Abstract
An experiment was conducted to investigate whether dietary yeast (Saccharomyces cerevisiae, SC) and its' structural components, i.e., yeast cell-extract (YE) and yeast cell-wall (CW) could influence growth performance, ileal morphology and serum lipids of male broiler chickens. There were four dietary treatments, each consisting of 6 replicates (10 birds per replicate). Chickens were fed a corn-soybean meal base control diet and diets containing SC ($0.5\%$), YE ($0.25\%$) and CW ($0.25\%$), respectively for 5-wk-experimental period. Dietary SC, YE and CW versus the control diet did not affect growth performance of male broiler chickens. Ileal morphology as to villus height, crypt depth and villus:crypt ratio of birds fed on the control diet was not significant from those fed on diets rich in SC, YE and CW, respectively. Dietary SC significantly lowered (P<0.05) serum total cholesterol by on average $19.7\%$ as compared to the control group. In addition, chickens fed on diets with either YE or CW lowered serum cholesterol by on average 15.3 and $12.5\%$, respectively as compared to the control albeit that the former only reached statistical significance. In conclusion, our study observed the hypocholesterolemic effect of SC in male broiler chickens. Moreover, YE, i.e., an extract of intracellular components of SC contains active molecules that are responsible far lowering serum cholesterol concentrations, but their identification at the molecular level needs to be assessed.
효모(Saccharomyces cerevisiae, SC)의 구성성분인 yeast cell-extract(YE)과 yeast cell-wall(CW)이 육계의 생산성, 장내융모 발달 및 혈청 콜레스테롤에 어떠한 영향을 미치는지 알아보고자 사양실험을 실시하였다. 육용 수평아리(Ross) 240수를 4처리 6반복, 반복당 10수를 공시하였다. 옥수수 및 대두박 위주 기본사료에 SC, YE 그리고 CW를 각각 0.5, 0.25 그리고 $0.25\%$로 첨가한 실험사료를 제조하여 육계에 5간 급여하였다. 효모의 급여는 육계의 생산성에 어떠한 영향을 미치지 못하였으며, villus height, crypt depth 및 villus:crypt ratio 역시 처리간 유의성은 발견되지 않았다. SC 급여 받은 육계의 혈청 콜레스테롤은 대조구에 비하여 $19.7\%$ 감소(P<0.05)를 나타내었다. 특히, 효모성분 중 YE가 혈청 콜레스테롤을 유의적으로 낮추었다(P<0.05). 결론적으로 사료내 효모의 첨가는 육계의 혈청 콜레스테롤을 유의적으로 감소시켰으며(P<0.05), 콜레스테롤을 감소시키는 성분은 효모의 세포내용물에 포함되어 있는 것으로 본 연구결과 알 수 있었다.