The Effect of Antibiotics on the Performance of Broiler Chicks

브로일러에 있어서 항생제의 성장촉진 효과

Two experiments were undertaken to study the growth promoting effect of Spiramycin and Virginiamycin at the level of 5ppm each. In the first experiment, 180 day - old male broiler chickens (Maniker parent stock) were divided into 18 groups of 10 birds each. Six groups were placed on one of the three experimental diets (Nonmedicated control, Spiramycin supplemented diet and Virginiamycin supplemented diet). Basal diet of Experiment 1 contained 21.9% crude protein and 3159kcal /kg diet. Second experiment employed same treatments as were used in the Experiment 1. Ninety male and 90 female day-old broiler chickens(Maniker commercial) were grouped by 10 birds of sane sex in each and assigned to 3${\times}$2 factorial design. Basal diet of Experiment 2 contained 19.95% crude protein and 2931kcal/kg diet. Chicks were fed for six weeks in battery with raised floor and kept further for metabolic trials. The results of feeding trials showed that there were no statistically significant differences between treatments in weight gain, feed intake, feed efficiency and mortality. However, birds fed Antibiotic B supplemented diet grew approximately 3% more than the control in Experiment 1 and than those fed Antibiotic A supplemented diet in Experiment 2. Feed efficiency was also improved by supplementing Antibiotic B in both experiments. There were significant(P〈0.01) differences between sexes in growth rate, feed intake and feed efficiency. Birds fed Antibiotic B supplemented diet of Experiment 1 showed significantly (P〈0.01) greater availability for crude fat than those fed other diets. Birds fed Antiobiotic A supplemented diet in Experiment 1 showed significantly (P〈0.05) lower availability of crude fiber than those of other treatments. Weight of small intestine of birds fed Antibiotic B tended to be heavier than those fed other diets.

항생제인 Spiramycin과 Virginiamycin의 성장촉진 효과를 측정하기 위하여 총 360수의 육용계 (broiler chicken) 초생추를 battery에 수용하여 각각 6주씩 2차에 걸친 사양시험과 4일간의 대사시험을 실시하였다. 1차 실험에서는 고단백(21.9%), 고열량( 3159kca1/kg) 사료를 사용하였으며 180수의 숫병아리를 10수씩 무첨가구 Spiramycin(5ppm)구 및 Virginiamycin(5ppm)구에 각각 6반복씩 완전임의 배치하였다. 2차실험에서는 중단백( 19,95%), 중열량(2931 kca1/kg) 사료를 사용하고 90수의 숫병아리와 90수의 암병아리를 10수씩 분리하여 처리당 암ㆍ수 각각 3 반복씩 배치하였다. 사양시험을 통하여 얻어진 증체량, 사료섭취량, 사료효율 및 폐사율은 처리구간에 통계적 유의차가 없었으나 1, 2차 실험 공히 항생제 B구가 무처리구(1차실험) 또는 항생제 A구(2차실험) 보다 약 3% 높은 증체량을 나타내었다. 사료효율에 있어서도 항생제 B구가 가장 좋은 경향을 보여주었다. 2차실험의 결과에 의하면 증체량, 사료섭취량 및 사료효율에 있어서 암수간에는 유의한(p〈0.01) 차이가 있었다. 대사시험결과 항생제 B구가 타처리구보다 영양소 이용률이 높은 경향을 나타내었으며 특히 1차 실험에 있어서 조지방의 이용률은 타처리에 비해 유의하게 (p〈0.01) 높았고 조섬유이용률도 항생제 A구에 비해 유의하게 (p〈0.05) 높았다. 한편 대사체중당 소장의 무게와 길이는 항생제 B구가 타처리구에 비해 무겁고 긴 경향을 보여주었다.