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 l...
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.