| The objective of this study was to determine the effects of aflatoxin B1(AFB1)on performance,digestion and metabolism in weaned piglets and the by which underlying mechanism AFB1 alter ingestion,digestion and metabolism.There are two experiments were included in this study.Exp.1 Effects of dietary AFB1 on performance,liver and gut health in weaned piglets.The objective of this study was to determine the effects of AFB1 on growth performance,liver and gut health in weaned piglets.12 healthy DLY 21-d-old weaned piglets were randomly allotted to 2 groups with 6 replicates of 1 piglet.Two groups fed the basic diet with or without 0.3mg/kg AFB1 respectively for 21 days.At the end of the experiment,the piglets were weighed on fasting condition and the samples were collected.The growth performance,organ index,liver pathology,hepatic fat metabolism related genes,pH of intestinal contents,intestinal morphology and intestinal microflora were investigated.The results showed that:1)Compared to control group,AFB1 decreased average daily gain,gain to feed ratio(P=0.08)and the average daily feed intake(P=0.09).2)Dietary AFB1 significantly increased the relative weight of the liver.(P<0.05);AFB1 induced the structure of liver lobule in toxin group was less clear and moderate hydropic degeneration in liver cellsand obvious hyperplasia of hepatic fibrosis.3)Dietary AFB1 had a tendency to decrease adipogenesis-related genes of the mRNA expression of ACC-1 in liver(P=0.06),and had no significant effect on the mRNA expression of FAS,CPT-1,LPL and PPAR-alpha.4)Dietary AFB1 significantly increased the villus height,crypt depth and the villus height to crypt depth ratio of duodenum and the crypt depth of jejunum(P<0.05)5)Dietary AFB1 reduced the counts of Bifidobacteriumspp.in cecal digesta of piglets(P<0.05),and there was no significant effects on the counts of Escherichia coli,Lactobacillus spp.and Bacillus spp.It was suggested that dietary supplemented with 0.3 mg/kgAFBl decreased the production performance and liver and intestinal health was slightly damaged in weaned piglets.Exp,2 Effects of AFB1 on ingestion,digestion and metabolism in weaned piglets fed diets with different concentrations of nutrientsThe objective of this study was to determine the effects of AFB1 on feeding,digestion,metabolism and its potential mechanism and the effects of nutrient levels on AFB1 toxicity in weaned piglets.The experiment is a 2 X 2 factorial design,namely,diets were formulated following NRC and 95%NRC recommended nutrient levels with or without 0.5mg/kgAFB1.Twenty-four healthy 21-d-old DLY weaned piglets were randomly allotted to 4 groups with 6 replicates of 1 piglet in each.Trial period was 28d.At the end of the experiment,the piglets were weighed on fasting condition and the samples were collected.The growth performance,blood biochemical parameters,digestive capacity,intestinal development,hypothalamic neuropeptides,serum FGF21,hepatic glycolipid metabolism related genes expressions were examined.The results showed that:1)Compared to control group,AFB1 significantly reduced ADFI and ADG during 15-28d and 0-28d(P<0.01).2)Dietary AFB1 significantly reduced the relative weight of kidney and pancreas(P<0.05).3)Dietary AFB1 significantly reduced the apparent digestibility of cysteine(P<0.05),increased the apparent digestibility of glutamic acid(P=0.09).4)Dietary AFB1 tended to decrease serum low-density lipoprotein cholesterol(P=0.05),increased the content of AST(P<0.05)and ALT(P=0.08)in serum.5)Dietary AFB1 significantly increased the depth of duodenal crypt(P<0.01),and had no significant effect on digestive enzyme activities.6)Dietary AFB1 significant increase the counts of Bacillus coli in colon(P<0.05).7)Dietary AFB1 significantly decreased the expression of NPY in hypothalamus(P<0.01),In addition,decreased the nutrient level further decraesed the expression of NPY.8)Dietary AFB1 significantly increased the concentration of FGF21 in serum(P<0.01).There were no significant effects on the mRNA expression of FGF21 and FGF21 regulated-gene in the liver.9)Dietary APB1 significantly decreased the mRNA expressions of lipometabolism-related genes ACC(P<0.01),DGAT(P<0.01)and FAS(P<0.05),significantly increased the expressions of lipolysis-related genes CPT-1(P<0.05),and ATGL(P=0.08).10)Dietary AFB1 significantly increased glycometabolism-related genes of the mRNA expression of PKM and GLUT1(P<0.05),It was suggested that diet with 0.5 mg/kgAFB1 decreased performance.AFB1 could inhibit the expression of NPY,increase the level of serum FGF21,mobilize body fat and increase the utilization of energy.There was no significant interaction between nutrient levels and AFB1.Taken together,dietary AFB1 decreased performance impaired hepatic and intestinal health in weaned piglets.Dietary AFB1 also resulted in decreased ADFI and increased hepatic lipolysis.The underlying mechanism might be related to that AFB1 decreased NPY expression in hypothalamus and increased serum FGF21 levels.There was no significant interaction nutrient levels and AFB1. |
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