• Asian-Australasian Journal of Animal Sciences
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• 제7권3호
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• pp.389-396
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• 1994

Effects of chemical treatments on in sacco and in vitro digestibility of barley straw by rumen fluid and pure cultures of cellulolytic bacteria were studied to evaluate the pretreatment and to improve the poor quality feed. Chemicals were applied by dissolving them in water equivalent to 40% of the weight of the straw (dry matter basis). Pretreatment with 5% NaOH yielded the largest increase in sacco digestion followed by pretreatment with 2% $(NH_4)_2SO_3$, 2.6% $NH_4OH$, 1.6% $NaHSO_3$ and untreated straw (control). In sacco dry matter digestibility of straw treated with NaOH and $(NH_4)_2SO_3$ continued to increase as the concentration of chemical increased (1 to 7.5%), as it was the in vitro dry matter loss by leaching. Treatment of barley straw with 5% NaOH enhanced significantly (p < 0.01) in vitro digestibility by rumen fluid, Fibrobacter suceinogenes and Ruminococcus albus though the fermentation products by cellulolytic bacteria were low, whereas the treatment with 5% $(NH_4)_2SO_3$ inhibited in vitro digestibility by F. succinogenes and R. albus together with lower fermentation products. Dry matter loss by leaching and bacterial digestion from barley straw treated with NaOH and $(NH_4)_2SO_3$ suggested the effect of pretreatment with these chemicals were based on leaching, and the cellulolytic bacteria had little to do with digestion.

• Asian-Australasian Journal of Animal Sciences
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• 제12권1호
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• pp.113-128
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• 1999

Protozoa can represent as half of the total rumen microbial biomass. Around 10 genera are generally present on the same time in the rumen. Based on nutritional aspects they can be divided in large entodiniomorphs, small entodiniomorphs and isotrichs. Their feeding behaviour and their enzymatic activities differ considerably. Many comparisons between defaunated and refaunated animals were carried out during the last two decades to explain the global role of protozoa at the ruminal or animal levels. It is now generally considered that a presence of an abundant protozoal population in the rumen has a negative effect on the amino acid (AA) supply to ruminants and contribute to generate more methane but, nevertheless, protozoa must not be considered as parasites. They are useful for numerous reasons. They stabilise rumen pH when animal are fed diets rich in available starch and decrease the redox potential of rumen digesta. Because cellulolytic bacteria are very sensitive to these two parameters, protozoa indirectly stimulate the bacterial cellulolytic activity and supply their own activity to the rumen microbial ecosystem. They could also supply some peptides in the rumen medium which can stimulate the growth of the rumen microbiota, but this aspect has never been considered in the past. Their high contribution to ammonia production has bad consequences on the urinary nitrogen excretion but means also that less dietary soluble nitrogen is necessary when protozoa are present. Changes in the molar percentages of VFA and gases from rumen fermentations are not so large that they could alter significantly the use of energy by animals. The answer of animals to elimination of protozoa (defaunation) depends on the balance between energy and protein needs of animals and the supply of nutrients supplied through the diet. Defaunation is useful in case of diets short in protein nitrogen but not limited in energy supply for animals having high needs of proteins.

• Asian-Australasian Journal of Animal Sciences
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• 제9권3호
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• pp.247-254
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• 1996

Three stages of growth of Italian ryegrass (pre-blooming, P-B; early-blooming, E-B; and late-blooming, L-B) were used to evaluate the effect of maturity on in vitro digestion of dry matter, fiber components and gas production. The rumen digestibility and gas production values were obtained by incubation of each sample in the rumen fluid of sheep for 12, 24, 36, 48 and 72 hr, respectively. The results showed that digestibility of dry matter (DM) significantly reduced (p < 0.05) as advancing maturity of the grass. Similarly, the digestibility of neutral detergent fiber (NDF) and acid detergent fiber (ADF) also significantly decreased (p < 0.05) with advancing maturity at all incubation times. However, the effect of maturity on digestibility of cellulose and hemicellulose was only detected when the samples were incubated more than 36 hr, where L-B was lower than P-B and E-B. Potential digestibility of nutrients, the maximum digestibility attainable in the rumen theoretically, was also higher at P-B than those of E-B and L-B. The amount of gas produced by microbial fermentation was closely related to the extent of DM digestion, and it was negatively correlated with advancing maturity of the grass.

• Asian-Australasian Journal of Animal Sciences
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• 제13권1호
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• pp.96-114
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• 2000

Genetically selected beef cattle are fed high-energy diets in intensive production systems developed in industrial countries. This type of feeding can induce rumen dysfunctions that have to be corrected by farmers to optimise cost-effectiveness. The risk of rumen acidosis can be reduced by using slowly degradable starch, which partly escapes rumen fermentation and goes on to be digested in the small intestine. Additives are proposed to stabilise the rumen pH and restrict lactate accumulation, thus favouring the growth of cellulolytic bacteria and stimulating the digestion of the dietary plant cell wall fraction. This enhances the energy value of feeds when animals are fed maize silage for example. Supplementation of lipids to increase energy intake is known to influence the population of rumen protozoa and some associated rumen functions such as cellulolysis and proteolysis. The end products of rumen fermentation are also changed. Lipolysis and hydrogenation by rumen microbes alter the form of fatty acids supplied to animals. This effect is discussed in relation with the quality of lipids in beef and the implications for human health. Conditions for optimising the amount of amino acids from microbial proteins and dietary by-pass proteins flowing to the duodenum of ruminants, and their impact on beef production, are also examined.

• Membrane and Water Treatment
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• 제10권3호
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• pp.213-221
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• 2019

Anaerobic digestion (AD) has been widely used to valorize food waste (FW) because of its ability to convert organic carbon into $CH_4$ and $CO_2$. Korean FW has a high content of fruits and vegetables, and efficient hydrolysis of less biodegradable fibers is critical for its complete stabilization by AD. This study examined the digestates from different anaerobic digesters, namely Rs, Rr, and Rm, as the inocula for the AD of vegetable waste (VW) and cellulose (CL): Rs inoculated with anaerobic sludge from an AD plant, Rr inoculated with rumen fluid, and Rm inoculated with anaerobic sludge and augmented with rumen fluid. A total of six conditions ($3\;inocula{\times}2\;substrates$) were tested in serial subcultures. Biogas yield was higher in the runs inoculated with Rm than in the other runs for both VW (up to 1.10 L/g VS added) and CL (up to 1.05 L/g VS added), and so was biogas production rate. The inocula had different microbial community structures, and both substrate type and inoculum source had a significant effect on the formation and development of microbial community structures in the subcultures. The overall results suggest that the bioaugmentation with rumen microbial consortium has good potential to enhance the anaerobic biodegradability of VW, and thereby can help more efficiently digest high fiber-content Korean FW.

• Asian-Australasian Journal of Animal Sciences
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• 제12권7호
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• pp.1054-1062
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• 1999

The effects of dry roasting whole faba beans (WFB) and whole lupin seeds (WLS) at 110, 130 or $150{^{\circ}C}$ for 15, 30 or 45 min on rumen (RDCP%), estimated intestinal (IDCP%) and total tract disappearance of CP (TDCP%) and intestinal availability (IARUCP%) of rumen undegraded CP (RUCP%) were determined. The RDCP values were estimated by in sacco technique by incubating nylon bags for 8, 12 and 24 h in the rumen of dairy cows. The IDCP and IARUCP values were estimated using a sequence of ruminal incubation, in vitro incubation in acid-pepsin for 1 h and then in pancreatin for 24 h of three-step in vitro procedure technique. Dry roasting at 130 and $150^{\circ}C$ decreased RDCP with correspondingly increasing IDCP. The IDCP value generally increased from 12.3(raw) to 8.6, 14.8 and 39.6% (WFB) and from 28.3 (raw) to 33.7, 36.2 and 56.2% (WLS) at 8 h rumen incubation; from 2.9 (raw) to 2.9, 4.6 and 23.3% (WFB) and from 19.6 (raw) to 19.0, 24.0 and 46.6% (WLS) at 12 h rumen incubation; from 1.3 (raw) to 1.9, 1.7 and 11.0% (WFB) and from 4.4 (raw) to 4.2, 10.7 and 36.7% (WLS) at 12 h rumen incubation as the temperatures rose to 110, 130 and $150{^{\circ}C}$ respectively. The TDCP values were always high and increased by time in the rumen, the average values of which were 97.9, 96.6; 99.2, 96.9 and 99.6, 98.7% for WFB and WLS, respectively, at 8, 12 and 24 h rumen incubation. But within the same retention time, TDCP was generally unchanged. The average IARUCP increased from 87.3 (raw) to 87.4, 88.7 and 92.0% (WFB); from 87.6 (raw) to 88.9, 91.5 and 93.0% (WLS) at roasting temperatures of 110, 130 and $150{^{\circ}C}$, respectively. It was concluded that dry roasting can shift the digestion of CP from rumen to the lower gastrointestinal tract without depressing the digestion of RUCP. The best processing condition in this study was dry roasting at $150{^{\circ}C}$ for 45 min in terms of effects on the disappearances and availability of CP. Research data on intestinal availability of individual amino acids need to be further investigated.

• Asian-Australasian Journal of Animal Sciences
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• 제15권11호
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• pp.1659-1676
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• 2002

Ruminant animals develop a diverse and sophisticated microbial ecosystem for digesting fibrous feedstuffs. Plant cell walls are complex and their structures are not fully understood, but it is generally believed that the chemical properties of some plant cell wall compounds and the cross-linked three-dimensional matrix of polysaccharides, lignin and phenolic compounds limit digestion of cell wall polysaccharides by ruminal microbes. Three adaptive strategies have been identified in the ruminal ecosystem for degrading plant cell walls: production of the full slate of enzymes required to cleave the numerous bonds within cell walls; attachment and colonization of feed particles; and synergetic interactions among ruminal species. Nonetheless, digestion of fibrous feeds remains incomplete, and numerous research attempts have been made to increase this extent of digestion. Exogenous fibrolytic enzymes (EFE) have been used successfully in monogastric animal production for some time. The possibility of adapting EFE as feed additives for ruminants is under intensive study. To date, animal responses to EFE supplements have varied greatly due to differences in enzyme source, application method, and types of diets and livestock. Currently available information suggests delivery of EFE by applying them to feed offers the best chance to increase ruminal digestion. The general tendency of EFE to increase rate, but not extent, of fibre digestion indicates that the products currently on the market for ruminants may not be introducing novel enzyme activities into the rumen. Recent research suggests that cleavage of esterified linkages (e.g., acetylesterase, ferulic acid esterase) within the plant cell wall matrix may be the key to increasing the extent of cell wall digestion in the rumen. Thus, a crucial ingredient in an effective enzyme additive for ruminants may be an as yet undetermined esterase that may not be included, quantified or listed in the majority of available enzyme preparations. Identifying these pivotal enzyme(s) and using biotechnology to enhance their production is necessary for long term improvements in feed digestion using EFE. Pretreating fibrous feeds with alkali in addition to EFE also shows promise for improving the efficacy of enzyme supplements.

• Asian-Australasian Journal of Animal Sciences
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• 제2권4호
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• pp.615-623
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• 1989

Three sheep fitted with rumen cannulae and abomasal cannulae were given daily 750 g (DM) of three diets consisting of straw-manure silage and barley mixture in the ratios of 75:25, 50:50 and 25:75. As the proportion of barley in the diet increased, there was an increase in the amount of OM apparently digested in the rumen and thole tract (P<.01). But ADF digestion was decreased. For the 25:75 diet the $NH_3-N$ content in the rumen showed the highest value, but the total VFA was the lowest. The rumen volume and dilution rate increased with increasing ratio of silage in diets. There were no significant differences between diets in abomasal NAN flow, and the bacterial-N for the 25:75 diet was 7.3 g N as compared with 9.2-9.6 g N for the other diets (P<.01). Rates of bacterial nitrogen synthesis in the rumen were 30.5, 24.1 and 14.9 g N per Kg OM apparently digested in the rumen for the 75:25, 50:50 and 25:75 diets, respectively.

• Asian-Australasian Journal of Animal Sciences
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• 제9권2호
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• pp.133-137
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• 1996

Duckweed, an aquatic plant of the family Lemnaceae, is a rich source of protein and also contains cell wall materials. Spirodela, Lemna and Wolffia, the most available species of duckweeds were evaluated in terms of their chemical composition, the rate and extent of digestion of their dry matter(DM) and crude protein(CP) in the rumen and also their acceptability to the cattle. The three species contained CP of 284, 399 and $299g{\cdot}kg^{-1}$ DM, respectively; NDF of 471, 574 and $476g{\cdot}kg^{-1}$ DM, respectively; ADF of 215, 203 and $227g{\cdot}kg^{-1}$ DM, respectively. The rumen digestibilities of DM of the three species for 24 h were 410, 570 and $731g{\cdot}kg^{-1}$ DM, respectively and of CP were 528, 740 and $778g{\cdot}kg^{-1}$ DM, respectively. The rates of digestion of DM of the three duckweeds were 2.22, 3.63 and $5.73%h^{-1}$, respectively and of CP were 5.14, 4.22 and $6.05%h^{-1}$, respectively. Similarly, the extent of digestion of DM were 853, 723 and $926g{\cdot}kg^{-1}$ DM, respectively and of CP were 801, 874 and $943g{\cdot}kg^{-1}$ DM, respectively. Mixed duckweeds as a component of a concentrate mixture were eaten by the cattle at the rate of 10% of their live weights. It may be concluded that the dry matter and crude protein of the available duckweeds wee highly degradable in the rumen and may be fed to cattle mixing with concentrates. For the effective utilization of duck weeds as cattle feed their effect on the rumen digestion kinetics of a roughage diet need to be studied carefully.

• Asian-Australasian Journal of Animal Sciences
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• 제13권1호
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• pp.23-30
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• 2000

The effects of grass lipids and long chain fatty acids (LCFA; palmitic, stearic and oleic acids), at low concentrations (0.001~0.02%), on the growth and enzyme activity of two strains of anaerobic fungi, monocentric strain Piromyces rhizinflata B157 and polycentric strain Orpinomyces joyonii SG4, were investigated. The addition of grass lipids to the medium significantly (p<0.05) decreased filter paper (FP) cellulose digestion, cellulase activity and fungal growth compared to control treatment. However, LCFA did not have any significant inhibitory effects on fungal growth and enzyme activity, which, however, were significantly (p<0.05) stimulated by the addition of oleic acid as have been observed in rumen bacteria and protozoa. This is the first report to our knowledge on the effects of LCFA on the rumen anaerobic fungi. Continued work is needed to identify the mode of action of LCFA in different fungal strains and to verify whether these microorganisms have ability to hydrogenate unsaturated fatty acids to saturated fatty acids.