• Asian-Australasian Journal of Animal Sciences
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• v.9 no.3
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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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• v.9 no.6
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• pp.637-642
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• 1996

This experiment was conducted to determine RDP values of locally available feedstuffs that are commonly used in ruminant rations in Bangladesh. Four cattle were fistulated in the rumen for the in situ nylon bag studies. Seventeen different feedstuff sample (9 roughages and 8 concentrates) were evaluated in $4{\times}14cm$ nylon bags and incubated in the rumen for different periods of time (2, 6, 12, 24, 48 and 72 h). The variation in crude protein (CP) contents reflected on the average CP disappearance value throughout the rumen incubation. Soluble fraction (a), insoluble but degradable fraction (b) along with the rate of degradation also varied widely among the various feedstuffs. Under 2% of rumen outflow rate, the percentages of the calculated protein degradabilities of roughages were rice straw, 16.7; maize grass, 70.6; oat grass, 70.8; dhal grass, 71.1; sunhemp, 78.4; napier grass, 62.4; matikalai grass, 72.1; khesarikalai grass, 76.9 and daincha browse, 78.4, respectively. The results in the protein degradabilities (%) in 8% ruminal outflow rate of concentrates were wheat bran, 61.6; rice polish (red), 61.3; rice polish (auto), 30.9; mustard oil cake, 71.8; sesame oil cake, 74.2; coconut oil cake, 57.9; soybean meal, 49.2 and fish meal, 37.9, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.1
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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.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.2
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• pp.198-203
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• 2003

Acetone, which is produced from butyric acid when it passes through the rumen wall, was infused into the rumen and jugular veins of three female goats to investigate the role of acetone in ruminating and masticating behavior. The ruminating behavior, as measured by the number of boli and the ruminating time, decreased (p<0.05) with intraruminal acetone infusion. However, the ruminating behavior did not change significantly in response to intravenous acetone infusion. Feed intake significantly decreased with intraruminal acetone infusion, but not with intravenous acetone infusion. The concentrations of acetone in the plasma increased significantly (p<0.05) with both acetone infusion regions. Ruminal fluid acetone, and isopropyl alcohol (IPA), which is one of the ketone bodies, produced from acetone by bacterial action in rumen, concentrations were significantly increased (p<0.05) with both acetone infusion regions. These results suggest that the chemoreceptors sensitive to acetone are more likely to be in the rumen epithelium, portal system, or liver, where they can respond to acetone levels.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.4
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• pp.611-615
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• 1992

Problems with maintaining service and equipment in some developing countries suggest that the rumen bag technique may be more appropriate for the determination of plant dry matter digestibility. The technique has been adapted for use in goats in the 16-25 kg liveweight range. Reliable results were obtained for animals maintained under shelter in cages and fed on a mixed legume/grass diet. The results showed that up to 7 bags containing dried and ground (2 mm screen) plant samples (1-3 g) could be satisfactorily used in each goat. The digestibility of the legumes studied did not increase with incubation times over 48 hours, but there was an increase in the digestibility of grasses. However an incubation time of 48 hours was adapted for both legumes and grasses as it allowed more efficient work scheduling for large numbers of samples while still giving acceptable comparisons between species. Losses of material from the bags during a 6 hour soaking in water were 2-9% as fine solids and 14-21% in solution. In the method finally adapted the disappearance was measured for plant samples that were placed in Dacron mesh bags ($7{\times}14cm$, 44 micron) and 6 bags suspended in the rumen of each sheep for 48 hours.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.313-317
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• 2004

The nutritional requirements for Prevotella sp. 4PCCNB2 isolated from the rumen of a native goat in Korea and those of the ATCC 19189 strain isolated from the bovine rumen were investigated. The two strains grew well with ammonium sulfate as the sole added nitrogen source. However, neither a complex of amino acids nor casein hydrolysate effectively replaced ammonium sulfate. Biotin, p-aminobenzoic acid, and vitamin $B_12$ were essential to culture the ATCC 19189 strain. Unlike the ATCC 19189 strain, however, $B_12$ was only stimulatory for the growth of the 4PCCNB2 strain. The 4PCCNB2 strain grew well in the basal medium without an individual acid such as acetic acid or valeric acid. In contrast, either acetic or valeric acid was absolutely required for the growth of the ATCC 19189 strain.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.2
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• pp.115-120
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• 1990

Extracellular nuclease(s) in buffalo rumen fluid were purified from strained rumen fluid by a procedure involving Seitz filtration, acetone fractionation and gel filtration on Sephadex G-100. The enzyme resolved into two peaks exhibiting both DNase and RNase activities. The molecular weight of enzyme corresponding to peaks I and II were approximately 30,000 and 12,000 respectively. The properties of enzymes from the two peaks, however, were same. Optimum temperature for both DNase and RNase activities was at $50^{\circ}C$. Whereas DNase activity was stable upto $60^{\circ}C$, RNase activity was stable only up to $50^{\circ}C$. DNase activity recorded two pH optima, one at pH 5.5 and the other at pH 7.0. RNase activity recorded a broad pH optimum between pH 6.0-8.0. pH stability of the enzyme coincided with pH optima for both the activities. DNase activity was stimulated by $Mg^{2+}$ and $Mn^{2+}$ and inhibited by $Fe^{2+}$, $Zn^{2+}$, $Hg^{2+}$ and $Ag^+$. RNase activity was also stimulated by $Mg^{2+}$ and $Mn^{2+}$ and inhibited by $Cu^{2+}$, $Fe^{2+}$, $Zn^{2+}$, $Hg^{2+}$ and $Ag^+$. Reducing agents stimulated both the activities.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.8
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• pp.1215-1221
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• 1999

Twelve rumen fistulated cross-bred calves were divided into three groups and fed wheat straw and concentrate mixture according to their maintenance requirement. Animals in group II and III were fed 50 and 100mg rumensin per day, in addition to basal feed. Supplementation of rumensin in the diet decreased the dry matter intake significantly (p<0.05) along with a significant decrease in the straw intake. Digestibility coefficients of all the nutrients were not affected significantly except that of CF digestibility which was lower (p<0.05) in groups II and III as compared to group I. Among N-parameters in the rumen fluid, mean $NH_3-N$ was significantly lower in groups II and III (19.13 and 18.63 mg N/100 ml respectively) than in group I (22.68); total-N and TCA-ppt-N did not differ among the three groups. Total VFA concentration did also not differ among the three groups, however, propionate increased from 24.33 molar % to 32.73 while acetate and butyrate decreased respectively from 65.85 to 58.81% and 9.79 to 8.46%. Total VFA, bacteria and protozoa production rates were not affected significantly due to rumensin in diet. Methane production per kg DDM as well as % of methane in total gas were reduced at both the levels of rumensin on different concentrate ratios with wheat straw as roughage. Similar trend was also observed with rice straw and concentrate mixture as substrate with rumensin addition.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.10
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• pp.1458-1468
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• 2002

There is increasing interest in exploiting natural products as feed additives to solve problems in animal nutrition and livestock production. Essential oils and saponins are two types of plant secondary compounds that hold promise as natural feed additives for ruminants. This paper describes recent advances in research into these additives. The research has generally concentrated on protein metabolism. Dietary essential oils caused rates of NH$_3$ production from amino acids in ruminal fluid taken from sheep and cattle receiving the oils to decrease, yet proteinase and peptidase activities were unchanged. Hyper-ammonia-producing (HAP) bacteria were the most sensitive of ruminal bacteria to essential oils in pure culture. Essential oils also slowed colonisation and digestion of some feedstuffs. Ruminobacter amylophilus may be a key organism in mediating these effects. Saponin-containing plants and their extracts appear to be useful as a means of suppressing the bacteriolytic activity of rumen ciliate protozoa and thereby enhancing total microbial protein flow from the rumen. The effects of some saponins seems to be transient, which may stem from the hydrolysis of saponins to their corresponding sapogenin aglycones, which are much less toxic to protozoa. Saponins also have selective antibacterial effects which may prove useful in, for example, controlling starch digestion. These studies illustrate that plant secondary compounds, of which essential oils and saponins comprise a small proportion, have great potential as 'natural' manipulators of rumen fermentation, to the potential benefit of the farmer and the environment.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.265-270
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• 1993

Ammonia and/or sulphur dioxide treated and untreated wheat leaf sheaths were compared for cell wall digestion by incubation with rumen liquor for 24 and 48 hours. Scanning electron microscope (SEM) was used to study the relative rate and extent of cell wall digestion. Treated wheat straw leaf sheaths were distorted, with more distortion observed in ammonia and sulphur dioxide combined treatment than any other treatment. Rumen liquor digestion for 24 hours of untreated leaf sheath showed disrupted phloem, partially ruptured parenchyma and vascular tissues and further partially distorted inner bundle sheaths and vascular bundle after 48 hours incubation. Sulphurated leaf sheaths showed extensive degraded parenchyma and sclerenchyma material in 24 hours incubation, however, all tissues were irregulary shaped in 48 hours incubation. In ammoniation, epidermal cell walls and small vascular bundles began to disintegrate by 24 hours incubation, extensively changed structure and degraded epidermal tissue by 48 hours incubation. Combination treatment of leaf sheaths degraded all cell walls of parenchyma, phloem and vascular bundle by 24 hours incubation, however, structures only of inner bundles sheath with extended land, sclerenchyma and cutinized epidermal cell walls remained.