• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.904-907
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• 1999

The experiment was aimed at studying the effect of ruminal $NH_3-N$ levels on ruminal fermentation, microbial population, urinary purine derivative excretion, digestibility and rice straw intake in swamp buffaloes. Five, 3 to 4 years old, rumen fistulated swamp buffaloes were randomly assigned according to a $5{\times}5$ Latin square design to rceive five different intraruminal infusions of $NH_4HCO_3$ (0, 150, 300, 450 and 600 g/d) on a continuous daily basis. Rice straw as a roughage was offered ad libitum while concentrate was given at 0.8% BW daily. The results were that as levels of $NH_4HCO_3$ increased, ruminal $NH_3-N$ concentrations increased from 7.1 to 34.4 mg%. The highest digestibility and voluntary straw intakes were found at 13.6 to 17.6 mg% ruminal $NH_3-N$ levels; straw intake was highest at 13.6 mg%. Total bacterial and protozoal counts linearly increased as the ruminal $NH_3-N$ increased and were highest at 17.6 mg%. Total urinary purine derivatives and allantoin excretion were highest (44.0, 37.4 mM/d) at 17.6 mg% ruminal $NH_3-N$. Highest total VFAs (115 mM) were obtained a 13.6 mg% ruminal $NH_3-N$ while blood urea nitrogen significantly increased as ruminal $NH_3-N$ increased. The results from this experiment suggest that optimum ruminal $NH_3-N$ in swamp buffaloes is higher than 13.6 mg%, for improving rumen ecology, microbial protein synthesis, digestibility and straw intake.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.6
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• pp.692-696
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• 1998

An experiment was conducted with eight growing sheep (average initial weight 20.6 kg and average final weight 23.7 kg) in a $4{\times}4$ Latin square design to study the effect of type of forage supplementation to a basal diet of rice straw (ad libitum) and cassava (Manihot esculanta, approximately 9 g of dry matter $(DM).kg^{-0.75}{\cdot}day^{-1}$) on voluntary intake, digestion, rumen microbial protein synthesis and daily weight gain. Forages used were Leucaena (L, Leucaena leucocephala), Gliricidia (G, Gliricidia maculata) and Tithonia (T, Tithonia diversifolia, wild sunflower) at a DM supplementation level of approximately $13g.kg^{-0.75}.day^{-1}$. Organic matter intake was 40.4, 55.5, 55.0 and $54.9g{\cdot}kg.^{-0.75}{\cdot}day^{-1}$ for control (C, ad libitum straw and cassava), L, G and T. respectively, significantly lower for C than for the supplemented diets. Intake of supplementary forage had also a significantly positive effect on voluntary rice straw intake. All forage supplemented diets showed a significantly higher whole diet organic matter digestion than C ($488g{\cdot}kg^{-1}$), while T ($557g{\cdot}kg^{-1}$) differed significantly from L ($516g{\cdot}kg^{-1}$) but not from G ($526g{\cdot}kg^{-1}$). Daily weight gain was -1.7, 5.2, 5.4 and $4.7g{\cdot}kg^{-0.75}$, for C, L, G and T. respectively, significantly lower for C than for the forage-supplemented diets. Efficiency of microbial protein synthesis estimated from urinary excretion of purine derivatives was lower for C (3.8 g microbial N. (kg digestible organic matter intake $(DOMI))^{-1}$ than for the forage supplemented diets (11.3, 9.0 and 9.4 g microbial $N.(kg\;DOMI)^{-1}$ for L, G and T. respectively).

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.139-147
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• 1999

Peptides are formed in the rumen as the result of microbial proteinase activity. The predominant type of activity is cysteine ptoteinase, but others, such as serine proteinases, are also present. Many species of protozoa, bacteria and fungi are involved in ptoteolysis; large animal-to-animal variability is found when proteinase activities in different animals are compared. The peptides formed from proteolysis are broken down to amino acids by peptidases. Different peptides are broken down at different rates, depending on their chemical composition and particularly their N-terminal structure. Indeed, chemical addition to the N-terminus of small peptides, such as by acetylation, causes the peptides to become stable to breakdown by the rumen microbial population; the microorganisms do not appear to adapt to hydrolyse acetylated peptides even after several weeks exposure to dietary acetylated peptides, and the amino acids present in acetylated peptides are absorbed from the small intestine. The amino acids present in some acetylated peptides remain available in nutritional trials with rats, but the nutritive value of the whole amino acid mixture is decreased by acetylation. The genus Prevotella is responsible for most of the catabolic peptidase activity in the rumen, via its dipeptidyl peptidase activities, which release dipeptides rather than free amino acids from the N-terminus of oligopeptides. Studies with dipeptidyl peptidase mutants of Prevotella suggest that it may be possible to slow the rate of peptide hydrolysis by the mixed rumen microbial population by inhibiting dipeptidyl peptidase activity of Prevotella or the rate of peptide uptake by this genus. Peptides and amino acids also stimulate the growth of rumen microorganisms, and are necessary for optimal growth rates of many species growing on tapidly fermented substrates; in rich medium, most bacteria use pre-formed amino acids for more than 90% of their amino acid requirements. Cellulolytic species are exceptional in this respect, but they still incorporate about half of their cell N from pre-formed amino acids in rich medium. However, the extent to which bacteria use ammonia vs. peptides and amino acids for protein synthesis also depends on the concentrations of each, such that preformed amino acids and peptides are probably used to a much lesser extent in vivo than many in vitro experiments might suggest.

• Journal of Microbiology and Biotechnology
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• v.16 no.6
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• pp.870-879
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• 2006

The present study describes the formation of succinic acid by a nonvirulent, highly osmotolerant Klebsiella pneumoniae strain SAP (succinic acid producer), its profile of metabolites, and enzymes of the succinate production pathway. The strain produced succinate along with other metabolites such as lactate, acetate, and ethanol under aerobic as well as anaerobic growth conditions. The yield of succinate was higher in the presence of $MgCO_3$ under $N_2$ atmosphere as compared with that under $CO_2$ atmosphere. Analysis of intracellular metabolites showed the presence of a smaller PEP pool than that of pyruvate. Oxaloacetate, citrate, and $\alpha$-ketoglutarate pools were considerably larger than those of isocitrate and fumarate. In order to understand the synthesis of succinate, the enzymes involved in end-product formation were studied. Levels of phosphoenolpyruvate carboxykinase, fumarate reductase, pyruvate kinase, and acetate kinase were higher under anaerobic growth conditions. Based on the profiles of the metabolites and enzymes, it was concluded that the synthesis of succinate took place via oxaloacetate, malate, and fumarate in the strain under anaerobic growth conditions. The strain SAP showed potential for the bioconversion of fumarate to succinate under $N_2$ atmosphere in the presence of $MgCO_3$. At an initial fumarate concentration of 10 g/l, 7.1 g/l fumarate was converted to 7 g/l succinate with a molar conversion efficiency of 97.3%. The conversion efficiency and succinate yield were increased in the presence of glucose. Cells grown on fumarate contained an 18-fold higher fumarate reductase activity as compared with the activity obtained when grown on glucose.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.5
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• pp.667-673
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• 2014

Eight multiparous Holstein cows ($632{\pm}12$ kg BW; $135{\pm}16$ DIM) were used in a replicated $4{\times}4$ Latin square design to evaluate the effects of forage sources on rumen fermentation characteristics, performance, and microbial protein (MCP) synthesis. The forage portion of the diets contained alfalfa hay (AH), oat hay (OH), Leymus chinensis (LC), or rice straw (RS) as the primary source of fiber. Diets were isonitrogenous and isocaloric, and cows were fed four corn silages based total mixed rations with equivalent nonfiber carbohydrate (NFC) and forage neutral detergent fiber (NDF). Dry matter intake was not affected by the source of dietary forages, ranging from 18.83 to 19.20 kg/d, consequently, milk yield was similar among diets. Because of the numerical differences in milk fat and milk protein concentrations, 4% FCM and ECM yields were unchanged (p>0.05). Mean rumen pH, NH3-N content, and concentrations of volatile fatty acids in the rumen fluid were not affected by the treatments (p>0.05). Dietary treatments did not affect the total tract apparent digestibility of dry matter, organic matter, and crude protein (p>0.05); however, digestibility of NDF and acid detergent fiber in RS diet was higher compared with AH, OH, and LC diets (p<0.05). Total purine derivative excretion was higher in cows fed AH, OH, and LC diets compared with those fed RS diet (p<0.05), consequently, estimated MCP synthesis was 124.35 g/d higher in cows fed AH diet compared with those fed RS diet (p<0.05). The results indicated that cows fed AH, OH, LC, and RS diets with an equivalent forage NDF and NFC have no unfavourable effect on the ruminal fermentation and productive parameters.

• Animal Bioscience
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• v.34 no.4
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• pp.594-602
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• 2021

Objective: An experiment was conducted to assess the effect of dragon fruit peel pellet (DFPP) as a rumen enhancer of dry matter consumption, nutrient digestibilities, ruminal ecology, microbial protein synthesis and rumimal methane production in Holstein crossbred bulls. Methods: Four animals, with an average live-weight of 200±20 kg were randomly assigned in a 4×4 Latin square design to investigate the influence of DFPP supplementation. There were four different dietary treatments: without DFPP, and with 200, 300, and 400 g/h/d, respectively. Results: Results revealed that dry matter consumption of total intake, rice straw and concentrate were not significantly different among treatments (p>0.05). It was also found that ruminal pH was not different among treatments (p>0.05), whilst protozoal group was reduced when DFPP increased (p<0.01). Blood urea nitrogen and NH3-N concentrations were increased at 400 g of DFPP supplementation (p<0.01). Additionally, volatile fatty acid production of propionate was significantly enhanced by the DFPP supplementation (p<0.05), while production of methane was consequently decreased (p<0.05). Furthermore, microbial protein synthesis and urinary purine derivatives were remarkably increased especially at 400 g of DFPP supplementation (p<0.05). Conclusion: Plant secondary compounds or phytonutrients (PTN) containing saponins (SP) and condensed tannins (CT) have been reported to influence rumen fermentation. DFPP contains both CT and SP as a PTN. The addition of 400 g of DFPP resulted in improved rumen fermentation end-products especially propionate (C3) and microbial protein synthesis. Therefore, DFPP is a promising rumen enhancer and indicated a significant potential of DFPP as feedstuff for ruminant feed to mitigate rumen methane production.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.440-447
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• 2009

Domestic ruminant animals are reared in diverse production systems, ranging from extensive systems under semi-arid and tropical conditions with poor feed resources to intensive systems in temperate and cold areas with high quality feed. Nitrogen (N) recycling between the body and gut of ruminants plays a key role in the adaptation to such diverse nutritional conditions. Ammonia and microbial protein produced in the gut and urea synthesized in the liver are major players in N-recycling transactions. In this review, we focus on the physiological factors affecting urea production and recycling. Sheep and buffalo probably have higher abilities to reabsorb urea from the kidney compared with cattle. This affects the degree of urea-N recycling between the body and gut at both low and high N intakes. The synthesis and gut entry of urea also differs between cattle bred for either dairy or beef production. Lactating dairy cows show a higher gut entry of urea compared with growing cattle. The synthesis and recycling of urea dramatically increases after weaning, so that the functional development of the rumen exerts an essential role in N transactions. Furthermore, high ambient temperature increases urea production but reduces urea gut entry. An increase in total urea flux, caused by the return to the ornithine cycle from the gut entry, is considered to serve as a labile N pool in the whole body to permit metabolic plasticity under a variety of physiological, environmental and nutritional conditions.

• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.987-996
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• 2003

This study was conducted to determine the effects of the artificial culture medium of wild-ginsengs on in vitro fermentation characteristics. NH$_3$-N concentration was showed the highest in 3% WGM treatment among all treatments and control. In addition, microbial protein synthesis was significantly different in all treatments throughout the incubation time, and WGM 3% treatment was the highest at the 9 h incubation(P〈0.05). Protozoa numbers within rumen were decreased in all WGM treatments at 9 h incubation time, whereas WGM 3% treatment was always decreased throughout the incubation(P〈0.05). NDF and ADF digestibility were proportionally increased as the incubation time in both control and treatments. NDF digestibility showed no significantly difference between control and the 3% treatment, and ADF digestibility was similar in all. Total volatile fatty acid(VFA) concentrations of WGM treatments without 5% were significantly higher than control (P〈0.05). No differences were observed in total VFA, acetate, propionate and butyrate concentration among the WGM treatments. Acetate/Propionate ratio of WGM treatments was higher than control after 12 h incubation(P〈0.05). As a result of the artificial culture medium of wild-ginseng on rumen fermentation characteristics in vitro, microbial protein synthesis of WGM treatment was higher than control, and WGM 3% was the highest in all treatments(P〈0.05). The effect of saponin in artificial culture medium of wild-ginseng tended to decrease NH$_3$-N concentration, while it increases the microbial synthesis in early incubation. Therefore, artificial cultures medium of wild-ginseng can increase utilization of feed by microbial and anti-protozoal effects of saponin, which may enhance microbial synthesis capacity in early fermentation period in rumen.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.7
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• pp.972-979
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• 2010

The objective of this paper was to review recent studies on nutrient synchrony and the effects of synchronization of energy and N supply in the rumen on nitrogen utilization and animal performance. Theoretically, synchronization of energy and N supply in the rumen should allow more efficient use of nutrients by rumen microbes, increase microbial protein and fermentation end products, and thus increase available nutrients in the small intestine. Efficient use of nutrients possibly improves animal performance and reduces nutrient excretion to the environment. However, a number of studies showed contradictory results in microbial protein synthesis, nitrogen retention and animal production performance. Since there are additional challenges to nutrient synchrony that must be addressed, further research is required to apply the nutrient synchrony concept directly to the field situation.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.187-193
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• 2014

As a result of the cost of grains, the replacement of grains by co-products (i.e. DDGS) in feedlot diets is a common practice. This change produces diets that contain a lower amount of starch and greater amount of fibre. Hypothetically, combining feed grade urea (U) with slow release urea (Optigen) in this type of diet should elicit a better synchrony between starch (high-rate of digestion) and fibre (low-rate of digestion) promoting a better microbial protein synthesis and ruminal digestion with increasing the digestible energy of the diet. Four cannulated Holstein steers ($213{\pm}4$ kg) were used in a $4{\times}4$ Latin square design to examine the combination of Optigen and U in a finishing diet containing different starch:acid detergent fibre ratios (S:F) on the characteristics of digestive function. Three S:F ratios (3.0, 4.5, and 6.0) were tested using a combination of U (0.80%) and Optigen (1.0%). Additionally, a treatment of 4.5 S:F ratio with urea (0.80% in ration) as the sole source of non-protein nitrogen was used to compare the effect of urea combination at same S:F ratio. The S:F ratio of the diet was manipulated by replacing the corn grain by dried distillers grain with solubles and roughage. Urea combination did not affect ruminal pH. The S:F ratio did not affect ruminal pH at 0 and 2 h post-feeding but, at 4 and 6 h, the ruminal pH decreased as the S:F ratio increased (linear, p<0.05). Ruminal digestion of OM, starch and feed N were not affected by urea combination or S:F ratio. The urea combination did not affect ADF ruminal digestion. ADF ruminal digestion decreased linearly (p = 0.02) as the S:F ratio increased. Compared to the urea treatment (p<0.05) and within the urea combination treatment (quadratic, p<0.01), the flow of microbial nitrogen (MN) to the small intestine and ruminal microbial efficiency were greater for the urea combination at a S:F ratio of 4.5. Irrespective of the S:F ratio, the urea combination improved (2.8%, p = 0.02) postruminal N digestion. As S:F ratio increased, OM digestion increased, but ADF total tract digestion decreased. The combination of urea at 4.5 S:F improved (2%, p = 0.04) the digestible energy (DE) more than expected. Combining urea and Optigen resulted in positive effects on the MN flow and DE of the diet, but apparently these advantages are observed only when there is a certain proportion of starch:ADF in the diet.