Effects Of The Firer Source And Exogenous Enzymes On The Degradation Of Cell Wall Components In Dual Cannulated Pig Digestive Tract

The aim of this paper was to evaluate the effects of the fiber source and exogenous enzymes(cellulase + xylanase + phytase)on the degradation of cell wall components in different segments of the pig digestive tract.The experiment selected broccoli residues and rice bran as the sole fiber source to prepare 2 basal diets,which were broccoli residues-based diet(BR)and rice bran-based diet(RB),respectively;After supplementation with an enzyme mixture in the 2 basal diets,The other two diets were formulated,namely broccoli residues-based diet with enzymes addition(BRE)and rice bran-based diet with enzymes addition(RBE).Eight male castrated crossbreed([Duroc×Landrace]×Large white)growing pigs with an average initial body weight of 30.1±1.5 kg were selected and each pig was surgically fitted with T-shaped cannulas at proximal duodenum and distal ileum simultaneously,according to a 4×4 Latin square design.A total of 4 periods was carried out and each period lasted for 14 days;the first five days was the adaptation period after replacing the feed and,feces and intestinal samples were collected in a formal trial period 9 d.The main results of the test were as follows:Experiment 1 Effects of the fiber source and exogenous enzymes on the degradation of detergent fiber and non-starch polysaccharides in the pig digestive tractThe aim of this experiment was to evaluate the effects of the fiber source and exogenous enzymes on the apparent digestibility of detergent fiber and non-starch polysaccharides,and the content of physiological soluble NSP(P-SNSP)and low degree of polysaccharides(LDP)in different tract segments.The results showed that broccoli residues showed a higher coefficient of apparent digestibility of NDF(P=0.001)and ADF(P=0.007)in the duodenum(CADD)than those of rice bran;Broccoli residues showed a higher coefficient of apparent digestibility of NDF(P<0.001),ADF(P<0.001),SNSP(P<0.001),TNSP(P<0.001)and INSP(P<0.001)in the total digestive tract(CATTD)than those of rice bran;The content of P-SNSP(P<0.001)of broccoli residues in the duodenum was significantly higher than that of rice bran;Except for Man and Fuc,P-SNSP and its monosaccharide components of broccoli residues in the terminal ileum showed also higher contents than those rice bran(P<0.05);The contents of LDP and its monosaccharide components in the terminal ileum were affected(P<0.05)by fiber source,not including Fuc.Adding exogenous enzymes could improve the CADD of NDF(P=0.046),ADF(P=0.021)and SNSP(P=0.026);Generally,the coefficients of apparent digestibility of NDF,ADF,SNSP and INSP in the terminal ileum(CAID)were affected by exogenous enzymes(P<0.05);Exogenous enzymes addition had a significant improvement on the CATTD of ADF(P=0.031)and TNSP(P=0.016);Exogenous enzymes addition significantly decreased the contents of P-SNSP(P=0.039)in the terminal ileum;The contents of LDP and its monosaccharide components Ara,Man and Gal in the terminal ileum were affected by exogenous enzyme(P<.0.05);Exogenous enzymes addition had a significant improvement on the contents of Man(P=0.049)and Glu(P=0.15)of LDP in feces.Fiber source and exogenous enzymes interacted to affect the CAID of TNSP(P=0.002)and INSP(P=0.020),and the contents of LDP(P=0.003)and its monosaccharide component Gal(P<0.001)in the terminal ileum.Generally,the apparent digestibility of NDF,ADF,NSP and monosaccharide components and the contents of P-SNSP and LDP of broccoli residues in growing pigs digestive tracts were higher than those of rice bran;Exogenous enzymes addition could improve the apparent digestibility of detergent fiber and NSP and its monosaccharide components in growing pigs digestive tracts.Experiment 2 Effects of the fiber source and exogenous enzymes on the degradation of minerals in the pig digestive tractThe aim of this experiment was to evaluate the effects of the fiber source and exogenous enzymes on the dissolution rate of combined minerals and the content of physiological soluble minerals(P-SME)in different tract segments.The results showed that broccoli residues showed a higher dissolution rate of combined Zn(P<0.001)in the duodenum than that of rice bran;The dissolution rate of combined Ca(P<0.001),P(P<0.001),Cu(P<0.001),Zn(P<0.001)and Mn(P=0.025)in the terminal ileum were affected by fiber source;The dissolution rate of combined Ca(P<0.001),P(P<0.001)and Mg(P<0.001)of broccoli residues in the total digestive tract were significantly higher than those of rice bran,while the dissolution rate of combined Cu(P<0.001)of broccoli residues in the total digestive tract was significantly lower than that of rice bran;Broccoli residues showed higher contents of Ca(P<0.001),P(P<0.001),Mg(P<0.001),Fe(P=0.001),Zn(P<0.001)and Mn(P<0.001)of P-SME in the terminal ileum than those of rice bran.Except for Zn,exogenous enzymes affected the dissolution rate of combined minerals in the duodenum(P<0.05);Exogenous enzymes addition improved the dissolution rate of combing minerals Ca(P=0.023),P(P<0.001),Zn(P<0.001)and Mn(P<0.001)in the terminal ileum;The dissolution rate of combined minerals in the total digestive tract were affected by exogenous enzymes(P<0.05),but not including Fe.The interaction between fiber source and exogenous enzymes affected the dissolution rate of combined minerals Mg(P=0.043)and Cu(P=0.009)in the duodenum and Zn(P=0.024)in the terminal ileum,and the dissolution rate of combined minerals Mg(P=0.003)and Cu(P<0.001)in the total digestive tract.Generally,the dissolution rate of combined minerals of broccoli residues were higher than those of rice bran,and the contents of P-SME in rice bran had a larger variation in different tract segments;Exogenous enzymes addition could improve the dissolution rate of some combined minerals in different tract segments,especially in the total digestive tract.