Effects Of Bacilus Subtilis Staged Supplementation In Diet On Laying Performance And Nutrient Metabolic Rate Of Laying Hens

Intensive cultivation in poultry industry makes the layers prone to stress,which affects production performance.In the early stage of growth and development,the intestinal ecosystem of layers are instability,the immune system is not perfect,so that they are stress-sensitive.The development of the laying hens is stage,applying to the laying hens in the early developmental stage,which will improve digestion and absorption capacity and production performance,and the industry has a positive effect to improve efficiency.As a healthy probiotic,bacillus subtilis is widely used in the production of livestock and poultry.It has a good effect on production by changing the host micro-ecology balance of intestine and improving the function of digestion and immune system.Therefore this research explores the influence on production performance and nutrient metabolism rate of addition of bacillus subtilis in deferent period according to growth stage of laying hens,which would release the nutrition manipulation in early stage and the positive effects on laying period.Exp.1 Effects of dietary Bacillus subtilis on laying performance of laying hensIn this trial,756 1-day-old healthy HY-LINE variety brown were divided into 9 groups,each group has 7 repeats,each repeat has 12 birds.Control group is treated with basal diet,other processing groups are: adding antibiotics in the 0-17 weeks of age and feeding the basic diet in the 18-39 weeks of age;adding bacillus subtilis throughout the period;adding bacillus subtilis and antibiotics in the 0-17 weeks of age and adding bacillus subtilis in the 18-39 weeks of age;adding bacillus subtilis and antibiotics in the 0-17 weeks of age and feeding the basic diet in the 18-39 weeks of age;adding bacillus subtilis and antibiotics in the 0-12 weeks of age and feeding the basic diet in the 13-39 weeks of age;adding bacillus subtilis and antibiotics in the 0-6 weeks of age and feeding the basic diet in the 7-39 weeks of age;adding bacillus subtilis and antibiotics in the 0-3 weeks of age and feeding the basic diet in the 4-39 weeks of age;adding antibiotics in the 0-17 weeks of age and adding bacillus subtilis and antibiotics in the 18-39 weeks of age.The trial period is 39 weeks.After that,we study the effect of addition of bacillus subtilis on laying performance.Results: In comparison with the group of whole term of bacillus subtilis,the group 0-3week combined addition and 0-12 week combined addition can decease daily feed intake(p<0.05);These two groups also can increase egg production in 39-week-old hens compared with control group(p<0.05).And there are no significant difference between the two groups(p>0.05).It increases the yolk color significantly in 23week-old layers by treated with combined addition in 0-3 weeks in comparison with separate addition(p<0.05).Results show that combined addition of bacillus subtilis and antibiotic in 0-3 week can achieve the effect of adding throughout the period,the early nutritional regulation has a lasting effect.Exp.2 Effects of dietary supplementation of Bacillus subtilis on nutrient metabolism in laying hensIn this trial,we collected the samples of duodenum,jejunum and ileum mucosa and detected intestinal digestive enzyme RNA expression and observed morphology.In 40 th week,metabolic test was carried out.The layers were divided into 9 groups,each group has 5repeats,each repeat has 1 birds.The treatment group is the same as the test one.We collected all manure every day in 6 days after 48-hour hunger strike to determine amino acids and nutrient apparent metabolic rate by feces and feed samples.Results: villus height and crypt depth ratio in layers treated by combined addition in 0-6week-old period are significantly increased compared with control group(p<0.05).And villus height in 39 week-old layers treated by combined addition in 0-17 week-old period are significantly increased(p<0.05)as well as expression of duodenal maltase(p<0.05)and digestion and absorption of cysteine and lysine(p<0.05)Likewise,digestion and absorption of cysteine is similar in layers treated by combined addition in 0-12 week-old period.There are no difference between 0-17 week-old and whole term combined addition in digestion and absorption of lysine.Nutrient apparent metabolic rate in 40 week-old layers by treat of 0-3week-old combined addition is significantly increased compared with antibiotics addition alone(p<0.05).Results reveal that combined addition of bacillus subtilis and antibiotics in0-17 week-old period has a good effect on the expression of duodenum maltase,Contribute to the digestion and absorption of cysteine and lysine;Meanwhile,the apparent digestibility for calcium in layers treated with 0-3 week-old combined addition can achieve the effect of adding antibiotic throughout the period.