• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.577-583
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• 2011

In 2007, pet food contaminated with melamine caused hundreds of dogs and cats to develop renal failure all over the world. In 2008, over 294,000 infants consumed infant formula and developed kidney stones in China. Further investigation revealed that fish feed also contained melamine; this raised concerns about melamine residues in edible fish tissues, which could have caused the urinary tract stone epidemic. In Korea, catfish fed with assorted feed that included cuttlefish organs that contained melamine developed whitening syndrome and fell dead in some populations in 2008. This event raised suspicions about the toxicity of melamine and all feeds containing melamine were immediately recalled. In this study, we investigated the rates of melamine accumulation and depletion in muscle and viscera of catfish to propose proper withdrawal periods. One group of catfish was fed a commercially available diet that contained 30, 100 and 300 mg melamine per kg diet for 14 days. To investigate residual melamine contents in muscle and viscera, other experimental groups were fed a melamine free diet after being fed melamine for 7 days. The residual amount of melamine was analyzed by LC-MS/MS. The melamine concentration in muscle was estimated to be 3.7 mg/kg after 6 days of feeding with a diet containing 300 mg melamine/kg. After 2 days of culture with a melamine free diet, the residual melamine was depleted and the concentration had decreased from 1.15 mg/kg to 0.19 mg/kg in the muscle of catfish fed a diet containing 300 mg melamine/kg for 7 days. The residual amount of melamine was reduced to 0.03 mg/kg in muscle after 7 days of culture with a melamine free diet and was undetectable after a prolonged culture period of 14 days. Catfish tend to excrete melamine rapidly after oral administration and changes in body color were not observed during the short dosing period.

• Journal of Animal Science and Technology
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• v.64 no.4
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• pp.717-726
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• 2022

The study evaluated different molt-inducing methods to achieve the main goal of molting in commercial layers during molting and post-molting periods. A total of 400 60-week-old Lohmann Brown layers were randomly divided into five groups (eight replicates of 10 birds for each group). Laying hens in the fasting control group received no diet from day 1 to day 10. The second group received a molt-inducing diet recommended by the breeding company. The third group received a wheat bran-based diet. The fourth group received a commercial layer diet with 8,000 ppm zinc (as zinc oxide, ZnO). The fifth group received an induced molting diet given to the second group with 8,000 ppm zinc, respectively. Egg production in the fasting control group and groups fed a diet with ZnO were significantly lower (p < 0.001) than those in groups fed the molt-inducing and wheat bran-based diets without ZnO during molting. Egg laying in the fasting control group was rapidly reduced and stopped on the 5.9th day of molting. In both groups having molt treatment with ZnO, egg production was similarly reduced and ceased on the 6.9th day and 7.0th day of molting, respectively, none of them differed significantly from the control. Layers fed molt-inducing diet or wheat bran-based diet did not reach the cessation of laying even on the 28th d of molting period. Relative weights of the ovary and growing oocytes of layers subjected to fasting or fed diets with ZnO were significantly lower than those of other groups. During the first two weeks of post molting, layers fed molt-inducing diet with ZnO showed higher egg production than the other two groups (p < 0.01). The eggshell strength in the group fed the commercial diet with ZnO was significantly higher than those fed the molt-inducing diet or wheat bran-based diets at 6 weeks of post molting (p < 0.05). These results suggest that the non-feed withdrawal molting using ZnO is more effective in inducing molting and increasing post-molt egg production and egg quality than other methods using a molt-inducing diet alone or wheat bran-based diet without ZnO.

• Animal Bioscience
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• v.36 no.1
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• pp.75-83
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• 2023

Objective: The objective of this study was to describe a methodological procedure to quantify the heat production (HP) partitioning in basal metabolism or fasting heat production (FHP), heat production due to physical activity (HPA), and the thermic effect of feeding (TEF) in roosters. Methods: Eighteen 54-wk-old Hy Line Brown roosters (2.916±0.15 kg) were allocated in an open-circuit chamber of respirometry for O₂ consumption (VO₂), CO₂ production (VCO₂), and physical activity (PA) measurements, under environmental comfort conditions, following the protocol: adaptation (3 d), ad libitum feeding (1 d), and fasting conditions (1 d). The Brouwer equation was used to calculate the HP from VO₂ and VCO₂. The plateau-FHP (parameter L) was estimated through the broken line model: HP = U×(R-t)×I+L; I = 1 if t<R or I = 0 if t>R; Where the broken-point (R) was assigned as the time (t) that defined the difference between a short and long fasting period, I is conditional, and U is the decreasing rate after the feed was withdrawn. The HP components description was characterized by three events: ad libitum feeding and short and long fasting periods. Linear regression was adjusted between physical activity (PA) and HP to determine the HPA and to estimate the standardized FHP (st-FHP) as the intercept of PA = 0. Results: The time when plateau-FHP was reached at 11.7 h after withdrawal feed, with a mean value of 386 kJ/kg^0.75/d, differing in 32 kJ from st-FHP (354 kJ/kg^0.75/d). The slope of HP per unit of PA was 4.52 kJ/mV. The total HP in roosters partitioned into the st-FHP, termal effect of feeding (TEF), and HPA was 56.6%, 25.7%, and 17.7%, respectively. Conclusion: The FHP represents the largest fraction of energy expenditure in roosters, followed by the TEF. Furthermore, the PA increased the variation of HP measurements.

• Journal of Animal Science and Technology
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• v.56 no.4
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• pp.14.1-14.7
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• 2014

Two trials were conducted to evaluate the influence of supplemental urea withdrawal on characteristics of digestion (Trial 1) and growth performance (Trial 2) of feedlot cattle during the last 40 days on feed. Treatments consisted of a steam-flaked corn-based finishing diet supplemented with urea to provide urea fermentation potential (UFP) of 0, 0.6, and 1.2%. In Trial 1, six Holstein steers ($160{\pm}10kg$) with cannulas in the rumen and proximal duodenum were used in a replicated $3{\times}3$ Latin square experiment. Decreasing supplemental urea decreased (linear effect, $P{\leq}0.05$) ruminal OM digestion. This effect was mediated by decreases (linear effect, $P{\leq}0.05$) in ruminal digestibility of NDF and N. Passage of non-ammonia and microbial N (MN) to the small intestine decreased (linear effect, P = 0.04) with decreasing dietary urea level. Total tract digestion of OM (linear effect, P = 0.06), NDF (linear effect, P = 0.07), N (linear effect, P = 0.04) and dietary DE (linear effect, P = 0.05) decreased with decreasing urea level. Treatment effects on total tract starch digestion, although numerically small, likewise tended (linear effect, P = 0.11) to decrease with decreasing urea level. Decreased fiber digestion accounted for 51% of the variation in OM digestion. Ruminal pH was not affected by treatments averaging 5.82. Decreasing urea level decreased (linear effect, $P{\leq}0.05$) ruminal N-NH and blood urea nitrogen. In Trial 2, 90 crossbred steers ($468kg{\pm}8$), were used in a 40 d feeding trial (5 steers/pen, 6 pens/treatment) to evaluate treatment effects on final-phase growth performance. Decreasing urea level did not affect DMI, but decreased (linear effect, $P{\leq}0.03$) ADG, gain efficiency, and dietary NE. It is concluded that in addition to effects on metabolizable amino acid flow to the small intestine, depriving cattle of otherwise ruminally degradable N (RDP) during the late finishing phase may negatively impact site and extent of digestion of OM, depressing ADG, gain efficiency, and dietary NE.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.2
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• pp.125-136
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• 1997

Digestion of a municipal wastewater sludge by the anaerobic sequencing batch reactor(ASBR) was investigated to evaluate the performance of the ASBR process at a critical condition of high-solids-content feed. The reactors were operated at an HRT of 10 days with an equivalent loading rate of 0.8-1.5 gVS/L/d at $35^{\circ}C.$ The main conclusions drawn from this study were as follows: 1. Digestion of a municipal wastewater sludge was possible using the ASBR in spite of high concentration of settleable solids in the sludge. The ASBRS with 3- and 4-day cycle period showed almost identical high digestion performances. 2. No adverse effect on digestion stability was observed in the ASBRS in spite of withdrawal and replenishment of $30\%\;or\;40\%$ of liquid contents. A conventional anaerobic digester could be easily converted to the ASBR without any stability problem. 3. Flotation thickening occurred in thicken step of the ASBRS throughout steady state, and floating bed volume at the end of thicken period occupied about $70\%$ of the working volume of the reactor. Efficiency of flotation thickening in the ASBRS could be comparable to that of additional gravity thickening of a completely mixed digester. 4. Solids were accumulated rapidly in the ASBR during start-up period. Solids concentrations in the ASBRS were 2.6 times higher than that in the completely mixed control reactor at steady state. Dehydrogenase activity had a strong correlation with the solids concentration. Dehydrogenase activity of the digested sludge in the ASBR was 2.9 times higher than that of the sludge in the control reactor, and about 25 times higher than that of the subnatant in the ASBR. 5. Remarkable increase in equivalent gas production of $52\%$ was observed at the ASBRS compared with the control reactor in spite of similar Quality of clarified effluent from the ASBRS and control reactor. The increase in gas production from the ASBRS was believed to be combined results of accumulation of microorganisms, higher driving force applied, and additional long-term degradation of organics continuously accumulated.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.3
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• pp.351-357
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• 2011

An experiment was conducted to evaluate the effects of castration on growth performance, carcass characteristics, and meat quality of goat kids. Fourteen Boer-cross buck and wether goat kids (n = 7; initial body weight (BW) $38.0{\pm}0.35\;kg$ and $34.8{\pm}0.35\;kg$, for bucks and wethers, respectively) were grazed on annual Marshall ryegrass (Lolium multiflorum Lam.) for 56 days. Body weights were recorded after 4 h withdrawal from feed and water for two consecutive days, every 2 wk. After d 56, animals were harvested and hot carcass weight (HCW), cold carcass weight (CCW), dressing percent (DP), kidney and pelvic fat (KPF), longissimus muscle (LM) area, back fat (BF), and other carcass parameters were measured. Day 0 BW was used as a covariate for analyses. However, bucks were heavier than wethers at d 15 (p = 0.09), 42 (p = 0.001) and 56 (p = 0.001). Bucks had higher ADG (146 vs. 74 g/d; p = 0.001), HCW (21.2 vs. 18.8 kg; p = 0.06) and CCW (20.3 vs. 17.9 kg; p = 0.04) when compared with wether goats. Dressing percentage (51 vs. 47%; p = 0.06), KPF (0.44 vs. 0.16%; p = 0.02) and BF (0.41 vs. 0.21 cm; p = 0.05) were higher in wethers vs bucks, respectively; however, USDA live or carcass grades were similar. Longissimus muscle tissue from wethers and bucks were similar in darkness ($L^*$) and redness ($a^*$), but wethers had more (p = 0.02) yellow tint ($b^*$). Palmitic (C16:0), stearic (C18:0) and oleic (C18:1) acids were higher (p = 0.001) in muscle tissue from wethers compared to bucks. The saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) contents of muscle tissue were lower (p = 0.001) for bucks with no difference in polyunsaturated fatty acids (PUFA). Longissimus muscle initial temperature was higher in bucks (p<0.04) and pH change post-mortem was similar for bucks and wethers. These results indicated that castration of young market goats reduced growth performance and produced carcasses with more fat and higher SFA.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.405-414
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• 2004

This study evaluated the effects of preslaughter feed withdrawal and chiller ageing on objective meat quality traits in longissimus dorsi (LD), biceps femoris(BF), and triceps brachii(TB) muscles of Korean native black pigs. Twenty males were assigned into a 2(pre-slaughter feeding) ${\times}$ 2(pre-slaughter stress) ${\times}$ 4(chiller ageing) factorial. Pre-slaughter fasting for 18 h resulted in significantly(P < 0.05) higher pHs at 1.5 h for both LD and BF. On the other hand, muscle temperature did not differ between the fasted and fed animals. The result implied that pigs with different pre-slaughter feedings experienced different pH-temperature profiles during rigor development. This was reflected by the significan(P < 0.05) increase in cooking loss and hunter $L^*$ for LD of the fed pigs. However, WB-shear force of LD was not affected by the treatment. Furthermore, objective meat quality of BF and TB did not differ between the treatments. Hunter $L^*$ value and cooking loss for LD were constant for 7 d, followed by a significant(P < 0.05) increase at 14 d. BF and TB had significantly(P < 0.05) higher hunter $L^*$ value and cooking loss at 14 d than at 1 d. Significant(P < 0.05) linear reductions in LD WB-shear force took place from 1 to 7 d, while BF and TB WB-shear forces were significantly (P < 0.05) reduced at 14 d. Simple correlation for WB-shear force between LD and BF, and between LD and TB indicated that 6 kg of shear force for LD was equivalent to approximately 3.5 and 6 kg for TB and BF, respectively. On the basis of the current result, feeding until the morning of slaughter appeared to contribute to favourable meat color for LD. However, negative effect on palatability due to increase in cooking loss should be taken into account. A 7-d chiller ageing was likely the best practice for LD, while TB appeared not to require chiller ageing. A 14-d ageing could improve the tenderness of BF, but could likely reduce juiciness.

• Korean Journal of Poultry Science
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• v.35 no.4
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• pp.391-398
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• 2009

The objective of the present study was to compare of the effects of four molting methods on performance of laying hens. In total, 120 White Leghorn layers (62 weeks of age) were used. The four molting methods consisted of 10 days of feeding and the first 3 days of water withdrawal (FW1, 2) followed by ad libitum access to a layer diet 1 and 2 from day 11; 28 days of restricted feeding (NFW1); 28 days without withdrawing their feed (NFW2). Egg production of postmolt decreased until $3{\sim}4$ days at FW1 and FW2 treatments and until $16{\sim}18$ days at NFW1 and NFW2. 50% recovery of egg production were 7, 6, 7 and 5 week at FW1, FW2, NFW1, and NFW2 treatments, respectively. At day 14 of postmolt, the weight of livers, hearts, and oviducts decreased at molting treatments (P<0.05). Egg quality was improved on egg weight, eggshell thickness, eggshell break strength, and Haugh unit except egg yolk color (P<0.05).