Alleviation of zearalenone toxicity by modified halloysite nanotubes in the immune response of swine

Protective effects of lycopene against zearalenone-induced reproductive toxicity in early pregnancy through anti-inflammatory, antioxidant and anti-apoptotic effects

Zearalenone is a mycotoxin that is widely present in feed and raw materials and can cause severe reproductive toxicity. Lycopene is a natural carotenoid with antioxidant and anti-inflammatory pharmacological effects, but the protective effects of lycopene against zearalenone-induced uterine damage have not been reported. The aim of this study was to investigate the protective effect of lycopene treatment in early pregnancy on zearalenone-induced uterine damage and pregnancy impairment and its mechanism. Reproductive toxicity was induced by consecutive gavages of zearalenone at 5 mg/kg body weight during gestational days (GDs) 0-10 and in the presence or absence of oral administration of lycopene (20 mg/kg BW). The results showed that lycopene may alleviate zearalenone-induced pathological uterine histological damage and disturbances in oestradiol (E2), follicle-stimulating hormone (FSH), progesterone (P) and luteinizing hormone (LH) secretion. Lycopene increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) production, providing protection against zearalenone-induced oxidative stress in the uterus. Additionally, lycopene significantly reduced levels of pro-inflammatory cytokines, including interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α), and elevated levels of the anti-inflammatory factor interleukin 10 (IL-10), inhibiting the zearalenone-induced inflammatory response. In addition, lycopene improved the homeostasis of uterine cell proliferation and death via the mitochondrial apoptosis pathway. These data provide strong evidence that lycopene can be further developed into a potential new drug for the prevention or treatment of zearalenone-induced reproductive toxicity.

The effect of dietary halloysite supplementation on the performance and meat quality of pigs and some air indices in piggery

Halloysite, a clay mineral of the kaolin, has specific properties, characteristic for the conditions in which it was formed. The aim of the study was to determine the effect of halloysite from the Dunino deposit in a complete diet for pigs on daily body weight gain (BWG), feed conversion ratio (FCR), blood parameters, chemical composition of meat and chosen environment indices in the piggery. The trial was conducted on 144 piglets from weaning (d 29) to 85th day of life, then on 40 porkers divided into two groups. Animals were fed diets without (group C) or with halloysite (group E; 1.5% until d 128, then 1.0%). Pigs from group E were characterized by a lower number of days with diarrhea. The average BWG in E group was 44 g higher than in group C (P < 0.01). In turn, during the fattening period, the difference in BWG between groups was 60 g in favor of E (P < 0.05) and average FCR in group E was 4.9% lower compared to group C (P < 0.05). At the end of the study, the pigs from group E had 6.9% higher final body weight (P < 0.01). During both the morning and evening measurements, ammonia concentration in the air was lower by 16.3% and 23.8%, respectively. The use of halloysite enabled improvement of pig fattening efficiency, while reducing the costs of pork production and the negative effect of ammonia on the animals' welfare and environment.

Toxicological Evaluations in Macrophages and Mice Acutely and Chronically Exposed to Halloysite Clay Nanotubes Functionalized with Polystyrene

Halloysite clay nanotubes (HNTs) have been proposed as highly biocompatible for several biomedical applications. Various polymers have been used to functionalize HNTs, but scarce information exists about polystyrene for this purpose. This work evaluated polystyrene-functionalized HNTs (FHNTs) by comparing its effects with non-FHNTs and innocuous talc powder on in vitro and in vivo models. Monocyte-derived human or murine macrophages and the RAW 264.7 cell line were treated with 0.01, 0.1, 1, and 100 μg mL^-1 FHNTs, HNTs, or talc to evaluate the cytotoxic and cytokine response. Our results show that nanoclays did not cause cytotoxic damage to macrophages. Only the 100 μg mL^-1 concentration induced slight proinflammatory cytokine production at short exposure, followed by an anti-inflammatory response that increases over time. CD1 mice treated with a single dose of 1, 2.5, or 5 mg Kg^-1 of FHNTs or HNTs by oral and inhalation routes caused aluminum accumulation in the kidneys and lungs, without bodily signs of distress or histopathological changes in any treated mice, evaluated at 48 h and 30 days post-treatment. Nanoclay administration simultaneously by four different parenteral routes (20 mg Kg^-1) or the combination of administration routes (parenteral + oral or parenteral + inhalation; 25 mg Kg^-1) showed accumulation on the injection site and slight surrounding inflammation 30 days post-treatment. CD1 mice chronically exposed to HNTs or FHNTs in the bedding material (ca 1 mg) throughout the parental generation and two successive inbred generations for 8 months did not cause any inflammatory process or damage to the abdominal organs and the reproductive system of the mice of any of the generations, did not affect the number of newborn mice and their survival, and did not induce congenital malformations in the offspring. FHNTs showed a slightly less effect than HNTs in all experiments, suggesting that functionalization makes them less cytotoxic. Doses of up to 25 mg Kg^-1 by different administration routes and permanent exposure to 1 mg of HNTs or FHNTs for 8 months seem safe for CD1 mice. Our in vivo and in vitro results indicate that nanoclays are highly biocompatible, supporting their possible safe use for future biomedical and general-purpose applications.

Protective Effects of Bacillus subtilis ANSB060, Bacillus subtilis ANSB01G, and Devosia sp. ANSB714-Based Mycotoxin Biodegradation Agent on Mice Fed with Naturally moldy Diets

Mycotoxins are toxic secondary metabolites produced by toxigenic fungi that commonly contaminate agricultural crops. The purpose of the current study was to evaluate whether Bacillus subtilis ANSB060, Bacillus subtilis ANSB01G, and Devosia sp. ANSB714-based mycotoxin biodegradation agent (MBA) could alleviate the negative effects of naturally moldy diet containing aflatoxin (AF), zearalenone (ZEN), and deoxynivalenol (DON) on growth performance, serum immune function, and antioxidant capacity as well as tissue residues in mice. A total of 54 mice were randomly divided into three dietary treatments: basal diet (CON), multi-mycotoxins contaminated diet (MCD) containing AF, ZEN and DON and multi-mycotoxins contaminated diet plus MBA at a dose of 1.0 g kg^-1 feed (MCD + MBA). Mice fed with moldy diet showed a significant decrease in body weight gain (p < 0.05), whereas the relative weight of the liver, spleen and uterus were remarkably increased (p < 0.05). Serum IgA and IgM contents were significantly decreased in MCD treatment compared with that in CON treatment (p < 0.05). In contrast, serum interleukin-1β (IL-1β), interleukin-2 (IL-2), and interleukin-6 (IL-6) concentrations were significantly promoted in mice fed with moldy diet (p < 0.05). Besides, the exposure to mycotoxins caused marked down-regulation of serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in mice (p < 0.05). The addition of MBA effectively counteracted these toxic effects of moldy diet on mice. And DON residues in kidneys of mice consuming moldy diet were eliminated by the supplementation with MBA. Taken together, Bacillus subtilis ANSB060, Bacillus subtilis ANSB01G, and Devosia sp. ANSB714-based mycotoxin biodegradation agent has great potential use as a microbial additive to counteract mycotoxins contamination in food and feed.

INOS-mediated acute stomach injury and recovery in mice after oral exposure to halloysite nanotubes

Natural halloysite nanotubes (HNTs) with a hollow lumen are already applied in numerous fields and enter the environment in increasing quantities, which may have effects on animal and human health. However their in vivo toxicity in mammals is still largely unclear. The aim of this study is to assess acute oral toxicity of HNTs in the stomach of mice and recovery. Oral HNTs at low dose (5 mg HNTs/kg BW) for 30 days increased in daily food and water intake and promoted mouse growth with no obvious adverse effect on the stomach. The promotive effect on mouse growth disappeared after cessation of oral administration of the nanotubes. Oral HNTs for 30 days at high dose (50 mg HNTs/kg BW) induced Si and Al accumulation in the stomach, which caused oxidative stress, inflammation and iNOS-mediated damage in the organ. The damage in the stomach led to slight atrophic gastritis and reduced mouse growth. Oral HNTs-induced changes at high dose were not observed after a 30-days recovery period. The findings provided the evidence that oral HNTs-induced acute toxicity in the stomach was reversible. More importantly, this research showed that Al and Si were cleared out of the mice by hepatic excretion and renal excretion, respectively, during the recovery period. The results suggest that HNTs at low concentration in environments have no adverse effect on mice, while there are health risks to mice under severe contamination by HNTs.

Modified Palygorskite Improves Immunity, Antioxidant Ability, Intestinal Morphology, and Barrier Function in Broiler Chickens Fed Naturally Contaminated Diet with Permitted Feed Concentrations of Fusarium Mycotoxins

This study investigated effects of modified palygorskite (MPal) on immunity, antioxidant capacity, and intestinal barrier integrity in broiler chickens challenged with permitted feed Fusarium mycotoxin concentrations. One-day-old chicks were allocated into three treatments with eight replicates. Chickens in three groups were fed a basal diet with normal corn (control), contaminated diet containing moldy corn, with Fusarium mycotoxins contents in the diets lower than permitted feed mycotoxin concentrations, and the contaminated diet supplemented with 1 g/kg MPal for 42 days, respectively. Compared with control, moldy corn decreased bursa of Fabricius weight, jejunal secreted immunoglobulin A concentration, ileal superoxide dismutase (SOD) activity, jejunal and ileal villus height (VH) and VH/crypt depth (CD) ratio, and jejunal zonula occludens-1 and mucin 2 mRNA abundances at 42 days as well as ileal VH/CD ratio at 21 days; while they increased jejunal malondialdehyde accumulation at 21 and 42 days, jejunal SOD activity at 21 days, and serum diamine oxidase activity at 42 days, which were almost recovered by MPal. Moreover, dietary MPal upregulated ileal claudin-2 mRNA abundance compared with other two groups. The results indicated that MPal addition exerted protective effects on immunity, oxidative status, and intestinal barrier integrity in chickens challenged with permitted feed Fusarium mycotoxins levels.

Mechanism and effects of Zearalenone on mouse T lymphocytes activation in vitro

Zearalenone (ZEA) is particularly toxic to the female reproductive system. Nevertheless, the effect of ZEA on the immune system is still not fully understood. The following study investigates the effects and mechanism of ZEA on mouse T cell activation in vitro. Briefly, T lymphocytes were extracted from primary splenic lymphocyte in mice, activated by concanavalin A, and then were exposed to different concentrations of ZEA for a certain period of time. Flow cytometry was used to detect the expression of activating and co-stimulatory molecules, and the secretion of cytokines in T cells at various stages. The expression of initiation regulatory protein in T cell activation, nuclear factor protein and co-stimulatory molecule related PI3K-Akt-mTOR signaling pathway proteins were detected by western blot. Our data showed that ZEA exposure inhibits the activity of T cell, and inhibits the expression of different activation signals in T cell. Additionally, ZEA exposure reduces the expression of initiative regulatory protein, i.e. LAT, Lck, Zap-70 during the activation of T cells. Thus, the results showed that ZEA exposure inhibits the formation and transmission of activated signal in T cells, interferes with signal pathway of T cell activation nuclear factor NFAT and NFκB, and decreases the secretion of cytokines after activation. Moreover, ZEA exposure interferes with co-stimulatory molecule CD28 during T cell activation, and with the activity of the PI3K-Akt-mTOR signaling pathway downstream of CD28. To conclude, our results indicated that ZEA toxin interferes with the activation of mouse T lymphocytes by affecting TCR signal and co-stimulatory signal, thus playing an essential role in immune toxicity.

Halloysite nanotubes-induced Al accumulation and oxidative damage in liver of mice after 30-day repeated oral administration

Halloysite (Al₂ Si₂ O₅ (OH)₄ ·nH₂ O) nanotubes (HNTs) are natural clay materials and widely applied in many fields due to their natural hollow tubular structures. Many in vitro studies indicate that HNTs exhibit a high level of biocompatibility, however the in vivo toxicity of HNTs remains unclear. The objective of this study was to assess the hepatic toxicity of the purified HNTs in mice via oral route. The purified HNTs were orally administered to mice at 5, 50, and 300 mg/kg body weight (BW) every day for 30 days. Oral administration of HNTs stimulated the growth of the mice at the low dose (5 mg/kg BW) with no liver toxicity, but inhibited the growth of the mice at the middle (50 mg/kg BW) and high (300 mg/kg BW) doses. In addition, oral administration of HNTs at the high dose caused Al accumulation in the liver but had no marked effect on the Si content in the organ. The Al accumulation caused significant oxidative stress in the liver, which induced hepatic dysfunction and histopathologic changes. These findings demonstrated that Al accumulation-induced oxidative stress played an important role in the oral HNTs-caused liver injury.

Halloysite Nanotubes-Induced Al Accumulation and Fibrotic Response in Lung of Mice after 30-Day Repeated Oral Administration

Natural halloysite (Al₂Si₂O₅(OH)₄· nH₂O) nanotubes (HNT) are clay materials with hollow tubular structure and are widely applied in many fields. Many in vitro studies indicate that HNTs exhibit a high level of biocompatibility; however, the in vivo toxicity of HNTs remains unclear. In this study, the biodistribution and pulmonary toxicity of the purified HNTs in mice were investigated after intragastric administration for 30 days. HNTs have high stability in biological conditions. Oral administration of HNTs caused significant Al accumulation predominantly in the lung with relative slight effects on Si biodistribution. Oral administration of HNTs stimulated the growth of the mice at low dose (5 mg/kg BW) with no pulmonary toxicity but inhibited the mouse growth and resulted in oxidative stress and inflammation in lung at high dose (50 mg/kg BW). In addition, oral HNTs at high dose could be absorbed from the gastrointestinal tract and deposited in lung and could also induce pulmonary fibrosis.

Toxicity of zearalenone on the intestines of pregnant sows and their offspring and alleviation with modified halloysite nanotubes

BACKGROUND

The objective of this study was to examine the effects of maternal exposure to zearalenone (ZEN) on the intestines of pregnant sows and offspring on postnatal days (PD) 1, 21 and 188. Eighteen pregnant sows (six per treatment) were fed a control diet (ZEN, 0.03 mg kg^-1 ), ZEN diet (ZEN, 2.77 mg kg^-1 ) and ZEN + 1% modified halloysite nanotube (MHNT) diet (ZEN, 2.76 mg kg^-1 ) respectively from gestation days (GD) 35 to 70. At the end of the experiment, three sows of each group on GD70 and the offspring on PD1, PD21 and PD188 were killed to analyze the changes of intestines.

RESULTS

The results showed that ZEN caused oxidative stress, an inflammatory response, changes in the structure of jejunum and alterations of the bacterial numbers in cecal digesta in pregnant sows and PD1 and PD21 piglets. On PD188, bacterial numbers were also altered. MHNTs supplementation reduced the amount of ZEN in the intestine and reversed to a large extent the effects induced by ZEN on the intestines of pregnant sows and offspring.

CONCLUSION

The results obtained from this study indicated that MHNTs treatment was beneficial for the adsorption of ZEN in the intestine of sows. © 2017 Society of Chemical Industry.