• Journal of Aquaculture
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• 제18권2호
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• pp.122-129
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• 2005

Ammonia is the major limiting factor in intensive aquaculture production systems. Therefore, quantification of ammonia excretion is important for the water quality management in aquaculture systems. Ammonia excretion is known to be affected by many factors such as body weight and dietary protein level (DPL). In this study, experiments were carried out to investigate the effects of body weight and DPLs on the rates of ammonia excretion of Nile tilapia Oreochromis niloticus. Three sizes of fishes (mean initial weight; 4.8 g,42.7 g and 176.8 g) were fed each of two dietary protein levels (30.5% and 35.5%). Daily feeding levels for the three fish sizes of 4.8 g, 42.7 g and 176.8 g were 6%, 3%, and 1.5% body weight per day, respectively. Each group of fish was stocked in a 17.1-L aquarium and all treatments were triplicated. Following feeding, the weight-specific ammonia excretion rate of O. niloticus increased, peaked at 4 to 8 h, and returned to pre-feeding levels within 24 h. Total ammonia nitrogen (TAN) excretion.ate per unit weight decreased with the increase of fish weight for each diet (P<0.05). The TAN excretion rate increased with increasing dietary protein content for each fish size (P<0.05). TAN excretion rates (Y) for each diet with different fish weights were described by the following equations: low DPL diet (30.5%): $Y\;(mg\;kg^{-1}\;d^{-1})=955.69-147.12\;lnX\;(r^2=0.95)$, high DPL diet (35.5%): $Y\;(mg\;kg^{-1}\;d^{-1})=1362.41-209.79\;lnX\;(r^2=0.99)$. Where: X=body weight (g wet wt.). The TAN excretion rates ranged 28.5%-37.1% of the total nitrogen ingested for the low DPL diet (30.5%) and 37.4-38.5% for the high DPL diet (35.5%). Total nitrogen losses of fish fed the high DPL diet $(35.5%;\;0.26\sim0.91g\;kg^{-1}\;d^{-1})$ were higher than those fed the low DPL diet $(30.5%;\;0.22\sim0.68g\;kg^{-1}\;d^{-1})$. The losses decreased per kg of fish as fish size increased. Results will provide valuable information fer water quality management and culture of Nile tilapia in recirculating aquaculture systems.

• Asian-Australasian Journal of Animal Sciences
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• 제14권9호
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• pp.1221-1227
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• 2001

Young lambs (Suffolk wethers, n=18), which were 22 to 26 kg average BW, were chronically exposed to temperatures of +1 to +$4^{\circ}C$ (cold) or +21 to +$24^{\circ}C$ (warm) during 10 wk experimental periods. The sheep were closely shorn and were housed in individual metabolism crates in controlled environment rooms. Sheep consumed pelleted diets ad libitum, which consisted of mainly barley grain and brome grass, and contained 7, 11, or 14% CP. The experimental design consisted of a $2{\times}3$ factorial with a single crossover of environment treatment. Feed intake, BW, feces, and urine excretion were measured. Apparent digestibilities were not affected by diet CP concentration or temperature treatments; however, voluntary intake per kg BW was increased (p<0.05) by diet CP content in both environments. Growing lambs gained weight slightly faster in a cold environment when N intake was above 27 g/d. Nitrogen excretion and N balance were positively related (p<0.01) with diet CP content, and fecal N excretion was significantly increased (p<0.05) in the cold environment. Therefore, dietary CP content strongly influenced N metabolism; however, cold exposure did alter only fecal N excretion. The higher DM intake per kg BW at 11% CP diet in the cold environment permitted ADG comparable to 14% CP diet in the warm environment. The results of this study do support the hypothesis that lambs are better able to utilize a moderate reduction in the CP content of the diet in a cold environment.

• Animal Bioscience
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• 제36권11호
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• pp.1718-1726
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• 2023

Objective: The objective of this study was to investigate the effect of supplementation with enzymolytic soybean meal (ESBM) on broilers fed low crude protein (CP) diets. Methods: A total of 360 one-day-old broilers were randomly assigned to six treatments with 6 replicates per treatment and 10 chicks per replicate for a period of 42 days. Chicks were fed a basal standard high-CP diet as a positive control (PC), a low-CP diet (reducing 10 g/kg CP from the PC) as a negative control (NC), or an NC + 0.5%, 1.0%, 1.5%, or 2.0% ESBM diet. Results: Compared to chicks fed the PC, chicks fed the NC had a decreased body weight gain (BWG, p<0.05) from 1 to 42 days, but supplementation with 2.0% ESBM restored BWG (p<0.05) and even linearly improved the feed conversion rate (FCR, p<0.05). Digestibility of CP and ether extract was increased (p<0.05) in chicks fed a 1.0% ESBM diet compared to the PC. With increasing levels of ESBM, nitrogen (N) excretion decreased (p<0.05). The addition of ESBM to the diet did not affect (p>0.05) serum concentrations of total protein, albumin and total cholesterol but led to a descending trend in triglycerides and an ascending trend in calcium and urea N at 42 days (p<0.10). There were no differences (p>0.05) in villus height (VH), crypt depth (CD), and VH/CD (V/C) of the duodenum and jejunum between the PC and NC at both 21 days and 42 days, while increasing dietary ESBM levels linearly (p<0.05) decreased CD and increased V/C of the duodenum and jejunum at both 21 days and 42 days. Conclusion: The findings indicated that ESBM could be used in broiler low-CP diets to improve production performance, decrease N excretion, and enhance intestinal health.

• Ocean and Polar Research
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• 제26권3호
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• pp.415-423
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• 2004

An experiment was conducted to investigate the differences of total ammonia nitrogen (TAN) excretion rates and feces production rates among the offsprings from cultured Japanese strain (JJ, mean BW; $17.1{\pm}0.1g$), intraspecific hybrid strain between cultured Japanese and selected Korean strain (JK, mean BW: $17.1{\pm}0.1g$) and selected Korean strain(KK, mean BW: $21.5{\pm}0.1g$) of red sea bream in order to compare their dietary protein utilization efficiency. Fish were hand-fed with a commercial diet containing 46.7% crude protein for 2 weeks, three times daily 09:00, 13:00 and 17:00. After daily feeding, the TAN excretion rates reached peaks of 49.03, 58.75 and 36.26mg/kg fish/hr for the JJ, JK and KK strain, respectively, during the daytime. The value of the KK strain was significantly lower than that of the JJ and JX shuin (P<0.05), however daily TAN excretion rates of the JJ, JK and KK strain were not different (P>0.05). When fish were fed at satiation after 4 days of starvation, TAN excretion rates reached the maximum values 4 hours after the feeding fur the KK (31.23 mg/kg fish/hr) and 6 hours after the feeding fur the JJ (44.19 mg/tg fish/hr) and JK strain (41.70 mg/kg fish/hr). After 3 days of starvation, the daily endogenous TAU excretion rates (ETE) for the JJ, JK. and KK strain were 286.91, 215.66 and 179.29mg/kg fish/day, respectively. The value of the KK strain was lower than that of the JJ and JK strain (P<0.05). The total feces production rates of the JJ, JK and KK strain were not significantly different, however the proportions of feces production rates by time for the JJ, JK and KK strain were different (P<0.05). As overall results, efficiency of dietary protein utilization of JJ, JK and KK seems to be different and KK strain could offer a desirable option for aquaculture purpose.

• Ocean and Polar Research
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• 제32권1호
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• pp.63-71
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• 2010

An experiment was conducted to investigate the effects of temperature and stocking density on daily patterns and rates of total ammonia nitrogen (TAN) excretion in juvenile red seabream Pagrus major (mean body weight: 29.0 g) under fasting and feeding conditions. Fish were acclimated over 7 days under four different temperatures (10, 15, 20, and $25^{\circ}C$) and at two different densities (5.5 and $11.0\;kg\;m^{-3}$). Each treatment had three replicates and a total of 216 fish were used. After 72 hours starvation, endogenous TAN excretion was measured for each temperature and density. To investigate exogenous TAN excretion, fish were handfed a commercial diet containing 51.6% crude protein twice a day for 7 days, at 08:00 and 16:00. Water was sampled from both inlets and outlets of chambers every 2 hours over a 24 hour period. Both endogenous and exogenous TAN excretion increased with increases in temperature and density (P<0.05). Mean daily endogenous TAN excretion rates at 10, 15, 20, and $25^{\circ}C$ were 88.8, 101.1, 125.0, and $143.3\;mg\;TAN\;kg^{-1}\;d^{-1}$ at low density, and 105.2, 119.2, 141.5, and $168.8\;mg\;TAN\;kg^{-1}\;d^{-1}$ at high density, respectively. Mean daily exogenous TAN excretion rates at 10, 15, 20, and $25^{\circ}C$ were 343.5, 403.7, 535.7, and $601.7\;mg\;TAN\;kg^{-1}\;d^{-1}$ at low density, and 391.9, 479.7, 611.9, and $683.4\;mg\;TAN\;kg^{-1}\;d^{-1}$ at high density, respectively. The exogenous TAN excretion rate peaked 10~12 hours after the first feeding under all temperatures and densities. The TAN loss for ingested nitrogen increased with increases in temperature and density (P<0.05), ranging from 27.9 to 50.1% at low density and 31.7 to 56.9% at high density. This study provides empirical data for estimating ammonia excretion and managing the culture of red seabream under the given temperatures and densities.

• Korean Journal of Ichthyology
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• 제22권3호
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• pp.147-153
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• 2010

A study was carried out to examine the effect of water temperature on daily pattern and rate of total ammonia nitrogen (TAN) excretion in juvenile Pacific cod Gadus macrocephalus (mean body weight: $36.5{\pm}0.8\;g$) under fasting and feeding conditions. Fish were acclimated over 10 days under three different water temperatures (9, 11 and $13^{\circ}C$), and transferred to TAN measuring system under each water-temperature condition. After 72 hours of starving, fasting TAN excretion was measured at each temperature. To investigate post-prandial TAN excretion, fish were hand-fed with a commercial diet containing 40.6% crude protein for 7 days, two times daily at 08:00 and 16:00 h. Water was sampled from both the inlet and outlet of the fish chamber every 2 h over a 24-h period. Both fasting and post-prandial TAN excretion increased with increased water temperatures (p<0.05). Mean fasting TAN excretion rates at 9, 11 and $13^{\circ}C$ were 9.3, 11.0 and $11.9\;mg\;TAN\;kg\;fish^{-1}\;h^{-1}$, respectively. The value of $9^{\circ}C$ was lower than those of 11 and $13^{\circ}C$ (p<0.05), but there was no significant difference between $11^{\circ}C$ and $13^{\circ}C$. Mean post-prandial TAN excretion rates at 9, 11 and $13^{\circ}C$ were 23.0, 31.6 and $45.4\;mg\;TAN\;kg\;fish^{-1}\;h^{-1}$, respectively. A peak value of post-prandial TAN excretion rate occurred after 2 h from each feeding, and the second value is always higher than the first value. Maximum post-prandial TAN excretion rate occurred after 10 h from the first feeding at $9^{\circ}C$ (mean $38.0\;mg\;TAN\;kg\;fish^{-1}\;h^{-1}$), $11^{\circ}C$ ($52.9\;mg\;TAN\;kg\;fish^{-1}\;h^{-1}$) and $13^{\circ}C$ ($77.5\;mg\;TAN\;kg\;fish^{-1}\;h^{-1}$), respectively. The TAN loss for ingested nitrogen at $9^{\circ}C$ (43.9%) was lower than those of $11^{\circ}C$ (46.4%) and $13^{\circ}C$ (48.4%). The overall results indicate that water temperature exhibits a significant effect on the nitrogen excretion of juvenile Pacific cod.

• Korean Journal of Poultry Science
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• 제12권1호
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• pp.17-24
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• 1985

In order to investigate an effect of non-protein nitrogen on the biological utilization of protein, hatched single comb White Leghorn male chicks were fed for the first 8 days with a commercial chicks mash, next 6 days with protein-free diet and subsequent 6 days with protein-free diets and protein diets containing 10.59% of crude protein supplemented with 0, 0.5, 1.0 and 1.5%, respectively. During experimental feeding period, chicks fed protein-free diets had intaked gradually lower feed and had shown a similar body weight loss though urea contents were increased. When birds fed protein diets, body weight gain and feed intake were not different among birds fed the graded levels of urea although feed conversions were shown a highering tendency along with increasing urea contents. According as supplemented urea were increased, protein efficiency ratio f (PER) and net protein ratio (NPR) were increased in chicks fed protein-free diets, which were shown a lowering trend in chicks fed protein diets. Effect of supplemented urea on the urinary excretion of uric acid were not found in birds fed protein-free diets, while which were increased in birds fed protein diets with the increase of urea contents. Urea addition did not affect the excretion of total creatine in birds fed protein-free or protein diets. Excretion of ammonia was jogjered in order to increasing level of urea in birds fed protein-free diets, but which were not found any particular effect in birds fed protein diets. Also urea excretion were gradually increased with the increasing contents of urea in protein-free and protein diets. Nitrogen balance of birds fed protein-free diets were minus values, which were increased with increasing urea contents in diets. When birds fed protein diets, nitrogen balance and urinary nitrogen excretion was highered and fecal nitrogen excretion were not altered as urea levels of diets increased. Digestibility of urea nitrogen supplemented in protein-free diets were lowered along with increasing contents of urea, but biological value(BV) and net protein utilization(NPU) was found a highering tendency in birds fed protein-free diet containing 1.5% of urea. When birds fed with protein diets, digestibility, BV and NPU of protein were found a highering trend in birds fed protein diets added with 0.5% of urea.

• Asian-Australasian Journal of Animal Sciences
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• 제19권9호
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• pp.1291-1297
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• 2006

The potential of the spot urine sampling technique as an alternative to performing a total urine collection to predict the microbial nitrogen supply was evaluated in crossbred bulls. In a completely randomized design, 20 growing crossbred bulls were assigned four levels of feed intake (120, 100, 80 and 60% of voluntary dry matter intake) on diets comprised of wheat straw and concentrate mixture (50:50). After three months of experimental feeding, a metabolism trial was conducted for ten days, during which spot urine collections were performed every 6 h post feeding on days 9 and 10. The daily urinary excretion of allantoin (A) and purine derivatives (PD) decreased with the reduction in feed intake while creatinine (C) excretion remained similar in animals fed at different levels. The microbial nitrogen (MN) supply calculated from the PD excreted in total urine (35.08 to 72.08 g/d) was higher at increased levels of feed intake. PD concentration in spot urine samples had poor correlation with feed intake except at 12 h post feeding. A/C ratio and PD/C ratio in spot urine samples remained similar irrespective of sampling time and significantly (p<0.01) correlated with daily urinary PD excretion, digestible organic matter intake and dry matter (DM) intake. However, no significant differences were evident in these ratios among animals fed at levels 120, 100 and 80% of voluntary dry matter intake (VDMI) at different times post feeding. These results suggests that the spot urine sampling technique to predict the microbial protein supply is not suitable for detecting small differences in MN supply and hence, estimation of PD excreted in total urine (mmol/d) is necessary to assess precisely the MN supply in crossbred bulls.

• Korean Journal of Poultry Science
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• 제38권1호
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• pp.37-43
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• 2011

The effect of cecal ligation on the utilization of dietary [15N]urea in chickens fed 5 % protein diet plus urea were investigated. Nitrogen balance and utilization tended (P<0.01) to increase by cecal ligation. Total uric acid excretion was significantly decrease by (P<0.01) cecal ligation in chickens from origin of diet and urea (P<0.01). Excretion of ammonia was increased in chickens from origin of diet, where as it decreased in chickens an urea diet (P<0.01). Amount of urea nitrogen excretion from origin of urea was significantly decrease (P<0.01) by cecal ligation, but cecal ligated chicken fed 5% protein diet with urea showed 51.6% urea utilization. Result obtained in present study indicates that ceca is having beneficial role for urea utilization in chicken fed protein deficient diets, but ceca do not always positive role for nitrogen utilization.

• Korean Journal of Poultry Science
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• 제29권4호
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• pp.249-253
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• 2002

A 2 ${\times}$ 2 factorial experiment was conducted to determine the effect of cecectomy and urea supplementation on nitrogen utilization In growing chicks. Birds were either cecectomized or shamoperated and fed a 19% protein diet with or without 1% urea supplementation. All chicks were provided ad libitum access to feed and water throughout the six-day experimental period. In the cecectomized chicks, fred efficiency was significantly decreased when fed a 19% protein diet supplemented with 1% urea (P<0.05). When chicks were fed a 19% protein diet, cecectomy significantly shortened gastrointestinal passage time (GPT) of food (P<0.05). However, the GPT was significantly lengthened in chicks fed a 19% protein diet supplemented with urea (P<0.05). Regardless of diets, cecectomized chicks increased the moisture contents of the excreta (P<0.05) and feeding a 1% dietary urea also significantly increased (P<0.05). Cecectomy significantly decreased uric acid N excretion by about 30 mg per 100 g body weight per day (P<0.05) and uric acid N/ total N excretion when fed both diets (P<0.05). The present study suggests that cecectomy improves nitrogen utilization rate by decreasing uric acid excretion in growing chicks. These results are in good agreement with those obtained previously in a cecectomy study of adult chickens.