Dietary supplementation of porcine bile acids improves laying performance,serum lipid metabolism and cecal microbiota in latephase laying hens

Due to the exceptional laying performance of hens,the demand on lipid metabolism and oxidation in vivo is vigorous,resulting in excessive lipid accumulation in late-phase hens,which lowers the production performance.Bile acids regulate lipid metabolism and gut microbiota in humans and animals.However,the effect of porcine bile acids on lipid metabolism and cecal microbiota in laying hens in the late phase is still unclear.A total of 360 healthy 45-week-old laying hens were chosen for a 24-week feeding trial,where 0,30,60 and 90 mg/kg porcine bile acids were added to a basal diet,respectively.The results showed that dietary supplementation of 60 mg/kg bile acids increased egg production and feed conversion(P<0.05).Also,60 and 90 mg/kg porcine bile acids reduced abdominal fat percentage and body weight(P<0.05).The levels of serum total cholesterol,triglyceride,and low-density lipoprotein cholesterol of hens decreased(P<0.05)in bile acids supplement groups.As for cecal microbiota,bile acids supplementation did not affect the alpha diversity of cecal microbiota at the genus level.Moreover,dietary supplementation of 90 mg/kg bile acids resulted in an increase in the abundance of beneficial bacteria in the cecum,such as Lactobacillus,Bifidobacterium and Turicibacter.The changes in the cecal microbiota caused by bile acids supplementation correlated with serum lipid indexes.According to KEGG pathway analysis,dietary supplementation of 60 and 90 mg/kg bile acids promoted structural transformation of the cecal microbiota to down-regulate steroid biosynthesis,up-regulate fatty acid degradation and up-regulate unsaturated fatty acid biosynthesis.Meanwhile,bile acids bioisomerization function of cecal microbiota was enhanced in 60 and 90 mg/kg bile acids treatment,and the short-chain fatty acid metabolism was also affected.In conclusion,the present study revealed dietary supplementation of porcine bile acids enriched probiotics in the gut and improved serum lipid metabolism of laying hens.These findings demonstrate that porcine bile acids can be a potential gut beneficial promoter for late-phase laying hens.

Mechanism of blood coagulation in common carp (Cyprinus carpio)

In vitro,carp blood was anticoagulated by using MgSO4 at a final concentration of 22.2 mmol L-1 and sodium citrate at a final concentration of 11.8 mmol L-1.The coagulation times for carp plasma diluted by ion-free water(1:1),and that of carp plasma to which thrombocytes and small lymphocytes were added,were measured at 23℃ using standard methods,and then contrasted with the coagulation times for plasma obtained from chickens and rabbits.The shapes of the thrombocytes and small lymphocytes,which were either wet mounted or stained with hematoxylin and eosin,were observed under a light microscope.We found that:(i)the coagulation reaction of carp blood was significantly(P<0.01)accelerated by the addition of ion-free water;(ii)the three types of blood cells(thrombocytes,small lymphocytes and red blood cells)promoted plasma coagulation to a similar extent(P>0.05);(iii)in carp Mg^(2+)plasma and K_(2)C_(2)O_(4) plasma,the thrombocytes were usually morphologically normal,but many small lymphocytes were destroyed and became aggregated;(iv)in the citrate plasma,thrombocytes were often aggregated,but the small lymphocytes were usually morphologically normal;and(v)the coagulation time for chicken and rabbit plasma was significantly extended by adding ion-free water.