Toxicity Of AFB₁from Contaminated Corn On Ducklings And Detoxication Effects Of Modified Montmorillonite

The experiment was conducted to investigated the effects of different levels of AFB₁from naturally contaminated moldy corn on growth performance, organ developmrnt andpartial serum parameters, and digestive physiology of ducklings with or without thermallymodified montmorillonite （a clay adsorbrnt, Calibrin-A）. The experiment contains two parts.To investigate the efficacy of clay adsorbent （CA） in preventing the toxicity of increasingaflatoxin B1（AFB₁） from naturally contaminated moldy corn on performance, organdevelopment, immunity, intestine development and digestive enzyme activities of ducklings,12801-d-old cherry valley ducks were randomly allocated into8treatments of8replicationsof20ducks. Diets were4levels of AFB₁-contaminated maize （0%,25%,50%,100%） with orwithout0.1%CA. Ducks were allowed to access feed and water ad libitum. Average daileygain （ADG）, average dailey feed intake （ADFI）, feed conversion ratio （FCR）, uniformity, andbeak decoloration ratio were recorded. Blood, tissue and small intestine chyme samples fromeight ducks per treatment were obtained at d21to determine serum immunoglobulin andprotein concentrations, relative organ weights, intestinal morphology and amylase、lipase andtrypsase activities. Regardless of CA supplementation, AFB₁-contaminated diets decreased （P<0.05） ADG, uniformity, relative weight of thymus and concentrations of total protein （TP）and albumin （ALB）, villus height（V） of ileum, villus/crypt ratio（V/C） and digestive enzymeactivities of small intestine, and increased （P <0.05） beak decoloration ratio and mortality. Increased levels of contaminated maize caused linear （P <0.05） or quadratic （P <0.05） or bothdecrease in ADG, uniformity, relative weight of liver, lung, spleen, thymus and brusa offabricius, IgM and serum protein concentrations, V and V/C and digestive enzyme activitiesof small intestine, and increase in beak decoloration ratio and mortality without CA. Additionof0.1%CA increased （P <0.05） uniformity, relative weight of small intestine, spleen andthymus, IgG and IgM concentration, V and V/C of duodenum and jejunum, amylase activityof duodenum, lipase activity of jejunum, trypsin and lipase activities of ileum, and decrease inbeak decoloration ratio, mortality and serum IgA concentration. The uniformity, relativeweight of thymus, concentration of IgA, TP and GLB, V/C of duodenum, V of jujenum, and Vand V/C of ileum decreased and beak decoloration ratio, mortality and serum IgG and IgMconcentration increased with the increase of contaminated maize concentrations with CAsupplementation.The metabolism test was conducted to evaluate the toxicity of increasing levels ofdietary aflatoxin B1（AFB₁） contaminated corn on nutrient availability in ducks fed diets withor without clay adsorbent （CA）. The experiment consisted of3treatments for each diet: acontrol diet with uncontaminated corn and test diets were formulated by replacinguncontaminated corn with AFB₁contaminated corn at the percentage of50%and100%（0%M,50%M, and100%M, respectively）. One hundred and sixty-two21-d-old Cherry Valleyducks （mixed sex） were randomly distributed into individual cages for six dietary treatmentswith nine replicates of three ducks for each diet. Endogenous losses were obtained fromanother27ducks. For the determination of nutrient digestibility, the total fecal collectionmethod was used. Excreta samples were collected to determine DM, OM, CP, amino acid（AA）, gross energy （GE）, and GE was analyzed for computation of AME and TME. Ducksfed contaminated diets had lower （P <0.05） apparent digestibility （AD） and true digestibility（TD） of DM, AME and TME with or without0.1%CA supplementation. The AD and TD of DM and OM, AME and TME were decreased （P <0.05） as the concentration of contaminatedcorn increased in ducks fed diets without CA. So did the AD and TD of DM in ducks fed dietswith0.1%CA.100%M diet decreased （P <0.05） AME and TME compared to0%M dietwithout CA supplementation. In ducks consuming diets without CA, contaminated dietslinearly （P <0.05） and quadratically （P <0.05） reduced AD and TD of Leu, Phe, Ala, Asp, Glu,Gly, Pro and Ser. In ducks fed diets with0.1%CA supplementation, the AD and TD of His,Leu, Lys, Phe, Thr, Ala, Cys, Glu, Gly and Pro were adversely （P <0.05） affected in acontaminated corn-dose dependent manner. Diet added0.1%CA neutralized the linear effectof AFB₁-contaminated corn on AD and TD of OM and Asp, AME and TME （P>0.05）. Ducksfed100%M diet supplemented with0.1%CA increased （P <0.05） AD and TD of Glycompared to100%M diet, and50%and100%M diet supplemented with0.1%CA increased（P <0.05） AD and TD of Pro compared to50%M and100%M diet, respectively. Inconclusion, ducks fed AFB₁contaminated corn decreased nutrient digestibility indose-dependent manner, and0.1%CA supplementation improved AD and TD of OM, Asp,Gly and Pro, AME and TME.Feeding AFB₁-contaminated corn has a dose-dependent detrimental effect on ducklingsin organ development, interferes with the normal organ function, disrupt metabolism andsuppress the immune performance. AFB₁can destroy pigment of corn to decrease thepigmentation of duck beak, injure intestine development and reduce amylase、lipase andtrypsase activities. This resulted in reduced nutrient utilization and growth suppression.Addition of0.1%modified montmorillonite to diet was effective in counteracting the toxiceffects of170μg/kg AFB₁in contaminated corn to some extent.