Effect Of Bacillus Subtilis Supplement In Diet On Egg Production Performance And Eggshell Quality Of Layer In Later Period Of Egg Production

With the increase of layers'age,the quality of eggshell gradually deteriorates.However nutritional modulation is one of the important measures to improve eggshell quality.In present research we performed studies on:1.Effects of Bacillus subtilis supplementation on egg performance and eggshell quality in Later period of egg production.480 Hy-Line Brown laying hens aged 52 weeks were randomly divided into 4 groups with 8 replicates per group and 15 hens per replicate.The control group was fed with corn-soybean basal diet,the treatment groups with supplement of Bacillus subtilis of 2×10~9 CFU/kg,4×10~9 CFU/kg and 8×10~9 CFU/kg respectively.After a week pre-feeding and12 weeks of formal trial.The results showed that supplementation of Bacillus subtilis:1)Have no significant effects on egg production,average egg weight and the feed-egg ratio(P>0.05),but significantly reduced the average daily feed intake(P<0.05);2)Significantly increased eggshell thickness and decreased broken rate(P<0.05);3)2×10~9 CFU/kg supplementation of Bacillus subtilis improved the crystal microstructure and the eggshell strength;increased the calcium content of eggshell and tibia.In conclusion,the supplementation of Bacillus subtilis at 2×10~9CFU/kg in diet for later layers showed best improving effects.2.Effects of calcium and Bacillus subtilis supplementation on egg performance and eggshell quality of Later Layers.576 Brown laying hens aged 72 weeks were randomly divided into 6 groups with 8 replicates per group and 12 hens per replicate.3×2 two-factorial design including 3.5%,4.0%and 4.5%calcium levels,and 2×10~9,0×10~9 CFU/kg Bacillus subtilis addition under each calcium level.After 2 weeks pre-feeding and 8 weeks formal trial.The results showed that:1)Dietary calcium levels and supplementation of Bacillus subtilis had no effects on eggshell thickness and broken rate(P>0.05),but eggshell strength increased by Bacillus subtilis addition(P<0.05).2)With the increase of calcium level,the average daily feed intake and the average egg weight was significantly increased(P<0.05).Bacillus subtilis significantly decreased the feed-egg ratio compared with the group without Bacillus subtilis addition;3)The increase of dietary calcium levels and the Bacillus subtilis supplementation significantly increased the calcium apparent metabolic rate,the height of microvilli in Duodenal epithelium,and the ratio of the height of Villi to the depth of recess(P<0.05);4)Supplementation of Bacillus subtilis significantly increased the mRNA level of the Duodenal calcium binding protein(P<0.05).Conclusion:4%dietary calcium levels,with the supplementation of Bacillus subtilis at2×10~9 CFU/kg showed best improving effects.