• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.207-212
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• 2004

Ruminal digestion of dry matter (DM) and neutral detergent fiber (NDF) of processed (ensiled, deepstacked or composted) broiler litter (BL) was determined in situ and in vitro, and compared with rice straw (RS). DM disappearances at 24 and 48 h and digestion of differently processed BL were higher than those of RS. Compared with RS, processed BL was low in NDF disappearance at 72 h incubation, digestion rate ($K_dB$) and digestibility at 0.025 of passage rate; however, deepstacked BL was similar in these NDF characteristics. Processing of BL affected ruminal digestion of nutrients such as DM and NDF adversely. NDF of composted BL, especially, was the most indigestible. This in situ nutritional evaluation indicated that deepstacked BL, the most widely used form of BL, was superior in DM characteristics (fractions, ruminal disappearance and digestibility) and similar in NDF characteristics (ruminal disappearance and digestibility) to RS.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1691-1698
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• 2000

An in situ digestion trial (Experiment 1) and a lactation trial (Experiment 2) were conducted to determine the effects of replacing corn and wheat bran with soyhulls (SH) in lactating dairy cow diets on the extent and kinetics of digestion of DM and NDF, and lactation performance. In experiment 1, five mixed feeds consisting of mixed concentrate and roughages (50:50 on a DM basis) were formulated on isonitrogenous and isoenergetic bases to produce five levels (0, 25, 50, 75 and 100%) of SH replacement for corn and wheat bran. SH had high in situ digestion (92 and 89% for potentially digestible DM and NDF) and fairly fast digestion rate (7.2 and 6.3 %/h for DM and NDF). Increasing level of SH replacement resulted in increased NDF digestibility (linear, p=0.001-0.04) and similar DM digestibility (beyond 12 h incubation, p=0.10-0.41). As level of SH replacement increased, percentage of slowly digestible fraction (b) of DM increased (linear, p=0.03), percentage of rapidly digestible fraction (a) of DM tended to decrease (linear, p=0.14), and DM digestion lag time tended to be longer (linear, p=0.13). Percentage of potentially digestible fraction (a+b) and digestion rate (c) of slowly digestible fraction of dietary DM remained unaltered (p=0.36-0.90) with increasing SH in the diet. Increasing level of SH for replacing corn and wheat bran in the diet resulted in increases in percentages of b (quadratic, p<0.001), a (linear, p=0.08), a+b (quadratic, p=0.001) and a tendency to increase in c for NDF (linear, p<0.19). It was also observed that there was a satisfactory fit of a non-linear regression model to NDF digestion data ($R^2=0.986-0.998$), but a relatively poor fit of the model to DM digestion data ($R^2=0.915-0.968$). In experiment 2, 42 lactating Holstein cows were used in a randomized complete block design. SH replaced corn and wheat bran in mixed concentrates at 0, 25, and 50%, respectively. These mixed concentrates were mixed with roughages and fed ad libitum as complete diets. Replacing corn and wheat bran with SH at 0, 25 and 50% levels did not influence (p=0.56-0.95) DM intakes (18.4, 18.6, and 18.5 kg/d), milk yields (27.7, 28.4 and 27.6 kg/d), 4% fat-corrected-milk (FCM) yields (26.2, 27.6, and 27.3 kg/d) and percentages of milk protein (3.12, 3.17 and 3.18%), milk lactose (4.69, 4.76 and 4.68%) and SNF (8.50, 8.64, and 8.54%). On the other hand, milk fat percentges linearly increased (3.63, 3.85 and 3.90% for SH replacement rates of 0, 25 and 50% in the diet, p=0.08), while feed costs per kg FCM production were reduced.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.3
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• pp.371-375
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• 1999

The present study was conducted to evaluate the mottgrass alone and in combination with berseem (Trifolium alexandrinum) at different intake levels to determine the lag time, rate and extent of digestion of DM and NDF of mottgrass. Four ruminally cannulated buffalo calves were used in a $4{\times}4$ Latin Square Design with $2{\times}2$ factorial arrangement of treatments. The two factors were forage intake levels (ad libitum versus restricted) and forage source (mottgrass versus mottgrass plus 25% berseem). Four dietary treatment consisted of 1) ad libitum mottgrass, 2) restricted feeding of mottgrass, 3) ad libitum mottgrass plus berseem with a ratio of 3:1 and 4) restricted mottgrass plus berseem in a ratio of 3:1 Calves fed ad libitum mottgrass supplemented with 25% berseem consumed 25% more DM and 15 % more NDF than those fed mottgrass only. The in situ DM digestibility, the lag time and extent of digestion were not affected by intake level. However, rate of disappearance was greater in restricted fed animals than those fed ad libitum. This increased rate could be due to greater concentration of fibrolytic bacteria in restrict fed animals. The DM digestibility was greater (64.1%) in calves fed mottgrass supplemented with 25% berseem than those fed mottgrass only (57.7%). The reduced mottgrass DM digestion may be due to its higher NDF contents. The NDF digestibility, the lag and extent of NDF digestion were not affected by varying intake levels. However, rate of digestion of NDF was higher in restricted fed animals than those of ad libitum fed animals. The NDF digestibility was greater (58.4%) in calves fed mottgrass supplemented with 25% berseem than those fed mottgrass (48.7%) only.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.2
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• pp.128-132
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• 1998

The relative disappearance and rate of degradation of dry matter (DM) and neutral detergent fiber (NDF) of nine different feedstuffs were determined by simultaneously suspending groups of substrates, using the nylon bags, in the rumen of males of Sahiwal cattle and Nili-Ravi buffalo. The digestion kinetics of leguminous forages (Lucerne, berseem and cowpeas) and feed byproducts (cotton seed cake, wheat bran and wheat straw) did not differ between the two species. However, the DM and NDF digestibilities and rates of digestion of grasses and wheat straw were greater in buffalo than in cow bulls, indicating that buffaloes are better converters of poor quality roughages than are Sahiwal. The lag time for DM of grasses did not differ between these two species but the NDF lag time was lower in buffalo than in cows, indicating that both the rate and lag time of digestion may be reliable indicators for assessing the NDF quality.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.515-521
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• 2004

Anaerobic digestion has many advantages over the more conventional aerobic treatment processes such as low levels of excess sludge production, low space (area) requirements, and the production of valuable biogas. The purpose of this study was to evaluate the effect of organic loading rate of anaerobic digestion on thermophilic($55^{\circ}C$) and mesophilic($35^{\circ}C$) conditions. Fluorescent in situ hybridization (FISH) method was also used to study the microbial community in the reactors. The stabilizing time in mesophilic anaerobic reactors was shorter as approximately 20 days than 40 days in the thermophilic anaerobic reactors. The amount of methane production rate in anaerobic reactors was independent of the concentrations of supplied substrates and the amount of methanogens. When the microbial diversity in the mesophilic and thermophilic reactors, which had been treated with acetate-based artificial wastewater, were compared, it was found that methanogenesis was carried out by microbial consortia consisting of bacteria and archaea such as methanogens. To investigate the activity of bacterial and archaeal populations in all anaerobic reactors, the amount of acetate was measured. Archaea were predominant in all reactors. Interestingly, Methanothrix-like methanogens appeared in mesophilic anaerobic reactors with high feed substrate concentrations, whereas it was not observed in thermophilic anaerobic reactors.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.3
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• pp.317-322
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• 2000

In situ and in vivo digestion trials were conducted to determine the degradation of dry matter (DM), crude protein (CP) and effective protein degtadability (EPD), and digestibility of nutrients of Hazelnut kernel oil meal (HKOM), and effects of HKOM on nitrogen (N) balance. In the in situ study, nylon bag were suspended in the rumen of 3 Karayaka rams to estimate protected protein. Protein sources were analyzed for pepsin soluble protein (PSP) using a Pepsin Digestion Method. In the digestion trials, 4 Karayaka rams (36 mo.) were used in a $4{\times}4$ Latin square to evaluate the digestibility of nutrients and N retention to measure effects of diets containing HKOM, soybean meal (SBM) corn gluten meal (CGM) and urea (U). The degradability of DM and CP, and PSP content of HKOM were lower (p>0.05) than that of SBM, but higher (p<0.001) than that of CGM. EPD of HKOM was higher (p<0.01) than that of SBM or CGM. The apparent digestion coefficients of organic matter and CP for HKOM were lower than for SBM, but higher than for CGM. N retention of HKOM was higher than that of SBM and lower than that of CGM (p>0.05). In conclusion, these data may indicate that the HKOM is a high digestible feed source with a value between SBM and CGM.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.7
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• pp.929-939
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• 2011

The effects of micronization on in situ and in vitro nutrient disappearances of wheat, barley and corn were investigated in a series of experiments. In Experiment 1, chemical composition and in situ dry matter disappearance (DMD) of six varieties of wheat were determined. In addition, an in vitro study was completed using ground micronized and unmicronized wheat (var. Kansas). In Experiment 2, three varieties of wheat (Kansas, Sceptre and Laura) and in Experiment 3, three cereal grains (wheat, barley and corn) were either micronized for 1 min to attain internal kernel temperatures of 90-100$^{\circ}C$ or not (controls), and DM, protein and starch disappearances were estimated. In Experiment 2, an in vitro study was also completed using ground micronized and unmicronized wheat (var. Kansas). Wheat samples varied with respect to crude protein (10.0-21.2%), starch (61.6-73.9%), NDF (8.5-11.8%), volume weight (753-842 g/L) and kernel hardness (0.0-32.0). Rate (p = 0.003) and extent (p = 0.001) of in situ DMD differed among wheat varieties. Correlations between in situ kinetics, and chemical and physical properties of wheat varieties showed that protein content was negatively correlated with the rate of disappearance ($r^2$ = -0.77). Micronization of all grains markedly reduced (p = 0.001) the rate and extent of DM, and protein disappearances as compared to control samples. Micronization increased (p<0.05) the digestion of starch in wheat. However, release of ammonia into the incubation medium was markedly reduced (p<0.05), suggesting that micronization increased the resistance of protein to microbial digestion. Disappearances of DM, protein and starch differed (p = 0.001) among cereal grains with wheat>barley>corn. Micronization reduced the rate of DM disappearance (p = 0.011) and slowly degradable protein fractions (p = 0.03), however, increased (p = 0.004) slowly degradable starch fractions of all three cereals. Examination of in situ samples by scanning electron microscopy confirmed that microbial colonization focused on starch granules in micronized grains, and that the protein matrix exhibited resistance to microbial colonization. These results suggest that micronization may be used to increase the ruminal escape value of protein in cereal grains, but may lead to increased starch digestion if grains are finely ground.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.6
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• pp.812-815
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• 2005

This study was conducted to see the influence of additives and fermentation periods on Mott grass silage (MGS) characteristics, its chemical composition and to compare the digestion kinetics of Mott grass (MG) and MGS in Nili buffaloes. Mott grass chopped with a locally manufactured chopper was ensiled using two additives, cane molasses and crushed corn grains each at 2, 4 and 6% of forage DM for 30 and 40 days in laboratory silos. The pH, lactic acid concentration, dry matter (DM), crude protein and fiber fractions of MGS were not affected by the type or level of additive and fermentation periods. The non-significant pH lactic acid concentration, and chemical composition of MGS indicated that the both molasses and crushed corn were utilized at similar rate for the growth of lactic acid bacteria and production of organic acids. The MG ensiled with molasses at 2% of fodder DM for 30 days was screened out for in situ digestion kinetics in Nili buffaloes. Ruminal DM and neutral detergent fiber (NDF) degradabilities of MGS were significantly (p<0.05) higher than that of MG. The DM and NDF rate of degradation, lag time and extent of degradation was nonsignificant between MGS and MG. The higher ruminal degradation of DM and NDF of MGS than MG was probably a reflection of fermentation of MG during ensilation that improved its degradability by improving the availability of easily degradable structural polysaccharides to ruminal microbial population. The results in the present study have indicated that MG ensiled with either 2% molasses or 2% crushed corn for 30 days has better nutritive value for buffalo.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1127-1133
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• 2006

This study examined the effect of cane molasses and fermentation time on chemical composition and characteristics of oat grass silage (OGS) and its in situ digestion kinetics, intake, digestibility, milk yield and composition in buffaloes (Bubalus bubalis). Oat grass (OG) harvested at 50-days of age was ensiled in laboratory silos with cane molasses at the rate of 0, 2, 4 and 6% of OG dry matter (DM) for 30, 35 and 40 days. Silage pH was decreased while lactic acid content increased with increasing level of cane molasses and fermentation time. Dry matter (DM), crude protein (CP) and true protein (TP) content of OGS were (p<0.05) significantly higher with higher cane molasses levels. However, they were not affected by the fermentation time. Similar trends were observed for neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose, acid detergent lignin and ash content of OGS. The OG ensiled for 30-days with 2% molasses was screened from laboratory study and used to determine comparative in situ DM and NDF digestion kinetics of OG and its silage. In situ DM and NDF digestibilities of OG were significantly (p<0.05) higher than OGS. Ruminal DM and NDF lag time, rate and extent of digestion of OG and its silage were similar. Two experimental diets of OG and OGS were formulated using 75:25 forage to concentrate ratio on a DM basis. Dry matter and CP intakes were similar in lactating buffaloes fed either OG- or OGS-based diets. However, NDF intake was higher in buffaloes fed the OG-compared with OGS-based diet. Apparent DM, CP and NDF digestibilities were similar in lactating buffaloes fed either OG- or OGS-based diets. Milk yield (4% FCM) was similar in buffaloes fed either OG-(10.3 kg/d) or OGS-(9.95 kg/d) based diets. Milk fat, total solids and true protein content were higher with OG compared with the OGS diet. Solids not fat and CP content were similar in milk of buffalo fed either OG or OGS. The results of this study indicate that OG ensiled with 2% molasses could safely replace 75% DM of green oat fodder in the diets of lactating buffaloes without negatively affecting intake, digestibility, milk yield and composition.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.1
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• pp.131-138
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• 2009

Among rumen microbes, bacteria play important roles in the biological degradation of plant fiber due to their large biomass and high activity. To maximize the utilization of fiber components such as cellulose and hemicellulose by ruminant animals, the ecology and functions of rumen bacteria should be understood in detail. Recent genome sequencing analyses of representative fibrolytic bacterial species revealed that the number and variety of enzymes for plant fiber digestion clearly differ between Fibrobacter succinogenes and Ruminococcus flavefaciens. Therefore, the mechanism of plant fiber digestion is also thought to differ between these two species. Ecology of individual fibrolytic bacterial species has been investigated using pure cultures and electron microscopy. Recent advances in molecular biology techniques complement the disadvantages of conventional techniques and allow accurate evaluation of the ecology of specific bacteria in mixed culture, even in situ and in vivo. Molecular monitoring of fibrolytic bacterial species in the rumen indicated the predominance of F. succinogenes. Nutritive interactions between fibrolytic and non-fibrolytic bacteria are important in maintaining and promoting fibrolytic activity, mainly in terms of crossfeeding of metabolites. Recent 16S rDNA-based analyses suggest that presently recognized fibrolytic species such as F. succinogenes and two Ruminococcus species with fibrolytic activity may represent only a small proportion of the total fibrolytic population and that uncultured bacteria may be responsible for fiber digestion in the rumen. Therefore, characterization of these unidentified bacteria is important to fully understand the physiology and ecology of fiber digestion. To achieve this, a combination of conventional and modern techniques could be useful.