Abstract
In order to study the effects of supplementation of live yeast(Saccharomyces cerevisiae) on the performance of laying hens, five experiments were conducted. Two experiment were conducted during summer period, one with 37 wk old Dekalb-Delta strain laying birds(Exp. 1) and the other one with 100 wk old molted Nick Chick Brown laying birds(Esp.2) . In each experiment, 240 birds were divided into 12 groups of 20 birds each and randomly distributed. Each of the two experimental diets(Control 71 and 0.05% live yeast supplemented 72) was fed to 6 groups for 4 wks in Exp.1 and 3 wks in Exp.2. Three experiments were conducted during winter period, Exp.2 with 54 wk old Hy-Line strain laying birds, Exp.4 with 52 wk old Hy-Line strain laying birds, and Exp.5 with 36 wk old broiler breeder(Indian River strain). In each experiment, 540 birds were divided into 18 groups of 30 birds each and randomly distributed. Each of the 3 experimental diets(Control：$T_1$0.05% live yeast supplemented：$T_2$ and 0.1% live yeast supplemented ： T$_3$) was fed to 9 groups for 6 wks in Exp.3, 9 wks in Exp.4 and 4 wks in Exp.5. In Exp.4, Latin Square design was employed to determine the effects of switching feeds at 3 wk intervals. All hens were housed in cages of commercial farm and experimental diets were made with commercial layer feeds. In Experiment 1, egg production was significantly(P＜0.05) higher in $T_2$. Feed intake was significantly (P＜higher in 72 at 1st wk but 4 wk average was not significantly different. Feed efficiency was significantly(P＜0.01) better in 72 at End wk but 4 wk average was not significantly different. Other parameters, such as weight, soft egg production, cracked egg production and mortality were not significantly different. In Experiment 2, egg production was significantly(P＜0.05) higher in $T_2$. Feed efficiency was significantly (P＜0.05 and P＜0.01) better at End wk and 3rd wk but 3 wk average was not significantly different. Soft egg production was significantly(P＜0.05) higher in 72. Other parameters were not significantly different. In Experiment 3, egg productions were significantly(P＜0.05) different among treatments ： $T_3$ was higher than $T_1$ and $T_2$ was higher than $T_1$. Egg weight of $T_1$ and $T_2$was significantly(P＜0.05) heavier than $T_3$. Feed intake of $T_2$ and $T_3$ was significantly(P＜0.05) higher than $T_1$ at 6th wk but overall average was not significantly different. Soft egg production were significantly(P＜0.01) different among treatments：$T_1$ was higher than $T_3$ was higher than $T_2$. Feed efficiency cracked e99 Production and mortality were not signifcantly different. In Experiment 4, egg production tended to increase as the level of live yeast supplementation increased but they were not statistically different. In Experiment 5, egg production of broiler breeders of $T_3$ was significantly(P＜0.01) higher than $T_1$. Feed intake of $T_3$ was significantly(P＜0.05) greater than $T_1$ and $T_2$ at 3rd wk but overall average was not significantly different. Fertility and hatchability tended to be higher in the supplemented groups than in the control.
활성효모의 첨가가 산란계에 미치는 영향을 알아보기 위하여 5개의 시험을 실시하였다. 시험 1과 2는 하절기에 실시하였는데 시험 1에서는 37주령의 Dekalb-Delta 산란계, 시험 2에서는 100주령의 환우계 Nick-Chick Brown 산란계를 공시하였다. 각 시험에 있어서 240수를 2처리 6반복으로 반복당 20수씩 완전임의 배치하였다. 시험사요는 대조구($T_1$)와 괄기효모 첨가수준이 0.05%인 첨가구($T_2$)로 하여 시험 1은 4주간, 시험 2는 3주간에 걸쳐서 실시하였다. 3개의 시험은 동절기에 실시하였는데 시험 3과 4는 각각 54영 및 52주령의 Hy-Line산란계, 시험 5는 36주령의 육용종계를 공시하였다. 시험은 각각 540수를 3처리 6반복으로 반복당 30수적 완전임의 배치하였다. 시험사료는 대조구($T_1$), 활성순모 0.05% 첨가구($T_2$) 및 0. 1 % 첨가구($T_3$)로 하여 시험 3과 4는 6주간 및 9주간 그리고 시험 5는 4주간에 걸쳐서 실시하였다. 시험 4는 시험사료를 3주마다 회전시켰을 때의 효과를 알아보기 위해 라틴 방각으로 배치하였다. 시험계는 일반농가에서 사육되었으며, 시험사료는 일반시중사료를 사용하였다. 시험 1에서 산란율은$T_2$가 높았으며(P＜0.05), 4주간의 평균에서는 유의차가 없었다. 사료효율은 2주에서 고도의 유의차가 있었지만(P＜0.01), 4주간의 평균에서는 유의차가 없었다. 난중과 연ㆍ파난율 및 사망율에서는 유의차가 없었다. 시험 2에서 산란율은 $T_2$가 높았으며(P＜0.05), 사요악률은 2주와 3주에서 $T_2$가 유의하게(P＜0.05, P＜0.01)좋았으나 3주간의 평균에서는 유의차가 없었다. 연난발생률은 $T_2$가 높았지만(P＜0.05) 1외 다른 조사항목에서는 유의차가 없었다. 시험 3에서 산란율은 처리간에 유의차가 있었고(P＜0.05), $T_3$는 $T_2$보다 그리고 $T_2$는 $T_1$보다 높았다. $T_1$과 $T_2$의 난중은 $T_3$보다 무거웠고(P＜0.05), $T_2$와 의 사료섭취양은$T_1$에 비해 6주에서 높았지만 (P＜0.05), 전 기간 평균에서는 유의차가 없었다. 연난발생율은 처리간에 고도의 유의차가 있었으며(P＜0.01). $T_1$은 $T_3$보다 높았고, $T_3$는 $T_2$보다 높았다. 사료효율, 연난발생률. 사망율에서는 유의차가 없었다. 시험 4에서 산란율은 활성효모 첨가수준을 증가시킬수록 증가하는 경향이 있었지만 통계적인 유의차는 없었다. 그외 다른 조사항목에서도 유의차는 없었다. 시험 5에서 육용종계의 산란율은 $T_3$가 $T_1$보다 유의하게 높았다(P＜0.01). 사료섭취양은 3주에서는 $T_3$과 $T_1$ $T_2$보다 높았지만(P＜0.05) 전 기간 평균에서는 유의차가 없었다. 수정률 및 부화율은 대조구보다 첨가구가 높은 경향이 있었다