• Asian-Australasian Journal of Animal Sciences
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• v.16 no.5
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• pp.748-763
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• 2003

Anaerobic rumen microorganisms mainly bacteria, protozoa and fungi degrade ligno-cellulosic feeds consumed by the ruminants. The ruminants in developing countries are predominantly maintained on low grade roughage and grazing on degraded range land resulting in their poor nutrient utilization and productivity. Hence, manipulation of rumen fermentation was tried during last two decades to optimize ruminal fermentation for improving nutrient utilization and productivity of the animals. Modification of rumen microbial composition and their activity was attempted by using chemical additives those selectively effect rumen microbes, introduction of naturally occurring or genetically modified foreign microbes into the rumen and genetically manipulation of existing microbes in the rumen ecosystem. Accordingly, rumen protozoa were eliminated by defaunation for reducing ruminal methane production and increasing protein outflow in the intestine, resulting in improve growth and feed conversion efficiency of the animals. Further, Interspecies trans-inoculation of rumen microbes was also successfully used for annulment of dietary toxic factor. Additionally, probiotics of bacterial and yeast origin have been used in animal feeding to stabilize rumen fermentation, reduced incidence of diarrhoea and thus improving growth and feed conversion efficiency of young stalk. It is envisaged that genetic manipulation of rumen microorganisms has enormous research potential in developing countries. In view of feed resource availability more emphasis has to be given for manipulating rumen fermentation to increase cellulolytic activity for efficient utilization of low grade roughage.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.8
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• pp.1084-1093
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• 2000

An in vitro gas production system was used to investigate the influence of various substrate mixtures on a natural mix of rumen microbes by measurement of fermentation end-products. The treatments were combinations of cassava (15.0, 30.0 and 45.0%) with different roughage sources (ruzi grass, rice straw or urea treated rice straw). Microbial biomass, net $^{15}N$ incorporation into cells, volatile fatty acid production, gas volume and rate of gas production increased linearly with increasing levels of cassava inclusion. There was also an effect of roughage source, with rice straw being associated with the lowest values for most parameters whilst similar values were obtained for ruzi grass and urea treated rice straw. The results suggest that microbial growth and fermentation rate increase as a function of readily available carbohydrate in the substrate mixture. A strong linear relationship between $^{15}N$ enrichment, total volatile fatty acid production and gas production kinetics support the suggestion of the use of the in vitro gas production system as a tool for screening feedstuffs as an initial stage of feed evaluation.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.643-649
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• 2002

Availability of feeds and fodder and amount of their intake by large ruminants in eight different agro-ecological zones (AEZ) of Bangladesh were recorded over a year. Roughages such as straw, naturally grown green grass, water hyacinth, tree leaves, legumes and sugarcane tops were the major feedstuffs fed to the large ruminants. Amount of intake of these ingredients differed (p<0.01) across AEZ studied, but did not differ across seasons or farmers' categories (p>0.05) except for green grasses (p<0.01). Byproduct concentrates offered to animals in the studied areas were rice bran, wheat bran and different oil cakes. The amount of intake of concentrates by the animals also differed (p<0.01) across AEZs, but did not differ across seasons or farmers' categories (p>0.05), except for rice bran and wheat bran which differed between season and farm category, and season respectively (p<0.01). The large standard errors of mean indicate that there are wide variations in intake of roughages and concentrates across AEZ's, seasons and farmers' categories and even across days. This further indicates that the feeding practices of large ruminants are largely heterogeneous. In addition to feeding roughage and concentrates, the animals were allowed to graze for six hours a day. Grazing hours also differed (p<0.01) across AEZ, but not by farmers' categories or seasons.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1238-1244
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• 2001

Two calorimetric experiments were performed to investigate the effects of two diets with same concentrate: roughage ratio (70:30) but varying in composition on energy metabolism and methane production in faunated (F) and defaunated (DF) Muzaffarnagari sheep. For experiment I, ten animals were divided equally into two groups of which one was kept normally F as such while other was DF using 10% sodium lauryl sulphate. All the animals were offered diet I which comprised of oat hay and concentrate mixture I (CM I) containing maize grain (93%) as a major ingredient in 70:30 ratio. Similarly, the experiment II was conducted for which four F and four DF sheep (same as used for experiment I) were switched to diet II that consisted of maize hay and CM II (maize grain 59% + molasses 36%). Through diet II, DM intake in DF sheep was significantly (p<0.05) lower. Intake of GE through both the diets was similar in F and DF sheep. Digestibility of DM, OM, CP and GE and also metabolisability (ME/GE) was similar in F and DF sheep on both the diets. Total urinary energy loss did not differ in F and DF on both the diets, but methane energy loss as a percent of GE in DF was significantly (p<0.05) lower on diet I (3.75 vs 2.48), while it did not differ on diet II (3.20 vs 3.60). Heat production was significantly (p<0.01) reduced in DF on both the diets. Although, efficiency of utilisation of ME for maintenance calculated as per ARC (1984) did not differ in F and DF on both the diets, efficiency for maintenance and growth was higher (0.60 vs 0.672) on diet I in DF. It was inferred that methane production in DF sheep reduces on good quality hay-based diet supplemented with slowly fermentable carbohydrate (maize grain) but supplementation of molasses (rapidly fermentable CHO) nullify this effect when sheep were fed diets with concentrate: roughage ratio of 70:30.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.46-54
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• 2014

This study was conducted to investigate the effects of eucalyptus (E. Camaldulensis) crude oils (EuO) supplementation on voluntary feed intake and rumen fermentation characteristics in swamp buffaloes. Four rumen fistulated swamp buffaloes, body weight (BW) of $420{\pm}15.0$ kg, were randomly assigned according to a $2{\times}2$ factorial arrangement in a $4{\times}4$ Latin square design. The dietary treatments were untreated rice straw (RS) without EuO (T1) and with EuO (T2) supplementation, and 3% urea-treated rice straw (UTRS) without EuO (T3) and with EuO (T4) supplementation. The EuO was supplemented at 2 mL/h/d in respective treatment. Experimental animals were kept in individual pens and concentrate mixture was offered at 3 g/kg BW while roughage was fed ad libitum. Total dry matter and roughage intake, and apparent digestibilites of organic matter and neutral detergent fiber were improved (p<0.01) by UTRS. There was no effect of EuO supplementation on feed intake and nutrient digestibility. Ruminal pH and temperature were not (p>0.05) affected by either roughage sources or EuO supplementation. However, buffaloes fed UTRS had higher ruminal ammonia nitrogen and blood urea nitrogen as compared with RS. Total volatile fatty acid and butyrate proportion were similar among treatments, whereas acetate was decreased and propionate molar proportion was increased by EuO supplementation. Feeding UTRS resulted in lower acetate and higher propionate concentration compared to RS. Moreover, supplementation of EuO reduced methane production especially in UTRS treatment. Protozoa populations were reduced by EuO supplementation while fungi zoospores remained the same. Total, amylolytic and cellulolytic bacterial populations were increased (p<0.01) by UTRS; However, EuO supplementation did not affect viable bacteria. Nitrogen intake and in feces were found higher in buffaloes fed UTRS. A positive nitrogen balance (absorption and retention) was in buffaloes fed UTRS. Supplementation of EuO did not affect nitrogen utilization. Both allantoin excretion and absorption and microbial nitrogen supply were increased by UTRS whereas efficiency of microbial protein synthesis was similar in all treatments. Findings of present study suggested that EuO could be used as a feed additive to modify the rumen fermentation in reducing methane production both in RS and UTRS. Feeding UTRS could improve feed intake and efficiency of rumen fermentation in swamp buffaloes. However, more research is warranted to determine the effect of EuO supplementation in production animals.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.5
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• pp.623-635
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• 2011

Inefficient rumen microbial fermentation is a major factor limiting intake of low quality roughage in ruminants. In this study, the effect of energy supplementation on rumen microbial fermentation, absorption of balanced digestion products and voluntary feed intake in sheep was investigated. A basal diet of a urea-treated mixture of wheaten chaff and barley straw (3:1 DM) containing 22.2 g N/kg DM was used. Four Merino-cross wethers weighing $45{\pm}4.38\;kg$ and fitted with permanent rumen and abomasal cannulae were allocated to four treatments in a $4{\times}4$ Latin square design. The dietary treatments were basal diet ($E_0$), or basal diet supplemented with sucrose (112.5 g/d) administered to the animals intra-ruminally ($E_R$), abomasally ($E_A$), or through both routes (50:50) ($E_{RA}$). Feed intake (basal and dietary) was increased (p<0.05) by sucrose supplementation through the rumen ($E_R$) or abomasum ($E_A$). However, there was no difference (p>0.05) in intake between animals on the control diet and those supplemented with sucrose through both intraruminal and abomasal routes ($E_{RA}$). The digestibility of DM and OM was highest in $E_R$ and $E_A$ supplemented animals. Although the rumen pH was reduced (p<0.001) in animals supplemented with sucrose entirely intra-ruminally ($E_R$), the in sacco degradation of barley straw in the rumen was not adversely affected (p>0.05). Intra-ruminal sucrose supplementation resulted in a higher concentration of total VFA, acetate and butyrate, while the pattern of fermentation showed a higher propionate: acetate ratio. Intra-ruminal supplementation also increased (p<0.05) the glucogenic potential (G/E) of the absorbed VFA. However, there was no difference (p>0.05) in microbial protein production between the four dietary treatments. Protozoa numbers were increased (p<0.05) by intra-ruminal supplementation of sucrose.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.2
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• pp.165-174
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• 2012

This study was conducted to develop Miscanthus as a new roughage resource for ruminant animals. Miscanthus sacchariflorus var. No 1, a newly developed germtype in Korea, was harvested at late maturity stage and its effect on rumen pH, ammonia nitrogen, gas production, volatile fatty acid (VFA) production and digestibility were evaluated using in vitro rumen fermentation. The effects of Miscanthus were compared with rice straw. Miscanthus showed significantly higher pH compared to rice straw (p<0.01). As for ammonia nitrogen, there was no significant difference after 12 h of incubation (p>0.05). Gas production in Miscanthus was significantly lower than that of rice straw in overall incubation time (p<0.05) after 6 h of incubation. In VFA production, acetate, propionate, butyrate, valerate and total VFA production in Miscanthus were lower than those in rice straw. However, production of iso-butyrate and iso-valerate were not different in between two forage materials. Dry matter digestibility of Miscanthus was significantly lower than rice straw (p<0.05) during 12~24 h of incubation. As a result, the availability of Miscanthus as roughage source showed approximately 80% that of rice straw.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.774-780
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• 2011

Inadequate supply of glucose or glucogenic substrates to the body tissues can affect metabolism of absorbed acetogenic metabolites from the gut and therefore, influence feed intake in ruminants. This study investigated the effect of energy supplementation on rumen kinetics in the gut, and the acetate clearance rate in the body tissues of sheep fed low quality basal roughage. A basal diet consisting of urea-treated mixture of wheaten chaff and barley straw (3:1 DM) containing 22.2 g N/kg DM was used. Four Merino cross wethers weighing $45{\pm}4.38\;kg$ fitted with permanent rumen and abomasal cannulae were allocated to four treatments in a $4{\times}4$ LSD. The treatments were basal diet ($E_0$), or basal diet supplemented with sucrose (112.5 g/d) administered intraruminally ($E_R$), abomasally ($E_A$), or via both routes (50:50) ($E_{RA}$). There was no difference (p>0.05) in the rumen liquid kinetics parameters between the four dietary treatments. However, there was a trend of animals supplemented with sucrose wholly or partly through the abomasum having lower faecal DM and therefore poor pellet formation, and low pH. Although the glucogenic potential of the fermentation products absorbed from the rumen was increased (p<0.001) by intra-ruminal supplementation with sucrose ($E_R$ and $E_{RA}$), there was no significant difference (p<0.05) in acetate clearance rate between the four dietary treatments.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.1
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• pp.45-49
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• 1996

A series of in vitro experiments was conducted to investigate response of rumen bacterial deamination to the ionophore salinomycin. Addition of salinomycin to the inoculum, strained rumen fluid, depressed ammonia production from casein, while increased accumulation of ${\alpha}$-amino acids. This suggests an inhibitory effect of salinomycin on ruminal deamination. When the effect in washed bacterial suspension was monitored with individual amino acid, aspartic acid degradation was markedly inhibited by salinomycin. This inhibition was not observed when the mixed rumen bacteria were ultrasonically disrupted and used as the enzyme source. Extent of the inhibition tended to be higher in the bacteria source from sheep on a high roughage diet. From these results it was speculated that the inhibition of deamination with salinomycin is caused by a decreased transport of amino acid into the bacterial cells as well as a decreased proportion of deaminating bacteria in the rumen.

• Journal of Animal Science and Technology
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• v.46 no.2
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• pp.201-208
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• 2004

This study, in which sheep were used as models for beef cattle, was conducted to determine the effect of replacing 100% of rice straw with deepstacked broiler Iitter(BL) as a roughage source on total tract apparent digestibility, digestible nutrient intake, ruminal and blood parameters, and N balance of sheep. Under the conventional formulated mix-rice straw(60: 40) feeding system(control), replacement of rice straw with BL resulted in similar(P> 0.05) total tract apparent digestibilities of fiber and organic matter, similar(P> 0.05) intake of digestible NDF, ADF and organic matter, and higher(P <0.05) intake of digestible crude protein. Feeding BL instead of rice straw resulted in 10wer(P <0.05) ruminal pH, higher(P <0.05) $NH^3-N$ concentration and similar(P> 0.05) rominal volatile fatty acid percentage and blood urea concentration. In a N balance study, increased(P<0.05) N intake for the BIAed group induced higher(P <0.05) quantities(g/d) of fecal and urinary N excretion, bodily N absorption, and N retention. It was concluded that deepstacked BL fiber was comparable to rice straw fiber as a roughage source and BL protein was also favorably utilized within the body of ruminant.