Effects of feeding aflatoxin-contaminated diets with and without clay to weanling and growing pigs on performance, liver function, and mineral metabolism

Nursery pigs fed with feed contaminated by aflatoxin B1 (Aspergillus flavus) and anti-mycotoxin blend: Pathogenesis and negative impact on animal health and weight gain

The present study aimed to evaluate whether a moderate dose of aflatoxin B1 in pigs' diet interferes with pigs' growth and health in the nursery phase and whether an anti-mycotoxin mixture minimizes the adverse effects of the toxin. One blend with Saccharomyces cerevisiae lysate, zeolite, silicon dioxide, propylene glycol, Carduus marianus extract, soy lecithin, and carbonate was used as an anti-mycotoxin. Four treatments, with six repetitions per treatment and three pigs/pen: Afla0-AntiMyc0 - negative control (without aflatoxin); Afla500-AntiMyc0 - positive control (500 ppb of aflatoxin); Afla0-AntiMyc1000 - 1000 mg/kg of anti-mycotoxin blend; Afla500-AntiMyc1000 - 500 ppb aflatoxin +1000 mg/kg of anti-mycotoxin blend. It was observed that pigs in the positive control (Afla500-AntiMyc0) had lower body weight and weight gain when compared to the other treatments during the experimental period. Also, pigs from Afla500-AntiMyc0 had lower feed intake between days 1-20 and 1 to 30 than Afla0-AntiMyc0. The pigs from Afla500-AntiMyc0 had higher levels of liver enzymes aspartate aminotransferase and alanine aminotransferase compared to other treatments. The pigs from Afla500-AntiMyc0 had higher villus height than the other treatments, while the folded size was smaller in this treatment. Crypts were deeper in the intestines of pigs in both treatments that consumed aflatoxin. In general, it is concluded that the intake of aflatoxin B1 by nursery pigs has negative impacts on the health and, consequently, the animals' growth performance; however, the addition of the contaminated feed with an anti-mycotoxin blend was able to protect the pigs, minimizing the adverse effects caused by the mycotoxin.

Effects of a Bentonite Clay Product and a Preservative Blend on Ileal and Fecal Nutrient Digestibility in Pigs Fed Wheat Naturally Contaminated with Deoxynivalenol

The objectives were to determine the effects of dietary deoxynivalenol (DON) on apparent ileal digestibility (AID) of nutrients and to evaluate the efficacy of a bentonite (BEN) and a preservative blend (PB) product for alleviating DON effects on the nutrient digestibility of pigs. Twelve crossbred barrows with an initial body weight of 69.4 kg (standard deviation = 3.5) equipped with a T-cannula in the distal ileum were allotted a triplicated 4 × 2 incomplete Latin square design with four dietary treatments and two periods. Dietary treatments were (1) an uncontaminated diet, (2) a contaminated diet (CD) mainly based on contaminated wheat with 1.6 mg/kg DON, (3) CD + 0.25% PB consisting of preservation components as major sources, antioxidants, microorganisms, and amino acids (AA), and (4) CD + 0.25% BEN. The AID and ATTD of dry matter, organic matter, crude protein, most minerals, and most AA were not affected by DON contamination. Dietary DON decreased the AID and ATTD of sodium (p < 0.05) but were restored by supplementing the PB product (p < 0.05). The AID of zinc was increased (p < 0.05) by dietary DON, but supplementing BEN decreased zinc digestibility (p < 0.05). The AID of Arg, Ile, Thr, and Asp was decreased (p < 0.05) by BEN addition. In conclusion, dietary DON affected the digestibility of some minerals but not AA in pigs. Supplemental BEN can negatively affect the nutrient digestibility of some minerals and AA in pigs. The addition of a PB product in pig diets can restore digestibility of sodium but not of other nutrients. Based on these observations, feed additives for alleviating DON effects on nutrient digestibility of pigs can be carefully selected by swine diet formulators.

Effects of Mycotoxin-Sequestering Agents on Growth Performance and Nutrient Utilization of Growing Pigs Fed Deoxynivalenol-Contaminated Diets

The objective of this study was to investigate the effects of supplemental mycotoxin-sequestering agents on growth performance and nutrient utilization in growing pigs fed deoxynivalenol (DON)-contaminated diets. Twelve barrows with an initial body weight of 35.5 kg (standard deviation = 1.3) were assigned to six dietary treatments in a replicated 6 × 5 incomplete Latin square design. Five experimental diets consisted of an uncontaminated diet (PC), a DON-contaminated diet at 6.89 mg/kg (NC), NC + bentonite 0.5%, NC + yeast cell wall 0.5%, and NC + a mixture product 0.5% which consisted of enzymes, microorganisms, minerals, and plant extracts. Pigs had ad libitum access to the five diets. In the last group, the PC diet was restrictedly provided to pigs at the quantity of feed consumption of the NC group. Average daily gain, average daily feed intake, and gain:feed were not affected by supplemental mycotoxin-sequestering agents except for the mixed product that tended to improve (p = 0.064) gain:feed in pigs fed DON-contaminated diets. The apparent total tract digestibility (ATTD) of dry matter was not affected by DON contamination or by supplemental mycotoxin-sequestering agents, whereas the ATTD of Ca was decreased (p = 0.032) by supplemental yeast cell wall in pigs fed DON-contaminated diets. The ATTD of P was greater (p = 0.042) in pigs fed the NC diet compared with the pigs fed the restricted amount of the PC diet. In conclusion, bentonite and yeast cell wall did not affect growth performance of pigs fed DON-contaminated diets, but a supplemental mixed product consisting of enzymes, microorganisms, minerals, and plant extracts partially alleviated the negative effects of dietary DON on the gain:feed of pigs. Calcium digestibility was decreased by supplemental yeast cell wall in pigs fed DON-contaminated diets. Based on the present work, the use of a mixed product consisting of enzymes, microorganisms, minerals, and plant extracts is suggested, and the reduction of Ca digestibility by yeast cell wall needs to be considered in diet formulations.

A Dose-Response Investigation of a Micronized Porous Ceramic Particle to Improve the Health and Performance of Post-weaned Pigs Infected With Salmonella enterica Serotype Typhimurium

The objective was to investigate the effects of supplementing increasing concentrations of PowerGuard (PG), a micronized ceramic particle, to weaned pigs on health and performance following a Salmonella enterica serotype Typhimurium infection. Forty barrows were transported to the USDA facility in Liberty, TX, USA. Pigs were randomly assigned to one of five treatments (n = 8): (1) uninfected control (CON), no Salmonella typhimurium (ST) and no PG treatment; (2) infected control (ST), infected with ST but no PG treatment; (3) PG0.05, infected with ST and supplemented with 0.05% PG; (4) PG0.25, infected with ST and supplemented with 0.25% PG; and (5) PG0.50, infected with ST and supplemented with 0.5% PG. All pigs were enrolled at 21.5 ± 1.33 days of age and did not differ in initial BW (1.98 ± 0.09 kg). Pigs were anesthetized to insert temperature recording devices into the abdominal cavity. Pigs were offered feed and water ad libitum. Pigs in ST, PG0.05, PG0.25, and PG0.50 were infected orally with 1.75 × 107 colony-forming units of Salmonella typhimurium on day 7. Pig body weights and peripheral blood samples were collected on days 0, 7, 10, 14, and 21. Pigs were harvested on day 21 and ileum and liver samples were collected for histopathological analyses. There was no treatment difference for final BW (P ≥ 0.201). There was a tendency (P = 0.087) for a treatment difference in the fecal score; ST and PG0.50 had more loose fecal scores than CON and PG0.25. There was a treatment × time interaction for intraperitoneal temperature (P &lt; 0.0001); PG0.05, PG0.25, and PG0.50 had attenuated febrile responses during the acute post-infection period compared with ST. There was a treatment × time interaction for total leukocyte counts (P = 0.007); PG treatments reduced leukocytosis post-infection compared with ST. Supplementing PG0.25 improved many health and performance variables when pigs were infected with Salmonella Typhimurium. Furthermore, supplementing PG0.05 attenuated the febrile response and many hematological variables. However, supplementing PG0.5 did not improve many aspects of health or performance. Therefore, supplementing PowerGuard between 0.05 and 0.25% of the diet may play a role in protecting weaned pigs from disease caused by Salmonella.

Effects of Deoxynivalenol and Mycotoxin Adsorbent Agents on Mitogen-Activated Protein Kinase Signaling Pathways and Inflammation-Associated Gene Expression in Porcine Intestinal Epithelial Cells

Deoxynivalenol (DON) is the most prevalent mycotoxin in swine feedstuffs. The intestinal epithelial cells represent the first target for the DON. Here, we studied the effects of DON and mycotoxin adsorbent agents on mitogen-activated protein kinase (MAPK) signaling pathways and inflammation-associated gene expression in porcine intestinal epithelial cells (IPEC-J2). Results showed that phosphorylation of MAPK signaling pathways (p38, ERK, and JNK) was increased after treatment of DON or lipopolysaccharide (LPS) in IPEC-J2 cells. The phosphorylation of p38, ERK, and JNK was not further enhanced after co-treatment with DON and LPS. The inos and cox-2 mRNA expression were significantly induced at 6 h after treatment of DON. DON treatment significantly increased the claudin 3 and occludin mRNA expression at 12 h. DON in combination with LPS treatment did not further increase the inflammation and tight junction-associated gene expression. The DON-induced phosphorylation of MAPK signaling pathways was impaired by mycotoxin adsorbent agent (nanoscale silicate platelets and the mixture of montmorillonites and yeast cell walls) treatment, thereby decreasing inflammation and tight junction-associated gene expression. Taken together, these findings demonstrate that DON triggers the inflammation in IPEC-J2 cells by phosphorylation of MAPK signaling pathways and LPS does not further augment the DON-induced inflammatory responses. Mycotoxin adsorbent agents can attenuate DON-induced inflammatory responses in IPEC-J2 cells through modulation of the phosphorylation of p38, ERK, and JNK.

Mycotoxin Occurrence, Toxicity, and Detoxifying Agents in Pig Production with an Emphasis on Deoxynivalenol

This review aimed to investigate the occurrence of mycotoxins, their toxic effects, and the detoxifying agents discussed in scientific publications that are related to pig production. Mycotoxins that are of major interest are aflatoxins and Fusarium toxins, such as deoxynivalenol and fumonisins, because of their elevated frequency at a global scale and high occurrence in corn, which is the main feedstuff in pig diets. The toxic effects of aflatoxins, deoxynivalenol, and fumonisins include immune modulation, disruption of intestinal barrier function, and cytotoxicity leading to cell death, which all result in impaired pig performance. Feed additives, such as mycotoxin-detoxifying agents, that are currently available often combine organic and inorganic sources to enhance their adsorbability, immune stimulation, or ability to render mycotoxins less toxic. In summary, mycotoxins present challenges to pig production globally because of their increasing occurrences in recent years and their toxic effects impairing the health and growth of pigs. Effective mycotoxin-detoxifying agents must be used to boost pig health and performance and to improve the sustainable use of crops.

Effects of Chronic Exposure to Low Levels of Dietary Aflatoxin B1 on Growth Performance, Apparent Total Tract Digestibility and Intestinal Health in Pigs

This study aimed to investigate the effects of chronic exposure to low levels of dietary aflatoxin B1 (AFB1) on growth performance, apparent total tract digestibility and intestinal health in pigs. In a 102-day experiment, fourteen barrows (Duroc×Landrace×Yorkshire, initial BW = 38.21 ± 0.45 kg) were randomly divided into control (CON, basal diet) and AFB1 groups (the basal diet supplemented with 280 μg/kg AFB1). Results revealed that the AFB1 exposure decreased the final BW, ADFI and ADG in pigs (p < 0.10). AFB1 exposure also decreased the apparent total tract digestibility of dry mater and gross energy at 50 to 75 kg and 105 to 135 kg stages, and decreased the apparent total tract digestibility of ether extract at 75 to 105 kg stage (p < 0.05). Meanwhile, AFB1 exposure increased serum diamine oxidase activity and reduced the mRNA abundance of sodium-glucose cotransporter 1, solute carrier family 7 member 1 and zonula occluden-1 in the jejunal mucosa (p < 0.05). Furthermore, AFB1 exposure decreased superoxide dismutase activity (p < 0.05) and increased 8-hydroxy-2'-deoxyguanosine content (p < 0.10) in jejunal mucosa. AFB1 exposure also increased tumor necrosis factor-α, interleukin-1β and transforming growth factor-β mRNA abundance in jejunal mucosa and upregulated Escherichia coli population in colon (p < 0.05). The data indicated that chronic exposure to low levels of dietary AFB1 suppressed growth performance, reduced the apparent total tract digestibility and damaged intestinal barrier integrity in pigs, which could be associated with the decreased intestinal antioxidant capacity and the increased pro-inflammatory cytokine production.

Investigation of the Efficacy of a Postbiotic Yeast Cell Wall-Based Blend on Newly-Weaned Pigs under a Dietary Challenge of Multiple Mycotoxins with Emphasis on Deoxynivalenol

Pigs are highly susceptible to mycotoxins. This study investigated the effects of a postbiotic yeast cell wall-based blend (PYCW; Nicholasville, KY, USA) on growth and health of newly-weaned pigs under dietary challenge of multiple mycotoxins. Forty-eight newly-weaned pigs (21 d old) were individually allotted to four dietary treatments, based on a three phase-feeding, in a randomized complete block design (sex; initial BW) with two factors for 36 d. Two factors were dietary mycotoxins (deoxynivalenol: 2000 μg/kg supplemented in three phases; and aflatoxin: 200 μg/kg supplemented only in phase 3) and PYCW (0.2%). Growth performance (weekly), blood serum (d 34), and jejunal mucosa immune and oxidative stress markers (d 36) data were analyzed using MIXED procedure of SAS. Mycotoxins reduced (p < 0.05) average daily feed intake (ADFI) and average daily gain (ADG) during the entire period whereas PYCW did not affect growth performance. Mycotoxins reduced (p < 0.05) serum protein, albumin, creatinine, and alanine aminotransferase whereas PYCW decreased (p < 0.05) serum creatine phosphokinase. Neither mycotoxins nor PYCW affected pro-inflammatory cytokines and oxidative damage markers in the jejunal mucosa. No interaction was observed indicating that PYCW improved hepatic enzymes regardless of mycotoxin challenge. In conclusion, deoxynivalenol (2000 μg/kg, for 7 to 25 kg body weight) and aflatoxin B1 (200 μg/kg, for 16 to 25 kg body weight) impaired growth performance and nutrient digestibility of newly-weaned pigs, whereas PYCW could partially improve health of pigs regardless of mycotoxin challenge.

Effect of toxin binders on immunity and aflatoxin M1 residues in milk in buffaloes

To investigate the effect of dietary toxin binders on AFM1 and immunity in buffaloes 48 Murrah buffaloes in same lactating phase were divided into 4 groups, viz. control (C), T1, T2 and T3 (toxin binder fed buffaloes) comprising of 12 animals each. The average milk AFM1 concentration decreased slightly in control group while marked decrease was found in T1 group throughout the experiment. The average milk SCC showed non significant increase in all the groups. Serum IgG concentration in control group decreased significantly from day 0 to day 45, while in groups T1, T2 and T3 there was significant increase, whereas no significant difference in serum IgG concentration was observed between the groups. The average serum total protein concentration in all the groups from day 7 through day 15, 30 and 45 was almost similar and within reference range. There was no significant difference between the groups. The average serum SGOT level was significant between the days in all the groups. The average SGPT concentration between the days was non significant in control and T1 groups and significant decrease was observed in T2 and T3 groups. The SGPT concentration was highly significant between control and T1, T2, T3 groups, respectively. The results suggested that feeding of toxin binder is effective in reducing AFM1 in milk at the dose rate of 50 mg/day having composition of exal 44.44% + bentonite 55.56% indicating that it provides a potential protective mechanism against aflatoxin exposure and also some alterations in biochemical parameters and IgG.

Silage review: Mycotoxins in silage: Occurrence, effects, prevention, and mitigation

Ensiled forage, particularly corn silage, is an important component of dairy cow diets worldwide. Forages can be contaminated with several mycotoxins in the field pre-harvest, during storage, or after ensiling during feed-out. Exposure to dietary mycotoxins adversely affects the performance and health of livestock and can compromise human health. Several studies and surveys indicate that ruminants are often exposed to mycotoxins such as aflatoxins, trichothecenes, ochratoxin A, fumonisins, zearalenone, and many other fungal secondary metabolites, via the silage they ingest. Problems associated with mycotoxins in silage can be minimized by preventing fungal growth before and after ensiling. Proper silage management is essential to reduce mycotoxin contamination of dairy cow feeds, and certain mold-inhibiting chemical additives or microbial inoculants can also reduce the contamination levels. Several sequestering agents also can be added to diets to reduce mycotoxin levels, but their efficacy varies with the type and level of mycotoxin contamination. This article gives an overview of the types, prevalence, and levels of mycotoxin contamination in ensiled forages in different countries, and describes their adverse effects on health of ruminants, and effective prevention and mitigation strategies for dairy cow diets. Future research priorities discussed include research efforts to develop silage additives or rumen microbial innocula that degrade mycotoxins.

Excess of dietary montmorillonite impairs growth performance, liver function, and antioxidant capacity in starter pigs

Montmorillonite (MMT) is widely used as a mycotoxin adsorbent in animal feeds, but its safety remains unclear. This study was conducted to investigate the safety of MMT supplementation in diets fed to starter pigs. A total of 120 32-d-old piglets (initial weight, 8.0 ± 0.9 kg) were randomly allotted into dietary treatments with graded MMT levels (0 [FS 0], 0.5% [FS 0.5], 1.0% [FS 1.0], 2.5% [FS 2.5], and 5.0% [FS 5.0]) with 6 replicate pens per treatment and 4 pigs per pen. All diets were fed for 28 d. As the MMT level increased, ADG and G:F changed in a linear and quadratic manner, while ADFI was linearly decreased ( > 0.05). Compared with FS 0, ADG, ADFI, and G:F of pigs in FS 1.0 increased ( < 0.05). However, the ADFI in pigs of FS 5.0 was lower than that in pigs of FS 0 ( < 0.05). The relative liver weight activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) changed in a linear and quadratic manner ( < 0.05). Compared with FS 0, pigs in FS 2.5 and FS 5.0 had a greater serum ALT ( < 0.05), while AST activity significantly increased in pigs of FS 5.0 ( < 0.05). Dietary MMT supplementation decreased serum Mg content in a linear and quadratic manner ( < 0.05), while Zn and Cu contents were linearly decreased ( < 0.05). Serum Zn and Cu contents of pigs in FS 0.5, FS 2.5, and FS 5.0 groups were lower than those in the control. Pigs fed with 2.5% and 5% MMT showed hepatic histopathological changes, including swelling, granular and vesicular degeneration, and apparent vacuolar degeneration. In addition, the content of serum total antioxidant capacity (T-AOC) and activity of glutathione peroxidase (GSH-PX) decreased in a linear and quadratic manner ( < 0.05). Compared to the control, 5.0% MMT significantly increased piglets' serum malondialdehyde (MDA) concentration and decreased GSH-PX activity ( < 0.05). T-AOC concentration in the pigs fed 2.5% and 5.0% MMT was lower than that in the control group ( < 0.05). Serum superoxide dismutase (SOD) activity changed in a quadratic manner ( < 0.05). Piglets in FS 1.0 showed a higher SOD activity when compared with the control ( < 0.05). These results indicate that supplementation of MMT higher than 1.0% can negatively affect liver structure and serum mineral content, and 5.0% MMT supplementation would also decrease feed intake, aggravate liver damage, and reduce the antioxidant capacity of starter pigs. Therefore, excess supplementation of MMT is not safe in starter pigs.

Vitamin C protects piglet liver against zearalenone-induced oxidative stress by modulating expression of nuclear receptors PXR and CAR and their target genes

Zearalenone (ZEN), a common mycotoxin found in human food and animal feed, is effectively detoxified by vitamin C by modulation of the nuclear receptor signaling pathway.

Determination of serum aflatoxin B1-lysine to evaluate the efficacy of an aflatoxin-adsorbing feed additive in pigs fed an aflatoxin B1-contaminated diet

In this study, serum aflatoxin B₁ (AFB₁)-lysine was determined in order to evaluate the in vivo efficacy of a hydrated sodium calcium aluminosilicate (HSCAS) in pigs fed AFB₁. Twenty-four 49-day-old crossbred barrows were maintained in individual cages and allowed ad libitum access to feed and water. A completely randomized design was used with six animals assigned to each of four dietary treatments for 21 days as follows: (A) basal diet (BD), (B) BD supplemented with 0.5 % HSCAS, (C) BD supplemented with 1.1 mg/kg AFB₁, and (D) BD supplemented with 0.5 % HSCAS and 1.1 mg/kg AFB₁. HSCAS was able to alleviate the toxic effects of AFB₁ on pigs and reduce (P < 0.05) the levels of serum AFB₁-lysine. Cumulative reductions of adduct yield values, calculated through the equation [(pg AFB₁-lysine/mg albumin) / (μg AFB₁/kg body weight)], were 53.0, 62.8, and 72.1 after 7, 14, and 21 days of oral exposure, respectively. AFB₁-lysine has potential as an AFB₁-specific biomarker for diagnostic purposes and for evaluating the efficacy of chemoprotective interventions in pigs.

Studies on the biological functions of CPS1 in AFB1 induced hepatocarcinogenesis

Carbamyl phosphate synthetase 1 (CPS1) was down-regulated in hepatocellular carcinoma (HCC), as treated by aflatoxin B1 (AFB1), a potent hepatocarcinogenesis mycotoxin. In this study, we firstly confirmed that AFB1 down-regulated the expression of CPS1 in a dose-dependent manner. At the meantime, both siRNA knock down of CPS1 and AFB1 treatment inhibited cell proliferation, and induced cell apoptosis. To further analysis the function of CPS1, the interacting proteins of CPS1 were searched by Co-IP, and three interacting proteins including type II cytoskeletal 1 (KRT1), albumin (ALB), and ubiquitin C (UBC) were found. Both KRT1 and ALB were new interacting proteins for CPS1. Our further study showed that CPS1 was regulating interacted and colocalized with KRT1 and ALB, and the intensity correlation was changed by AFB1. KRT1, ALB and CPS1 were all reported to play an important role in differentiation and tissue specialization. These results may offer an increasing understand that CPS1 might have a function in differentiation.

Nutritional value of high fiber co-products from the copra, palm kernel, and rice industries in diets fed to pigs

High fiber co-products from the copra and palm kernel industries are by-products of the production of coconut oil and palm kernel oil. The co-products include copra meal, copra expellers, palm kernel meal, and palm kernel expellers. All 4 ingredients are very high in fiber and the energy value is relatively low when fed to pigs. The protein concentration is between 14 and 22 % and the protein has a low biological value and a very high Arg:Lys ratio. Digestibility of most amino acids is less than in soybean meal but close to that in corn. However, the digestibility of Lys is sometimes low due to Maillard reactions that are initiated due to overheating during drying. Copra and palm kernel ingredients contain 0.5 to 0.6 % P. Most of the P in palm kernel meal and palm kernel expellers is bound to phytate, but in copra products less than one third of the P is bound to phytate. The digestibility of P is, therefore, greater in copra meal and copra expellers than in palm kernel ingredients. Inclusion of copra meal should be less than 15 % in diets fed to weanling pigs and less than 25 % in diets for growing-finishing pigs. Palm kernel meal may be included by 15 % in diets for weanling pigs and 25 % in diets for growing and finishing pigs.

Rice bran contains the pericarp and aleurone layers of brown rice that is removed before polished rice is produced. Rice bran contains approximately 25 % neutral detergent fiber and 25 to 30 % starch. Rice bran has a greater concentration of P than most other plant ingredients, but 75 to 90 % of the P is bound in phytate. Inclusion of microbial phytase in the diets is, therefore, necessary if rice bran is used. Rice bran may contain 15 to 24 % fat, but it may also have been defatted in which case the fat concentration is less than 5 %. Concentrations of digestible energy (DE) and metabolizable energy (ME) are slightly less in full fat rice bran than in corn, but defatted rice bran contains less than 75 % of the DE and ME in corn. The concentration of crude protein is 15 to 18 % in rice bran and the protein has a high biological value and most amino acids are well digested by pigs. Inclusion of rice bran in diets fed to pigs has yielded variable results and based on current research it is recommended that inclusion levels are less than 25 to 30 % in diets for growing-finishing pigs, and less than 20 % in diets for weanling pigs. However, there is a need for additional research to determine the inclusion rates that may be used for both full fat and defatted rice bran.

Clays as dietary supplements for swine: A review

Clays are crystalline, hydrated aluminosilicate molecules composed of alkali and alkaline earth cations along with small amounts of various other elements. The best-known are montmorillonite, smectite, illite, kaolinite, biotite and clinoptilolite. The molecules in these clays are arranged in three-dimensional structures creating internal voids and channels capable of trapping a wide variety of molecules. As a result of this structure, clay minerals are regarded as a simple and effective tool for the prevention of the negative effects of many toxic compounds. Dietary supplementation with clays has been shown to improve weight gain and feed conversion in pigs. Where improvements in performance have been noted, one of the most likely explanations for the improvement is the fact clays increase nutrient digestibility. Clays reduce the speed of passage of feed along the digestive tract which allows more time for digestion. Feeding clays also causes morphological changes in the intestinal mucosa such as an increase in villus height and an increase in the villus height to crypt depth ratio. These changes increase the surface area of the gastrointestinal tract thus increasing nutrient digestibility. Several studies have indicated that feeding clay reduces the incidence, severity and duration of diarrhea in pigs. The mechanism for the reduction in diarrhea is likely due to increases in the numbers of Bifidobacteria and Lactobacillus and decreases in Clostridia and E. coli in the small intestine of pigs fed clays. In addition, the numbers of pigs born alive and weaned, birth weight and weaning weight have been shown to be higher for sows fed clays. Several studies have indicated that clays can help mitigate the effects of mycotoxins. The aim of the present review is to focus on the various clays which have been given attention in recent research and to discuss their potential to improve pig performance.

The aflatoxin-detoxifizyme specific expression in mouse parotid gland

The aflatoxin-detoxifizyme (ADTZ) gene derived from Armillariella tabescens was cloned into parotid gland-specific expression vector (pPSPBGPneo) to construct the parotid gland-specific vector expressing ADTZ (pPSPBGPneo-ADTZ). Transgenic mice were generated by microinjection and identified by using PCR and Southern blotting analysis. PCR and Southern blotting analysis showed that total six transgenic mice carried the ADTZ gene were generated. RT-PCR analysis indicated that the expression of ADTZ mRNA could be detected only in parotid glands of the transgenic mice. The ADTZ activity in the saliva was found to be 3.72 ± 1.64 U/mL. After feeding a diet containing aflatoxin B1 (AFB1) for 14 days, the effect of ADTZ on serum biochemical indexes and AFB1 residues in serum and liver of mice were evaluated. The results showed that total protein and globulin contents in the test treatment (transgenic mice) produced ADTZ were significantly higher than that of the positive control, while alanine aminotransferase and aspartate aminotransferase activity in serum of the test treatment (transgenic mice) were remarkably lower compared to that of the positive control (P < 0.05). Moreover, AFB1 residues in serum and liver of the test treatment (transgenic mice) were significantly lower compared with that of the positive control (P < 0.05). These results in the study confirmed that ADTZ produced in transgenic mice could reduce, even eliminate the negative effects of AFB1 on mice.

Short-term safety and efficacy of calcium montmorillonite clay (UPSN) in children

Recently, an association between childhood growth stunting and aflatoxin (AF) exposure has been identified. In Ghana, homemade nutritional supplements often consist of AF-prone commodities. In this study, children were enrolled in a clinical intervention trial to determine the safety and efficacy of Uniform Particle Size NovaSil (UPSN), a refined calcium montmorillonite known to be safe in adults. Participants ingested 0.75 or 1.5 g UPSN or 1.5 g calcium carbonate placebo per day for 14 days. Hematological and serum biochemistry parameters in the UPSN groups were not significantly different from the placebo-controlled group. Importantly, there were no adverse events attributable to UPSN treatment. A significant reduction in urinary metabolite (AFM1) was observed in the high-dose group compared with placebo. Results indicate that UPSN is safe for children at doses up to 1.5 g/day for a period of 2 weeks and can reduce exposure to AFs, resulting in increased quality and efficacy of contaminated foods.

Alternatives to antibiotics as growth promoters for use in swine production: a review

In the past two decades, an intensive amount of research has been focused on the development of alternatives to antibiotics to maintain swine health and performance. The most widely researched alternatives include probiotics, prebiotics, acidifiers, plant extracts and neutraceuticals such as copper and zinc. Since these additives have been more than adequately covered in previous reviews, the focus of this review will be on less traditional alternatives. The potential of antimicrobial peptides, clay minerals, egg yolk antibodies, essential oils, eucalyptus oil-medium chain fatty acids, rare earth elements and recombinant enzymes are discussed. Based on a thorough review of the literature, it is evident that a long and growing list of compounds exist which have been tested for their ability to replace antibiotics as feed additives in diets fed to swine. Unfortunately, the vast majority of these compounds produce inconsistent results and rarely equal antibiotics in their effectiveness. Therefore, it would appear that research is still needed in this area and that the perfect alternative to antibiotics does not yet exist.

The use of feed additives to reduce the effects of aflatoxin and deoxynivalenol on pig growth, organ health and immune status during chronic exposure

Three feed additives were tested to improve the growth and health of pigs chronically challenged with aflatoxin (AF) and deoxynivalenol (DON). Gilts (n = 225, 8.8 ± 0.4 kg) were allotted to five treatments: CON (uncontaminated control); MT (contaminated with 150 µg/kg AF and 1100 µg/kg DON); A (MT + a clay additive); B (MT + a clay and dried yeast additive); and C (MT + a clay and yeast culture additive). Average daily gain (ADG) and feed intake (ADFI) were recorded for 42 days, blood collected for immune analysis and tissue samples to measure damage. Feeding mycotoxins tended to decrease ADG and altered the immune system through a tendency to increase monocytes and immunoglobulins. Mycotoxins caused tissue damage in the form of liver bile ductule hyperplasia and karyomegaly. The additives in diets A and B reduced mycotoxin effects on the immune system and the liver and showed some ability to improve growth. The diet C additive played a role in reducing liver damage. Collectively, we conclude that AF and DON can be harmful to the growth and health of pigs consuming mycotoxins chronically. The selected feed additives improved pig health and may play a role in pig growth.

Reduction in the urinary aflatoxin M1 biomarker as an early indicator of the efficacy of dietary interventions to reduce exposure to aflatoxins

Aflatoxin B1 is a persistent public health issue in Ghana. Assessment of AFB1 intervention efficacy is currently dependent on long-term biomarkers. This study was designed to determine whether daily AFM1 biomarker levels could be utilized as an early detection method for intervention efficacy. Participants were treated with a refined calcium montmorillonite clay (UPSN) or a placebo (calcium carbonate) in a crossover study. Urine samples were assessed for AFM1 levels daily. UPSN treatment reduced AFM1 biomarkers by 55% compared to the placebo. This is the first study to show that daily urinary AFM1 levels can be used as a biomarker of internal aflatoxin B1 exposure in short-term intervention trials to determine efficacy.

In vitro evaluation of the capacity of zeolite and bentonite to adsorb aflatoxin B1 in simulated gastrointestinal fluids

Anin vitro study using single concentration and isotherm adsorption was carried out to evaluate the capacity of Vietnamese produced zeolite and bentonite to adsorb aflatoxin B1 (AFB1) in simulated gastrointestinal fluids (SGFs), and a commercial sorbent hydrated sodium calcium aluminosilicate (HSCAS) was used as reference. In this study, AFB1 solution was mixed with sorbents (0.3, 0.4 and 0.5% w/v) in SGFs at pH 3 and pH 7 and shaken for 8 h, centrifuged and the supernatant measured by Vicam fluorometer. Adsorption of AFB1 onto zeolite and bentonite varied according to the pH of SGFs and was lower than HSCAS. Linearity between the increased amount of AFB1 adsorbed on sorbents and the decrease of sorbent concentration was observed for bentonite and HSCAS, except for zeolite in SGFs at pH 7. The observed maximum amounts of AFB1 adsorbed on bentonite and HSCAS were 1.54 and 1.56 mg/g, respectively. The adsorption capacities of bentonite and HSCAS for AFB1 were 12.7 and 13.1 mg/g, respectively, from fitting the data to the Freundlich isotherm equation. Improvement in processing and purification for bentonite is needed to enhance the surface area, which would probably result in better adsorptive capacity for this sorbent.

Aflatoxins and growth impairment: a review

Aflatoxins, fungal toxins produced by Aspergillus flavus and Aspergillus parasiticus in a variety of food crops, are well known as potent human hepatocarcinogens. Relatively less highlighted in the literature is the association between aflatoxin and growth impairment in children. Foodborne aflatoxin exposure, especially through maize and groundnuts, is common in much of Africa and Asia--areas where childhood stunting and underweight are also common, due to a variety of possibly interacting factors such as enteric diseases, socioeconomic status, and suboptimal nutrition. The effects of aflatoxin on growth impairment in animals and human children are reviewed, including studies that assess aflatoxin exposure in utero and through breastfeeding. Childhood weaning diets in various regions of the world are briefly discussed. This review suggests that aflatoxin exposure and its association with growth impairment in children could contribute a significant public health burden in less developed countries.

Aflatoxin toxicity reduction in feed by enhanced binding to surface-modified clay additives

Animal feeding studies have demonstrated that clay additives, such as bentonites, can bind aflatoxins in ingested feed and reduce or eliminate the toxicity. Bentonite deposits are found throughout the world and mostly consist of expandable smectite minerals, such as montmorillonite. The surfaces of smectite minerals can be treated with organic compounds to create surface-modified clays that more readily bind some contaminants than the untreated clay. Montmorillonites treated with organic cations, such as hexadecyltrimethylammonium (HDTMA) and phenyltrimethylammonium (PTMA), more effectively remove organic contaminants, such as benzene and toluene, from water than untreated clay. Similarly, montmorillonite treated with PTMA (K_d = 24,100) retained more aflatoxin B1 (AfB1) from aqueous corn flour than untreated montmorillonite (K_d = 944). Feed additives that reduced aflatoxin toxicity in animal feeding studies adsorbed more AfB1 from aqueous corn flour than feed additives that were less effective. The organic cations HDTMA and PTMA are considered toxic and would not be suitable for clay additives used in feed or food, but other non-toxic or nutrient compounds can be used to prepare surface-modified clays. Montmorillonite (SWy) treated with choline (K_d = 13,800) and carnitine (K_d = 3960) adsorbed much more AfB1 from aqueous corn flour than the untreated clay (K_d = 944). A choline-treated clay prepared from a reduced-charge, high-charge montmorillonite (K_d = 20,100) adsorbed more AfB1 than the choline-treated high-charge montmorillonite (K_d = 1340) or the untreated montmorillonite (K_d = 293). Surface-modified clay additives prepared using low-charge smectites and nutrient or non-toxic organic compounds might be used to more effectively bind aflatoxins in contaminated feed or food and prevent toxicity.

Effect of low levels of aflatoxin B₁ on performance, biochemical parameters, and aflatoxin B₁ in broiler liver tissues in the presence of monensin and sodium bentonite

Aflatoxins (AF) are a major problem in broiler production and are significant economic and public health burdens worldwide. A commercial sodium bentonite (Na-B) adsorbent was used to prevent the effect of AF [50 µg of aflatoxin B₁ (AFB₁)/kg of feed] in broiler productivity, biochemical parameters, macroscopic and microscopic liver changes, and AFB₁ liver residues. The influence of Na-B (0.3%) and monensin (MON, 100 mg/kg), alone or in combination, was investigated in depth. The dietary treatments were as follows: treatment (T) 1: basal diet (B); T2: B + MON; T3: B + Na-B; T4: B + Na-B + MON; T5: B + AFB₁; T6: B + AFB₁ + Na-B + MON; T7: B + AFB₁ + MON; T8: B + AFB₁ + Na-B. Birds were fed dietary treatments for 28 d (d 18 to 46). No significant differences (P < 0.05) were observed among treatments with respect to broiler performance, biochemical parameters, or relative liver weights. With the exception of T8, all livers showed histopathological alterations, with accumulation of fat vacuoles. The normal appearance of livers from T8 showed the protective effect of Na-B against aflatoxicosis. The residual AFB₁ levels in livers from T5 to T8 ranged from 0.2 to 1.0 ng/g and were higher in livers from T6 (P < 0.05). Results of this study indicate a competition between AFB₁ and MON for adsorption sites on Na-B when feed contains low levels of the toxin, indicating a nonselective adsorption capacity of this particular Na-B. In addition, significant levels of AFB₁ in livers indicate that this determination is an important technique not only for diagnosis of aflatoxicosis in broilers, but also for quality control of avian products.

Immunotoxicological and biochemical effects of aflatoxins in rats prevented by Tunisian montmorillonite with reference to HSCAS

BACKGROUND AND AIM

Previously we reported that hydrated sodium calcium aluminosilicate (HSCAS) and Tunisian Montmorillonite (TM) had an ability to sorb aflatoxins with a high affinity. Addition of these compounds to feedstuffs contaminated with aflatoxins has shown protective effects against the development of aflatoxicosis in farm and laboratory animals. The objective of the current study was to compare the efficiency of HSCAS and the TM in respect to the protection against immunotoxicological effects of aflatoxins in rats.

MATERIALS AND METHODS

Animals fed an aflatoxin-contaminated diet (2.5 mg/kg diet) showed a significant decrease in all hematological parameters, cholesterol, triglycerides, cholinesterase, total protein, albumin, zinc and copper concentrations.

RESULTS

Such feeding significantly increased createnine, bilirubin, urea nitrogen, alkaline phosphatase and transaminases concentrations. The immunological results showed a significant decrease in lymphocytes of the total white blood cells, immunoglobulin profile (Ig G and Ig A), T-cells sub-types (CD3(+), CD4(+) and CD8(+)), NK and pro-inflammatory cytokines (TNFalpha and IL-1beta) typical of aflatoxicosis. Both HSCAS and TM at the level of 5 g/kg contaminated diet resulted in a significant improvement in all immunological parameters-in lymphocyte, immunoglobulin profile, T-cells sub-types and pro-inflammatory cytokines as well as the mineral status and the biochemical parameters.

CONCLUSIONS

The deleterious effects of aflatoxin could be overcome or, at least, diminished by the addition of sorbents. Moreover, both tested sorbents by themselves had no toxic effects and bind aflatoxin with high affinity.

Influence of ascorbic acid supplementation on the haematological and clinical biochemistry parameters of male rabbits exposed to aflatoxin B1

This study was undertaken to evaluate the effectiveness of L-ascorbic acid (AA) in alleviating the toxicity of aflatoxin B1 (AFB1) in male New-Zealand white rabbits. Five rabbits (6 months of age and mean body weight 3.12 kg) per group were assigned to 1 of 6 treatment groups: 0 mg AA and 0 mg AFB1/kg BW (control); 20 mg AA/kg BW; 15 microg AFB1/kg BW; 15 microg AFB1 plus 20 mg AA/kg BW; 30 pg AFB1/kg BW; 30 pg AFB1 plus 20 mg AA/kg BW. Rabbits were orally administered their respective doses every other day for 9 weeks, followed by a 9-week recovery period where all drugs were withdrawn. Evaluations were made for hemato-biochemical parameters and enzymatic activities. Results showed that AFB1 significantly (p < 0.05) decreased hemoglobin (Hb), total erythrocytic count (TEC) and packed cell volume (PCV), in a dose-dependent manner, and these effects were continued during the recovery period. Ascorbic acid caused an increase in these parameters, and alleviated the negative effect of AFB1 during the treatment period. Additionally, serum concentrations of total protein, albumin and glucose were significantly (P < 0.05) declined by treatment with the high dose of aflatoxin and these effects were continued during the recovery period. Ascorbic acid caused non-significant increases in these parameters and alleviated the harmful effect of AFB1. On the other hand, aflatoxin treatment caused significant increases (P < 0.05) in the activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (AlP) during the treatment period in a dose dependent manner, and this effect was continued during the recovery period, especially with the high dose. Also, treatment with the high dose of aflatoxin caused significant increases (P<0.05) in cholesterol and total bilirubin. Ascorbic acid caused significant decreases in these parameters and alleviated the harmful effects of AFB1. Whereas, Total leukocyte count (TLC), urea and creatinine were not significantly affected by aflatoxin-treatment. Generally, it is interesting feature that the treatment with AA alone had no negative effects on most of the previous parameters. Also, the presence of AA could diminished the adverse effects of AFB1 on most of hematological and biochemical values, and enzymatic activities in rabbits.

Mycotoxin detoxication of animal feed by different adsorbents

The contamination of animal feed with mycotoxins represents a worldwide problem for farmers. These toxins originate from molds whose growth on living and stored plants is almost unavoidable particularly under moist conditions. Mycotoxin-containing feed can cause serious diseases in farm animals resulting in suffering and even death and thus can cause substantial economic losses. The most applied method for protecting animals against mycotoxicosis is the utilization of adsorbents mixed with the feed which are supposed to bind the mycotoxins efficiently in the gastro-intestinal tract. Aluminosilicates are the preferred adsorbents, followed by activated charcoal and special polymers. The efficiency of mycotoxin binders, however, differs considerably depending mainly on the chemical structure of both the adsorbent and the toxin. This review describes the most important types of adsorbents and the respective mechanisms of adsorption. Data of the in vitro and in vivo efficacy of detoxication are given.

Aflatoxicosis in rabbits: Effectiveness of Egyptian raw bentonite in prevention or diminution the detrimental effects of naturally aflatoxin contaminated diets

Thirty five females and 15 males of New Zealand White mature rabbits about 6 months of age, were assigned to 1-5 dietary treatments (7 does+3 bucks for each): uncontaminated control diet, naturally aflatoxin contaminated diet without or with 1,2 and 3% bentonite. Rabbit fed with the aflatoxin-diet had a decreased (P<0.01 or 0.05) physical semen characteristics of bucks and a reproductive performance traits of does. The values of conception rate (%), gestation length (days), litter size (n) and litter weights (g) at birth and viability (%) of litters of doe rabbits, fed with the aflatoxin-diet, recorded, respectively: 64.5; 31.0; 4.4; 275.0 and 57.1 versus 85.6; 30.3; 7.9; 508.0; and 100 for those fed with the uncontaminated diet. Addition of bentonite to the aflatoxin contaminated diet improved in general the physical semen characteristics of buck and reproductive performance traits of doe rabbits. The results of the study demonstrate that adding 1% of Egyptian raw bentonite to the naturally aflatoxin contaminated rabbit diets can provide an effective, cheap and safe practical technique for preventing the aflatoxicosis in mature rabbits.

Potential protective effect of HSCAS and bentonite against dietary aflatoxicosis in rat: with special reference to chromosomal aberrations

Bentonite and hydrated sodium calcium aluminsilicate (HSCAS) were added at a level of 0.5% (w/w) to the diets containing 2.5 mg aflatoxins (AF) per kg diet and fed to male mature rats for 15 successive days. Aflatoxin alone significantly decreased feed intake and altered serum biochemical parameters of liver and kidney functions. Aflatoxin caused chromosomal aberrations in bone marrow cells. Bentonite or HSCAS did not alter any of the parameters measured. The addition of bentonite or HSCAS to the AF-contaminated diet diminished most of the deleterious effects of the aflatoxin. Pathological examinations of liver and kidney proved that both bentonite and HSCAS were hepatonephroprotective agents against aflatoxicosis. The cytogenetic findings demonstrated that the addition of bentonite or HSCAS to AF-contaminated diet suppressed chromosomal aberrations. These findings indicated that bentonite and HSCAS could diminished many of the adverse effect of dietary AF in rats.

Interactive effects of sodium bentonite and coccidiosis with monensin or salinomycin in chicks

Three experiments (Exp.) were conducted to determine the interactive effects of sodium bentonite (NaB) with the efficacy of monensin (MON) or salinomycin (SAL) in coccidiosis-infected chicks. Male broiler chicks 5 to 14 d of age were used, and each treatment was replicated with eight (Exp. 1) or four (Exp. 2 and 3) pens of five chicks each. In Exp. 1, MON (80 ppm), NaB (0.50%), or MON+NaB were fed to uninfected and coccidiosis-infected (5 x 10(5) sporulated Eimeria acervulina oocysts on Day 2 of the Exp.) chicks in a 2 x 2 x 2 factorial arrangement of treatments. Experiment 2 was identical to Exp. 1, but SAL (30 ppm) replaced MON as the anticoccidial additive. In Exp. 3, MON (55 ppm) or SAL (22 ppm) were added individually or with NaB (0.50%) to diets for uninfected or coccidiosis-infected chicks. Coccidial infection reduced (P < 0.01) gain, feed intake, gain:feed, plasma carotenoids, and percentage tibia ash in all experiments. The MON and SAL additions increased these response criteria in infected chicks (coccidiosis by anticoccidial, P < 0.07), except MON did not increase (P > 0.10) feed intake or tibia ash in Exp. 3. In Exp. 3, NaB partially reduced the positive effect of MON on daily gain (NaB by MON, P < 0.03), and of SAL on feed intake (NaB by SAL, P < 0.08). The NaB addition also increased gain:feed (P < 0.08), and the increase was greater in infected chicks (coccidiosis by NaB, P < 0.08). Also in Exp. 3, SAL increased feed intake more in chicks not fed NaB than in chicks fed NaB (SAL by NaB, P < 0.08). Dietary NaB (0.5%) may reduce the efficacy of MON and SAL in coccidiosis-infected chicks when these additives are added at less than recommended levels.

Hydrated sodium calcium aluminosilicate (HSCAS), acidic HSCAS, and activated charcoal reduce urinary excretion of aflatoxin M1 in turkey poults. Lack of effect by activated charcoal on aflatoxicosis

In one experiment, the effect of inorganic sorbents on the metabolic fate of aflatoxin B1 (AFB1) was studied in turkey poults. At 5 weeks of age, female poults were surgically colostomized and 9 days later orally dosed with 0.75 mg AFB1/kg BW. Hydrated sodium calcium aluminosilicate (HSCAS), acidic HSCAS, and activated charcoal (AC) were tested, by concomitant administration with AFB1. Urine was collected up to 48 h post-dosing and analyzed for aflatoxin M1 (AFM1) which was the major metabolite found in all treatment groups. Hydrated sodium calcium aluminosilicate, previously proven beneficial in alleviating aflatoxicosis in farm animals, reduced urinary AFM1 output when orally dosed simultaneous with AFB1. Also, acidic HSCAS and AC significantly decreased AFM1 excretion when administered concomitantly with AFB1. A second experiment was conducted to evaluate the ability of two types of AC to modify aflatoxicosis when added to aflatoxin (AF)-contaminated (from culture material) diets of turkey poults. Although AC was able to decrease AFM1 excretion in the first experiment, no protective effects from AF toxicity were observed in the feeding study.

Effect of sodium bentonite or hydrated sodium calcium aluminosilicate on growth performance and tibia mineral concentrations in broiler chicks fed nutrient-deficient diets

An experiment was conducted to determine whether sodium bentonite (NaB) or hydrated sodium calcium aluminosilicate (HSCA) would affect growth performance and tibia mineral concentrations in chicks fed nutrient-deficient diets. Two identical trials were conducted; each using 240 5- to 19-d-old broiler chicks (4 replicates of 5 chicks each) in a completely random design. A factorial arrangement of treatments consisted of four types of nutrient deficiencies [nutritionally complete basal (C), macromineral-deficient (-MM), trace mineral- and vitamin-deficient (-TMV), and crude protein-deficient (-CP)], and three types of additive (none, .5% NaB, and .5% HSCA). The -MM and -TMV diets reduced (P < .01), gain, feed intake, and gain:feed. The -CP diet decreased (P < .01) gain and gain:feed but did not affect (P > .10) feed intake. Sodium bentonite increased feed intake (P < .01) of all diets; resulting in an increase in gain (P < .09). Sodium bentonite increased gain:feed in chicks fed the -MM diet but did not affect gain:feed in chicks fed the C, -TMV, or -CP diets (NaBx-MM interaction, P < .02). The -MM and -TMV diets decreased (P < .01) tibia ash, but the -CP diet increased (P < .01) tibia ash. The -MM diet decreased (P < .01) tibia Ca but increased (P < .01) tibia P. Neither NaB nor HSCA affected percentage of tibia ash, Ca, or P. Tibia Zn and Mn concentrations were increased (P < .01) by the -MM diet and decreased (P < .01) by the -TMV diet.(ABSTRACT TRUNCATED AT 250 WORDS)