| To reveal the possible mechanism of effect of maize naturally contaminated with mycotoxins on the performance and intestinal health and to verify whether mannan-oligosaccharide(MOS) could alleviate the damage of mycotoxin to the intestinal health, this experiment was conducted to investigate the effect of maize naturally contaminated with mycotoxins and the addition of MOS on the growth performance, the digestive and absorptive function, the oxidative and antioxidative status, and intestinal flora and metabolic products in intestinal tract of piglets. A 2×2+2 design experiment was carried out. The 2×2 design was introduced to four of treatments--the control group(corn-soybean basal diet), mouldy corn group(MT group, the corn in the basal diet were all replaced by mouldy corn), MOS group (basal diet+0.2% MOS) and mouldy corn +MOS (MT+MOS group, diet in MT group+0.2% MOS). The remaining two groups were administrated with feed of control group and MOS group at the same amount of feed everyday with MT group and MT+MOS group, respectively, to pair the feed intake. Thirty healty PIC piglets (35 days old) were random assigned to 6 treatments, with 5 replicates per treatment and 1 piglet per replicate. The trial lasted for 21d. At the end of the experiment, the piglets were slaughtered after blood sampled from precava vein. The mucosa of duodenum and jejunum were scraped, the rectal and cecal contents were collected to determine the microorganism and their metabolite. Results showed that:1. Mouldy corn significantly reduced the average daily gain in the first two weeks (P<0.05) and average feed intake in the whole experiment period (P<0.01), trended to reduce ADFI in the first two weeks. There was no interaction between mouldy corn and MOS. The F/G over the whole experiment of piglets in MT group was lower than that of the MT-paired group.2. Mouldy corn extremely reduced the organic matters, energy, Ca and P digestibility of piglets (P<0.01), while MOS improved CP and energy digestibility (P<0.05) and P digestibility (P<0.01), trended to improve organic matter digestibility. The MOS addition in the MT diet improved P digestibility (P<0.01) significantly. Compared with the MT-paired group, OM, energy, Ca and P digestibility in MT group were significantly decreased (P<0.01), however, CP digestibility was no difference between the two group.3. Mouldy corn significantly elevated the serum leptin level (P<0.05). The MOS and MT trended to interact on the leptin level (P=0.08). MOS showed a declined trend on the CCK level (P=0.08). Ghrelin and leptin level in MT group and MT-paired group had no difference. However, the serum CCK level was elevated (P<0.05).4. Mouldy corn significantly decreased the villus length, the ratio of villi length and crypt depth. The mouldy corn, MOS and their interaction showed no effect on the duodenal and jejunal mucosa thickness, duodenal and jejunal villus length, crypt depth and the ratio of villi length and crypt depth. Compared with the MT-paired group, the villi length and the ratio of villi length and crypt depth in MT group significantly decreased (P<0.01), while the crypt depth was elavated.5. Mouldy corn significantly decreased the activity of SOD and T-AOC in jejunal mucosa, and trended to elevate the MDA (P=0.08). MOS significantly declined the jejunal MDA concentration, and trended to enhance the SOD activity (P=0.06). Obvious interaction was showed between MT and MOS. The MDA concentration in MT group piglets was significantly higher than that of the MT-paired group (P<0.05), while the T-AOC was 15.2% lower than the MT-paired group.6. Mouldy corn significantly decreased the relative expression of sodium-glucose cotransporter 1(SGLTl) mRNA, dipeptide transporter 1(PepT1) mRNA in duodenum (P<0.01), elevated the jejunal SGLT1 expression (P<0.05). MOS and the interaction between mouldy corn and MOS showed no effect on jejunal and duodenal SGLT1 and PepTl expression. Compared with the MT-paired group, the duodenal SGLT1 expression in MT group declined (P<0.05), while the jejunal PepTl and SGLT1, duodenal PepTl had no difference.7. Mouldy corn raised the amout of Escherichia coli in rectal feces of the second weekend. The amout of Escherichia coli and lactobacillus was increased in rectal and cecal contents of the third weekend and the ratio of lactobacillus and Escherichia coli was also increased.These results indicated that the mouldy corn decreased the feed intake of piglets through changing the feed intake relative hormone in serum to inhibit the growth of piglets. Meanwhile, mouldy corn leaded to oxidize damage, structure change and nutrient transport carrier in jejunum, these adverse effects also inhibited the growth of piglets. In addition, mouldy corn could alter the microflora of piglets through improving the amout of lactobacillus and Escherichia coli to reduce the growth performance. However, the addition of MOS had no obvious improvement on these adverse impacts from mouldy corn. |
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