h of processing (P˂0.05). According to the results of this experiment, it can be concluded that processing FM using O3 for 48 h increases its nutritional value in ruminant nutrition.

A comparative study of the intestinal digestive characteristics of different feeds for Holstein cows

This experiment was conducted with lactating Chinese Holstein cows to study the nutritional value of local protein feed resources. A three-step method (TSP) and a modified three-step method (MTSP) were used to measure the in vitro digestibility of rumen undegraded protein (RUP) for 11 feedstuffs and correlation. Eleven experimental feeds were chosen and air-dried to investigate the effects of different growth periods and varieties on nutrition value and RUP digestibility. The small intestinal digestibility of RUP by TSP in concentrated feed was determined to be higher than that of roughage, approximately 65%. The highest concentrate (79%) was SBM (soybean mean), while the lowest was corn (65%). The proportions of DDGS (with soluble wine lees) and SFM (sunflower meal) were 70.9 and 74.9%, respectively. ASS (alfalfa mowed at the squaring stage) had the highest small intestinal digestibility of RUP (55%) among roughages, and WCS (whole-plant corn silage) had the lowest digestibility (40.5%). When the small intestinal digestibility of RUP was determined using the MTSP method, it exhibited similar results to the TSP method. Nevertheless, the values were generally higher, and there was a strong significant correlation between them (R2 = 0.967, P < 0.01). The comparative study of these two methods help us have a better understanding of small intestine digestibility of different feeds, make a reasonable feed formula to effectively prevent diseases.

Effects of rumen-degradable-to-undegradable protein ratio in ruminant diet on in vitro digestibility, rumen fermentation, and microbial protein synthesis.

Background and Aim:Feeding ruminants must notice the degradability of feed, especially protein. Microbial rumen requires ammonia from rumen degradable protein (RDP) beside that ruminant require bypass protein or rumen undegradable protein (RUP) and microbial crude protein. The aim of the study was to discover the best RDP:RUP ratio in beef cattle diets commonly used by Indonesian farmers using an in vitro methodology.Materials and Methods:Samples of Pennisetum purpureum, Leucaena leucocephala, Indigofera zollingeriana, cassava, maize, palm kernel cake, rice bran, and tofu waste were formulated into dietary treatments (dry matter [DM] basis). All experiments were carried out using a 3×3×2 factorial, randomized block design with three replications. Treatments consisted of three protein levels (12%, 14%, and 16%), two energy levels (65% and 70%), and three RDP:RUP ratio levels (55:45, 60:40, and 65:35). The experimental diets were incubated in vitro using buffered rumen fluid for 48 h at 39°C. After incubation, the supernatants were analyzed to determine pH, ammonia concentration, total volatile fatty acid (VFA), and microbial protein synthesis. The residues were analyzed to determine DM, organic matter, protein, and RUP digestibility.Results:Increased protein, energy, and RDP levels increased digestibility, ammonia concentrations, total VFAs, and microbial protein synthesis (p<0.05), while rations with 16% protein lowered these parameters (p<0.05).Conclusion:Increased dietary protein (from 12% to 14% DM), energy (from 65% to 70% DM), and RDP (from 55% to 65% crude protein [CP]) levels increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. The diet containing 14% DM dietary protein and 70% DM energy, which contained 55%, 60%, or 65% CP RDP optimally increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. Thus, feed based on these RDP:RUP ratios can optimize ruminant productivity.

55 Rumen undegradable protein content of native range and sub irrigated meadow forages

Abstract The in situ mobile bag procedure was used to compare rumen undegradable protein (RUP) content and RUP digestibility of Nebraska Sandhills range and meadow diet samples. Meadow samples (n = 12) were from June, July and August of 2 years while range samples (n = 19) were from June, July, September and December of 6 years. Samples were collected using esophageally fistulated cows (samples from 2 cows composited per time point), freeze-dried, and ground through a 2 mm screen. For each sample, 1.25 g was weighed into 8 replicate 8×10 cm Dacron bags with 50-µm pore size. Rumen incubation time was based on estimated digestibility and passage rate. Following rumen incubation, analysis of neutral detergent insoluble N (NDIN) on one-half of the bags was used to calculate RUP content. Remaining bags were treated with pepsin/HCl solution (37 °C) and stirred for three hours before duodenal incubation. Analysis of NDIN after recovery from feces determined RUP digestibility. Data were analyzed using month as a fixed effect and year and experiment as random effects. In meadow samples, CP (15.0% of DM) was consistent across June, July, and August (P = 0.72). Range samples tended to differ in CP content (P = 0.11), with June, July and September being similar (8.15% of DM) while December was 6.01%. In meadow samples, RUP averaged 21.9% of CP while range samples averaged 26.7% of CP, with no differences due to month (P ≥ 0.32). Because CP content was changing in range samples, RUP as a % of DM tended (P = 0.14) to decrease in December (1.66) compared to June, July, and Sept (2.25). In meadow samples, RUP digestibility (%) declined from 74.7% in June to 61.4% in July and Aug (P = 0.07). RUP digestibility (%) averaged 43.9% for all range samples (P = 0.66).

Characterization of dietary protein in Brassica carinata meal when used as a protein supplement for beef cattle consuming a forage-based diet.

As a novel oilseed crop in Florida, Brassica carinata has the capacity of producing high-quality jet biofuel, with a protein-dense meal (~40% crude protein; CP) obtained as a by-product of oil extraction. Characterization of the meal protein is limited, yet necessary for formulation of beef cattle diets; therefore, the objective of this experiment was to determine ruminal and postruminal digestibility of protein from B. carinata. Eight ruminally cannulated Angus crossbred steers (473 ± 119 kg) were used in a duplicated 4 × 4 Latin square design, in which in situ ruminal and postruminal degradability of nutrients were evaluated. The three-step in vitro procedure was used to compare CP and amino acid (AA) degradation in B. carinata meal pellets (BCM) with that of cottonseed meal (CSM), dry distillers grains with solubles (DDGS), and soybean meal (SBM). In situ bags were incubated in the rumen for 0 to 96 hr, with the undegraded supplement remaining after 16 hr subjected to serial in vitro enzymatic solutions. Data were analyzed using the MIXED procedure of SAS. Ruminal rate of degradation of dry matter, organic matter, and CP was greatest (P ˂ 0.01; 10.9, 11.3, and 11.5 %/h, respectively) for SBM. Rumen degradable protein (RDP) content did not differ (P = 0.20; 47.8% and 55.1%, respectively) between CSM and DDGS, but was decreased (P ˂ 0.01) compared with SBM and BCM, which did not differ (P = 0.99; 72.3% and 71.8% RDP, respectively). Compared with DDGS, SBM had greater (P < 0.01) intestinal digestibility of rumen undegradable protein (RUP). Intestinally absorbable digestible protein (IADP) was greatest (P < 0.01) for CSM, with SBM and BCM having the least IADP. Total tract digestibility of CP (TTDP) was greater (P < 0.01) for SBM compared with CSM and DDGS. The contribution of RUP to intestinally absorbable AA was 7.2 and 3.1 g of lysine and methionine per kilogram of CP in BCM, respectively. The evaluation of B. carinata meal as protein supplemented for cattle consuming a forage-based diet resulted in 71.8% RDP and 97.1% TTDP, thus indicating its viability as a high-quality protein supplement for beef cattle.

PSXII-5 Feed processing-induced changes in protein molecular structure in relation to nutrient utilization and availability of warm-season Sorghum grain (Sorghum bicolor) in ruminants

Abstract The objective of this study was reveal heat related processing (HP) induced changes in protein molecular structure in relation to nutrient utilization and availability of warm-season sorghum grain (Sorghum bicolor) in dairy cows. Three new warm-season genotypes of sorghum grain (Sorghum bicolor) were studied. The nutrient utilization and availability of sorghum grain (Sorghum bicolor) in dairy cows include: protein subfractions, energy values, rumen degradation, and intestinal digestibility of rumen undegraded protein. The protein structure change on molecular level were revealed with cutting edge non-invasive vibrational ATR-FTIR molecular spectroscopy. The warm-season sorghum grains were either maintained in their raw state (as control) or treated with for 80 min at 121°C with the Lindberg/Blue M™. The RCBD data were analyzed using SAS9.4 with Mixed model procedure. Tukey method was used for mean separation. The results showed that compared with the control, the HP treatment altered (P &amp;lt; 0.05) nutrient profiles and utilization and availability in dairy cows and increased (P &amp;lt; 0.05) metabolizable energy and net energy values in dairy cows. The HP treatment also altered (P &amp;lt; 0.05) the protein molecular structure profile of the warm-season sorghum grain. It increased (P &amp;lt; 0.05) the ratio of protein Amide I and Amide II height and decreased (P &amp;lt; 0.05) the ratio of α-helix to β-sheet. In conclusion, the HP treatment altered molecular structure and nutrient profiles without negatively affecting the nutritive value and digestion of warm-season sorghum grain. The molecular spectral profiles revealed by rapid and non-invasive ATR-FTIR molecular spectroscopy could be used as a fast predictor for the warm-season sorghum grain utilization and digestion in dairy cows.

High Fiber Cakes from Mediterranean Multipurpose Oilseeds as Protein Sources for Ruminants.

Simple SummaryRecovery and valorization of residues are key factors for agro-industry to progress towards circular-economy models and more sustainable productions. In the vegetable oils industry, large quantities of spent seed cakes are produced downstream of the oil extraction processes, and their use as animal feedstuffs, mainly as protein supplements for ruminants, is a possible valorization strategy. In this study, we analyzed chemical composition and in vitro digestibility of spent cakes from sunflower, pomegranate, cardoon, tobacco and hemp that are multipurpose cultures emerging in Mediterranean area. The results showed that the cakes of tobacco, cardoon and hemp might be interesting alternative protein feeds for ruminants. The valorization of these cakes may potentially improve economic and environmental sustainability of the emerging vegetable-oil production chains.Fifteen oilseed cakes from sunflower, pomegranate, cardoon, tobacco and hemp were characterized with regard to chemical composition, Cornell Net Carbohydrate and Protein System (CNCPS) fractionation, in vitro digestibility of dry matter, neutral detergent fiber, and crude protein. All the cakes presented low moisture, rather variable ether extract contents and medium to high levels of crude protein and neutral detergent fiber. The cakes significantly differed in terms of CNCPS partitioning and in vitro digestibility. Tobacco and hemp cakes presented high contents of slow degradable fractions of crude protein and carbohydrate joined to good post-ruminal protein digestibility. Cardoon cakes presented the highest rumen protein degradability. Based on crude protein content and intestinal digestibility of rumen undegraded protein, cakes of tobacco and hemp showed the better potential as alternative protein supplements for ruminants, while pomegranate appears to be the least suitable for ruminant feeding.

Infrared attenuated total reflection spectroscopic analysis and quantitative detection of forage spectral features in ruminant systems.

This study aimed to (1) access protein molecular structure profile and metabolic characteristics of model forages [Foreign sourced-origin (coded as: "FSO", n = 7 vs. Chinese sourced-origin alfalfa hay "CSO", n = 5] in ruminant systems; (2) Quantify the relationship between forage protein molecular structures and protein utilization and availability. Advanced non-invasive vibrational molecular spectroscopic technique (ATR-FTIR: Attenuated Total Reflection Fourier Transform Infrared spectroscopy) with chemometrics was applied to reveal forage protein molecular structure. Both univariate and multivariate molecular spectral analyses were applied to study molecular structure features in model forages. The molecular structure study provided the detailed protein structure profiles of Amide I and Amide II areas and height, total Amide I and II area ratios, Amide I to II height ratio as well as Amide I to II area ratio using ATR-FTIR spectroscopy. The results showed FSO and CSO had similar (P > 0.05) protein rumen degradation kinetics. However, FSO had superior quality than CSO in intestinal (IDP) and total digestible protein (TDP) and truly absorbed nutrient supply (P < 0.05). As intestinal digestion of protein, FSO was higher (P < 0.05) in protein digestion in terms of: intestinal digestibility of rumen undegraded protein (dIDP: 47.5 vs. 38.3 %RUP); Intestinal digestible protein (IDP: 17.6 vs. 13.7 %CP). As truly absorbed nutrient supply, FSO contained higher (P < 0.05) truly absorbed rumen synthesized microbial protein, absorbable rumen undegradable feed protein in the small intestine, total truly digested protein in the small intestine, metabolizable protein and Feed Milk Value (FMVDVE: 1.2 vs. 1.1 g/kg DM). The molecular structure-nutrition interactive relationship study showed that protein molecular structure profiles were highly associated to protein rumen degradation kinetics, significantly correlated to protein subfractions, protein intestinal digestion, and truly absorbed nutrient supply in ruminant systems.

Genotypic impact on molecular structural, physicochemical, and nutritional characteristics of warm-season adapted sorghum kernels grown under warm climate conditions

Three genotypes of warm-season adapted sorghum grain have been developed. The objectives of this study were to systematically investigate the magnitude differences in detailed chemical and nutrient profiles, protein subfractions, energy value, rumen degradation, intestinal digestibility of rumen undegraded protein as well as protein-related molecular structures in these genotypes of warm-season adapted sorghum grain (Sorghum bicolor L. Moench). The protein molecular structures were revealed by using vibrational non-invasive ATR-FTIR molecular spectroscopy. The results showed that the physicochemical, nutritional, and molecular structural features among three genotypes of warm-season adapted sorghum grain were different (P < 0.05). These sorghum genotypes had markedly (P < 0.05) differences in the protein-related molecular structures, including amides spectral intensity area, height and their intensity ratios. The results indicated that the molecular spectral profiles collected by non-invasive ATR-FTIR molecular spectroscopy could be used as a potential approach to predict nutrient flow and utilization in ruminant systems.

Protein molecular structure, degradation and availability of canola, rapeseed and soybean meals in dairy cattle diets

ObjectiveThe aims of this study were to reveal the magnitude of the differences in protein structures at a cellular level as well as protein utilization and availability among soybean meal (SBM), canola meal (CM), and rapeseed meal (RSM) as feedstocks in China.MethodsExperiments were designed to compare the three different types of feedstocks in terms of: i) protein chemical profiles; ii) protein fractions partitioned according to Cornell Net Carbohydrate and Protein System; iii) protein molecular structures and protein second structures; iv) special protein compounds-amino acid (AA); v) total digestible protein and energy values; vi) in situ rumen protein degradability and intestinal digestibility. The protein second structures were measured using FT/IR molecular spectroscopy technique. A summary chemical approach in National Research Council (NRC) model was applied to analyze truly digestible protein.ResultsThe results showed significant differences in both protein nutritional profiles and protein structure parameters in terms of α-helix, β-sheet spectral intensity and their ratio, and amide I, amide II spectral intensity and their ratio among SBM, CM, and RSM. SBM had higher crude protein (CP) and AA content than CM and RSM. For dry matter (DM), SBM, and CM had a higher DM content compared with RSM (p<0.05), whereas no statistical significance was found between SBM and CM (p = 0.28). Effective degradability of CP and DM did not demonstrate significant differences among the three groups (p>0.05). Intestinal digestibility of rumen undegradable protein measured by three-step in vitro method showed that there was significant difference (p = 0.05) among SBM, CM, and RSM, which SBM was the highest and RSM was the lowest with CM in between. NRC modeling results showed that digestible CP content in SBM was significantly higher than that of CM and RSM (p<0.05).ConclusionThis study suggested that SBM and CM contained similar protein value and availability for dairy cattle, while RSM had the lowest protein quality and utilization.

Protein molecular structural, physicochemical and nutritional characteristics of warm-season adapted genotypes of sorghum grain: Impact of heat-related processing

Three warm-season genotypes of sorghum grain (Sorghum bicolor) have been developed. The objectives of this study were: (1) to systematically investigate the heat-related processing (HRP)-induced changes/alteration on: (a) detailed chemical and nutrient profiles, (b) protein subfractions, (c) energy values, (d) rumen degradation, (e) intestinal digestibility of rumen undegraded protein; and (2) to use vibrational non-invasive ATR-vFt/IR molecular spectroscopy to determine protein-related molecular structures in the warm-season genotypes of sorghum grain. The warm-season sorghum seeds were either maintained in their raw state (as control) or treated with the HRP using the Lindberg/Blue M™ for 80 min at 121 °C (the condition was chosen based on previous study). Compared with the control, the HRP treatment altered chemical and nutrient profiles and utilization and availability of warm-season sorghum grain. The HRP treatment increased metabolizable energy and net energy values. The HRP treatment also altered the protein molecular structure profile. Furthermore, it increased the ratio of Amide I and Amide II height and decreased the ratio of α-helix to β-sheet. In summary, the HRP treatment altered chemical nutrient profiles without negatively affect the nutritive value and digestion of warm-season sorghum grain. The molecular spectral profiles could be used as a potential predictor for the warm-season sorghum grain utilization and digestion.

In situ degradation kinetics of 6 roughages and the intestinal digestibility of the rumen undegradable protein.

Three ruminally fistulated Xuanhan steers weighting 312.5 (±23.85) kg were used to determine the kinetics of ruminal degradation of nutrients using in situ nylon bag technique, and a modified 3-step in vitro procedure was adopted to estimate intestinal digestibility of 16-h rumen undegradable protein (RUP) of maize cob (MC), distillers grains (DG), spent mushroom substrate (SMS), starch residue of sweet potato (SRSP), citrus pulp (CPP), and rice straw (RS). Samples were incubated for 0, 2, 6, 16, 24, 36, 48 and 72 h. Additional samples were incubated for 16 h in the rumen, and the residues from these bags were transferred to the nitrogen-free polyester bags for determination of intestinal digestibility in vitro. The highest DM disappearance at 6-h incubation was in SRSP (P < 0.01), and that at 36, 48, and 72 h was in CPP (P < 0.01). The lowest DM disappearance at 2- and 6-h incubation was in RS and SMS (P < 0.01), and that at 36, 48, and 72 h incubation was in RS, MC, and DG (P < 0.01). The lowest and greatest CP disappearance was in RS and DG, respectively, at all the incubation times (P < 0.01). There was no difference (P > 0.07) on CP disappearance between DG and MC at all the time points except for 16 and 24 h. NDF and ADF disappearance for SRSP was significantly higher (P < 0.01) than other roughages at all the time points except for ADF at 72 h. The lowest NDF and ADF disappearance was in DG at all the time points (P < 0.01) except 2 and 6 h. The effective degradability (ED) of DM was the highest in CPP (P < 0.01) and the lowest in MC and RS (P < 0.01). The highest and lowest ED of CP was in DG and in RS (P < 0.01), respectively. The ED of NDF was the highest in SRSP (P < 0.01), followed by CPP and RS, and the lowest in DG (P < 0.01). The ED of ADF was the highest in SRSP and CPP (P < 0.05), and the lowest in DG (P < 0.01). For MC, DG SMS, SRSP, CPP, and RS, the intestinal digestibility of RUP was 95.28%, 37.23%, 38.72%, 48.06%, 54.49%, and 37.88%, respectively, and the content of intestinal digestible crude protein (IDCP) was 23.65, 83.63, 35.63, 15.03, 25.60, and 12.03 g/kg, respectively. Distillers grain was considered to be of good quality for the greatest content of IDCP. Although not readily degraded in rumen, CP in MC may be digested well in small intestine.

Application of FT/IR-ATR vibrational spectroscopy to reveal protein molecular structure of feedstock and co-products from Canadian and Chinese canola processing in relation to microorganism bio-degradation and enzyme bio-digestion

The principal objective of this study was to apply FT/IR-ATR vibrational spectroscopy to inspect the relationship between rumen dry matter (DM) and protein degradation, rumen undegraded protein (RUP) intestinal digestion and processing induced protein molecular structure changes in feedstock (canola oil seeds) and co-products (canola meal) from bio-oil processing from different crushing plants in Canada and China. The rumen DM and protein degradation, rumen undegraded protein intestinal digestion and protein molecular structure affected by bio-oil processing were examined using in situ, three step in vitro digestion and Fourier transform infrared (FT/IR) molecular spectroscopy techniques, respectively. The results showed that the protein molecular structure; α-helix height and α-helix to β-sheet height ratio had a close association with rumen DM and protein degradation and rumen undegraded protein intestinal digestibility. Multiple regression analyses showed that protein β-sheet height and α-helix to β-sheet height ratio spectral intensity can be used to predict rumen DM and protein degradation, while intestinal digestibility of rumen undegraded protein can be predicted by α-helix height and β-sheet height. In conclusion, the co-product canola meal from bio-oil processing is a good source of intestinally digestible protein. Rumen DM and protein degradation and intestinal digestibility of rumen undegraded protein are related to the protein molecular structures of the co-products affected by changes during bio-oil processing.

Rumen undegradable protein (RUP) and its intestinal digestibility after steam flaking of cereal grains

While it is known that heat treatment of cereal grains generally improves the nutritional value for ruminants, simultaneous information on rumen degradability and intestinal digestibility of the rumen by-pass is scarce, especially for non-starch constituents. The effect of steam flaking at 90°C for 30 min on protein quality of maize, wheat, and barley was studied. In addition to proximal chemical analyses, protein rumen degradability was determined in vitro and intestinal digestibility of rumen undegraded protein was determined using the mobile bag method. No significant effects of steam flaking on chemical composition of cereal grains (crude protein, acid detergent fibre, neutral detergent fibre, and starch) were observed. The protein fractions that are relevant to rumen degradability were significantly influenced by the steam flaking: the non-protein nitrogen fraction (A) was reduced (P &amp;lt; 0.05) by 43–93% for all three cereal grains, whereas the fraction that represents true soluble protein (B1) was reduced (P &amp;lt; 0.05) for wheat grains (by 77%) and barley (by 93%). Although the difference was not significant, a decrease of 41% for B1 fraction was also observed for maize. On the other hand, steam flaking markedly increased buffer insoluble but neutral detergent soluble protein fraction (B2) by 15–25% for all three cereal grains, whereas effects on B3 fraction were not significant. Steam flaking was also associated with an increase of the rumen undegradable protein fraction (C) in the case of barley, from 6.6 to 11.1% of total N (P &amp;lt; 0.05) and wheat, from 5.2 to 8.4% of the total N (P &amp;lt; 0.05). Overall, the changes of the protein fractions led to a considerable increase of the rumen undegradable protein (RUP) for all steam-flaked cereal grains (P &amp;lt; 0.05). Steam flaking also increased (P &amp;lt; 0.05) intestinal digestibility of RUP of the cereal grains (by 3.6–34.8%), leading to a more efficient protein use in ruminants.

Degradabilidade ruminal e digestibilidade intestinal dos grãos de soja crus e tostados em bovinos leiteiros

RESUMO Objetivou-se estudar o efeito de diferentes tratamentos térmicos, tempos e procedimentos na degradação ruminal de grãos de soja crus e tostados e sua ação na digestão intestinal da proteína não degradada no rúmen (PNDR) pelo método dos três estágios. Para a degradação ruminal in situ foram pesados cinco gramas de matéria natural em sacos de náilon incubados durante 2; 4; 8; 16; 24 e 48 horas. No tempo zero foi efetuado o mesmo procedimento, excetuando a incubação ruminal. Os resíduos de cada tratamento formaram uma amostra composta para determinar a matéria seca (MS) e proteína bruta (PB). Para a digestibilidade intestinal realizou-se a incubação in situ por 16 horas, usando a técnica dos três estágios. A degradabilidade efetiva da MS com taxa de passagem de 5%/hora para a soja crua (SC) foi de 71,94% e tostada entre 52,23% a 68,78%. Após 16 horas de incubação a PNDR variou de 32,12 a 67,72% e a digestibilidade intestinal de 73,21% a 86,02%. A menor degradação da MS e PB foi da soja tostada a 145°C durante um minuto com steeping (STC1). A digestibilidade intestinal in vitro dos grãos crus foi superior e diferiu dos tostados, exceto a soja tostada a 115°C durante quatro minutos com steeping. A menor degradação proteica foi obtida da STC1de 67,72% da PNDR,52,33% a mais do que à SC. A tostagem dos grãos de soja a 145°C(STC1)contribuiu para uma menor degradabilidade ruminal da proteína bruta.

Effects of canola meal pellet conditioning temperature and time on ruminal and intestinal digestion, hourly effective degradation ratio, and potential nitrogen to energy synchronization in dairy cows

The increase in bio-oil production in North America has resulted in millions of tonnes of co-products: canola meal and carinata meal. Little research has been conducted to determine the effect of pellet conditioning temperature, time, and their interaction on processing-induced changes in nutrient digestibility in the rumen and intestine (in vitro) of dairy cattle. The objectives of this study were to investigate the effects of conditioning temperature (70, 80, and 90°C), time (50 and 75 s), and their interaction (temperature × time) during the pelleting of canola meal on (1) rumen degradation kinetics and effective rumen degradability of dry matter, crude protein (CP), and neutral detergent fiber; (2) intestinal digestibility of rumen-undegradable protein (RUP); and (3) hourly effective rumen degradation ratio and potential N to energy synchronization in dairy cattle. The results showed that the temperature and duration of pellet conditioning significantly altered the degradation characteristics of nutrients in the rumen. Pelleting increased CP degradation in the rumen, and CP digestion site was shifted to the rumen rather than to the small intestine. When conditioning temperature was set 80°C, the rumen degradation of CP and neutral detergent fiber was highest, but postrumen digestion was lowest. With respect to intestinal digestion, the available CP for intestinal digestion became less because of reduced RUP supply to the small intestine. The pelleting process tended to significantly affect the intestinal digestibility of RUP. However, the total digestible CP content of canola meal was not affected. In conclusion, pelleting induced changes in rumen and intestinal digestion profiles, and altered the potential N to energy synchronization and hourly effective rumen degradation ratio of canola meal in dairy cattle.

Measurement of the Intestinal Digestibility of Rumen Undegraded Protein Using Different Methods and Correlation Analysis

Four methods were adopted, including the mobile nylon bag (MNB) method, modified three-step in vitro (MTS) method, original three-step in vitro (OTS) method, and acid detergent insoluble nitrogen (ADIN) estimating method, to evaluate the intestinal digestibility of rumen undegradable protein (DRUP) of 10 types of concentrates and 7 types of roughages. After correlation analysis to determine the DRUP values using the MNB, MTS, OTS, and ADIN methods, the study aimed to find out appropriate methods to replace the MNB method due to its disadvantages such as high price, long time period, and use of a duodenal T-fistula. Three dairy cows with a permanent ruminal fistula and duodenal T-fistula were used in a single-factor experimental design. The results showed that the determined DRUP values using the MNB method for soybean meal, cottonseed meal, rapeseed meal, sunflower meal, corn germ meal, corn, rice bran, barley, wheat bran, corn fiber feed, Alfalfa (Zhao dong), Alfalfa (Long mu 801), Alfalfa (Long mu 803), grass (North), Grass (Inner Mongolia), corn silage and corn straw were 98.13%, 87.37%, 88.47%, 82.60%, 75.40%, 93.23%, 69.27%, 91.27%, 72.37%, 79.03%, 66.72%, 68.64%, 73.57%, 50.47%, 51.52%, 54.05%, and 43.84%, respectively. The coefficient of determination (R2 = 0.964) of the results between the MTS method and the MNB method was higher than that (R2 = 0.942) between the OTS method and the MNB method. The coefficient of determination of the DRUP values of the concentrates among the in vitro method (including the MTS and OTS methods) and the MNB method was higher than that of the roughage. There was a weak correlation between the determined DRUP values in concentrates obtained from the ADIN method and those from the MNB method, and there was a significant correlation (p<0.01) between the determined DRUP values of the roughage obtained from the MNB method and those obtained from ADIN method. The DRUP values were significantly correlated with the nutritional ingredients of the feeds. The regression equation was DRUP =100.5566+0.4169CP − 0.4344SP − 0.7102NDF − 0.7950EE (R2 = 0.8668, p<0.01; CP, crude protein; SP, soluble protein; NDF, neutral detergent fiber; EE, ether extract). It was concluded that both the MTS method and the OTS may suitable to replace the MNB method for determining the DRUP values and the former method was more effective. Only the ADIN method could be used to predict the values of the roughages but conventional nutritional ingredients were available for all of the samples’ DRUP.

Effect of Heating Method on Alteration of Protein Molecular Structure in Flaxseed: Relationship with Changes in Protein Subfraction Profile and Digestion in Dairy Cows.

This study evaluated the effect of heating methods on alteration of protein molecular structure in flaxseed (Linum usitatissimum L.) in relation to changes in protein subfraction profile and digestion in dairy cows. Seeds from two flaxseed varieties, sampled from two replicate plots at two locations, were evaluated. The seeds were either maintained in their raw state or heated in an air-draft oven (dry heating) or autoclave (moist heating) for 60 min at 120 °C or by microwave irradiation (MIR) for 5 min. Compared to raw seeds, moist heating decreased (P < 0.05) soluble protein (SP) content [56.5 ± 5.55 to 25.9 ± 6.16% crude protein (CP)] and increased (P < 0.05) rumen undegraded protein (RUP) content (36.0 ± 5.19 to 46.9 ± 2.72% CP) and intestinal digestibility of RUP (61.0 ± 2.28 to 63.8 ± 2.67% RUP). Dry heating did not alter (P > 0.05) the protein subfraction profile and rumen degradation kinetics, whereas MIR increased (P < 0.05) the RUP content from 36.0 ± 5.19 to 40.4 ± 4.67% CP. The MIR and dry heating did not alter (P > 0.05) the amide I to amide II ratio, but moist heating decreased (P < 0.05) both the amide I to amide II ratio and α-helix-to-β-sheet ratio. Regression equations based on protein molecular spectral intensities provided high prediction power for estimation of heat-induced changes in SP (R2 = 0.62), RUP (R2 = 0.71), and intestinal digestibility of RUP (R2 = 0.72). Overall, heat-induced changes in protein nutritive value and digestion were strongly associated with heat-induced alteration in protein molecular structures.

Vibrational spectroscopic investigation of heat-induced changes in functional groups related to protein structural conformation in camelina seeds and their relationship to digestion in dairy cows

The objective of this study was to use Fourier transform/infrared-attenuated total reflectance (FT/IR-ATR) molecular spectroscopy to quantify the heat-induced changes in feed protein molecular structures in relation to protein digestion in dairy cows. Camelina seeds were evaluated in this study as a model for feed protein. The seeds were either heated in air-draft oven (dry heating) or in autoclave (moist heating) at 120°C for 60 min or kept as raw (control). The parameters evaluated were Cornell net protein and carbohydrate system (CNCPS) subfractions, in situ ruminal degradation kinetics, intestinal digestibility of rumen undegraded protein (RUP) and protein molecular structures. Moist heating decreased (P &lt; 0.05) the content of total rumen degradable (RDP) crude protein (CP) subfractions and increased the content of total RUP subfractions compared with raw seeds, indicating a significant shift at the site of protein digestion from rumen to post-ruminal tract. The decrease in RDP was mainly related to the marked decrease in rapidly solubilised (PA) and degradable (PB1) fractions, whereas the moderately degradable (PB2) and slowly degradable (PB3) fractions increased, suggesting a decrease in degradation rate of RDP. The in situ rumen incubation study revealed that moist heating decreased (P &lt; 0.05) RDP and increased (P &lt; 0.05) RUP and its intestinal digestibility. The molecular spectroscopy study revealed that moist heating altered protein molecular structures. Except PA and lag time, dry heating did not significantly alter any of the CNCPS CP subfraction, in situ ruminal CP degradation parameters, intestinal digestibility of RUP, and protein molecular structures. The correlation analysis showed that the heat-induced changes in protein secondary structures, α-helix-to-β-sheet ratio, were positively correlated (P &lt; 0.05) with the contents PA (r = 0.90), PB1 (r = 0.89), RDP (r = 0.72) and intestinal digestibility (r = 0.91) of RUP, and negatively correlated (P &lt; 0.05) with PB2 (r = –0.90), PB3 (r = –0.85) and RUP (–0.87). These results showed that compared with dry heating, moist heating significantly changed protein subfractions, rumen degradability and intestinal digestibility, and these changes were strongly associated with changes in protein molecular structures.

Ruminal degradation and intestinal digestibility of protein and amino acids in high-protein feedstuffs commonly used in dairy diets

A study was conducted to determine the rumen degradation and intestinal digestibility of crude protein (CP) and AA, and AA composition of the rumen-undegradable protein (RUP) from 3 sources of blood meal (BM1, BM2, and BM3), canola meal (CM), low-fat distillers dried grains with solubles (LFDG), soybean meal (SBM), and expeller soybean meal (ESBM). Two Holstein cows fitted with ruminal and proximal duodenal cannulas were used for in situ incubation of 16h and for the mobile bag technique. To correct for bacterial contamination of the RUP, 2 methods were used: purines and DNA as bacterial markers. Ruminal degradations of CP were 85.3, 29.8, 40.7, 75.7, 76.9, 68.8, and 37.0±3.93% for BM1, BM2, BM3, CM, LFDG, SBM, and ESBM, respectively. Ruminal degradation of both total essential AA and nonessential AA followed a similar pattern to that of CP across feedstuffs. Based on the ratio of AA concentration in the RUP to AA concentration in the original feedstuff, ruminal incubation decreased (ratio <1) the concentrations of His, Lys, and Trp, and increased (ratio >1) the concentrations of Ile and Met across feedstuffs. Compared with purines, the use of DNA as bacterial marker resulted in a higher estimate of bacterial CP contamination for CM and lower estimates for LFDG and ESBM. Intestinal digestibility of RUP could not be estimated for BM1, BM3, and SBM due to insufficient recovery of residue. For the remaining feedstuffs, intestinal digestibility of RUP was highest for ESBM, followed by BM2 and LFDG, and lowest for CM: 98.8, 87.9, 89.7, and 72.4±1.40%, respectively. Intestinal absorbable dietary protein was higher for BM2 compared with CM and LFDG, at 61.7, 17.9, and 20.7±2.73% CP, respectively. As prices fluctuate, intestinal absorbable protein or AA may be used as a tool to aid in the selection among feedstuffs with different protein quality.