Intestinal Crude Protein Digestibility Research Articles

Comparative evaluation of nutrient composition, in vitro nutritional value, and antioxidant activity of de-oiled meals from walnut, hazelnut, almond, and sesame.

This study aimed to establish a comparative database on the chemical composition, in vitro nutritional value, and antioxidant activity of the de-oiled meals produced from walnut, hazelnut, almond, and sesame seeds from the ruminant nutrition perspective. The meals were provided in dried form after their oil harvest using the cold-pressing oil extraction method. Crude protein (CP) constituted the major component of the meals and was the greatest in walnut and almond (average of 45.6% of dry matter (DM)], intermediate in hazelnut meal (41.4%), and least in sesame meal (33.3%)). Potassium was the most abundant mineral in walnut, hazelnut, and almond meals, followed by phosphorus, calcium, and magnesium. The CP fractions determined using the Cornell Net Carbohydrate and Protein System were largely different across the meals, with fraction A being the greatest in hazelnut (40.9% of CP) and intermediate in almond, sesame, and walnut meals (11.4% of CP). The unavailable CP fraction (fraction C) was the least abundant fraction in all meals, ranging from 0.13% of CP in walnut to 3.30% of CP in hazelnut meal. Oleic and linoleic acids were the predominant unsaturated fatty acids, and palmitic acid was the principal fatty acid in all meals analyzed. The fractional degradation rate (h-1) ranged from 0.043 in almond meal to 0.017 in walnut meal. In vitro intestinal CP digestibility (% of rumen-undegraded protein) ranged from 91.6 in hazelnut meal to 97.2 in almond meal. Total phenolics expressed as milligram tannic acid equivalent/gram DM was greatest in walnut meal (11.9), resulting in the greatest antioxidant activity recorded for walnut meal (83.2%). This study provided a database on the nutrient composition, in vitro nutritional value, and antioxidant capacity of the selected de-oiled meals. Additional investigation is needed to identify the in vivo response of their inclusion in the diet of ruminants.

In Vitro Rumen Fermentation and Post-Ruminal Digestibility of Sorghum-Soybean Forage as Affected by Ensiling Length, Storage Temperature, and Its Interactions with Crude Protein Levels.

The study aimed to evaluate the effects of ensiling length, storage temperature, and its interaction with crude protein (CP) levels in sorghum−soybean forage mixtures on in vitro rumen fermentation and post-ruminal digestibility of nutrients. The dietary treatments consisted of fresh forages (d 0) and silages of sorghum and soybean stored indoors or outdoors for 75 and 180 d with additional ingredients to make two dietary CP levels, 90 and 130 g/kg dry matter (DM) and a forage-to-concentrate ratio of 80 to 20. An in vitro procedure was conducted using the ANKOM RF technique to study rumen fermentation. The dietary treatments were incubated in duplicate for 8 and 24 h in three runs. After each incubation time, in vitro rumen fermentation parameters were measured, and the protozoa population was counted using a microscope. Post-ruminal digestibility was determined using the pepsin and pancreatic solubility procedure. Cumulative gas production (GP) increased quadratically with ensiling length (8 h, p < 0.01; 24 h, p = 0.02), and the GP differed between CP levels at both incubation times (p < 0.01). However, total short-chain fatty acid (SCFA) concentrations in rumen inoculum increased quadratically with ensiling length (p < 0.01; for both incubation times), and interaction between ensiling length and CP levels was observed in proportions of acetate and propionate after 24 h of incubation (p < 0.01; for both incubation times). Similarly, an interaction between ensiling length and CP levels was found in the proportion of valerate after 24 h of incubation (p < 0.01). There was a quadratic response to ensiling length in the NH4−N concentration after 8 h (p < 0.01) and 24 h (p < 0.05), and the CP level also differed (p < 0.01) at both incubation times. The ciliate protozoa count after 24 h was higher in low CP diets than in high CP diets (p = 0.04). The amount of CP in the undegraded substrate at both incubation times differed between CP levels (p < 0.01; for both incubation times). An interaction effect between ensiling length and storage temperature after 8 h (p = 0.02) and 24 h (p < 0.01) was observed for intestinal CP digestibility. The effect of CP levels on intestinal CP digestibility differed after 8 h (p < 0.01) and 24 h (p < 0.01). In conclusion, increasing ensiling length beyond 75 d reduced CP digestibility, and additional CP inclusion did not ameliorate this.

Diets for Dairy Cows with Different Proportions of Crude Protein Originating from Red Clover Silage versus Soybean Meal: Ruminal Degradation and Intestinal Digestibility of Amino Acids.

Simple SummaryThe purpose was to assess the effect of exchanging crude protein of soybean meal with red clover silage (RCS) in total mixed rations (TMR) on ruminal degradation and intestinal digestibility (ID) of essential amino acids (EAA). Increasing proportions of RCS in the TMR increased the ruminal degradation and reduced the ID of EAA. The ruminal degradation of EAA of the TMR followed that of CP, but the ID of EAA differed from that of CP at higher levels of RCS in the diet. In conclusion, increasing proportions of RCS in TMR reduced the extent of EAA flow into the small intestine, reduced the ID of EAA, and consequently the intestinal absorbable EAA.The purpose was to assess the effect of exchanging crude protein (CP) of soybean meal (SBM) with red clover silage (RCS) in total mixed rations (TMR) on ruminal degradation and intestinal digestibility (ID) of essential amino acids (EAA). Four TMR and their individual feed components were studied. The TMR were composed of forage and concentrates (75:25), with proportions of RCS in TMR of 0.15, 0.30, 0.45, and 0.60 on a dry matter basis, resulting in diet groups RCS15, RCS30, RCS45, and RCS60, respectively. The ruminal degradation of EAA was determined using the nylon bag technique. For this, samples of TMR and their individual feed components were ruminally incubated for 16 h. The feed residues of TMR obtained after 16 h of incubation were used for the determination of ID of EAA using the mobile-bag technique. Increasing RCS and reducing SBM proportions linearly increased (p < 0.01) the in situ ruminal degradation of individual EAA from 75.5% to 83.5%. The degradation of EAA followed the trend of CP degradation among TMR, except for Cys that was lower (p < 0.05) than that of CP in RCS60 (79.7% vs. 86.3%). The degradation of EAA in individual feed ingredients not always corresponded to the degradation of CP and was feed dependent. Increasing the proportions of RCS in the TMR linearly reduced (p < 0.001) the ID of EAA (except for Ile) from 78.2% to 67.3%. However, the ID of EAA did not always reflect the ID of CP, and in general, the differences between the ID of CP and EAA increased as RCS increased in the TMR. The ID values of most of the EAA were similar (p > 0.05) to ID of CP in RCS15 and RCS30, while they mostly differed (p < 0.05) in RCS45 and RCS60, and being higher for EAA than CP (except for Cys that was lower than CP, p < 0.05). Similar trends were observed for intestinal absorbable AA, resulting in higher values (p < 0.05) of intestinal absorbable for all EAA than of CP in diet RCS60. In conclusion, increasing levels of RCS in TMR reduced the extent of EAA flow into the small intestine, the ID of EAA, and consequently the intestinal absorbable EAA. Therefore, accurate determination of metabolizable AA must be considered for optimal diet formulation when including high proportions of RCS in diets of high-producing dairy cows.

PSVII-35 Late-Breaking Abstract: Microwave heat treatment feed effect on ruminal degradability and intestinal protein digestibility - a brief review

Abstract Rumen degradability of crude protein (CP) of feed is a major factor that determines the utilization of CP in ruminant production. This study briefly reviewed the findings from six international studies of microwave (MW) heat treatment effect on feed CP rumen degradability and intestinal CP digestibility. Six in vitro studies of concentrate feed (canola seed, canola meal, soya bean meal, cottonseed meal, corn, and barley) showed a decrease in effective rumen degradability of dry matter and protein by 4–40% and 17–40%, respectively compared to control group (untreated concentrate feed). Among the six studies, four studies identified the MW heat treatment effect on intestinal protein digestibility. Due to MW heat treatment, canola seed, canola meal, soya bean meal, and cottonseed meal showed an increase in intestinal CP digestibility by 17%, 20%, 21%, and 19%, respectively. Overall the briefly reviewed studies showed that, MW heat treatment substantially reduced feed CP ruminal degradability and increased in vitro CP digestibility of ruminally undegraded CP.

Effect of heat processing methods on the protein molecular structure, physicochemical, and nutritional characteristics of faba bean (low and normal tannin) grown in western Canada

This study aimed to determine the heat processing impact on the protein molecular structure (amide I, amide II, α-helix, and β-sheet), and the nutritional characteristics (nutrient profiles, rumen degradation, intestinal digestion, and true protein supply) of faba bean grown in western Canada. Low tannin (LT) and normal tannin (NT) faba bean varieties were used for the present study, where varieties (n = 3) for each tannin level were used as a replicate. Based on previously published studies, sample groups were either heated with steam pressure at 121 °C for 30 minute (min) using a medium steam sterilizer or with microwave irradiation for 3 min in a conventional microwave with a power of 900 W and irradiation frequency of 2450 MHz. All seed was ground using a roller mill before heating. Heat-induced molecular structure changes were determined with Fourier Transformed Infrared spectroscopy (FTIR) while nutrient profiles, including dry matter (DM), crude protein (CP), soluble crude protein (SCP), and starch were obtained with traditional chemical analyses. An in situ rumen degradation study and a modified three-step in vitro technique was performed to analyze the degradation parameters and intestinal digestibility of feed nutrients in faba bean. Results showed that the peak area ratio of amide I to amide II was lower in normal tannin faba bean types (1.835 vs. 2.073 absorbance units (AU), P < 0.0001) compared to low tannin faba bean types with both heat treatments, while the peak height ratio of α-helix to β-sheet was higher in normal tannin types (1.249 vs. 1.090 AU, P < 0.0001) relative to low tannin types. Additionally, steam pressure reduced the SCP (45 vs. avg. 188 g/kg DM, P < 0.01), and increased the intestinal digestibility of crude protein (dIDP, 0.89 vs. avg. 0.79, P = 0.03) compared to other treatments. The truly absorbed protein supply in the small intestine was higher with steam pressure (DVE, 180 vs. 130 and 117 g/kg DM, P < 0.01) relative to the control and microwave irradiation, respectively. The feed milk value was higher with steam pressure (FMV, 3.65 vs. 2.65 and 2.38 kg milk/kg DM feed, P < 0.01) compared to the control and microwave irradiation, respectively. In the present study, steam pressure reduced the soluble crude protein and the effective degraded crude protein, increasing the truly digested protein in the small intestine more than microwave irradiation. These results suggest that steam pressure toasting of faba bean was a better treatment to improve protein degradability and supply in dairy cattle compared to microwave irradiation.

Effect of heat-treated canola meal and glycerol inclusion on performance and gastrointestinal development of Holstein calves

The objectives of this study were to assess the effect of using heat-treated canola meal (CM) and glycerol inclusion in starter mixtures on starter intake, growth, and gastrointestinal tract development in Holstein bull calves. In the first study, a protocol for the heat treatment of CM was evaluated by comparing commercial CM that was exposed to 0, 100, 110, or 120°C of heat treatment for 10 min. Following heat treatment, in situ crude protein (CP) ruminal degradability and estimated intestinal CP digestibility were assessed. It was observed that the degradable fractions of dry matter and CP in CM decreased linearly with increasing temperature of heat treatment. The estimated intestinal CP digestibility was greatest when CM was heated to 110°C. In the second study, 28 bull calves were used in a randomized complete block design. Calves were fed pelleted starters containing CM or CM that was heat-treated to 110°C for 10 min. Diets also contained 0 or 5% glycerol on a dry matter basis. The study lasted 51 d, ending on the first day of weaning. Starter intake, average daily gain (ADG), ruminal short-chain fatty acid concentrations, morphology of the rumen and small intestine, gene expression (MCT1, GPR41, GPR43, UTB, AQP3, PEPT1, PEPT2, ATB0+, and EAAC1) in the ruminal, jejunal, and ileal epithelium, and brush border enzyme activities in the duodenum, jejunum, and ileum were investigated. Few interactions between heat-treated CM and glycerol inclusion were observed. Feeding heat-treated CM did not affect starter intake. However, feeding heat-treated CM to calves tended to reduce ADG and decreased the weight of ruminal and jejunal tissue. Heat treatment did not affect gene expression or brush border enzyme activities in the small intestine. Glycerol inclusion tended to increase cumulative starter intake and increased cumulative body weight gain. Use of glycerol reduced ruminal pH and increased the concentration of ruminal short-chain fatty acids. Additionally, glycerol inclusion increased abomasal, duodenal, jejunal, and cecal digesta weights and tended to increase the weight of the jejunal tissue. Glycerol supplementation tended to downregulate the expression of MCT1 in the ruminal epithelium, and upregulated the expression of MCT1 in the epithelium of proximal jejunum. In conclusion, heat treatment of CM may negatively affect calf growth and gastrointestinal tract development. Glycerol inclusion may increase starter intake, ADG, ruminal fermentation, and intestinal development in calves when CM is used as a main source of protein in pelleted starter mixture.

Ruminal fermentation kinetics of Moringa oleifera leaf and seed as protein feeds in dairy cow diets: in sacco degradability and protein and fiber fractions assessed by the CNCPS method

The present study aimed to evaluate in sacco fermentation kinetics of Moringa oleifera leaf meal (MOL), whole seeds (MOS), and partially (PDMM) or completely defatted seed meal (DMM). Four dry non-lactating cows (Holstein–Friesian cows, weighing 600 kg, 4 years old), with rumen cannula and T-cannula installed in the distal duodenum were used for the study. The cows were fed a mixed forage (17 kg maize silage and 4.5 kg alfalfa hay) and concentrate diet at 7:3, respectively. Samples were incubated in nylon bags (in sacco) for 3, 6, 9, 16 and 24 h. Proximate analysis showed that DMM and PDMM had greater concentrations of crude protein (CP) and fiber compared with MOL and MOS. Lower concentrations of condensed tannins were noted in both MOL and DMM compared to MOS and PDMM. Oleic acid was the most abundant fatty acid in both MOL and MOS. The Cornell Net Carbohydrate and Protein System analysis showed that MOL followed by MOS had more non-protein nitrogen; however, MOS and PDMM had more true soluble protein compared with MOL and DMM. Numerically, more intermediate and low degradable protein were observed with DMM. Results showed that MOL had the highest (P < 0.05) rate of CP disappearance, effective degradability and intestinal digestibility of CP. Whole MOS had the highest (P = 0.045) lag time for CP disappearance; however, MOL had the highest DM disappearance value. M. oleifera leaves, MOS and PDMM had greater effective degradability (P < 0.001) compared to DMM. It could be concluded that MOL showed better protein nutritive value compared with MOS, DMM or PDMM, and the use of MOL is recommended for practical application.

Protein value of diets for dairy cows with different proportions of crude protein originating from red clover silage versus soybean meal

The objective of this study was to evaluate the effect of replacing crude protein (CP) of soybean meal (SBM) with red clover silage (RCS) in total mixed rations (TMR) on ruminally undegraded feed CP (RUP) and intestinal digestibility (ID) of RUP. Four TMR were formulated to replace CP from SBM with RCS. The TMR was comprised of forage and concentrates (0.75:0.25), with ratios of RCS in TMR of 0.15, 0.30, 0.45, and 0.60 on a dry matter (DM) basis. The ruminal degradation of CP was determined using the nylon bag technique. For this, samples of TMR were incubated for 2, 8, 16, 24, 32 and 72 h. The RUP content of TMR was estimated using passage rates of 2, 5 and 8%/h. Additionally, samples of TMR were incubated in the rumen for 16 h, and their feed residues were used for determination of ID of RUP using the mobile-bag technique. For in situ ruminal degradation, increasing RCS and reducing SBM proportions increased linearly the rapidly degradable CP (a) from 26.2 to 212 g/kg CP (P < 0.001). The potentially degradable CP (b) decreased linearly from 810 to 676 g/kg CP (P < 0.001). Assuming a passage rate of 8%/h, RUP reduced linearly from 315 to 253 g/kg CP (P < 0.001). The ID of RUP reduced linearly from 760 to 574 g/kg CP (P < 0.001) with increasing RCS levels. Although differences in ruminal CP degradation and ID of RUP were apparently caused by differences in the proportion of RCS and SBM, neither linear nor quadratic effects on total tract digestible CP were observed (P = 0.22 and 0.21, respectively), and averaged 943 g/kg CP among all TMR tested. This suggests that increasing RCS and decreasing SBM proportion shifted the site of CP utilization. The CP degraded in the rumen increased, and the amount of intestinally absorbable RUP reduced linearly from 184 to 79 g/kg CP (P < 0.001). In general, replacing CP from SBM with RCS in the TMR reduced its protein value. It is concluded, that an almost complete replacement of CP from SBM by RCS in rations of high-yielding dairy cows cannot be recommended. However a replacement rate up to 0.30 does not lead to a substantial reduction in RUP supply and digestibility, and therefore considerably reduces the use of SBM.

Molecular spectroscopic features of protein in newly developed chickpea: Relationship with protein chemical profile and metabolism in the rumen and intestine of dairy cows

The first aim of this study was to investigate the nutritional value of crude protein (CP) in CDC [Crop Development Centre (CDC), University of Saskatchewan] chickpea varieties (Frontier kabuli and Corinne desi) in comparison with a CDC barley variety in terms of: 1) CP chemical profile and subfractions; (2) in situ rumen degradation kinetics and intestinal digestibility of CP; 2) metabolizable protein (MP) supply to dairy cows; and (3) protein molecular structure characteristics using advanced molecular spectroscopy. The second aim was to quantify the relationship between protein molecular spectral characteristics and CP subfractions, in situ rumen CP degradation characteristics, intestinal digestibility of CP, and MP supply to dairy cows. Samples (n=4) of each variety, from two consecutive years were analyzed. Chickpeas had higher (P<0.01) CP content (21.71–22.11 vs 12.96% DM), with higher (P<0.05) soluble CP subfraction (59.07–70.27 vs 26.18% CP), and in situ soluble (23.44–25.85 vs 1.30% CP) and rumen degradable (RDP; 72.23–72.57 vs 58.48% CP) fractions than barley. The potentially slowly rumen degradable (D; 74.14–76.56 vs 93.31% CP) and undegradable (RUP; 27.43–27.66 vs 41.52% CP) fractions were lower (P<0.01) in the chickpeas than barley. The effective degradability ratio of N to organic matter (OM) (36.07–38.44gN/kg OM) of the chickpeas was higher than the optimal for achieving optimum microbial CP (MCP) synthesis. The truly digested MCP (64.94–66.43 vs. 41.43g/kg DM); MP (81.10–83.67 vs 61.0g/kg DM) feed milk value (1.64–1.70 vs 1.24) was higher in the chickpeas than barley grain. The chickpeas had higher (P<0.05) amide I and II peaks area and height, and α-helix and β-sheet peaks height than barley. Multivariate analysis showed that protein molecular spectral data of chickpeas can be distinguished from the barley. The two chickpeas did not differ in CP content, and any of the measured in situ degradation and molecular spectral characteristics of protein. The content of RUP was positively (r=0.94, P<0.01) and that of RDP was negatively (r=−0.94, P<0.01) correlated with amide I/II area ratio. The regression analysis showed that the content of CP (R2=0.91) D-fraction (R2=0.82), RDP (R2=0.77), RUP (R2=0.77), TDP (R2=0.98), MP (R2=0.80), and FMV (R2=0.80) can be predicted from amide II peak height. Despite extensive ruminal degradation, chickpea is a good source of MP for dairy cows, and molecular spectroscopy can be used to rapidly characterize feed protein molecular structures and predict their digestibility and nutritive value.

In vitro microbial protein synthesis, ruminal degradation and post-ruminal digestibility of crude protein of dairy rations containing Quebracho tannin extract.

This study evaluated the effects of Quebracho tannin extract (QTE) on in vitro ruminal fermentation, chemical composition of rumen microbes, ruminal degradation and intestinal digestibility of crude protein (iCPd). Three treatments were tested, the control (basal diet without QTE), the basal diet with 15g QTE/kg dry matter (DM) and the basal diet with 30g QTE/kg DM. The basal diet contained (g/kg DM): 339 grass silage, 317 maize silage and 344 concentrate. In vitro gas production kinetic was determined using the Hohenheim gas test (Experiment 1). The Ankom RF technique, a batch system with automatic gas pressure recordings, was used to determine in vitro production of short-chain fatty acids (SCFA) and ammonia-nitrogen concentration (NH3 -N), as well as nitrogen and purine bases content in liquid-associated microbes (LAM) and in a residue of undegraded feed and solid-associated microbes (Feed+SAM) (Experiment 2). Ruminal degradation and iCPd were determined using the nylon bag technique and the mobile nylon bag technique, respectively (Experiment 3). Gas production (Experiment 1), total SCFA and NH3 -N (Experiment 2) decreased with increasing QTE levels. Microbial mass and composition of LAM were not affected by QTE, but total mass of Feed+SAM linearly increased, likely due to decreased substrate degradation with increasing QTE levels. The total amount of N in microbial mass and undegraded feed after the in vitro incubation increased with increasing QTE levels, suggesting a potential greater N flow from the rumen to the duodenum. In contrast to in vivo studies with the same QTE, no effects were detected on ruminal effective degradability and iCPd, when using the nylon bag techniques. Based on the in vitro procedures, QTE increased the supply of N post-rumen; however, some evidence of a decreased fibre degradation were also observed. Therefore, the benefit of adding QTE to diets of cattle is still questionable.

Effect of conventional and extrusion pelleting on in situ ruminal degradability of starch, protein, and fibre in cattle

Rumen degradability kinetics was investigated for pelleted compound concentrates differing in physical functional properties of pellets. Six compound concentrate meals were produced containing either 100% wheat, 100% maize, 50% wheat+50% soybean meal (SBM; as is basis), 50% maize+50% SBM, 50% wheat+50% sugar beet pulp (SBP), or 50% maize+50% SBP. Meals were pelleted by either conventional pelleting, or by cooking extrusion using two distinct settings giving pellets with either high density (HD) or low density (LD). Ruminal degradation of starch, crude protein (CP) and NDF, and intestinal digestibility of CP were evaluated using in situ methods in cattle. Overall, processing (pelleting, extruding HD, or extruding LD) increased effective starch degradability (ESD) of pure maize and maize mixtures. The ESD increased with intensity of processing (Extruding LD>Extruding HD>Pelleting>Meal). In contradiction, ESD for pure wheat and wheat mixtures was reduced, though differences were minor. Conventional pelleting reduced the effective protein degradability (EPD) for pure wheat, but extrusion did not further affect the EPD. In contrast, the most intense processing with extrusion LD increased EPD for pure maize. Processing reduced EPD in both cereal+SBM mixtures, and further, the most intense processing with extruding LD led to the lowest EPD in cereal+SBM mixtures. In contrast, extruding increased EPD in both cereal+SBP mixtures as compared with meal and pelleting, but extruding with steam addition did not further increase the EPD. Compared to meal and pelleting, extruding without steam addition increased the effective NDF degradability for maize+SBP. The observed responses in EPD were not associated with decreases in CP disappearances from mobile bags. In conclusion, pelleting and extrusion affected ruminal degradability of starch, protein, and NDF differently depending on both type of cereal and composition of the concentrate mixture.

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.

An assessment of differences in the ruminal degradability and intestinal digestibility of crude protein in brewer's grains and maize draff

The submitted thesis aims to assess the differences between the ruminal degradability and intestinal digestibility of crude protein contained in brewer’s grains (BG) and maize draff (AMG). The effectiveness of ruminal degradability was tested using the “in sacco” method on 3 dry Holstain cows fitted with rumen cannulas. The dynamics of ruminal degradability of crude protein (CP) was detected after 0, 4, 8, 16, and 24 hours of samples incubation in the rumen. The intestinal digestibility of crude protein undegradable in the rumen was determined using the “mobile bag” method on 3 dry Holstain cows fitted with duodenal cannulas. The crude protein degradability of BG was detected in the above-mentioned hours (%): 4.06; 18.16; 32.40; 38.56, and 50.70; crude protein degradability of AMG: 42.04; 63.56; 84.47; 85.16, and 87.19. The effectiveness of rumen degradability of BG crude protein at the rate of passage of rumen content 6 % per hour was calculated at 35.33 % and that of AMG, at 76.29 %. Intestinal digestibility of BG crude protein and dry matter at the rate of passage of intestinal content 6 % per hour was calculated at 79.41 % and 22.84 %, respectively, and that of AMG, at 57.01 % and 11.33 %, respectively. The differences between the indicators of both feedstuffs were significant (P &lt; 0.05). The results show that BG are mostly a source of crude protein with higher intestinal digestibility than AMG.

Intake and ruminal digestion determined using omasal and reticular digesta samples in cattle fed diets containing sugar cane in natura or ensiled sugar cane compared with maize silage

Sugar cane is widely used in an in natura forage in tropical countries, but the adoption of silage methods facilitates the preservation of its nutritional value and improves the logistics of its use. To explain differences in performance using alternative forages, it is important to conduct studies that evaluate the various digestion sites for the nutrients provided in diets. However, considering that the collection of omasal digesta is quite laborious and requires the use of a vacuum pump, reticular sampling has been suggested as a promising alternative. Thus, the objective of this study was to evaluate the intake and ruminal digestibility obtained from samples of digesta collected in the reticulum and omasum of cattle fed different diets. Five rumen-fistulated crossbred cattle with an average initial live weight of 336±16.6kg were used, being distributed in a 5×5 Latin square design. Five diets were evaluated, which contained 60% forage and 40% concentrate on dry matter basis using different forages: maize silage (CS); sugar cane in natura (SCIN); sugar cane silage (SCS0%); sugar cane silage treated with 0.4% calcium oxide (SCS0.4%) or 0.8% calcium oxide (SCS0.8%) on wet basis. The percentage of crude protein (CP) in all of the forages was corrected to 11% based on dry matter (DM) using a mixture of urea/ammonium sulfate (9:1). Six collections of reticular and omasal digesta were obtained over three days at 12h intervals. To calculate the flow of reticular and omasal nutrients, a double marker system was employed, using cobalt–EDTA and indigestible neutral detergent fiber (NDFi) as markers. The reticular and omasal digesta were similar (P>0.05) to estimate ruminal digestibility of DM, organic matter (OM), CP, neutral detergent fiber (NDF) and non-fiber carbohydrates (NFC). However, the ruminal digestibility of ether extract (EE) and the intestinal digestibility of CP and EE differed (P<0.05) between sampling sites. The results indicate that the omasal digesta is more suitable than the reticular digesta for measuring the ruminal digestion of diet components.

English

&nbsp; Samples of common vetch (CV), bitter vetch (BV) and chickling vetch (CLV) were collected and determined for chemical composition, rumen degradability and the effect of particle losses and intestinal digestibility of crude protein by using&nbsp;in situ-in vitro&nbsp;and&nbsp;in vitro&nbsp;techniques. In addition, the apparent digestibility of experimental diets was stated in Iranian hybrids sheep. The results showed the high protein concentration for CV (278 g/kg dry matter) and low concentration for BV (255 g/kg dry matter). The rapidly degradable and effective degradability of protein for legumes ranged from 0.40 to 0.51 and 0.72 to 0.76, respectively, and following correction for particle losses, the values for the rapidly degradable protein fraction were lower (from 0.16 to 0.17) than those found without correction. Different intestinal digestibility values were obtained with both procedure significant relationship between them (Y = 2.170X - 129.5, R&sup2; = 0.469, P = 0.0139, SEM = 5.545). There were no differences in the apparent digestibility of dry matter (DM), crude protein (CP), ether extract (EE) and energy among diets. Neutral&nbsp;detergent fiber (NDF) and acid detergent fibre (ADF) digestibility was lowest (P &lt; 0.05) when&nbsp;soybean meal&nbsp;(SBM) was replaced with BV and CV seeds, respectively. The presence of anti-nutritional factors (ANFs) and structural substances of cell wall also may affect the NDF and ADF digestibility of these feeds. Based on the results of the current study, it might be concluded that legume grains cannot be considered in high production ruminant diet due to more rumen undegradable protein requirement. &nbsp; Key words:&nbsp;Degradability, intestinal digestion, Lathyrus sativus, Vicia ervilia, Vicia sativa.

Effects of Temperature during Moist Heat Treatment on Ruminal Degradability and Intestinal Digestibility of Protein and Amino Acids in Hempseed Cake.

The objective of this study was to evaluate ruminal degradability and intestinal digestibility of crude protein (CP) and amino acids (AA) in hempseed cake (HC) that were moist heat treated at different temperatures. Samples of cold-pressed HC were autoclaved for 30 min at 110, 120 or 130°C, and a sample of untreated HC was used as the control. Ruminal degradability of CP was estimated, using the in situ Dacron bag technique; intestinal CP digestibility was estimated for the 16 h in situ residue using a three-step in vitro procedure. AA content was determined for the HC samples (heat treated and untreated) of the intact feed, the 16 h in situ residue and the residue after the three-step procedure. There was a linear increase in RUP (p = 0.001) and intestinal digestibility of RUP (p = 0.003) with increasing temperature during heat treatment. The 130°C treatment increased RUP from 259 to 629 g/kg CP, while intestinal digestibility increased from 176 to 730 g/kg RUP, compared to the control. Hence, the intestinal available dietary CP increased more than eight times. Increasing temperatures during heat treatment resulted in linear decreases in ruminal degradability of total AA (p = 0.006) and individual AA (p<0.05) and an increase in intestinal digestibility that could be explained both by a linear and a quadratic model for total AA and most individual AA (p<0.05). The 130°C treatment decreased ruminal degradability of total AA from 837 to 471 g/kg, while intestinal digestibility increased from 267 to 813 g/kg of rumen undegradable AA, compared with the control. There were differences between ruminal AA degradability and between intestinal AA digestibility within all individual HC treatments (p<0.001). It is concluded that moist heat treatment at 130°C did not overprotect the CP of HC and could be used to shift the site of CP and AA digestion from the rumen to the small intestine. This may increase the value of HC as a protein supplement for ruminants.

Postruminal degradation of crude protein, neutral detergent fibre and starch of maize and grass silages in dairy cows

The Dutch feed evaluation system for ruminants uses assumptions and regression equations to estimate the intestinal digestibility of crude protein (CP), neutral detergent fibre (NDF) and starch. These assumptions and equations are based on many different studies, obtained over a very long period. The objective of this study was to develop a unique dataset on the ruminal degradability and the postruminal digestibility of CP, NDF (aNDFom, amylase neutral detergent fibre organic matter basis) and starch in maize and grass silages, using the mobile nylon bag technique. Twenty samples of maize silage and 20 samples of grass silage were used. The samples were selected to represent a broad range in digestibility and chemical composition. Prior to the intestinal incubations, samples were incubated in the rumen for 6h (starch), 12h (CP) or 24h (aNDFom) using the rumen nylon bag technique. Residues from the rumen incubations were transferred to mobile nylon bags and inserted in the duodenum through a cannula. Half of the bags for CP and starch were collected from the ileal cannula and the remaining half of the bags from the faeces. For aNDFom, all the bags were collected from faeces. There was a large variation in the rumen degradability and the intestinal digestibility (small and/or large intestine) of CP, aNDFom and starch. The rumen degradable fractions, the intestinal digestible fractions and the total tract undigested fractions of CP, aNDFom and starch were influenced by their proportions in the maize and grass silages. The results proved the assumption of the Dutch feed evaluation system that the rumen undegraded starch is completely digested in the small intestine of dairy cows. Regression showed that the rumen degradability, the intestinal digestibility and the total tract undigested contents were influenced by the chemical composition of the maize and grass silages.

Effect of Mobile Bag and Sample Sizes on Intestinal Digestibility of Forage in Sheep

This study aimed to clarify the effect of mobile bag size and ratio of sample size to bag surface area on intestinal digestibility of forage in sheep. Four Suffolk ewes fitted with ruminal and proximal duodenal cannulae were fed second-cut Italian rye- grass (Lolium multiflorum Lam.) hay twice daily, and the same forage was used to measure intestinal digestibility. The forage samples were incubated in the rumen for 16 h and then in pepsin-HCl solution for 3 h before intestinal incubation. The incubated forage samples were placed in a nylon mobile bag. The bag sizes used were either 20 mm×20 mm (small bag size; SBS) or 30 mm×30 mm (large bag size; LBS) and the ratio of the sample size to the surface area of the bag was either 5.5 mg/cm 2 (low ratio; LR) or 11.0 mg/cm 2 (high ratio; HR) resulting in four different treatment conditions: SBS-LR, SBS-HR, LBS-LR and LBS-HR. Eight bags per animal were inserted through the duodenal cannulae at 15-min intervals and were subsequently collected from the feces of the animal. The mean intestinal bag transition time did not differ significantly between animals, but ranged from 23.2 to 27.0 h. The intestinal digestibility of dry matter (IDDM) ranged from 0.162±0.019 g/g in the SBS-HR treatment group to 0.195±0.018 g/g in the SBS-LR treatment. The intestinal digestibility of crude protein (IDCP) ranged from 0.610±0.031 g/g in the LBS-LR treatment to 0.693±0.018 g/g in the SBS-LR treatment. There was no difference in the IDDM and IDCP between different treatments. It was therefore concluded that the size of the mobile bag and the ratio of the sample size to the bag surface area did not influence the intestinal digestibility of forage. Future studies

Effects of pressure toasting on in situ degradability and intestinal protein and protein‐free organic matter digestibility of rapeseed

AbstractBACKGROUND: Rapeseed is a protein supplement that contains up to 40% crude protein (CP) on a dry matter (DM) basis, but a large part of its protein can be easily degraded in the rumen. Therefore, before inclusion in ruminant's diet, the extent of its protein degradation in the rumen must be reduced without altering its intestinal digestibility. A study was conducted to investigate the effects of pressure toasting (T, 130 °C) at two residence times (1.5 and 10 min) alone or in combination with soaking in water (ST, 4 h) on ruminal degradability and intestinal digestibility of CP and protein‐free organic matter (PFOM) in whole full‐fat rapeseed.RESULTS: Regardless of the processing time (1.5 or 10 min), T significantly (P &lt; 0.05) increased the fraction of undegraded intake protein (UIP) compared to the untreated rapeseed samples. Soaking prior to further toasting did not improve the rumen degradation characteristics of rapeseed CP. Compared to the untreated rapeseed samples, both T and ST significantly (P &lt; 0.0001) improved the true protein digested in the small intestine (DVE) and degraded protein balance (OEB), effects that were more evident in samples heated for 10 min. Soaking prior to pressure toasting, however, did not further improve the DVE or OEB in the rapeseed samples in comparison with T treatment.CONCLUSIONS: It was concluded that ruminal protein degradability of rapeseed decreased after pressure toasting, without seriously affecting its intestinal digestibility. Copyright © 2008 Society of Chemical Industry

Ruminal and Intestinal Degradability of Distillers Grains plus Solubles Varies by Source

Currently in the dairy industry, there is a concern about the variability in the nutrient content among sources of distillers grains plus solubles (DG), but little research has evaluated the variability in metabolizable AA among sources. The ruminal degradability of crude protein (CP) in soybean meal (SBM), dried DG from 5 sources (DG1, DG2, DG3, DG4, and DG5), and 1 source of wet DG (WDG) were determined using 2 lactating ruminally cannulated Holstein cows. Feeds were incubated in the rumen for 3, 6, 12, 18, 24, and 36h. Intestinal CP digestibility via pepsin and pancreatin and AA profiles were measured on residue from 12-h ruminal incubation of feeds. Ruminal undegradable protein (RUP) was less for SBM (46.4%) than for DG. The WDG (53.6%) had less RUP than dried DG. The RUP concentrations of DG3 (59.1%) and DG5 (60.3%) were lower than DG1 (71.7%) and DG4 (67.5%), with DG1 having more than DG2 (63.7%) and DG4. Intestinal digestibility of RUP was greater for SBM (86.7%) than DG. The DG2 (76.8%) and DG3 (74.2%) had greater intestinal digestibility compared with DG1 (59.2%), DG4 (63.0%), and DG5 (68.1%). The intestinal digestibility in WDG (65.8%) was similar to all other DG except for DG1, which was lower. Total digestibility of CP was greater in SBM (93.9%) compared with DG. Among the DG sources, the CP in DG2 (85.3%) and DG3 (84.9%) was more digestible compared with DG1 (70.7%), DG4 (74.9%), and DG5 (80.8%) but not WDG (81.9%). Based on the milk protein score (MPS), which is an estimate of the proportion of milk protein that a protein source can sustain until the first limiting AA is depleted, Met was the first limiting AA in SBM and Lys in DG. The concentrations of essential AA in the RUP were not different among DG sources, but the greater MPS in WDG (0.306) compared with the dried DG (0.240) sources indicated that WDG may have been the more ideal RUP source; but, the MPS of the metabolizable protein indicated that the protein quality of WDG was similar to that in DG2, DG3, and DG5. In conclusion, protein degradability and digestibility differed greatly among DG sources, but these differences were actually not as prominent in the concentrations of metabolizable AA and MPS among these sources.