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Korean J. Food Sci. Ani. Resour. Vol. 30, No. 3, pp. 504~511(2010) ARTICLE 복합생균제와항생제급여가육계의생산성및육질에미치는영향 박성현 최정석 정동순 어중혁 1 최양일 충북대학교축산학과, 1 중앙대학교식품공학과 Effects of Complex Probiotics and Antibiotics on Growth Performance and Meat Quality in Broilers Sung-Hyun Park, Jung-Suk Choi, Dong-Soon Jung, Joong-Hyuck Auh 1, and Yang-Il Choi Department of Animal Science, Chungbuk National University, Cheongju 361-763, Korea 1 Department of Food Science & Technology, Chungang University, Ansung 456-756, Korea Abstract This study was undertaken to investigate the effects of feeding complex probiotics (Lactobacillus casei, Bacillus subtilis, Saccharomyces cerevisiae, Aspergillus oryzae, Streptomyces griseus, 1.5 10 10 CFU/kg) and antibiotics (oxytetracycline (OTC), 110 ppm) on growth performance and meat quality characteristics of broiler chicks. In the experiment 1, 0.3% complex probiotics feeding level was chosen to be proper addition level due to better average daily gain (ADG), feed conversion (FC) and dressing percent (DP) results among 3 levels (0.1, 0.3 or 0.5%). In the experiment 2, 5 treatments (T1, no probiotics + no antibiotics; T2, probiotics 0.3% + no antibiotics; T3, probiotics 0.3% + antibiotics 50%; T4, probiotics 0.3% + antibiotics 100%; T5, no probiotics + antibiotics 100%) were investigated. In the growth performance of broilers, T5 (antibiotics 100% only) showed the highest (p<0.05) ADG and FC values while T1 (control) showed the worst growth performance. However, T3 (probiotics 0.3% + antibiotics 50%) showed higher ADG (p<0.05), FC (p<0.05) and DP (p>0.05) values compared to control. In the breast and leg meat quality, T3 showed similar ph, proximate composition, cooking loss and meat color values except shear force value compared to T5. Addition of 0.3% probiotics with 50% antibiotics (T3) tended to lower the blood cholesterol levels of broiler chicks and Escherichia coli or Salmonella counts in cecum microflora of broiler chicks compared to T5. In the residual antibiotics analysis, T3 contained 0.04 ppm of residual antibiotics in the breast meat while T4 or T5 contained 0.1 ppm of residual antibiotics and addition of 0.3% probiotics with 50% antibiotics in broiler diets could lower the residual antibiotics level to 40% in the meat. As a result, 0.3% probiotics addition with 50% antibiotics in the broiler diets could be recommended for the production of high quality broiler meat. Key words: complex probiotics, antibiotics, growth performance, meat quality, broiler 서 국민소득의증대로인한연간일인당육류소비량은 1975년 6.4 kg에서 2007년 35.8 kg으로 5.6배이상증가하였다. 그중닭고기의소비는단연높은증가율을보이고있다. 축산물소비자들은예전의양적소비에서개선된육질에대한욕구와건강에대한관심은그어느때보다도높다. 그중에서도육계의사료에함유되어있는항생제의남용은심각한수준이다. 항생제는질병의예방차원에서뿐만아니라육계의성장촉진및사료효율을개선시키 Corresponding author : Yang-Il Choi, Department of Animal Science, Chungbuk National University, Cheongju 361-763, Korea. Tel: 82-43-261-2550, Fax: 82-43-273-2240, E-mail: yangilchoi@chungbuk.ac.kr 론 는목적으로이용되었으나 (Bird, 1969; Guest, 1976), 과도하게사용시축산물에잔류되어인체에전이되고결과적으로알레르기등의질환을일으키거나, 인체의내성을증가시켜질병발생시약물치료효과를감소시키는등의문제를일으킬수있어사용규제가제기되고있다 (Mitsubashi et al., 1961; Roe와 Pillai, 2003). 수의사처방에의한동물용의약품의사용을의무화하고있는미국, 일본을비롯한주요축산선진국가들은인체의건강에미치는영향을고려하여과학적근거에바탕을둔항균성물질의위험평가에따라기존에사용이승인된항균성물질에대한대폭적인감축이나엄격한사용규제를위한법적제도의정비에대한논의를이미오래전부터진행하고있다. 국내의경우에도최근농림수산식품부는축산물에대한소비자의신뢰제고를위해 2011년하반기부터사료에항생 504

Probiotics on Growth Performance and Meat Quality of Broiler 505 제첨가를전면금지한다고발표하였다 ( 농림수산식품부, 2010). 최근에이러한문제들의인식으로인해항생제대체물질로서동물에게유익한미생물을계획적으로투여할수있는생균제의개발과이용분야는많은관심을받고여러연구들이이루어지고있다. 생균제란사람이나동물의장내균총을개선함으로써유익한효과를주는단일또는복합균주형태의생균제재를말하는데 (Parker, 1974), 그종류에는효모를포함하여곰팡이류나젖산균들이많이이용된다. 이러한생균제가항생제대체물질로서각광받는이유는항생제가장내정상적인균총형성을억제시키지만생균제는장내정상적인균총형성에도움을주고병원성미생물의항생제내성발생과는관계가없기때문이다 (Isolauri et al., 200. 또한항생제의첨가로인한잔류문제를유발하지않고장내미생물의균형유지와대장균의감소를통한성장촉진및하리방지효과가있다 (Jin et al., 1996; Line et al., 1998; Higgins et al., 2008). 육계에있어서생균제급여효과에관한연구에서는맹장과대장내의균총에영향을주며, 이들로부터성장개선효과가있는것으로보고되었다 (Han et al., 1984; Jin et al., 1998; Kim et al., 2000; Yeo and Kim, 1997; Yu et al., 2004; Zhang et al., 2005). Kim 등 (2000) 은복합생균제를육계사료에첨가하여 4주간사육한결과, 증체량과사료요구율이개선되었으며, 혈중콜레스테롤수치도낮았고, 장내균총에서도 Coliform spp. 는현저하게감소하였다고발표하였다. Yu 등 (2004) 도복합생균제를육계사료에첨가하여 7주간사육한결과육계초기부터급여된생균제가육계후기에그균총이장내에정착하게됨으로장내유해세균의수는감소시켰고, 영양소흡수에최적의조건을조성하여생산성이개선된다고보고하였다. 그러나이러한생균제들의연구에서생산성이외에육질특성에대한결과는그다지많지않으며, 육질개선에대한효과도일관성있게나타나지않았다 (Kim, 2007; Kim and Yoon, 2008; Park and Yoo, 2000; Pelicano et al., 2003; Yu et al., 2004). Pelicano 등 (2003) 은생균제를육계에급여시계육의명도가감소하였고, ph와관능검사중풍미가증가하였으나, 보수력, 가열감량및전단력에는큰영향이없었다고하였다. 그외 Yu 등 (2004) 은복합생균제를육계에급여시계육의가열감량은대조구에비해유의적으로낮았으나, 전단력은오히려유의적으로높았다고하였으며, 다른연구결과에서는생균제급여가육게의육질에큰영향을나타내지않았다 (Kim, 2007; Kim and Yoon, 2008; Park and Yoo, 2000). 따라서본연구에서는복합생균제와항생제첨가수준을달리하여육계의생산성및육질에미치는영향을조사하여항생제저감가능성을구명하고자수행하였다. 재료및방법 사양시험 1 육계사료에첨가목적으로국내외에서다양한생균제가시도되었는데, 이에는 Lactobacillus spp., Bacillus spp., Saccharomyces cerevisiae 등을들수있는데, 육계의짧은사육기간의특성으로많은실험결과에서단독생균제보다는복합생균제의급여가우수한것으로보고되어본사양실험에서도복합생균제를사용하였다 ( 유등, 2004; 김, 2007; 김과윤, 2008). 복합생균제 (Lactobacillus casei, Bacillus subtilis, Saccharomyces cerevisiae, Aspergillus oryzae, Streptomyces griseus, 1.5 10 10 CFU/kg) 의적정첨가수준을결정하기위해생후 17일령수평아리 160수를 4 개시험구 ( 각처리구당 10수, 4반복 ) 로하여 4일간적응시험후 21일령부터 35일령까지사양시키면서제반생산성을구명하였다. 사양시험에이용된후기사료는 Table 1에서보는바와같다. 복합생균제첨가수준은 0, 0.1, 0.3과 0.5% 로하였으며, 항생제 (oxytetracycline, OTC) 수준은기존첨가수준 (110 ppm) 의 50% 인 55 ppm으로각 4개처리구에동일하게첨가하였다. 국립수의과학검역원고시 (2003) 에의하 Table 1. Composition of experimental diets Ingredients (%) Finisher (3-5 wk) Yellow corn 59.35 Corn gluten meal 2.79 Soybean meal 30.66 Limestone 0.63 Tricalcium phosphate 1.77 Salt 0.36 Choline Cl 0.03 Animal fat 3.69 Lysine HCl 0.06 DL-methionine 0.32 Mineral premix 0.11 Vitamin premix 0.07 Total 100.00 Calculated analysis Dry matter (%) 87.63 Crude protein (%) 21.00 Ether extract (%) 5.73 Crude fiber (%) 3.10 Ash (%) 5.51 Ca (%) 0.90 Available P (%) 0.46 TMEn (kcal/kg) 3,080.00 Mineral mix providing following nutrients per kg of diet : Mn, 77 mg; Zn, 57.2 mg; I, 0.32 mg; Se, 0.11 mg; Cu, 27.5 mg. Vitamin mix providing following nutrients per kg of diet : Vitamin A, 15,600 IU; Vitamin D3, 3,120 IU; Vitamin E, 15.6 mg; Vitamin K, 30.91 mg; Vitamin B1, 1.3 mg; Vitamin B12, 0.026 mg; Niacin, 52 mg; Oxystat, 65 mg; Biotin, 0.039 mg; Pyridoxin, 1.3 mg; Riboflavin, 13 mg; Pantothenic acid, 15.6 mg.

506 Korean J. Food Sci. Ani. Resour., Vol. 30, No. 3 (2010) 면육계에항생제 (OTC) 사용시 500 mg 이하의양을 1L의음수에녹여경구투여하는것으로권장되었으나, 본연구에서는박과유 (2000) 의방법에따라사료에첨가하였다. 사양시험 2 상기예비실험에서구명된복합생균제적정첨가수준 (0.3%) 을토대로생균제와항생제첨가에의한육계의생산성과육질특성을구명하였다. 시험처리구는 Table 2에서보는바와같으며, 생후 17일령수평아리 300수를 5개시험구 ( 각처리구당 20수, 3반복 ) 로하여사양시험 1과동일한방법으로 4일간적응시험후 21일령부터 35일령까지사양시키면서제반사양성적과육질특성및잔류항생물질수준을조사하였다. 시험방법 일반성분 육질분석에서가슴육의수분, 단백질, 지방및회분 (%) 은 AOAC방법 (1995) 에따라건조법, 켈달법, 속실렛법및회화법을사용하여분석하였다. ph ph는시료 10 g에증류수 90 ml를가하여 1분간균질시킨후 digital ph meter(mettler Delta 340, Mettler- Toledo, Ltd., UK) 로측정하였다. 가열감량 가열감량 (cooking loss) 은두께 1cm의가슴육시료를 70 o C 에서 40분간가열하여가열한후의감량을가열전무게로나눈백분율로표시하였다. 전단력 시료를 70 o C water-bath에넣고 40분간가열한후 30분간방냉시킨후시료를가로 세로 높이를각각 1 2 1cm 가되도록절단하여 Rheo meter(model Compac-100, SUN SCIENTIFIC Co., Ltd.) 의 Shearing, Cutting Test로 Max weight를측정하였다. 사용프로그램은 R.D.S(Rheology Data System) Ver 2.01을이용하였다. Table Speed 는 110 mm/ Table 2. Experimental design for complex probiotics addition T1 (Control) T2 T3 T4 T5 Complex probiotics - 0.3% 0.3% 0.3% - Antibiotics - -.50% 100% 100% Lactobacillus casei, Bacillus subtilis, Saccharomyces cerevisiae, Aspergillus oryzae, Streptomyces griseus, 1.5 10 10 CFU/kg. Compared to ordinary addition level (110 ppm), 50% or 100% of oxytetracycline was added. min, Graph Interval은 20 msec, Load cell(max) 는 10 kg의조건으로하였다. 육색 가슴육의표면육색은 30분간발색후백색판 (L, 89.39; a, 0.13; b, -0.5 으로표준화시킨 Spectro Colormeter (Model JX-777, Color Techno. System. Co., Japan) 로측정하였는데, 이때광원은백색형광등 (D65) 을사용하여 CIE L( 명도 ), a( 적색도 ), b( 황색도 ) 값으로나타내었다. 장내미생물조사 시험종료시장내미생물조사는한등 (1984) 의방법을기초로하여각처리구별로 3수씩을임의선발하여도계후맹장 (cecum) 내용물을무균적으로채취한후멸균된생리식염수로연속희석하여 Escherichia coli와 Salmonella 균수를측정하였다, E. coli는 MacConkey agar를, Salmonella 는 SS agar를이용하여 37 o C에서 48시간동안배양한후장내용물 g당미생물수 (colony forming unit) 로표시하였다. 혈중콜레스테롤분석 혈액시료는 Kim 등 (2000) 의방법을기초로하여시험종료후각처리구별로 3수씩을임의선발하여익하동맥에서채취하였고, 혈액응고를방지하기위해 heparin 처리된 tube에냉장보관하였다. Plasma는냉장보관후 15분동안 2,000 rpm에서원심분리하여채취하였다. 혈장내 cholesterol 농도는효소적방법으로정량하였다. 항생물질분석 근육내잔류항생물질인 oxytetracycline(otc) 을분석하기위한시료전처리는컬럼충진제인 C18을이용한 MAPD (Matrix solid-phase dispersion) 법으로시료가 C18에의해균질화되어넓은표면적을갖게한후추출용매에의해 OTC성분을용출시켰다. 추출된용매는 40 o C의건열농축상에서질소로농축시킨후이동상에의해용해되어 0.45 µm acrodisc로여과시킨후 HPLC로분석하였다. 표준용액은 OTC 단일표준품을사용하여잔류성분을측정하였다. 통계분석본실험의통계처리는 SAS(1999) 의 General Linear Model을이용하여분석하였고, Duncan 다중비교로유의성 5% 수준에서비교하였다. 결과및고찰 복합생균제첨가수준에따른육계의사양성적복합생균제첨가수준에따른육계의사양성적과도계율에대한결과는 Table 3에서보는바와같다. 일당증체량

Probiotics on Growth Performance and Meat Quality of Broiler 507 Table 3. Effect of complex probiotics addition levels on growth performance and dressing percent of broiler Items Control Probiotics addition 0.1% 0.3% 0.5% Initial body wt (21d, g) 618.10±18.71 a 620.00±6.31 ab 626.20±08.30 a 630.30±11.5 a 0 Final body wt (35d, g) 1469.02±12.11 a 1490.80±8.51 ab 1540.40±24.30 a 1559.80±17.80 a Average daily gain (g) 60.80±11.4 b 1 62.20±1.8 ab 1 65.30±01.5 a 0 64.80±01.2 a 0 Feed conversion 1.98±00.02 a 1.96±0.05 ab 1.89±00.02 b 1.92±00.04 b Dressing percent (%) 66.10±00.51 a 65.50±0.91 ab 66.70±01.00 a 65.20±00.6 a 0 Oxytetracycline was added at 55 ppm to all experimental diets (50% of ordinary addition level). Feed intake/body weight gain (day 21 to 35). a,b Means in the same row with different superscripts differ (p<0.05). 의경우생균제무첨가구인 T1에서가장낮았으며, 첨가수준이증가할수록일당증체량이증가하여생균제 0.3% 첨가구인 T3에서유의적으로높았다. 도계율은처리구간에유의적인차이가없었지만, 처리구 T3에서가장높았고, 반면에처리구 T4에서가장낮은경향을보였다. 사료요구율은무첨가구인 T1에서가장높았으며, 첨가수준이증가할수록사료요구율이유의적으로감소하였는데, 생균제 0.3% 첨가구인 T3에서가장낮았다. 위의결과는복합생균제를육계사료에첨가하여사육한결과증체량, 사료요구율과도체율이개선되었다는 Yu 등 (2004) 의연구결과와일치되는경향이었다. 이상의결과에서생균제 0.3% 첨가구의경우일당증체량과사료요구율이가장우수하였으며, 도계율도가장높은경향을나타내어적정첨가수준으로선택되었다. 복합생균제첨가에의한육계의생산성과육질특성사양성적예비실험에서규명된생균제적정첨가수준을 0.3% 로고정시키고, 생균제와항생제첨가수준을달리한육계의사양성적과도계율에대한결과는 Table 4에서보는바와같다. 일당증체량과사료요구율은항생제만을 100% 급여한처리구 T5에서가장좋게나타났으나, 생균제 0.3% 와항생제 50% 를첨가한처리구 T3에서도우수한일당증체량과사료요구율성적을나타내었다. 생균제의육계급여시장내미생물에영향을미치는여러대사산물을생산하 여맹장과대장내의미생물균총에영향을주어일당증체량이나사료요구율등의성장개선효과가있는것으로보고된바있으며 (Han et al., 1984; Jin et al., 1998; Kim et al., 2000; Yeo and Kim, 1997; Yu et al., 2004; Zhang et al., 2005), 본연구결과도일치하는경향을나타냈다. 도계율은복합생균제 0.3% 와항생제 50% 만을급여한처리구 T3 에서가장높게나타났으나, 처리구간에유의적인차이는없었다. Park and Yoo(2000) 는육계사료에항생제, 생균제및효모제를 0.1% 첨가시증체량과사료섭취량은첨가구간에유의차는없었으나항생제첨가구가높은경향이었으며, 사료요구율은항생제와생균제첨가구에서낮은경향을나타내어항생제대용으로생균제나효모제를육계에급여하여안전한계육생산에효과적이라고하였다. 일반성분 생균제와항생제첨가수준을달리한육계가슴육의일반성분은 Table 5에서보는바와같다. 처리구간에가슴육의수분, 단백질, 지방및회분성분에는유의적인차이는보이지않았다. Park and Yoo(2000) 와 Kim(2007) 에의하면육계에생균제첨가는계육의일반성분에유의적인영향을미치지않았다고하여본실험결과와일치하는경향을보였다. 가슴육의 ph 및가열감량, 전단력, 육색 생균제와항생제첨가수준을달리한육계가슴육의육질특성은 Table 6에서보는바와같다. 가슴육의 ph는생 Table 4. Effect of complex probiotics addition and antibiotics levels on growth performance and dressing percent of broiler Items T1 T2 T3 T4 T5 Initial body wt (21d, g) 640.10±08.20 a 636.50±12.10 aa 630.30±14.70 a 644.50±08.70 a 618.80±11.60 a Final body wt (35d, g) 1429.90±12.50 a 1458.50±17.20 aa 1480.80±10.50 a 1447.80±20.20 a 1507.40±23.40 a Average daily gain (g) 60.70±01.4 c 0 63.20±00.7 bc 0 65.40±01.3 b 0 61.80±00.5 c 0 68.40±01.5 a 0 Feed conversion 1.95±00.02 a 1.89±00.03 ba 1.84±00.02 b 1.98±00.04 a 1.71±00.02 c Dressing percent (%) 69.00±00.90 a 68.50±00.60 aa 71.70±00.80 a 69.70±00.50 a 69.40±00.90 a a-c Means in the same row with different superscripts differ (p<0.05).

508 Korean J. Food Sci. Ani. Resour., Vol. 30, No. 3 (2010) Table 5. Effect of complex probiotics addition and antibiotics levels on proximate composition of breast meat Composition (%) T1 T2 T3 T4 T5 Moisture 74.68±0.14 75.10±0.10 75.05±0.39 75.11±0.38 74.70±0.24 Protein 24.18±0.20 23.58±0.13 23.70±0.50 23.67±0.36 23.94±0.26 Fat 0.58±0.13 0.71±0.08 0.64±0.13 0.69±0.15 0.73±0.12 Ash 0.56±0.03 0.61±0.04 0.62±0.04 0.55±0.08 0.61±0.03 Table 6. Effect of complex probiotics addition and antibiotics levels on meat quality characteristics of broiler breast meat T1 T2 T3 T4 T5 ph 06.00±0.20 06.20±0.06 06.02±0.09 06.05±0.22 06.14±0.17 Cooking loss (%) 18.51±1.57 16.22±1.47 18.48±3.07 18.84±3.08 16.32±1.19 Shear force (g) 1709.80±693.41 1768.00±971.64 2044.70±1013.96 2549.30±731.78 1880.50±608.84 L ab 64.10±5.51 ab a 58.17±2.99 b a 67.60±3.27 a a 66.89±5.27 a a 66.78±6.14 a CIE a 02.01±0.69 02.76±1.48 03.46±1.67 03.33±2.35 02.10±0.70 b 0 a 9.48±1.22 a a 07.06±1.70 b 0 aa 9.15±1.88 ab a 09.61±2.30 a 0 aa 9.09±1.17 ab CIE L (lightness), a (redness), b (yellowness). a, b Means in the same row with different superscripts differ (p<0.05). 균제 0.3% 만을첨가한처리구 T2와항생제 100% 만을급여한 T5 처리구에서높게나타났으나, 처리구들간에유의적차이는없었다. 가열감량은 ph가높은 T2와 T5 처리구에서낮은경향이었으며, 상대적으로 ph가낮은처리구들에서높은가열감량을보였다. 전단력의경우생균제 0.3% 와항생제 100% 를급여한 T4 처리구에서가장높았고, 대조구인 T1이나복합생균제 0.3% 만을급여한 T2처리구에서는낮은수치를나타냈으나, 유의적인차이는없었다. 육색은생균제 0.3% 만을첨가한 T2 처리구에서가장낮은백색도와황색도를나타냈으나, 다른처리구들간에는유의적인차이가없었다. 생균제첨가에의한육계가슴육의육질특성연구에서 Yu et al.(2004) 은생균제첨가가무첨가구에비해가열감량을유의적으로낮추었으나, 전단력의경우는유사하거나높아지는결과를나타내어본연구결과에서처럼일정한경향을보이지않았다. Pelicano 등 (2003) 도생균제를육계에급여시가슴육의명도가감 소하였고, ph는증가하였으나, 가열감량및전단력에는큰영향이없었다고하였다. 다리육의 ph 및가열감량, 육색생균제와항생제첨가수준을달리한육계다리육의육질특성은 Table 7에서보는바와같다. 다리육의 ph는가슴육에비하여높은 ph를나타내었으며, 항생제 100% 만을급여한 T5 처리구에서대조구보다유의적으로높은 ph 를나타냈으나, 대조구와생균제처리구들사이에는유의적인차이가없었다. 가열감량의경우 ph가높은생균제 0.3% 와항생제 50% 가급여된 T3와 T5 처리구에서낮은경향을나타냈으나, 전처리구간에유의적인차이는없었다. 육색은처리구 T2, T3와 T5에서상대적으로높은명도를나타냈으며, 적색도는처리구 T5에서, 황색도는처리구 T4에서높았으나, 처리구들간에유의적인차이는나타나지않았다. Kim(2007) 은육계에복합생균제 0.2% 를 Table 7. Effect of complex probiotics addition and antibiotics levels on meat quality characteristics of broiler leg meat T1 T2 T3 T4 T5 ph 16.58±0.17 b 16.63±0.07 ab 16.71±0.07 ab 16.70±0.08 ab 16.77±0.09 a Cooking loss (%) 19.12±1.36 18.78±1.18 18.60±1.81 19.58±3.55 18.61±2.30 CIE a 18.36±2.37 17.84±2.95 18.90±1.62 16.64±1.24 19.20±2.28 L 69.20±4.42 70.77±4.42 72.36±3.76 67.52±1.50 71.26±1.19 b 15.42±3.18 13.95±1.72 14.12±2.88 15.75±2.63 12.96±3.03 CIE L (lightness), a (redness), b (yellowness). a,b Means in the same row with different superscripts differ (p<0.05).

Probiotics on Growth Performance and Meat Quality of Broiler 509 Table 8. Effect of complex probiotics addition and antibiotics levels on cecum microflora of broiler chicks Treatments Escherichia coli (Log CFU/g) Salmonella (Log CFU/g) T1 6.93±0.21 6.61±0.23 T2 6.55±0.46 6.83±0.44 T3 6.28±0.40 6.37±0.31 T4 6.39±0.83 6.51±0.48 T5 6.72±0.36 6.94±0.65 T1 (No probiotics), T2 (probiotics 0.3%), T3 (probiotics 0.3% + antibiotics 50%), T4 (probiotics 0.3% + antibiotics 100%), T5 (antibiotics 급여하여 5주간사양시험한결과대조구에비해다리육의 ph, 전단력, 보수성및가열감량에는유의적인차이가없었으나, 육색의명도는유의적으로높았다고보고하여본연구결과와일치하는경향을나타냈다. 이상의결과에서육계의생균제첨가는다리육의육질특성에나쁜영향을미치지않았으며, 가슴육의결과와유사한경향이었다. 장내미생물변화생균제와항생제첨가수준을달리한육계의맹장내미생물분석결과는 Table 8에서보는바와같다. 전체적으로처리구간에통계적인유의성은없었으나, 항생제와생균제를처리하지않은 T1구에서맹장내 E. coli균이가장높은경향이었으나, 생균제나항생제만이각각처리된 T2나 T5구에서 E. coli균의수가다소감소하였으며, 특히생균제와항생제가복합처리된 T3나 T4구에서는 E. coli균의수가가장낮은경향이었다. 맹장내 Salmonella균의변화에서는무처리구인 T1구에비해생균제단독처리한 T2구나항생제단독처리한 T5구에서는 Salmonella균의수가다소증가한반면에, 생균제와항생제가복합처리된 T3나 T4구에서는 Salmonella균의수가감소하는경향을나타냈다. 이러한결과는육계의생균제급여가장내용물의 ph 저하와함께 coliforms, Salmonella 등유해미생물의성장 을억제시킨다는다른연구결과와일치된경향이었으며 (Han et al., 1984; Jin et al., 1998; Kim et al., 2000; Yeo and Kim, 1997; Yu et al., 2004; Zhang et al., 2005), 이렇게맹장및대장내의미생물균총에영향을줌으로써성장개선효과가나타난것으로사료된다 (Table 3과 4). Yu 등 (2004) 도복합생균제를육계사료에첨가하여 7주간사육한결과육계초기부터급여된생균제가육계후기에그균총이장내에정착하게됨으로장내유해세균의수는감소시켰고, 영양소흡수에최적의조건을조성하여생산성이개선된다고보고하였다. 혈중콜레스테롤분석생균제와항생제첨가수준이육계의혈중콜레스테롤수준에미치는영향은 Table 9에서보는바와같다. 전체적으로처리구간에통계적인유의성은없었으나, 대조구 (T 에비해서생균제단독이나 (T, 생균제와항생제가복합처리된 T3나 T4에서혈중내고밀도콜레스테롤수준이다소감소하는경향이었다. 혈중총콜레스테롤수준에서는대조구 (T 에비해서생균제단독첨가된 T2구나생균제와항생제 50% 가복합첨가된 T3구에서만수준이다소감소하는경향을나타냈다. Jin 등 (1998) 과 Kim 등 (2000) 의연구결과에서도육계의생균제급여는혈액내 cholesterol 수준을저하시켰다고하여본연구결과와유사한경향을보였으며, 이는생균제급여가장내유익한혐기성세균의성장을촉진시켜, 그들에의한 cholesterol assimilation과 bile acids의 deconjugation작용이활발하게일어난데서기인한다고하였다. 계육내잔류항생물질분석생균제와항생제첨가수준을달리하여사양시킨육계가슴육의잔류항생물질의분석결과는 Table 10에서보는바와같다. 사료에첨가된항생물질 (Oxytetracycline, OTC) 의잔류검사수준을분석한결과, 첨가하지않은처리구 T1과 T2에서는전혀검출되지않았다. 반면에항생제 50% 를첨 Table 9. Effect of complex probiotics addition and antibiotics levels on blood cholesterol level of broiler chicks Item (mg/dl) T1 T2 T3 T4 T5 HDL-cholesterol 107.3±0.8 101.3±1.1 196.3±0.4 103.8±0.7 199.0±1.6 Total-cholesterol 145.8±1.3 141.5±0.3 136.8±1.6 150.8±2.1 145.5±1.2 Table 10. Residual oxytetracycline (OTC) level of broiler breast meat by probiotics and antibiotics addition Item T1 T2 T3 T4 T5 OTC(ppm) 0 0 0.04±0.02 0.09±0.01 0.10±0.03 Level approved : below 0.1 ppm.

510 Korean J. Food Sci. Ani. Resour., Vol. 30, No. 3 (2010) 가한 T3의경우 0.04 ppm 수준을그리고항생제 100% 를첨가한처리구 T4와 T5의경우각각 0.09와 0.1 ppm 수준을나타내어, 생균제 0.3% 와항생제 50% 만을혼합첨가한처리구 T3의경우항생물질잔류수준을 40% 수준으로낮출수있음을확인할수있었다. 요 본연구는복합생균제 (Lactobacillus casei, Bacillus subtilis, Saccharomyces cerevisiae, Aspergillus oryzae, Streptomyces griseus) 와항생제급여가육계의생산성및육질에미치는영향을구명하고자수행하였다. 사양시험 1에서, 생균제첨가수준은 0.1, 0.3, 0.5% 첨가구중에서 0.3% 첨가구가일당증체량, 사료요구율, 도계율에서가장우수한결과를나타내어적정첨가수준으로판단되었다. 생균제와항생제첨가수준을달리한사양시험 2에서는항생제 (oxytetracycline) 100% 만을첨가한처리구에서일당증체량과사료요구율이가장우수한것으로나타났으나, 복합생균제 0.3% 를첨가한대신항생제수준을 50% 로낮춘처리구에서도타처리구에비해우수한일당증체량과사료요구율을나타내었고, 도계율은가장높은경향이었다. 복합생균제 0.3% 와항생제 50% 를혼합첨가한처리구의육질특성에서도전단력이다소높은것을제외하고는일반성분, ph, 보수력과육색에서는큰차이가없었다. 그외항생제 100% 만을첨가한처리구에비해복합생균제 0.3% 와항생제수준을 50% 로낮춰첨가한처리구에서맹장내 E. coli와 Salmonella균의성장억제경향이관찰되었으며, 혈액내총콜레스테롤수치와고밀도콜레스테롤수치의감소경향도나타나저항생제수준의고품질닭고기생산에적합한사양방법으로사료되었다. 그외계육내잔류항생물질분석에서항생제 100% 처리구에서는 0.1 ppm 수준을보였으나, 생균제 0.3% 와항생제 50% 복합처리구에서는잔류항생물질을 40% 수준으로낮출수있음을확인할수있었다. 사 이논문은 2008년도충북대학교학술연구지원사업의연구비지원에의하여연구되었음. 약 사 참고문헌 1. AOAC (1995) Official methods of analysis 16th Ed. Association of Official Analytical Chemists. Washington, DC. 2. Bird, H. R. (1969) Biological basis for the use of antibiotics in poultry feeds. Proc Symp NAS Washington, DC, USA. 3. Guest, G. B. (1976) Status of FAD's program on the use of antibiotics in animal feeds. J Ani Sci. 68, 1318. 4. Han, I. K., Lee, S. C., Lee, J. H., Lee, K. K., and Lee, J. C. (1984) The effect of lactobacillus sporogenes on the growing performance and the changes in microbial flora of the feces and intestinal contents of the broiler chicks. Korean J. Anim. Sci. 26, 150. 5. Higgins, S. E., Higgins, J. P., Wolfenden, A. D., Henderson, S. N., Torres-Rodriguez, A., Tellez, G., and Hargis, B. (2008) Evaluation of a Lactobacillus-Based Probiotic Culture for the Reduction of Salmonella Enteritidis in Neonatal Broiler Chicks. Poultry Sci. 87, 27. 6. Isolauri, E., Sutas. Y, Kankaanpaa. P, Arvilommi. H, and Salminen, S. (200 Probiotics: Effects on immunity. Am. J. Clin. Nutr. 73, 444S. 7. Jin, L. Z., Ho, Y. W., Abdullah, N., and Jalaludin, S. (1996) Influence of dried Bacillus subtillis and Lactobacillus cultures on intestimal microflora and performance in broiler. Asian-Australasian J. Anim. Sci. 9, 397. 8. Jin, L. Z., Ho, Y. W., Abdullah, N., and Jalaludin, S. (1998) Growth performance, intestinal microbial population, and serum cholesterol of broilers fed diets containing Lactobacillus culture. Poultry Sci. 77, 1259. 9. Kim, Y. J. (2007) Effect of dietary supplementation with probiotics, illite, active carbon and hardwood vinegar on the performance and carcass characteristics of broiler. Korean J. Poult. Sci. 34, 165. 10. Kim, Y. J. and Yoon, Y. B. (2008) Effect of the feeding probiotics, illite, activated carbon, and hardwood vinegar on the meat quality and shelf-life in chicken thigh. Korean J. Food Sci. Ani. Resour. 28, 480. 11. Kim, Y. R., Ahn, B. K., Kim, M. S., and Kang, C. W. (2000) Effect of dietary supplementation of probiotics on performance, blood cholesterol level, size of small intestine and intestinal microfloral in broiler chicks. J. Anim. Sci. Technol. (Kor) 42, 849. 12. Line, J. E., Bailey, J. S., Cox, N. A., Stern, N. J., and Tompkins, T. (1998) Effect of yeast-supplemented feed on Salmonella and Campylobacter population in broilers. Poultry Sci. 77, 405. 13. Ministry for food, agriculture, forestry and fisheries. (2010) Bulletin 2010-4. 14. Mitsubashi, S., Harada, K., and Kameda M. (196 On the drug registance of enteric bacteria. 6. Spontaneous and artificial elimination of transferable drug registance factors. Japan J. Microbiol. 31, 119. 15. National veterinary research & quarantine service. (2003) Bulletin 2003-4. 16. Park, S. J. and Yoo, S. O. (2000) Effect of supplementation of antibiotic, probiotic and yeast culture on performance and meat quality in broiler chicks. Korean J. Poult. Sci. 27, 203. 17. Parker, R. B. (1974) Probiotics : the half of the antibiotic story. An. Nutr. & Health 29, 4. 18. Pelicano, E. R. L., Souza, P. A., Souza, H. B. A., Oba, A., Norkus, E. A, Kodawara, L. M., and Lima, T. M. A. (2003) Effect of different probiotics on broiler carcass and meat quality. Brazilian J. Poultry Sci. 5, 207.

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