| High-purity Attapulgite(APT)and montmorillonite (MMT)were selected to preparate montmorillonite -attapulgite(M-A) composites . The objective of this study was to evaluate the effect of dietary supplementation with APT,MMT and M-A on morphological structure and physiological function of intestines, apparent digestibility of nutrient and chyme mean retention time(MRT) in weanling piglets.Thirty six healthy 24-day-old weanling Landrace×Large White castration male weanling piglets with initial weight of (7.32±0.12)kg were randomly divided into four groups with nine replicates per group and one pig per replicate. The piglets in control group were fed the basal diet (without antibiotics), and the piglets in treatment I group (APT) ,treatment II group (MMT) and treatmentⅢgroup (M-A) were fed the basal diet supplemented with 3000 mg/kg APT, MMT and M-A to replace the premix vector (rice husk powder), respectively. The trial lasted 42 days. In orde to observe the growth performance, diarrhea incidence of pigs, feed intake and diarrhea were recorded everyday,and pigs were weighted on the1st day, 21st day and 42nd day of the trial. In orde to observe the mean retention time(MRT)in alimentary canalon, three piglets in each group were fed dietary supplementation with Cr2O3 on the 26th day of the trial ,and then collected the feces samples for five days. Six piglets in each treament were selected to observe the nutrients apparent digestibility of pigs from the method of exogenous indicator (Titanium dioxide, TiO2). Three piglets whose body weight closed to the average were selected from each group on the 21st day and 42nd day of the trial for blood collection and slaughtered for Intestinal samples.The results were as follows:(1)Pigs in treatment group had higher ADG and ADFI than control group,but there were no differences among control group and treatments (P>0.05); Pigs in control group had higher F/G than treatment groups (P<0.05), and there were no significantly difference (P>0.05) among treatment groups.(2)There were no differences in diarrhea frequency among groups (P>0.05),except that Pigs accepted dietary supplementation with MMT and M-A have lower diarrhea frequency than control group in the early stages of trial (P<0.05). (3) Contrary to the control group, Pigs receiving diets contains APT and M-A had lower GLB level (P<0.05) ;No differences in other serum biochemistry indexes were observed among groups (P>0.05). (4) At the 21st day, piglets in MMT and APT group had higher villous surface area in ileum than control group (P<0.05) ;At the 42nd day, piglets in MMT group had higher villous heigh /crypt depth(V/C) than other groups (P<0.05);piglets in APT group had higher villous surface area in ileum than control group (P<0.05).No differences in villous heigh were observed among groups (P>0.05) .(5) As for the activities of trypsin, ,and lipase in the duodenum contents in duodenum and jejunum and the activities of amylase and maltase in the jejunum contents, APTgroup>MMTgroup,M-Agroup>control group,and there no significantly difference between groups(P>0.05). (6) Contrary to control group, piglets in treatment groups had fewer goblet cells in villus in duodenum(P>0.05),but more in jejunum and ileum (P>0.05).(7)Contrary to control group, piglets in treatment groups had fewer Escherichia coli and salmonella in caecum on the 21st day and in colon on the 42nd day,and salmonella in colon on the 21st day(P>0.05). (8)The number of intraepithelial lymphocytes(IEL) in duodenum for piglets in treament groups was larger than in control group, as well as the content of Secretory Immunoglobulin A (SIgA);As for the the number of IEL in jejunum and the conten of SIgA in ileum on the 21st day and in jejunum on the 42nd day, APTgroup>control group> M-Agroup>MMTgroup, and there was no significantly difference between groups(P>0.05). As for the the number of IEL in ileum and the conten of SIgA in jejunum on the 21st day, MMTgroup>control group>M-Agroup>APTgroup, and there was no significantly difference between groups(P>0.05).(9)In the early stages of trial ,Pigs in treatment group had higher D-lactate level in plasma than control group,and there were no differences in D-lactate level among treaments.;as for the diamine oxidase (DAO)level in plasma , control group>M-Agroup>APTgroup>MMTgroup , there were significantly differences among APTgroup,MMTgroup and control group ,as well as between MMT group and M-A group . No differences in endotoxin were observed among groups(P>0.05). (10) There were no differences in mean retention time(MRT) among groups (P>0.05),except that pigs accepted dietary supplementation with MMT have higher MRT than M-A group (P<0.05).(11) There were no differences in apparent digestibilities of dry matter (DM)among groups(P>0.05),except that Pigs accepted dietary supplementation with MMT have higher DM digestibilities than APT group (P<0.05); Pigs in M-A groups had lower apparent digestibilities of crude protein(CP) than APTgroup,MMTgroup and control group(P<0.05),and there was no significantly difference among APTgroup,MMTgroup and control group; Pigs in M-A group and APTgroup had lower apparent digestibilities of crude extract (EE) than MMT group and control group(P<0.05),while there was no significantly difference between APTgroup and M-A group .In summary,these results showed that the addition of APT,MMT and M-A to the diet have positive effect on small intestine morphology, maintaining integral intestinal barrier and the diarrhea incidence to improve the growth performance in piglets. Therefore, APT,MMT and M-A had protection on the intestinal mucosa ,and APT,MMT were more useful than M-A.Dietary supplementation with APT,MMT and M-A had no influence on MRT,and the addition of APT and M-A reduce the apparent digestibilities of crude extract .
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