The Influence Of Vitamin K₃ And Bacillus Subtilis On The Bone Health Of Broilers And The Interaction Effects Of Them

This study was designed to investigate the effects of dietary supplementation of Bacillus subtilis and vitamin K₃ on vitamin K-deficient broiler performance,blood parameters,slaughter performance,and bone health.The experiment used720 AA⁺500 broilers,male and female,half and half,according to the 3×2×2factor design,divided into 12 treatment groups,each group of 3 repeats,each repeat20 chickens（half male and female）.Vitamin K₃（VK₃）levels in diets were 0,0.5,and 4 mg/kg,respectively;Bacillus subtilis PB6（BS）was added at 0 and 500 g/t;male and female chickens.It is bred on-line and the chickens freely eat and drink water.All broilers were pre-fed with a diet that did not add VK₃ for 3 days,and then a formal trial was started.The test period was 42 days.The results show:1.Broiler growth performance（1）Gender significantly affected the growth performance of 0-21 d broilers.The 42 d body weight,ADG and ADFI of the roost were significantly higher than those of the hen（P<0.05）.（2）Adding VK₃ affected fasting body weight and 0-21 d ADG in 21 d broilers（P<0.05）.There was an interaction effect between VK₃ level and sex on 0-21 d ADFI（P<0.05）.The average daily feed intake was 0.5 mg/kgVK₃ in the rooster diet,and the average daily feed intake（4 mg/kg VK₃）in the hen diet was highest.（3）Adding 500 g/t Bacillus subtilis（BS）to the diet significantly increased 42d body weight and daily gain 21-42 d（P<0.05）.2.Serum biochemical levels in broilers（1）BS increased 21 d osteocalcin（OCN）,bone-derived alkaline phosphatase（BALP）levels（P<0.05）,and increased 42 d OCN levels（P<0.01）.BS and gender had a significant interaction effect on BALP levels in broilers（P<0.01）.（2）Adding 4.0 mg/kg VK₃ to diet 21 increased the activity of aspartate aminotransferase（AST）in serum（P<0.05）;the total bilirubin（TB）in cock serum was significantly higher than that of hens,but The levels of TP,ALB,AST,ALT and Ca were significantly lower than those of hens（P<0.05）;VK₃,BS and gender had an interaction effect on the increase of total cholesterol（TC）（P<0.05）.VK₃ and gender were the glucose levels.The interaction effect was increased（P<0.05）.Adding 4.0 mg/kg VK₃ to the rooster diet reduced the serum glucose（GLU）content（P<0.05）;there was interaction between BS and sex on serum phosphorus（P<0.05）.P<0.05).In the absence of Bacillus subtilis,the phospholipid content in hens was higher than that in roosters（P<0.05）;VK₃ and BS had an interaction effect on the content of CREA（P<0.05）.No Bacillus subtilis was added.In the case of Bacillus,the addition of 4.0 mg/kg VK₃ increased the CREA content in the serum.In the case of Bacillus subtilis,the addition of 4.0 mg/kg VK₃ reduced the serum creatinine content.（3）There was interaction effect of total protein and albumin content in serum of 42 d,Bacillus subtilis and sex（P<0.05）.Without addition of Bacillus subtilis,the total protein content of cock serum was higher than In the case of hens,the total protein content of the rooster sera was lower than that of the hens in the case of BS;in the case of BS,the albumin content in the hens’sera was also higher than that of the rooster;VK₃,Bacillus subtilis,and sex-paired sera There was an interaction effect between aminotransferase and alkaline phosphatase activity in mid-grass（P<0.05）.In the absence of Bacillus subtilis,serum glutamic oxaloacetic enzyme with 0.5 mg/kg VK₃ added had the highest activity and 4.0 mg was added.The serum alkaline phosphatase activity was highest in hens with/kg VK₃.There was an interaction between VK₃ and Bacillus subtilis on serum alanine aminotransferase activity（P<0.05）.Without addition of probiotics,the addition of 0.5 mg/kg VK₃significantly increased serum alanine aminotransferase activity.TG in hens was higher than roosters（P<0.05）;addition of BS reduced CREA in serum（P<0.05）.There was an interaction effect between BS and gender on serum calcium（P<0.05）.In the case of BS,the serum calcium content of hens was higher than that of roosters（P<0.05）.3.Tibial weight and calcium and phosphorus content in broilers（1）BS reduced the 21 d leg muscle rate,but increased femur weight,femur length,tibial weight,tibia length,and tibia diameter（P<0.05）;femur weight,femur diameter,tibial weight,tibia length,and tibia Diameter was significantly higher than that of hens（P<0.05）;BS increased tibial diameter at 42 d（P<0.05）;cock had lower 42 d breast muscle than hens,but femur and tibia weight,length,and diameter were higher than those of hens.（P<0.05）;addition of Bacillus subtilis to42 d significantly increased crude ash content and calcium content in tibia（P<0.05）.（2）There was an interaction between sex and VK₃ and Bacillus subtilis on 42 d leg muscles（P<0.05）.Adding 4.0 mg/kg VK₃ to the rooster diet reduced the leg muscle rate.0.5 was added to the hen diet.And 4.0 mg/kg VK₃ increased the leg muscles;In the pre-growth phase of broilers 24 d,0.5 mg/kg and 4.0 mg/kg VK₃ in the diet significantly increased the content of crude ash in the tibia（P<0.05）;The addition of 4.0 mg/kg VK₃ significantly increased the content of calcium and phosphorus in tibia（P<0.05）.（3）Bacillus subtilis could significantly increase the ratio of calcium and phosphorus in bones when 0 mg/kg and 0.5 mg/kg VK₃ were added to the diet（P<0.05）.The content of calcium and phosphorus in the humerus of hens was significantly lower than that of roosters（P<0.05）.In summary,there was a significant interaction effect between Bacillus subtilis and VK₃ on crude ash,calcium and Ca/P ratio in the tibia（P<0.05）.4.Effect of skeletal related mRNA levels in broiler chickens（1）In 21 d,0.5 mg/kg VK₃ diet increased RUNX2 mRNA level（P<0.001）;BS down-regulated RUNX2 mRNA levels and down-regulated CYP3A4 mRNA levels（P<0.05）;compared with hens,The RUNX2 mRNA level of the rooster was down-regulated（P<0.05）.The level of UNX2 mRNA was significantly reduced,while VK₃ and Bacillus subtilis and their interaction with sex significantly reduced the OCN mRNA level（P<0.05）.（2）On 42 d,0.5 mg/kg VK₃ diet increased RUNX2 mRNA level（P<0.001）;BS up-regulated CYP3A4,RUNX2 and ALPL mRNA levels（P<0.05）and up-regulated OCN mRNA levels（P<0.001）;Compared with hens,OCN mRNA levels were down-regulated in males（P<0.05）.In summary,dietary supplementation of Bacillus subtilis in the presence of vitamin K deficiency can increase the performance of broilers,also the levels of osteocalcin,bone-derived alkaline phosphatase,slaughter rate,and bone calcium and phosphorus levels.Thus improving the bone health status of broilers;adding VK₃ to improve the production performance of broilers,VK₃ and Bacillus subtilis have interaction effect on the production performance;VK₃ can significantly improve the effect of bone health on the content of calcium and phosphorus in the tibia.The interaction effect of VK₃ and Bacillus subtilis on the calcium and phosphorus content of the bone existed.