• Asian-Australasian Journal of Animal Sciences
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• v.10 no.4
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• pp.364-370
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• 1997

Four local cattle were ($145{\pm}9.7kg$) used in a $4{\times}4$ Latin square design to study the effect of different levels of rumen degradable protein (RDP) in straw based ration on purine derivatives excretion and microbial N supply in cattle. The four rations were formulated at the same amount of energy but varying RDP approximately 50 (U0), 75 (U1), 100 (U2) and 150 (U3) percent levels of RDP requirement for maintenance. They were fed ranged from 101 to 304 g RDP/d. Apparent digestibility of all nutrients increased significantly (p < 0.01) in cattle fed ration U2 than other rations. Rumen $NH_3-N$ concentration increased from 43 to 130 mg/l in response of RDP intake. Purine derivatives excretion increased significantly (p < 0.01) with incremental level of 203 g RDP/d (U2) intake and positively correlated (r=0.69, p < 0.01, n=16) with amount of RDP intake. The rates of rumen microbial N supply were 16.8, 27.2, 39.1 and 32.9 g/d for rations U0, U1, U2 and U3 respectively. Efficiency of microbial N supply (EMNS) per kg of DOMR were 19.0, 25.3, 33.0, and 28.6 g and per MJ of ME. Intake were 0.62, 1.00, 1.44 and 1.21 g for U0, U1, U2 and U3 respectively and highest results were obtained in cattle fed U2 ration. Results of this study suggest that PD excretion and EMNS were increased as incremental level of RDP intake (U2) in local cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1137-1142
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• 2003

In a balanced incomplete block design, two dry Holstein cows were used to investigate the effect of $\beta$ 1-4 galactooligosaccharides (GOS) supplementation on nitrogen (N) utilization, rumen fermentation and microbial N supply in the rumen. During the experiment, cows were fed four diets: orchardgrass (Dactylis glomerata L.) silage (OS), OS with GOS supplementation (OSG), OS mixed with alfalfa (Medicago sativa L.) silage (MS) and MS with GOS supplementation (MSG). GOS was supplemented at 2% of dry matter intake. Diets were fed at maintenance level of protein and energy. Results showed that N digestion was affected by silage and interaction of silage and GOS supplementation. Cows fed OSG had the highest N digested (p<0.05) followed by MS, OS and MSG. Supplementation of GOS to OS or MS diets tended to improve N utilization through reducing the N losses on dairy cows. There was no effect of GOS supplementation on rumen fermentation parameters (i.e. pH, $NH_3$-N and total VFA) at 1 h and 6 h after feeding. Compared to cows fed MS, cows fed OS silage had higher (p<0.05) allantoin excretion (80.8 vs. 67.1 mmol/d) and higher (p<0.05) total purine derivatives excretion (92.9 vs. 78.5 mmol/d). The microbial N supply in cows fed OSG was higher (p<0.05) than those fed OS, MS and MSG.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.378-387
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• 2009

To investigate the effects of sago palm pith (SPP) substitution of corn in the diets on intake, digestibility, rumen fermentation characteristics, nitrogen balance and microbial N Supply, five ruminally fistulated Southern indigenous cattle (mean initial BW = 226${\pm}$5 kg) were randomly assigned to a 5${\times}$5 Latin Square Design to receive five diets, $T_1$ = concentrate with 0% SPP, $T_2$ = 25% SPP, $T_3$ = 50% SPP, $T_4$ = 75% SPP and $T_5$ = 100% SPP, of dietary dry matter, respectively. Plicatulum hay (PH) was offered ad libitum as the roughage. A metabolism trial lasted for 21 days during which liveweight changes and feed intakes were measured. Based on this experiment, there were no significant differences (p>0.05) among treatments groups regarding total DM intake (OMI, NDFI and ADFI) and digestion coefficients of nutrients (DM, OM, CP, NDF and ADF), while total DM intake (% BW) was significantly (p<0.05) higher as higher levels of SPP were incorporated into diets. Rumen parameters (ruminal temperature, pH, glucose, packed cell volume, volatile fatty acid and rumen microorganism populations) were similar among treatments (p>0.05), whereas $NH_3-N$, blood urea nitrogen and molar proportion of propionate concentrations were significantly (p<0.05) higher as higher levels of SPP were incorporated into diets. The amount of N absorption, N retention and microbial protein synthesis were similar among treatments. These results indicate that SPP can be included in diets for Southern indigenous cattle to supply up to 100% of supplemental corn when fed with PH without negative impact on animal performance and it was a good approach in exploiting the use of local feed resources for beef cattle production.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.10
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• pp.1567-1574
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• 2007

A study was carried out to study the response of total purine derivatives (PD) excretion in urine to determine microbial N (MN) supply at four fixed levels of feed intake (namely 95, 80, 60 and 40% of voluntary intake). The crossbred (CB) calves were allocated according to a $4{\times}4$ Latin Square Design and fed wheat straw and concentrate (1:1). The rate of PD excretion (mmol/d) as a linear function of feed intake was 15.85/kg DMI and 20.12/kg DOMI. Based on the endogenous and PD excretion rates obtained in this study, a relationship between daily urinary PD excretion (Y, mmol) and daily microbial protein supply (X, mmol) was developed for crossbred calves as Y = 0.83X+0.296 kg $W^{0.75}$. The derived microbial N values using this equation differed (p<0.001) among the 4 groups and was the highest in L-95 followed by L-80, L-60 and L-40. The relationship between urinary nitrogen loss (Y, g/d) and DOMI (X, kg/d) was established as: Y = 6.038X+21.753 ($r^2$ = 0.663, p<0.01). When urinary excretion of PD (Y, mmol/d) was plotted against intake of DM and DOM (X, kg/d), the equations obtained were: Y = 7.1711X+8.674 ($r^2$ = 0.889, p<0.01) and Y = 12.434X+7.683 ($r^2$ = 0.896, p<0.01), respectively. The proportional contribution of allantoin and uric acid to total PD remained stable irrespective of level of feed intake. Similarly, urinary excretion of creatinine did not differ (p>0.05) between animals fed at different levels. The MN supply was the highest to animals at intake levels L-95, and decreased linearly with corresponding decrease in feed intake. However, the MN supply when expressed per kg DOMI remained statistically (p>0.05) similar irrespective of level of intake. The results revealed that the excretion of urinary purine derivatives were positively correlated with the level of feed intake as well as rumen microbial supply and thus it could be a good indicator for measuring the microbial protein supply and nutritional status of animals.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.11
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• pp.1568-1574
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• 2012

Three Holstein steers in the growing phase, each with a ruminal cannula, were used to test the hypothesis that the synchronization of the hourly rate of carbohydrate and nitrogen (N) released in the rumen would increase the amount of retained nitrogen for growth and thus improve the efficiency of microbial protein synthesis (EMPS). In Experiment 1, in situ degradability coefficients of carbohydrate and N in feeds including Korean rice wine residue (RWR) were determined. In Experiment 2, three total mixed ration (TMR) diets having different rates of carbohydrate and N release in the rumen were formulated using the in situ degradability of the feeds. All diets were made to contain similar contents of crude protein (CP) and neutral detergent fiber (NDF) but varied in their hourly pattern of nutrient release. The synchrony index of the three TMRs was 0.51 (LS), 0.77 (MS) and 0.95 (HS), respectively. The diets were fed at a restricted level (2% of the animal's body weight) in a $3{\times}3$ Latin-square design. Synchronizing the hourly supply of energy and N in the rumen did not significantly alter the digestibility of dry matter, organic matter, crude protein, NDF or acid detergent fiber (ADF) (p>0.05). The ruminal $NH_3$-N content of the LS group at three hours after feeding was significantly higher (p<0.05) than that of the other groups; however, the mean values of ruminal $NH_3$-N, pH and VFA concentration among the three groups were not significantly different (p>0.05). In addition, the purine derivative (PD) excretion in urine and microbial-N production (MN) among the three groups were not significantly different (p>0.05). In conclusion, synchronizing dietary energy and N supply to the rumen did not have a major effect on nutrient digestion or microbial protein synthesis (MPS) in Holstein steers.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.75-81
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• 2007

The object of this study was to determine the influence of supplementation of concentrate containing high levels of cassava chip on rumen ecology, microbial protein and digestibility of nutrients. Four, rumen fistulated crossbred beef steers with initial body weight of 400${\pm}$10 kg were randomly assigned according to a 4${\times}$4 Latin square design. The dietary treatments were concentrate cassava chip based offering at 0, 1, 2 and 3% BW with urea-treated rice straw fed ad libitum. It was found that ruminal pH was significantly decreased with increase of concentrate. Volatile fatty acids (VFA) concentration in the rumen was significantly different among treatments. In addition, a molar proportion of propionate was higher in supplemented groups at 2 and 3% BW (p<0.05), leading to significantly decreased acetate:propionate ratio. Furthermore, microbial N supply was significantly improved and was highest at 2% BW supplementation. The efficiency of rumen microbial-N synthesis based on organic matter (OM) truly digested in the rumen was highest in level of concentrate supplementation at 2% BW (80% of cassava chip in diets). Moreover, bacterial populations such as amylolytic bacteria was linearly increased, while cellulolytic bacteria was linearly decreased (p<0.01) when cattle received concentrate supplementation in all levels. The total protozoal counts were significantly increased, while fungal zoospores were dramatically decreased in cattle receiving increased levels of concentrate. In conclusion, cassava chip can be use as energy source at 80% in concentrate and supplementation of concentrate at 2% BW with urea-treated rice straw as roughage could improve rumen fermentation efficiency in beef cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.11
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• pp.1623-1631
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• 2006

The objective of this study was to evaluate the effect of protein and energy on goats fed oil palm fronds (OPF) as roughages. Twenty-four male Saanen goats aged between 7 and 8 months and weighing $23.4{\pm}1.6kg$ were used in a $2{\times}3$ factorial design. Factors were three levels of urea (3%, 4% or 5%) and two levels of energy (low energy (LE) or high energy (HE)). On average, all parameters measured, including dry matter intake (DMI), nutrient digestibility, digestible nutrient intakes, ruminal ammonia-N ($NH_3$-N), ruminal total volatile fatty acid (total VFA) and individual VFA concentrations (mM/L), microbial N supply, P/E ratio and N retention were higher for HE compared to LE diets. Significant (p<0.05) interactions were found between levels of urea and energy for nonstructural carbohydrate (NSC) and energy (DE) digestibilities, ruminal $NH_3$-N and total VFA concentrations. HE diets had higher N absorption and retention than LE diets. Interactions between urea and energy for plasma urea nitrogen (PUN), heat production (HP), and urine and faeces N excretion were significantly lower (p<0.05) for the HE diets than those recorded for the LE diets. The results indicated that supplementation of energy enhanced utilization of urea and resulted in higher animal performance as a consequence of improved ruminal fermentation, microbial yield and N balance. However, the optimal level of urea supplementation remained at 3% in the HE diet.

• Environmental Engineering Research
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• v.19 no.1
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• pp.101-105
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• 2014

Three magnesium compounds, $MgO_2$, MgO, and $Mg(OH)_2$, which are supposed to supply oxygen continuously, were applied onto contaminated bay sediment and its ecology in order to activate the local microbial flora. Those compounds were found to reduce chemical oxygen demand (COD), total nitrogen (T-N), and total phosphorus (T-P). Magnesium oxide, in particular, reduced COD by 30% and T-N and T-P considerably. All compounds also suppressed the release of pollutants in the order $MgO_2$, MgO, and $Mg(OH)_2$. Analysis of microbial flora showed that the microbial group treated by $MgO_2$ and $Mg(OH)_2$ was predictably stable; meanwhile, that treated by MgO increased the number of species, but decreased the total number of microorganisms.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.3
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• pp.347-355
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• 2006

A study was conducted to predict the rumen microbial protein production based on urinary excretion of purine derivatives in buffaloes fed a diet of wheat straw and concentrate (40:60) at four fixed levels of feed intake. (95, 80, 60 and 40% of preliminary voluntary feed intake) following experimental protocol of IAEA (Phase I). The buffaloes were allocated according to a $4{\times}4$ latin square design. The urinary allantoin, uric acid, total PD excretion (mmol/d) in treatments L-95, L-80, L-60 and L-40 was 20.13, 16.00, 12.96 and 9.17; 1.88, 2.12, 2.11 and 2.15; 22.01, 18.12, 15.07 and 11.32, respectively and were significantly (p<0.05) different among treatments except for uric acid. The rate of PD excretion (mmol/d) was positively correlated with the digestible organic matter intake. Variations were observed in PD and creatinine concentration in spot samples collected at 6-hour interval. However, daily PD:Creatinine ratio (PDC index) appears to be a reasonably good predictor of microbial-N supply. The contribution of basal purine excretion to total excretion of purine derivatives (PD) was determined in pre-fasting period followed by a fasting period of 6 d (Phase II). Daily PD and creatinine excretion (mmol/kg $W^{0.75}$) during fasting averaged 0.117 and 0.456 respectively for buffaloes. The excretion rates of PD decreased significantly (p<0.01) during fasting compare to pre-fasting period, the urinary creatinine excretion remained almost similar. Except for creatinine, plasma concentration of target parameters significantly (p<0.01) declined during fasting. Likewise, glomerular filtration rate (GFR) and renal clearance of allantoin and uric acid also decreased. Based on the PD excretion rates during fasting and at different levels of feed intake obtained in this study, a relationship between daily urinary PD excretion (Y-mmol) and microbial purine absorption (X-mmol) was developed for buffaloes as Y = 0.74X+0.117 kg $W^{0.75}$. The microbial N supply (g/kg DOMI) remained statistically similar irrespective of dietary treatment. The results showed that excretion of urinary purine derivatives is positively correlated with the levels of feed intake in Murrah buffaloes and thus, estimation of urinary purine derivatives and PDC index could be used to determine microbial nitrogen supply when there is large variation in level of feed intake.

• 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.