• Journal of Animal Science and Technology
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• v.48 no.4
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• pp.541-554
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• 2006

Present review is to introduce an omasal sampling technique in rumen proteolysis and to consider some information on the omasal sampling technique with particular emphasis on methodological aspects. Use of the omasal sampling technique provides a new opportunity for accurate estimation of rumen metabolism with overcoming limitations of previous in vivo, in vitro and/or in situ methods. The potential advantages of the present technique compared with post-ruminal sampling techniques include following points; 1) only rumen cannulated animals are required, 2) less endogenous nitrogen (N) is contaminated in omasal digesta and 3) omasal digesta are devoid of exposure to acid peptide hydrolysis occurring in the abomasum. Estimates of soluble non-ammonia N (SNAN) in omasal digesta indicate that the assumptions underlying the in situ method that rapidly degradable N fraction can be degraded at an infinite rate and only insoluble dietary N escapes the rumen may be not valid. Quatitatively higher peptide concentration rather than free amino acid and soluble protein in escapable SNAN suggests that hydrolysis of peptide to amino acid may be the rate-limiting step in rumen proteolysis.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1708-1716
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• 2000

A study was made of diurnal changes in the ruminal bacteria associated with feed particles, i.e., non-associated (NAB), loosely associated (LAB), and tightly associated with particles (TAB), and the TAB concentration in different particle sizes from sheep fed orchardgrass (OG) or alfalfa (ALF) hay. Diaminopimelic acid (DAPA) was used to determine the TAB mass. Results showed that the bacterial masses in NAB and LAB were small, but comprised over 90% in TAB. The TAB mass in the ALF group sharply increased within 2 h after feeding and decreased afterward. The TAB mass showed the same trend in the OG group, increasing from 0 h to 2 h, but remained at the same level up to 14 h after feeding. The peak bacterial mass was, however, lower in the OG than the ALF group. The TAB concentration reflected the changes in total particulate tightly associated bacterial masses in both groups of hay fed sheep. Number of bacterial colonies per particle increased as the particulate size decreased in both groups. This difference, however, tended to decline as the postprandial period was prolonged. DAPA, however, tended to overestimate the TAB mass in the reticulo-rumen digesta of the hay fed sheep.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.443-454
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• 2003

This study was conducted to investigate the effects of dietary full-fat soybeans and linseed as fat sources on in vitro ruminal disappearances of dry matter and unsaturated fatty acids and fatty acids profile. The full-fat soybeans and linseed were high in linoleic acid (C18:2n-6) and $\alpha$-linolenic acid (C18:3n-3), respectively. The incubation times were 0, 3, 6, 12, 24, 48 and 72 h. After each time of incubation, medium digesta was lyophilized for analyzing its DM and fatty acids contents. DM disappearance was significantly higher in linseed treatment compared to full-fat soybeans treatment on 6 h (p<0.01), 12 h (p<0.05) and 24 h (p<0.01), but cumulative gas production was not significantly different between both treatments. Stearic acid (C18:0) content in medium digesta was increased in both soybeans and linseed as a result of complete biohydrogenation with increased incubation time and C18:0 and C18:1 contents of full-fat soybeans were significantly higher than those of linseed (p<0.05). The content of C18:2 and C18:3 in digesta of each treatment were decreased by biohydrogenation as incubation time was increased. The content of C18:2 in full-fat soybeans was significantly higher than that of linseed (p<0.05) while the content of C18:3 in linseed was significantly higher than that of full-fat soybeans (p<0.001). Net C18:0 production was significantly higher in full-fat soybeans (332.24%) than linseed (133.16%) on 72 h. Disappearance of C18:1 was significantly lower in full-fat soybeans than linseed (p<0.05), especially full-fat soybeans showed negative (-) values on 3, 6, 12 and 24 h. The disappearance of C18:3 was significantly higher in linseed than full-fat soybeans (p<0.05). The disappearance of C18-unsaturated fatty acid was significantly higher in linseed than full-fat soybeans. In conclusion, polyunsaturated fatty acid (PUFA) in both full-fat soybeans and linseed were extensively biohydrogenated. In addition, biohydrogenation of PUFA was more completed to C18:0 in full-fat soybeans than linseed, reflecting dietary PUFA composition.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.3
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• pp.571-582
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• 1992

Soybeans were dry extruded at three different temperatures (125, 135 and $145^{\circ}C$) for 30 s. Four lambs fitted with cannulae in the rumen and abomasums were used in a balanced $4{\times}4$ Latin square design. Lambs were fed at 2 h intervals for 12 times a day with automatic feeder to maintain steady state conditions in digestive tract. A dual-phase marker system was used to estivate ruminal flow rate of both liquid and solid digesta. Objectives of this study were to determine the effect of extrusion temperature of raw soybean on the ruminal liquid and solid dilution rate, nitrogen digestion and flow at the abomasum and availability of amino acid in lambs. There were no significant effects of extrusion on liquid and solid dilution rate, and liquid volume. Ruminal liquid flow rate was not influenced by extrusion and ranged from 389 to 435 ml/hr. Extrusion had no influence on ruminal OM digestion and flow rate to the abomasums. Dietary N flow to the abomasums increased (p < 0.05) as extruding temperature increased. Extruding temperature had a significant effect (p < 0.05) on flow of N escaping ruminal degradation and ranged from 34.91 to 57.38%. Microbial N synthesized/kg OMTDR ranged from 27 to 37 g and highest with $145^{\circ}C$ ESB diet. Extrusion decreased the amount of degradable amino acid in the rumen and increased the supply of amino acid to the lower gut, especially with 135 and $145^{\circ}C$ ESB diets.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.55-61
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• 1992

To determine the effect of time after feeding on distribution of particle size of digesta in the gastrointestinal tract, 16 sheep given orchardgrass first cut hay were slaughtered at 2, 8, 16 and 24 hours after feeding and digesta in diverse sites of the tract were sieved into four fractions of particle size larger than $1180{\mu}m$, 300-1180, 45-300 and less than 45. Following results were obtained: 1) In the reticulo-rumen, the proportion of particles larger than $1180{\mu}m$ decreased with the time after feeding, while the other particle size fractions did not change with time after feeding. 2) In the post-ruminal alimentary tract, the proportion of particles larger than $1180{\mu}m$ was significantly smaller than that in the reticulo-rumen and distribution of fractions of every particle size stayed consistently at about the same level irrespective of the time after feeding. 3) In the cecum, the fraction of particle size less than $45{\mu}m$ appeared to be selectively retained when the passage rate was considered.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.11
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• pp.1634-1641
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• 2003

In vivo digestion and metabolism trials were conducted with 10 wethers equipped with ruminal, abomasal, and ileal cannulae to evaluate digestion of ensiled broiler litter (EBL), deepstacked broiler litter (DBL), and composted broiler litter (CBL). Wethers were fed a low protein (6.3% CP) basal diet alone or supplemented to 10.3% CP with EBL, DBL, CBL or soybean meal (SBM). All diets were formulated to be isoenergetic (56% TDN, DM basis). Apparent digestibilities of DM, OM, and ADF were not affected (p<0.05) by diet, but digestibility of CP was improved (p<0.05) by N supplementation. Apparent digestibility of CP was lower (p<0.05) for diets supplemented with CBL and DBL than for diets supplemented with SBM and EBL. Ruminal $NH_3$ concentration was 20 to 24 mg/dl at 2 h after feeding litter-supplemented diets compared with 13 mg/dl for SBM. Abomasal N, $NH_3$ N, and nonammonia N flows were increased (p<0.05) by N supplementation, whereas microbial N flow was not influenced (p<0.05) by diet. Compared with SBM and EBL, undegraded dietary CP flow to the abomasum tended to be greater (p<0.1) when wethers were fed DBL and CBLsupplemented diets. Retention of N (g/d) also was greater (p<0.05) due to greater (p<0.05) N intake and lower (p<0.05) urinary N excretion when wethers were fed diets supplemented with litter (especially EBL) vs. SBM. Overall, characteristics of ruminal fermentation and digestion indicated that broiler litter N was utilized efficiently by wethers, but ensiling may be preferable to deepstacking or composting.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.5
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• pp.659-665
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• 2016

The effects of three different feeding systems on beef cattle production performance, rumen fermentation, and rumen digesta particle structure were investigated by using 18 Limousin (steers) with a similar body weight ($575{\pm}10kg$) in a 80-d experiment. The animals were equally and randomly divided into three treatment groups, namely, total mixed ration group (cattle fed TMR), SI1 group (cattle fed concentrate firstly then roughage), and SI2 group (cattle fed roughage firstly then concentrate). The results showed that the average daily gain was significantly higher in cattle receiving TMR than in those receiving SI1 and SI2 (p<0.05). Consumption per kg weight gain of concentrate, silage, and combined net energy (NEmf) were significantly decreased when cattle received TMR, unlike when they received SI1 and SI2 (p<0.05), indicating that the feed efficiency of TMR was the highest. Blood urea nitrogen (BUN) was significantly decreased when cattle received TMR compared with that in cattle receiving SI1 (p<0.05), whereas there was no difference compared with that in cattle receiving SI2. Ammonia nitrogen concentration was significantly lower in cattle receiving TMR than in those receiving SI1 and SI2 (p<0.05). The rumen area of cattle that received TMR was significantly larger than that of cattle receiving SI1 (p<0.05), but there was no difference compared with that of cattle receiving SI2. Although there was no significant difference among the three feeding systems in rumen digesta particle distribution, the TMR group trended to have fewer large- and medium-sized particles and more small-sized particles than those in the SI1 and SI2 groups. In conclusion, cattle with dietary TMR showed increased weight gain and ruminal development and decreased BUN. This indicated that TMR feeding was more conducive toward improving the production performance and rumen fermentation of beef cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.479-484
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• 2001

The effect of dietary supplementation of sodium salt of isobutyric acid in low protein (10% CP) wheat straw based diet on nutrient utilization and rumen fermentation was studied in ruminally fistulated male crossbred cattle. The study included a 7 day metabolism and a 3 day rumen fermentation trials. The cattle were distributed into two equal groups of 4 each. The animals of control group were fed a basal diet consisting of wheat straw, concentrate mixture and green maize fodder in 40:40:20 proportion whereas branched chain volatile fatty acid (BCFA) supplemented group received a basal diet + isobutyric acid at 0.75 percent of basal diet. The duration of study was 36 days. The feed intake between experimental groups did not differ significantly and the average total DMI (% BW) was 2.01 and $2.28kg\;day^{-1}$ in control and BCFA supplemented diets. The dietary supplementation of BCFA improved (p<0.05) the DM, OM, NDF and cellulose digestibility by 4.46, 6.63, 10.57 and 11.31 per cent over those fed control diet. The total N retention on BCFA supplementation was improved (p<0.01) due to decreased (p<0.05) urinary N excretion. The concentrations of ruminal total N was 37.07 and $34.77mg\;100ml^{-1}$ in control and BCFA fed groups, respectively. Dietary supplementation BCFA significantly (p<0.01) reduced the ruminal ammonia N concentration as compared to control and the mean values ($mg\;100ml^{-1}$) were 13.18 and 9.42 in control and BCFA fed groups. The total VFA concentration was higher (p<0.01) in BCFA supplemented group (101.14 mM) than the control (93.05 mM). Among the VFAs, the molar proportion of acetate was higher (p<0.01) in BCFA supplemented group (71.07 mM) as compared to control (64.98 mM). However, the concentration of propionate and butyrate remained unchanged. Amino acids composition of bacterial hydrolysates was similar in both the groups. Ruminal outflow rate of liquid digesta was higher (p<0.01) in BCFA fed group ($67.56l\;day^{-1}$) than control ($52.73l\;day^{-1}$). It is concluded that the dietary supplementation of Na-salt of isobutyric acid in low protein diet improved the nutrient utilization and ruminal fermentation characteristics.

• Journal of Animal Science and Technology
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• v.48 no.3
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• pp.393-400
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• 2006

The present study was conducted to evaluate feeding value of brown rice in Korean native beef steers (Hanwoo) fed concentrates and orchardgrass hay (50:50 on a wet basis) as a basal diet. Either 50% or 100% of corn in concentrates was substituted for brown rice, and ruminal fermentation characteristics, in situ degradability of feeds and in vivo digestibility of concentrate were investigated. The digestibility and nutritive values of corn and brown rice feeds were similar, whereas rumen degradability of brown rice was higher than that of corn. Compared with corn-based diets, the brown rice substitution decreased (P<0.05) ruminal NH3-N concentration, but did not affect rumen pH. Total volatile fatty acid content in ruminal digesta for the corn based diet was higher than those for the brown rice-contained diets. The brown rice substitution increased (P<0.05) the ratio of ruminal acetic acid to propionic acid (A/P) compared with corn-contained diets.Present results indicate that corn might nutritionally be substituted for brown rice as cattle feeds. In addition, we expect that relatively high A/P with brown rice may produce affirmative effects in rumen physiological aspect, particularly under the grain based feeding system for beef cattle in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.3
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• pp.267-273
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• 1995

The differences in rumen particle pool size, passage rate and rumen degradability in sheep receiving three varieties of orchardgrass hay harvested at pre-heading (H1), early-bloom (H2) and late-bloom (H3) were investigated using four ruminal-cannulated wethers (68 kg) fed 1,300 g of the hay once a day. Representative samples of whole rumen contents were collected at different times after feeding and the quantities of rumen particle pools [large particle pool (LPP), retained on a $1,180{\mu}m$ sieve; small particle pool (SPP), retained on a 47 but passed a $1,180{\mu}m$ sieve; and soluble fraction (SOL), passed a $47{\mu}m$ sieve (SOL)] were determined by a wet-sieving technique. The fullowing results were obtained: 1) The dry weight of whole rumen contents were significantly lower (p < 0.05) for HI than for H2 or H3. The reduction rate of whole rumen contents was slightly but significantly greater for HI that, the other hay varieties. 2) The LPP disappearance rates were 26.2, 25.3 and 21.7 g DM/h for H1, H2 and H3, respectively, and no statistical differences were found among the hay varieties. Appreciable changes were not observed with SPP and SOL throughout measurements for all hay varieties; however the SPP was markedly greater (p <0.05) for H2 and ill than for HI, while SOL did not differ among hay varieties. 3) The SPP passage rate (g DM/h) and effective rumen degradability (%) for HI, H2 and ill were, respectively, 9.7, 56.6; 16.9, 42.3; and 18.0, 28.9. The ruminal tum-over rate for SPP appeared to be higher for HI than for the other hay varieties.