• Journal of Microbiology and Biotechnology
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• 제18권11호
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• pp.1853-1857
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• 2008

Salmonella contamination in chicken meat was studied with 100 chicken meat samples purchased from 55 shops located in various regions. A total of 21 isolates of Salmonella enterica were isolated from 21 chicken meat samples from four shops located at open markets, whereas there were none from supermarkets with well-equipped cold systems. Among these, 18 isolates were identified as Salmonella enterica serotype Haardt (S. Haardt) and three isolates were S. enterica serotype Muenchen. When the minimal inhibitory concentrations of the S. Haardt isolates were assayed with the agar dilution method to determine susceptibility to ampicillin, chloramphenicol, sulfisoxazole, tetracycline, and nalidixic acid, all 18 isolates were resistant to tetracycline and nalidixic acid and nine of these were resistant to ampicillin. These isolates showed reduced susceptibility to eight fluoroquinolones including ciprofloxacin, enrofloxacin, levofloxacin, gatifloxacin, gemifloxacin, moxifloxacin, norfloxacin, and ofloxacin. When quinolone resistance determining regions of gyrA and gyrB were sequenced, every isolate had the same missense mutation Ser83$\rightarrow$Tyr (TCC$\rightarrow$+TAC) in gyrA, whereas no mutation was found in gyrB. Pulsed-field gel electrophoresis with XbaI revealed a close relationship among these isolates, suggesting a contamination of raw chicken meat with clonal spread of nalidixic acid-resistant and quinolone-reduced susceptibility S. Haardt in chickens. Results in this study show the importance of a well-equipped cold system and the prudent use of fluoroquinolone in chickens to prevent the occurrence of quinolone-resistant isolates.

• Journal of Animal Science and Technology
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• 제63권4호
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• pp.815-826
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• 2021

The objective of the current study was to investigate the effects of stocking density (SD) and dietary supplementation of vitamin C on growth performance, meat quality, intestinal permeability, and stress indicators in broiler chickens. The study was conducted using a completely randomized design with a 2 × 2 factorial arrangement consisting of 2 different SD and 2 supplemental levels of dietary vitamin C. A total of 1,368 Ross 308 broiler chickens of 21 days of age with similar body weights (BW) were randomly allotted to 1 of 4 treatments with 6 replicates each. Different numbers of birds per identical floor pen (2.0 m × 2.4 m) were used to create 2 different SD levels of low SD (9 birds/m²) and high SD (18 birds/m²). The basal diet was formulated with no supplemental vitamin C to meet or exceed nutrient recommendations of the Ross 308 manual. The other diet was prepared by supplementing 200 mg/kg vitamin C in the basal diet. The study lasted for 14 days. At the end of the study, 3 male birds per replicate were selected to analyze meat quality, intestinal permeability, and stress indicators such as blood heterophil:lymphocyte (H:L) and feather corticosterone (CORT) concentrations. Results indicated that there were no interactions between different SD and dietary supplementation of vitamin C for all measurements. For the main effects of SD, birds raised at high SD had less (p < 0.01) BW, BW gain, and feed intake with increasing stress responses including greater blood H:L and feather CORT concentrations (p < 0.01) than those raised at low SD. Transepithelial electrical resistance in the jejunal mucosa was decreased (p < 0.05) at high SD, indicating an increase in intestinal permeability. However, the main effects of dietary supplementation of 200 mg/kg vitamin C were insignificant for all measurements. In conclusion, high SD of broiler chickens impairs growth performance and intestinal barrier function with increasing stress responses. However, dietary supplementation of vitamin C may have little beneficial effects on broiler chickens raised at the high SD condition used in the present study.

• Asian-Australasian Journal of Animal Sciences
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• 제22권3호
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• pp.448-458
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• 2009

It has been well documented from animal and human studies that conjugated linoleic acid (CLA) has numerous beneficial effects on health. In chickens, CLA exerts many effects on performance ranging from egg quality and yolk lipids to meat quality. Although there are several CLA isomers available, not all CLA isomers have the same incorporation rates into egg yolk: cis-9,trans-11 and trans-10,cis-12 CLA isomers are more favorably deposited into egg yolk than other isomers investigated, but of the two isomers, the former has a higher incorporation rate than the latter. CLA alters the amounts and profiles of lipids in plasma, muscles and liver. Furthermore, increased liver weight was reported in chickens fed dietary CLA. As observed in egg yolk, marked reduction in intramuscular lipids as well as increased protein content was observed in different studies, leading to elevation in protein-to-fat ratio. Inconsistency exists for parameters such as body weight gain, feed intake, feed conversion ratio, egg production rate and mortality, depending upon experimental conditions. One setback is that hard-cooked yolks from CLA-consuming hens have higher firmness as refrigeration time and CLA are increased, perhaps owing to alterations in physico-chemistry of yolk. Another is that CLA can be detrimental to hatchability when provided to breeders: eggs from these breeders have impaired development in embryonic and neonatal stages, and have increased and decreased amounts of saturated fatty acids and monounsaturated fatty acids (MUFAs), respectively. Thus, both problems can be fully resolved if dietary sources rich in MUFAs are provided together with CLA. Emerging evidence suggests that CLA exerts a critical impact on stress and immune functions as it can completely nullify some of the adverse effects produced by immune challenges and reduce mortality in a dose-dependent manner. Finally, CLA is a key regulator of genes that may be responsible for lipid metabolism in chickens. CLA down-regulates both expression of the gene encoding stearoyl-CoA desaturase-1 and its protein activity in the chicken liver while up-regulating mRNA of sterol regulatory element-binding protein-l.

• 대한수의학회지
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• 제49권2호
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• pp.135-139
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• 2009

Streptomyces (S.) fradiae is a microbe with broad-spectrum antimicrobial activity, isolated from soil. In the present study, antibacterial effects of S. fradiaea against Salmonella (S.) gallinarum was determined. S. fradiae inhibited growing of S. gallinarum in Luria-Bertani media agar. Moreover, ingestion of S. fradiae markedly inhibited mortality of chickens experimentally infected with S. gallinarum. There is no side effect by S. fradiaeon, in safety of chickens and antibiotic material residues in chicken meat. Taken together, S. fradiae have the antibacterial effects against S. gallinarum. Therefore, we concluded that S. fradiae might be a good microbial candidate for treatment or control of fowl typhoid in chickens.

• 농업과학연구
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• 제45권1호
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• pp.50-57
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• 2018

Meat comes from the skeletal muscles of farm animals, such as pigs, chickens, and cows. Skeletal muscles are composed of many muscle fibers. Muscle fibers are categorized into three types, fiber type I, IIA, and IIB, based on their contractile speed and metabolic properties. Different muscle fiber types have different biochemical, physiological, and biophysical characteristics. Especially, the characteristics of muscle fiber type I and IIB are opposite to each other. Muscle fiber type I has a relatively strong oxidative metabolic trait and a higher content of lipids. In contrast to fiber type I, muscle fiber type IIB has a strong glycolytic metabolic trait and a relatively lower content of lipids and a higher content of glycogen. Muscle fiber type IIA has intermediate properties between fiber type I and IIB. Thus, muscles with different fiber type compositions exhibit different ante- and post-mortem muscle characteristics. In particular, the different metabolic traits of muscles due to the different compositions of the fiber types strongly affect the biochemical and physiological processes during the conversion of muscle to meat and subsequently influence the quality of the meat. Therefore, understating muscle metabolism and muscle fiber characteristics is very important when discussing the traits of meat quality. This review is an overview on basic muscle metabolism, muscle fiber characteristics, and their influence on meat quality and finally provides a comprehensive understanding about the fundamental traits of muscles and meat quality.

• 한국가금학회지
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• 제32권2호
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• pp.101-106
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• 2005

산란노계를 닭고기로서 자원화하여 농가의 수익과 단백질 공급원으로 활용하기 위한 목적으로, 생산성이 낮고 경제적 가치가 적은 산란노계 사료에 목초액을 첨가${\cdot}$급여하여 육질 개선 효과를 조사하기 위하여 계획하였다. 이사브라운 갈색종 240수를 배치하여 대조구에는 육계용 배합사료, 시험 1구에는 국산 목초액 $0.8\%$, 시험 2구에는 외국산 목초액 $0.4\%$를 첨가하여 급여하였다. 사료 섭취량은 대조구가 시험구보다 3g 정도 적었는데 목초액의 유기산이 사료의 소화에 영향을 준 것으로 사려된다. 사육성적의 차이는 국산과 외국산 목초액의 구성성분의 차이에 기인하며, 외국산 목초액의 첨가는 성페르몬과 성분이 유사한 목초액이 내분비 물질의 분비를 촉진한 결과 산란율이 증가하였고, 목초액의 첨가에 따라 조지방 함유량은 다리 고기가 가슴고기보다 많았으며 육색의 개선 효과도 있었다. 다리고기의 육질과 관능검사는 근섬유의 조직을 가늘게 하고 보습력을 증가시키는 외국산 목초액 첨가구에서 좋은 평가를 받았다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권12호
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• pp.1614-1625
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• 2010

Two experiments were conducted to evaluate the use of fish silage prepared from Indian oil sardines, Sardinella longiceps, as partial replacement of soybean meal as a sole source of protein for growing broiler chickens. The main objective of Experiment 1, an ileal digestibility assay, was to assess the nutritional value of fish silage compared with soybean meal for feeding broiler chickens. The two test ingredients, soybean meal and dried fish silage, were incorporated into semi-synthetic diets, as the only component containing protein. The ileal digestibility coefficients of amino acids of fish silage were considerably higher than those of soybean meal (p<0.001). The lower digestibility of amino acids from soybean meal was related to the presence of anti-nutritional factors such as trypsin inhibitors. Fish silage had higher levels of sulphur-containing amino acids than soybean meal. The objective of Experiment 2, a growth study, was to evaluate the effect of feeding fish silage on performance and meat quality characteristics of broiler chickens raised under closed and open-sided housing systems. Four diets containing various levels of fish silage (0, 10, 20 and 30%) were evaluated. Daily feed intake, body weight gain and feed conversion ratio were measured. At the end of Experiment 2, 96 birds were randomly selected and slaughtered to evaluate meat quality characteristics. Housing type had significant effects on feed intake and body weight gain (p<0.01). Birds in the open-sided house consumed 4.7% less amount of feed and gained 10.6% less than their counterparts in a closed house. Birds in both houses fed diets containing 10 and 20% fish silage gained more than birds fed 30% fish silage. The current study produced evidence that fish silage can replace up to 20% of soybean meal in broiler diets without affecting either growth performance or the sensory quality of broiler meat.

• 한국가금학회지
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• 제31권3호
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• pp.151-155
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• 2004

본 실험은 육계사료 내에 맥반석 분말을 첨가 급여했을 때 육계의 성장에 미치는 효과와 생산된 계육의 관능적 품질에 미치는 영향을 조사하기 위하여 실시하였다. 5일령 Avian 육계 수평아리를 반복별로 체중이 동일하도록 임의 배치하였다. 맥반석 분말을 첨가하지 않은 대조구에 맥반석 분말을 1% 및 2% 수준으로 첨가한 처리구를 두었으며, 각각의 처리구 내에는 항생제 음수 투여구와 무투여구를 두어 5처리에 3반복, 반복당 30수씩 총450수를 공시하여 30일간 실험사료를 급여하였다. 실험기간 중의 사료섭취 량 및 증체량을 조사하여 사료요구율을 구하였고, 5주령에 각 반복구 내에서 체중의 평균치에 해당하는 개체를 2수씩 선발하여 희생시킨 후 필요 조직을 채취하였고, 근육 내의 화학적 조성과 육질 평가를 실시하였다. 종료 시 체중 및 증체량은 대조구에 비해 맥반석 분말을 첨가 급여한 처리구에서 다소 증가하는 경향을 나타내었다. 맥반석 분말 1% 첨가구에서 사료 요구율이 개선되었으나, 유의한 차이는 아니었다. 단위 체중당 간 중량 및 복강지방 중량은 맥반석 분말의 첨가 급여에 의해 다소 감소하는 경향을 보여 주었다. 맥반석 분말 2% 첨가구에서 가슴근육의 중량이 가장 높았으며, 다리근육중량은 반대로 낮아지는 경향이 관찰되었으나 통계적인 유의차는 인정되지 않았다. 관능검사 결과에서는 대조구에 비해 맥반석 분말 1% 첨가구에서는 첨가 효과가 나타나지 않았으나, 맥반석 분말 2% 첨가구에서는 맛, 연도 및 다즙성의 전 항목에 걸쳐 유의하게 높아지거나 높아지는 경향을 보여 주었다.

• Animal Bioscience
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• 제35권3호
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• pp.484-493
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• 2022

Objective: This study was conducted to evaluate the effects of the supplementation of diets of broiler chickens with hot-melt extruded CuSO₄ (HME-Cu) on their growth performance, nutrient digestibility, gut microbiota, small intestinal morphology, meat quality, and copper (Cu) bioavailability. Methods: A total of 225 broilers (Ross 308), one-day old and initial weight 39.14 g, were weighed and distributed between 15 cages (15 birds per cage) in a completely randomized experimental design with 3 treatments (diets) and 5 replicates per treatment. Cages were allotted to three treatments including control (without supplemental Cu), IN-Cu (16 mg/kg of CuSO₄), and HME-Cu (16 mg/kg of HME processed CuSO₄). Results: The HME-Cu treatment tended to increase the overall body weight gain (p<0.10). The apparent digestibility of Cu was increased by supplementation of HME-Cu at phase 2 (p<0.05). The Escherichia coli count in cecum tended to decrease with the supplementation with Cu (p<0.10). In addition, the HME-Cu treatment had a higher pH of breast meat than the control and IN-Cu treatments (p<0.05). Significant increases in the cooking loss, water-holding capacity, and lightness in the breast were observed in the HME-Cu treatment compared to the control (p<0.05). The Cu content of excreta increased with the Cu supplementation (p<0.05). The concentration of excreta Cu in broilers was decreased in the HME-Cu compared to the IN-Cu in phase 2 (p<0.05). The Cu concentration in the liver was increased with the HME-Cu supplementation, compared with the control diets (p<0.05). Conclusion: This study showed that HME-Cu supplementation at the requirement level (16 mg/kg diets) in broiler diets did not affect the growth performance and the physiological function of Cu in broilers. However, supplementation of Cu in HME form improved the meat quality and the bioavailability of Cu.

• 한국가금학회지
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• 제39권3호
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• pp.163-166
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• 2012

This study was carried out to compare the cut meat yields of Cobb and Avian and their profits at productive aspect. Two different breeds, Cobb (34,086,758 birds) and Avian (4,087,600 birds) produced from January 2009 to August 2009 were used. The whole chickens were divided into cut meats including tenderloins, breast fillets, whole wings, boneless thighs, and drumsticks. The growth performance and cut meat yield of Cobb and Avian were measured to investigate possible profit difference. Cobb was superior in the aspect of production performance to Avian with significant differences in survival rate and slaughtering age. As the weight gained, the yields of Cobb increased in breast fillets and boneless thighs as well as lean meat percentage. Significantly higher yield (%) of breast fillets was produced by Cobb at size 14 when compared with Avian. However, there was no significant difference in expected market prices for both cut meat and whole chicken meat between the two breeds in all sizes.