Effects Of Dietary Soluble Or Insoluble Fiber Intake In Late Gestation On Reproductive Performance,Immune Function And Intestinal Microbiota Of Sows Around Parturition

The objective of this study was to investigate the effects of dietary soluble fiber(SF)or insoluble fiber(ISF)intake in late gestation on reproductive performance,immune function and intestinal microbiota of sows around parturition.A total of 60 Yorkshire sows were randomly allocated into 3 dietary treatments with 20 replicates and one sow per replicate,based on parity(4?6)and body weight(267.8±2.8kg).Sows were fed middle dietary fiber(CON,16.15% dietary fiber),high insoluble dietary fiber(ISF,30.11% dietary fiber)and high soluble dietary fiber(SF,30.14% dietary fiber)diet.In addition to dietary fiber,all the nutrients intake were identical via adjusting feed intake from days 90(d 90)of gestation to parturition,and the daily dietary fiber intake of ISF and SF groups were about twice as much as CON group(484g/d in CON,964g/d in ISF and 965 g/d in SF).In this experiment,wheat bran,soybean hull and sugar beet pulp were used as fiber source,whereas sugar beet pulp was only used as a source of soluble fiber in the SF diet.The experiment started on d 90 of gestation and ended on d 21 of lactation.The experimental diets were fed from d 90 of gestation to parturition.All the sows were fed a same diet during lactation.Body weights of sows were measured on d 90,d110 of gestation and on d 21 of lactation.Blood samples were collected on d 107 of gestation and within one hour after farrowing.Fresh fecal samples were collected on d 110 of gestation.Colostrum and milk were collected within one hour after farrowing and d 7 of lactation,respectively.The litter performance was recorded at parturition.The average daily feed intake(ADFI)of sows during lactation was recorded every day and piglets were weighed at parturition(d 1),d 7,d 14 and d 21 of lactation to determine average daily gain(ADG).Results showed that:(1)High SF or ISF intake in late gestation did not markedly affect body condition and litter performance(P>0.05).However,sows fed ISF diet tended to short farrowing duration when compared with sows fed CON diet(-70 min.,P=0.064).Sows fed SF diet tended to have lower number of weaned piglets(P=0.060)and total litter weight(P=0.053)and higher pre-weaning mortality(P=0.058),when compared with sows fed ISF diet.(2)Compared with sows fed CON diet,both colostrum(P=0.069)and milk(P=0.080)from sows fed SF diet tended to contain more fat content.(3)Sows fed either ISF or SF treatment had higher Ig G concentration in the plasma on both d 107 and parturition(P<0.05).Compared with sows fed CON diet,moreover,sows fed SF diet tended to decrease C-RP concentration in the plasma on d 107 of gestation(P=0.084).Besides,sow fed ISF diet tended to have higher activity of GSH-Px on d 107(P=0.062).(4)Sows fed ISF diet tended to increase the concentration of acetic acid in the feces(P=0.085)on d 110 of gestation.Moreover,sows fed ISF diet had significantly increased concentrations of acetic acid,propionic acid,iso-valeric acid and total SCFA in plasma(P<0.05)at parturition,while sows fed SF diet had markedly increased concentration of total SCFA(P<0.05).Further analysis based on 16 S pyrosequencing showed that sows fed SF or ISF diet had markedly increased abundance of Bacteroidetes(P<0.05),but decreased the ratio of Firmicutes to Bacteroidetes(P<0.05).Furthermore,sows fed SF or ISF diet had significantly higher abundance of Prevotellaceae,Bacteroidales and Alloprevotella(P<0.05),which are related to the production of SCFA.Compared with sows fed SF diet,moreover,sows fed ISF diet markedly increased the abundance of Oscillospira and Christensenellaceae(P<0.05).(5)Metabolomics analysis based on UHPLC-Q-TOF MS technique indicated that a total of 12 metabolites in blood and 16 metabolites in feces significantly changed after high ISF intake in late gestation,especially increased the production of metabolites related to body fat or energy mobilization.In conclusion,high fiber intake in late gestation did not markedly affect the reproductive performance of sows,but improved humoral immunity and redox status of sows.Moreover,high ISF intake tended to short farrowing duration,but increased SCFA concentration of feces and plasma,also metabolites related to body mobilization of fat and energy,which may be related to the influence of high ISF intake on bacterial profile.