• Korean Journal of Poultry Science
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• v.41 no.3
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• pp.151-157
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• 2014

Korean native chicken (KNC) is classified as five lines (grey, black, red, white, brown) based on the plumage colors. The KNC has superior meat quality and flavor compared with those of the commercial broilers, which can be explained by the high arachidonic acid contents. The current study was conducted to investigate arachidonic acid contents in five lines of KNC and used for the development of commercial KNC. Breast and thigh muscles from 597 F1 KNC birds were used in this study and linoleic (precursor of the arachidonic acid) and arachidonic acid contents were measured by the standard protocol. In addition, heritabilities and genetic correlations were estimated. As the results, arachidonic acid contents were significantly different among the KNC lines. Also, relatively high heritabilities (0.414~0.570) for arachidonic acid contents were estimated in both breast and thigh muscles. The estimated genetic correlation was negative between linoleic and arachidonic acids. This study indicated that selection of KNC is possible for improving meat flavor in relation to the arachidonic acid. Also, this study can be used for making breeding plans for commercial KNC in the future.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.2
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• pp.75-84
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• 2018

Thermal stress of livestock has been issued due to recent climate change trends and this causes reproductive disorders, decreased feed consumption, immunosuppression, and increased mortality of animals. Concept of THI has been widely used to quantitatively evaluate the degree of thermal stress for animals, however use of this concept is restricted for animals living in the enclosed facilities such as mechanically ventilated broiler houses. In this study, time-based internal energy flow and variation trends of temperature and humidity were analyzed based on BES technique. Local weather data, insulation characteristics of building materials, heat and moisture generation rate from broilers according to age, algorithm of ventilation operation were adopted for boundary condition of the model to accurately compute THI values inside the mechanically ventilated broiler house. From the BES computation, excess frequency of THI threshold in Jeju city was highest on the assumption that air conditioning equipments were not installed. When general raising density ($39kg\;m^{-2}$) was adopted, total 2,191 hours were exceeded. Excess hours of THI threshold were strongly related to the cumulative air temperature ($R^2=0.87$).

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.527-539
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• 1993

To investigate the effects of crude protein and thyroxine on growth performance, nutrient utilizability, carcass composition, the content of total fat and cholesterol in leg muscle, breast muscle and liver, and caloric efficiency in broiler chicks. The experiment involved 3 levels of dietary crude protein (1-3 weeks: 20, 23, 26%; 4-6 weeks: 17, 20, 23%) and 3 levels of thyroxine (0.0, 1.5, 3.0 mg/kg). In the starting period (1-3 weeks), body weight gain of chicks fed diets containing 26% crude protein and 1.5 mg/kg thyroxine was higher than any other groups, and among thyroxine levels, 3.0 mg/kg thyroxine groups were lower. The best feed efficiency was obtained at 26% crude protein with no thyroxine supplemented or 1.5 mg/kg thyroxine supplemented groups. In the finishing period (4-6 weeks) the highest body weight gain was obtained at 23% crude protein with no thyroxine supplemented group. Feed intake of 17% crude protein with 1.5 mg/kg thyroxine supplemented group was higher than those of the other groups. It was found that the utilizability of crude protein in the starting period, showed the best utilizability at 20% crude protein with 1.5 mg/kg thyroxine group. Increasing crude protein level from 17 to 23%, utilizability of crude fat was decreased. The carcass composition was significantly (p<0.05) influenced by crude protein and thyroxine. Increasing thyroxine level from 0.0 to 3.0 mg/kg, crude protein content was increased whereas, crude fat content was decreased. Chicks fed diet containing 1.5 mg/kg thyroxine showed the lowest total fat content in liver tissue. In breast muscle, it was significantly (p<0.05) affected by crude protein and thyroxine. Present data revealed that the cholesterol content was increased for the chicks fed 3.0 mg/kg thyroxine. It the caloric efficiency, chicks fed a diet containing 20% crude protein with no thyroxine supplementation showed the highest caloric efficiency and the lowest efficiency was from 23% crude protein group with 1.5 mg/kg thyroxine. From this study it may be concluded that crude fat content of carcass could be successfully reduced by dietary supplementation of thyroxine, whereas crude protein content was increased.

• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.399-406
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• 2002

An experiment was conducted to investigate the effects of supplemental copper or/and zinc methionine chelates(Cu-Met or/and Zn-Met) on the performance, nutrient digestibility, serum IgG level, gizzard erosion, and the contents of Cu and Zn in liver and excreta of broiler chickens. One thousand d-old broiler chickens (Ross$^{(R)}$) were assigned to 4 treatments: control, 100 ppm Cu in methionine chelate(Cu-Met), 100 ppm Zn in methionine chelate(Zn-Met) and 100 ppm Cu plus 100 ppm Zn in methionine chelate(Cu-Zn-Met). Each treatment had five replications of 50 (25 male + 25 female) birds each. Average weight gains of chicks fed chelated Cu or/and Zn were significantly higher than that of chicks fed the control (P<0.05). Moreover, feed conversion rates of chicks were better in the chicks fed chelated Cu or/and Zn than in the chicks fed the control (P<0.05). The birds fed the chelated Cu and Zn(Cu-Zn-Met) tended to perform the best growth rate and feed conversion rate. Nutrient digestibilities were not affected by the dietary treatments. Serum IgG level of chicks fed Cu-Zn-Met was significantly higher than that of chicks fed the control (P<0.05). Gizzard erosion index was not significantly different among the treatments. The contents of Cu and Zn in liver were not significantly affected by the dietary treatments. The excreta contents of Cu or/and Zn were significantly high in the birds fed supplementary Cu or/and Zn. It was concluded that dietary supplementation of Cu or/and Zn in methionine chelated form improved growth and feed conversion efficiency of broilers.

• Journal of Animal Science and Technology
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• v.59 no.10
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• pp.23.1-23.11
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• 2017

Background: Although soybean meal (SBM) is excellent source of protein in diets for poultry, it is sometimes inaccessible, costly and fluctuates in supply. The SBM can partially be replaced by full-fat SBM, but the meals prepared from raw full-fat soybean contain antinutritional factors. To avoid the risk of antinutritional factors, heat treatment is always advisable, but either excessive or under heating the soybean could negatively affect the quality. However, the potential for further improvement of SBM by supplementing with microbial enzymes has been suggested by many researchers. The objective of this study was to evaluate the performance and ileal nutrient digestibility of birds fed on diets containing raw soybeans and supplemented with microbial protease. Methods: A $3{\times}2$ factorial, involving 3 levels of raw full-fat soybean (RFFS; 0, 45 or 75 g/kg of diet) and 2 levels of protease (0 or 15,000 PROT/kg) was used. The birds were raised in a climate-controlled room. A nitrogen-free diet was also offered to a reference group from day 19 to 24 to determine protein and amino acid flow at the terminal ileum and calculate the standardized ileal digestibility of nutrients. On days 10, 24 and 35, body weight and feed leftover were recorded to calculate the body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR). On day 24, samples of ileal digesta were collected at least from two birds per replicate. Results: When RFFS was increased from 0 to 75 g/kg of diet, the content of trypsin inhibitors was increased from 1747 to 10,193 trypsin inhibitors unit (TIU)/g of diets, and feed consumption of birds was also reduced (P < 0.05). Increasing RFFS level reduced the BWG from hatch 0 to 10 d (P < 0.01) and hatch to 24 d (P < 0.05). The BWG of birds from hatch to 35 was not significantly (P = 0.07) affected. Feed intake was also reduced (P < 0.05) during 0 to 35 d. However, protease supplementation improved (P < 0.05) the BWG and FCR during 0 to 24 d. Rising levels of RFFS increased the weight of pancreas (P < 0.001) and small intestine (P < 0.001) at day 24. Except for methionine, apparent and the corresponding standardized ileal digestibility of CP and AA were reduced (P < 0.01) by increasing levels of RFFS in diets. Conclusion: This study showed that some commercial SBM could be replaced by RFFS in broiler diets, without markedly compromising productivity. The AID and SID of CP and lysine were slightly improved by dietary supplementation of microbial protease.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.396-403
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• 2009

Male broiler chicks were fed graded levels of organic zinc (zinc-methionine) supplementation to investigate the effects of partial or complete substitution of the organic zinc source for inorganic ones on the development of lymphoid organs and immunological responses. A total of 450 day-old male broilers were distributed into groups of 10 chicks and randomly assigned to nine experimental diets during a 42-day feeding trial. Dietary treatments consisted of two basal diets supplemented with 40 mg/kg added zinc as feed-grade Zn sulfate or Zn oxide in which, Zn was replaced with that provided from zinc-methionine (ZnMet) complex at the levels of 25, 50, 75 or 100%. Two randomly-selected birds from each pen replicate were bled and then slaughtered by cervical cutting on the final day of the trial to measure leukocyte subpopulations and relative weights of lymphoid organs. Among lymphoid organs, only thymus weight was affected (p<0.05) by dietary treatments. The sulfate-supplemented birds were heavier (p<0.01) in relative weight of thymus than oxide-supplemented birds. The 10 days of age-assessed cutaneous hypersensivity reaction was stronger in chicks fed ZnMet-containing diets. Dietary ZnMet supplementation caused (p<0.05) an increase in proportion of lymphocytes and consequently a decrease in heterophil to lymphocyte ratio. Diet fortification by zinc-methionine complex increased (p<0.01) Newcastle antibody titer at 19 days of age. Also, a similar response was observed in antibody titers at 6 and 12 d after infectious bronchitis vaccine administration. There was no significant effect of replacement of dietary zinc on antibody titer against infectious bursal disease virus (IBDV) at the 6th d post-vaccine inoculation; however, at d 12 after vaccination, ZnMet-fortified diets improved antibody titer against IBDV. Although dietary inclusion of ZnMet had no marked effect on primary antibody titer against sheep erythrocytes, effective responses were observed during secondary reaction from the viewpoint of both total antibody and immunoglobulin Y (IgY) titers. From the present findings, it can be concluded that dietary supplementation with organic zinc improves both cellular and humoral immune responses. It is necessary to replace 75% of supplemental inorganic zinc with organic ZnMet complex to achieve the optimum immunological responses in broiler chicks.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.404-409
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• 2009

A total of 240 day-old broiler chicks were used to study the effects of phytase on performance and phosphorus (P) excretion from birds fed diets containing low phytate barleys formulated without inorganic P. A positive control based on Harrington barley (HB) was formulated to meet requirements for total P. Three experimental diets, based on either HB (0.39% total P with 0.28% phytate P) or the low phytate varieties LP 422 (0.36% total P with 0.14% phytate P) and LP 955 (0.40% total P with 0.01% phytate P), were formulated to be below requirements for total P by removing all the inorganic P from the diet. The four diets were fed with and without 1,000 FTU/kg phytase. Apparent P digestibility was significantly higher (p<0.01) for birds fed the low phytate barleys than for birds fed HB either supplemented or un-supplemented with inorganic P. P excretion was significantly lower (p<0.01) for birds fed HB without inorganic P than with inorganic P. P excretion was further reduced by the use of the low phytate barleys LP 422 and LP 455 (p<0.01). Phytase supplementation did not affect P excretion (p = 0.39). Body weight gain and feed intake were highest for birds fed the HB diet with inorganic P and lowest for birds fed the HB diet without inorganic P (p<0.01). Among the three low P diets, body weight gain and feed intake of broilers increased as the level of phytate in the barley declined (p<0.01). Phytase modestly increased body weight gain (p = 0.08) and feed intake (p = 0.04). The overall results of this study indicate that it may be possible to reduce the amount of inorganic P used when formulating diets with low phytate barley compared with the levels needed when formulating diets with normal phytate barley. However, it is not possible to completely replace the inorganic P in diets containing low phytate barley without impairing poultry performance. Feeding diets devoid of supplementary inorganic P in combination with low phytate barley resulted in a significant reduction in P excretion by poultry.

• Korean Journal of Poultry Science
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• v.9 no.2
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• pp.63-101
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• 1982

A study was conducted to investigate the possibility of improving the effectiveness of the existing method(s) to estimate the edible meat weight in live broiler chicken. Four. breeds of chicken, white Cornish broiler chicks(parent stock), Single Comb White Leghorn(SCWL) egg strain chicks (parent stock), and two reciprocal cross breds of these parent stocks were employed in this study. A total of 480 birds, 60 male and 60 female chicks for each breed, were used. Ten male and 10 female chicks from each breed were randomly sacrificed at 0, 2, 4, 6, 8 and 10 weeks of ages in order to measure the body weight, edible meat weight of breast and 1eg(thigh and drum-stick), various components of body weight and various body shape measurements. In addition, chemical analyses of edible meat were carried out. Results obtained from this sturd were summarized as follows. 1. The average body weights of White Cornish broiler chicks and SCWL egg strain chicks were 1.82${\pm}$0.048kg(X${\pm}$S.E.) and 0.67${\pm}$0.029 kg. respectively, at 8 weeks of age. The feed to gain ratio for White Cornish and SCWL chicks were 2.24 and 3.28, respectively, for 0 to 8 weeks of age. The reciprocal cross bred chicks (White Cornish ${\times}$ SCWL) showed intermediate values in both parameters.

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.49-54
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• 2003

This study was carried out to investigate the effects of the inoculated diet with Paecilomyces japonica on weight gain, feed efficiency and cordycepin contents in the breast and thigh meats of broilers. One hundred and twenty broiler chicks were divided into four dietary groups ; 1) control (basal diet), 2) T1 (substituted with 5% inoculated diet), 3) T2 (substituted with 10% inoculated diet) 4) T3 (substituted with 20% inoculated diet) during 4 weeks. Cordycepin contents of inoculated diet with Pacilomyces japonica was significantly higher than before inoculation (P<0.05). Body weight gain and feed efficiency were highest in T1 group when fed starter diet (P<0.05) but these were lowest in T3 group fed when fed finished diet (P<0.05). Body weight gain and feed efficiency were the lowest in T2 group for overall period than other groups. Cordycepin contents of breast and thigh meats were significantly higher in Pacilomyces japonica groups than control at 5 weeks of age (P<0.05). However, it was similar among the T1, T2 and T3 groups. These results indicated that body weight gain and feed efficiency tended to increase in birds fed replaced 5% inoculation diet Cordycepin contents of breast and thigh meats would be increased significantly in birds fed inoculated diet (P<0.05).

• Korean Journal of Poultry Science
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• v.34 no.2
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• pp.129-136
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• 2007

The objectives of this study were to examine the effects of Korean mistletoe (KM) on performance and blood characteristics in broiler chickens. A total of four hundred eighty, 1-d-old male broiler chicks (Ross) were divided into 4 groups with 4 replicates of 30 birds each. The treatments were NC (antibiotics-free diet), PC (NC diet added antibiotics), 0.5% KM (NC diet added 0.5% of KM) and 1.0% KM (NC diet added 1.0% of KM), and the birds were raised for 49 days. There were no significant differences in feed intake and body weight gain among treatments. On d 49, the relative length of jejunum in 1.0% KM tended to be increased or significantly (P<0.05) increased compare to those of other groups. On d 35, the colony forming unit of Salmonella spp. of ceca significantly (P<0.05) decreased by feeding KM. The counts of lymphocyte of KM significantly (P<0.05) increased compare to those of the PC.