Abstract
Two experiments were conducted to investigate the effect of dietary organic selenium levels on performance and selenium retention in broiler chickens and laying hens. In experiment 1, the effects of dietary organic selenium levels on the weight gain, feed intake, feed conversion, and selenium retention of meat and liver in broiler chickens were investigated. For each growth phase, the basal diet was supplemented with 0 (control), 0.60, 1.20, 1.80 and 2.40 ppm Se from selenium yeast(SY). Weight gain, feed intake, and feed conversion were not affected by the selenium addition in diets. Breast muscle Se levels were linearly increased (P<0.05) as dietary Se level increased by SY. Selenium concentration of liver tissue was increased (P<0.05) in supplemental SY compared to the control, and was increased (P<0.05) in supplemental 1.20, 1.80 and 2.40 ppm SY compared to the 0.60 ppm SY. In Experiment 2, 12-week-experiment using Hy-Line laying hens (68 wk of age) was conducted to examine the effects of dietary organic selenium on egg Production, egg weight, daily egg mass, feed intake, feed conversion, egg quality, and selenium concentration of eggs. A corn-soybean meal basal diet was supplemented with 0 (control), 0.30, 0.60, 0.90 and 1.20 ppm Se from selenium yeast (SY). Egg Production was significantly improved(P<0.05) in supplemental 0.30 and 0.90 ppm SY compared to the control and 0.60 ppm SY during week 1 to 12, but daily egg mass, feed intake, and feed conversion showed no difference in supplemental SY and control. Haugh unit, yolk color and eggshell breaking strength showed no difference in supplemental SY and control. Eggshell thickess was significantly (P<0.05) higher in supplemental 0.60 and 1.20 ppm SY compared to the 0.90 ppm SY in week 9. Egg Se levels were linearly increased (P<0.05) as dietary Se level increased by SY.
유기태 셀레늄의 수준별 첨가가 육계 및 산란계의 생산성에 미치는 영향을 구명하고, 닭고기와 계란 내의 셀레늄 축적에 미치는 효과를 알아보기 위하여 2차례의 시험을 수행하였다. 시험 1은 selenium yeast로 셀레늄을 0.60, 1.20, 1.80 및 2.40 ppm을 첨가하였을 때 육계의 사료 섭취량, 증체량, 사료 요구율 및 가슴근육과 간 내의 셀레늄 축적에 미치는 영향을 조사하였다. 증체량, 사료 섭취 량 및 사료 요구율은 대조구를 포함한 모든 처리구에서 차이가 없었으며, 가슴살의 셀레늄 함량은 대조구에 비하여 유기태 셀레늄의 첨가 수준을 증가시킬수록 높았다(P<0.05). 간조직의 셀레늄 함량은 대조구에 비하여 유기태 셀레늄을 첨가한 모든 처리구에서 높았으며(P<0.05),특히 유기태 셀레늄을 1.20 ppm이상 첨가할 경우에는 효과가 크게 나타났다(P<0.05). 시험 2에서는 유기태 셀레늄의 첨가 수준이 산란계의 생산성 및 계란 내 셀레늄의 축적에 미치는 영향을 구명하기 위하여 selenium yeast로 셀레늄을 0.30, 0.60, 0.90 및 1.20 ppm을 첨가하였을 때 산란율, 난중, 사료 섭취 량, 사료 요구율, 난질 및 계란 내 셀레눔 함량을 조사하였다. 산란율은 유기태 셀레늄 0.30 ppm과 0.90 ppm 첨가구에서 높았으나(P<0.05), 1일 산란량, 사료 섭취량 및 사료 요구율은 대조구를 포함한 모든 처리구에서 차이가 없었다. Haugh unit는 대조구를 포함한 모든 처리구에서 차이가 없었으나, 난각 두께는 유기태 셀레늄 0.60 및 1.20 ppm첨가구가 각각 385 및 $386{\mu}m$으로 유기태 셀레늄 0.90 ppm 첨가구의 $368{\mu}m$에 비하여 유의적으로 두꺼웠다(P<0.05). 계란 내 셀레늄 함량은 유기태 셀레늄 첨가 수준을 높일수록 더욱더 증가하였다(P<0.05).