• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.658-664
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• 2002

This study was conducted to determine a proper feeding regime for lactating Holstein cows during the warm season in Taiwan. In Feeding Trial, 21 lactating Holstein cows were randomly allotted into three feeding regimes in a Completely Randomized Design. The feeding regimes were roughage fed ad libitum along with concentrate fed either twice daily (2C) or four times daily (4C), and total mixed ration (TMR) for 8 weeks. No significant differences among the three feeding regimes were found in body weight changes, and intakes in terms of dry matter, crude protein and net energy. For milk yield and 4% FCM yield, 4C were higher than the other two feeding regimes (p<0.05). No significant differences were found in milk compositions or differences noted in the yields of the respective milk components. TMR was worse than 2C and 4C (p<0.05) in milk production efficiencies in terms of dry matter intake per kg milk yield, crude protein intake per kg milk protein yield, as well as dry matter intake, net energy intake and crude protein intake per kg 4% FCM yield. Three ruminally fistulated Holstein dry cows were randomly assigned into the same three feeding regimes in a 3${\times}$3 Latin Square Design. No significant differences were found among the feeding regimes in ruminal pH, ammonia nitrogen, total VFA concentration, molar percentages of VFA, and acetic acid: propionic acid ratio (C$_2$/C$_3$). Taken all together, roughage fed ad libitum and concentrate fed four times daily was the better feeding regime for lactating cows during the warm season in Taiwan.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1052-1057
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• 2005

Recently, the ozone treatment of wasting activated sludge has become one of the effective and feasible process for the sludge reduction. The objective of this study is to investigate the availability of ozonized wasting sludge on external carbon sources 13r phosphorus release. Experiment results showed that the ozone treatment of activated sludge could produce a large amount of VFA such as acetic acid and isobutyric acid. For example, 50.24 mg/L acetic acid was produced with the ozone dose of 0.05 g $O_3/g$ SS, and 123.56 mg/L acetic acid with 0.5 g $O_3/g$ SS. The higher ozone dose was applied, the more VFA was produced from sludge reduction into a limited point. Finally, using ozonated sludge as only carbon source, the batch experiment, to measure phosphorus release rate in anaerobic condition were performed. The specific phosphorus release rates were investigated as 0.94, 1.37, 1.48, 1.68 mg P/g VSS/hr with ozone dose of 0.05, 0.1, 0.2, 0.5 g $O_3/g$ SS, respectively. Considering the degree of mineralization, VFA production, phosphorus release rate, and economical aspect, the optimal ozone dose for sludge reduction and using carbon sources ranged from 0.05 to 0.1 g $O_3/g$ SS.

• Journal of Animal Science and Technology
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• v.51 no.5
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• pp.379-386
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• 2009

The aim of this study was tofind out the effects of supplementation of vitamin A to the diets of high or low amounts of concentrates for ruminants. In the first experiment, ruminal fermentation patterns with the data of pH, VFA production and cellulose disappearance rates in the rumen in vitro were investigated. In the second experiment, enzyme activities, gas production and dry matter degradabilities using cellulolytic bacteria, Ruminococcus flavefaciens were investigated. Ruminal pH was higher in low amounts of concentrates than in high amounts of concentrates as expected, however, no significant differences were found. Cellulose disappearance rates improved in vitamin A addition particularly in early incubation time (before 24h) and also the production of volatile fatty acids increased in vitamin A addition. These trends were more evident in diets containing high amounts of concentrates than in low amounts of concentrates and it may indicate that vitamin A is more required in the diets of high amounts of concentrates. In the second experiment, gas production, enzyme activities and dry matter degradabilities using cellulolytic bacteria, Ruminococcus flavefaciens were not different between vitamin A added and non-added diets. Ruminococcus flavefaciens may not require additional vitamin A for its own growth.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.3
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• pp.217-233
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• 1998

Milk yield and its composition is governed by level of nutrition and the composition of diet. Higher concentrate input improves milk yield, whereas its input at moderate levels improves yield of milk fat. High level of dietary protein improves dry matter intake and milk production, however, CP content above 14% has less advantage. Milk yield is enhanced by the feeding of cottonseed and soyabean meal, whereas milk fat increases by the supplementation of cottonseed. Dietary fat increases energy intake, production of milk and milk fat. Quality and quantity of feeds consumed affect fermentation patterns in rumen. Among the rumen metabolites, volatile fatty acids (VFA) content and propionate proportion have been related positively with milk yield, whereas proportion of acetate and butyrate have been related positively with milk fat content. Dietary carbohydrates through the source of sugar, starch, roughage and fibre affect VFA concentration in rumen. Therefore, concentration of volatile fatty acids could be altered to the advantage of consumer through judicious manipulation of diet.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1508-1513
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• 2000

The aim of this trial was to study the response of laboratory animals including omnivores (rats) and herbivores (rabbits, guinea pigs and hamsters) to the same level of dietary fiber on their digestive enzymes and hindgut fermentation. Ten weanling animals of each of four species, rabbits, guinea-pigs, rats and Syrian hamster, were fed a basal diet of 18% crude protein and 10% crude fiber for six weeks. The digesta and tissue of each intestinal segment were collected to measure the activity of digestive enzymes. Rabbits contained the highest secreted pepsin activity in the stomach, whereas rats contained the highest protease and ${\alpha}-amylase$ activity in the small intestine, and lower fibrous hydrolases in the hindgut than rabbits, guinea pigs and hamsters. The total VFA productions in the caecum and colon were highest in rats, followed by hamsters and rabbits, while the guinea pigs contained the lowest VFA and a different pattern of VFA molar ratio from the other laboratory animals. The degree of hindgut fermentation in these laboratory animals was in reverse to the trend for their fiber digestion.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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• pp.273-279
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• 2006

The performance of an autothermal thermophilic aerobic digestion (ATAD) system was studied to determine if nitrogen loss, as ammonia, was affected by an exhaust gas condenser. The system was run with and without a condenser while treating $8m^3$ of piggery slurry for 8 days. The system with a condenser (SWC) maintained the reactor temperatures above $40^{\circ}C$ for 2 days during the 8 days run, while the system without a condenser (SWOC) remained above $40^{\circ}C$ for 6 days. The SWC maintained the reactor temperatures mostly at mesophilic conditions while the SWOC at thermophilc conditions. Differences in operation conditions for the two runs were mainly caused by differences in atmospheric temperatures. Soluble chemical oxygen demand (SCOD) and volatile solids (VS) removal efficiencies of the SWC (SCOD: 62%, VS: 41%) were higher than those of the SWOC (SCOD: 40%, VS: 20%). The total Kjeldal nitrogen (TKN) removal efficiency of the SWC (7%) was less than that of the SWOC (25%). The concentration of total volatile fatty acids (VFA) in the SWC was observed to be lower than the threshold value of 0.23 g total VFA/L after 6 days, while the SWOC progressed below the threshold value after 3 days. No offensive odor emissions were observed in either run, which suggest that the use of the ATAD system may be a good odor removal strategy.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.9
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• pp.1283-1290
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• 2006

The effect of substituting potato by-products based silage (PBS) for concentrates on ruminal fermentation, methane production and nitrogen utilization in Holstein steers was evaluated. Three growing Holstein steers ($490{\pm}19kg$, initial body weight) were used in a $3{\times}3$ Latin square experiment with three experimental diets in which PBS was included at (1) 0, (2) 19 and (3) 27%, on a dry matter basis, replacing concentrates and wheat bran. Increasing replacement levels of PBS slightly increased dry matter (DM), organic matter (OM), NDF and ADF intakes by the steers (p<0.05). Inclusion of PBS at 19% increased crude protein (CP) digestibility of the experimental diets compared with the control (p<0.05). Substitution with PBS increased ADF digestibility and nitrogen retention (p<0.05), but did not affect energy retention. Energy loss as methane ranged between 5.0 and 6.1% of the total gross energy intake. There were no significant differences in carbon dioxide and methane production among all PBS levels, while daily methane production numerically increased with PBS inclusion. Substituting PBS for concentrates did not significantly affect ruminal pH and ammonia N concentration. Total VFA concentration, VFA molar proportions and blood metabolites were also unaffected by PBS replacement. These results suggest that substitution of PBS up to 27% of diet dry matter did not significantly increase methane production and was equal or superior to concentrates in ADF digestibility and nitrogen retention for growing steers.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.542-549
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• 2009

An in vitro study was conducted to determine the effect of nitrate-nitrogen used as a sole dietary nitrogen source on ruminal fermentation characteristics and microbial nitrogen (MN) synthesis. Three treatment diets were formulated with different nitrogen sources to contain 13% CP and termed i) nitrate-N diet (NND), ii) urea-N diet (UND), used as negative control, and iii) tryptone-N diet (TND), used as positive control. The results of 24-h incubations showed that nitrate-N disappeared to background concentrations and was not detectable in microbial cells. The NND treatment decreased net $CH_4$ production, but also decreased net $CO_2$ production and increased net $H_2$ production. Total VFA concentration was lower (p<0.05) for NND than TND. Suppression of $CO_2$ production and total VFA concentration may be linked to increased concentration of $H_2$. The MN synthesis was greater (p<0.001) for NND than UND or TND (5.74 vs. 3.31 or 3.34 mg/40 ml, respectively). Nitrate addition diminished methane production as expected, but also increased MN synthesis.

• Journal of environmental and Sanitary engineering
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• v.23 no.4
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• pp.73-82
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• 2008

In this study, a dry single-phase anaerobic digestion process (Dranco system) was investigated to evaluate the optimum operational conditions. Several factors such as injection rate of organic waste, biogas production, $CH_4$ content in the biogas, pH of the sludge, $NH_3$-N and VFA concentration were investigated based on the operation of the digestion process for 2 months (short term) and 8 months (long-term). The operation results showed that a small quantity of food waste should be injected every week and that a 10% increase of the microorganism injection rate should be needed. However, normal operation was conducted after 11 weeks based on the designed quantity. The $CH_4$ content in the biogas was high at the beginning and the end of the food injection. However, it was low during week days. When the biogas production was high, the $CH_4$ concentration was low. The biogas production increased with an increase of the injection rate. $100m^3$/ton of biogas was produced from normal operation of the digestion process based on the designed quantity. The pH values of the digestion tank based on short-term operation ranged from 8 to 8.5. However, the pH values ranged from 7.45 to 8.15 after 4 weeks of long-term operation. The $NH_3$-N concentration of short-term operation ranged from 4,500 to 5,500 ppm and it gradually decreased to 2,000ppm after normal operation was commenced. For long-term operation, it was 5,000ppm initially and 3,800ppm after normal operation was commenced. The VFA concentration of sludge was less than 900ppm and 2,500ppm for short and long-term operations, respectively, after normal operation. Overall, the differences between sludge pH, $NH_3$-N and VFA concentrations may be due to the different types of microorganisms and the digestion ability of the microorganisms which exist in the accumulation of non digested organics. Moreover, it may be also caused by the type of food waste. Further investigation is needed to confirm these relationships.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.9
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• pp.1285-1292
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• 2014

An in vitro experiment was conducted to evaluate the effects of Aspergillus oryzae culture (AOC) and 2-hydroxy-4-(methylthio)-butanoic acid (HMB) on rumen fermentation and microbial populations between different roughage sources. Two roughage sources (Chinese wild rye [CWR] vs corn silage [CS]) were assigned in a $2{\times}3$ factorial arrangement with HMB (0 or 15 mg) and AOC (0, 3, or 6 mg). Gas production (GP), microbial protein (MCP) and total volatile fatty acid (VFA) were increased in response to addition of HMB and AOC (p<0.01) for the two roughages. The HMB and AOC showed inconsistent effects on ammonia-N with different substrates. For CWR, neither HMB nor AOC had significant effect on molar proportion of individual VFA. For CS, acetate was increased (p = 0.02) and butyrate was decreased (p<0.01) by adding HMB and AOC. Increase of propionate was only occurred with AOC (p<0.01). Populations of protozoa ($p{\leq}0.03$) and fungi ($p{\leq}0.02$) of CWR were differently influenced by HMB and AOC. Percentages of F. succinogenes, R. albus, and R. flavefaciens (p<0.01) increased when AOC was added to CWR. For CS, HMB decreased the protozoa population (p = 0.01) and increased the populations of F. succinogenes and R. albus ($p{\leq}0.03$). Populations of fungi, F. succinogenes (p = 0.02) and R. flavefacien (p = 0.03) were increased by adding AOC. The HMB${\times}$AOC interactions were noted in MCP, fungi and R. flavefacien for CWR and GP, ammonia-N, MCP, total VFA, propionate, acetate/propionate (A/P) and R. albus for CS. It is inferred that addition of HMB and AOC could influence rumen fermentation of forages by increasing the number of rumen microbes.