The effects of low levels of aflatoxin B1 on health, growth performance and reproductivity in male rabbits

[EN] This study investigated the chronic effects of relatively low exposure to aflatoxin B1 (AFB1) on the growth performance, immune situation and reproduction in male rabbits. Bucks (n=32, 4.82±0.22 kg) were individually assigned to 4 treatments (8 replicates each) using a randomised complete block design. Four diets containing 0, 0.02, 0.05, and 0.1 mg AFB1/kg, were provided to bucks for 8 wk. Growth performance and semen quality were measured. Blood, organ and tissue samples were collected to measure haematological indices, liver function, organ weights and immune parameters. Compared to control, AFB1-contaminated diets reduced body weight and average daily gain (P<0.05), altered certain haematological indices and liver function with decreased monocytes percentage and mean corpuscular haemoglobin concentration, and increased plateletcrit and albumin (P<0.05), slightly impaired reproductive parameters with enhanced ratio of morphologically abnormal sperm cells at early stage and reduced post-stage acrosome integrity, testis weight and serum testosterone concentration (P<0.05), decreased immune function with reduced relative liver weight (%) and tumour necrosis factor-α levels in serum and liver tissue, and increased serum 8-hydroxy-2’-deoxyguanosine levels (P<0.05). Furthermore, bucks fed diets with relatively high AFB1 (0.05 and 0.1 mg AFB1/kg) had reduced red blood cell and haematocrit (P<0.05) in contrast with the low AFB1 group (0.02 mg AFB1/kg). In conclusion, diets containing 0.05 and 0.1 mg AFB1/kg had negative effects on bucks’ growth performance, haematology, reproductivity and immune function, whereas diet containing 0.02 mg AFB1/kg had only minor effects on the parameters measured.The study was funded by the Fundamental Research Funds for the Central Universities (XDJK2015C081).Sun, Y.; Dong, G.; E, G.; Liao, M.; Tao, L.; Lv, J. (2018). The effects of low levels of aflatoxin B1 on health, growth performance and reproductivity in male rabbits. World Rabbit Science. 26(2):123-133. https://doi.org/10.4995/wrs.2018.7433SWORD123133262Abdelaziz S.A., Hamada M.M. 2007. Phytic acid exposure alters AflatoxinB1-induced reproductive and oxidative toxicity in Albino Rats (Rattus norvegicus). eCAM, 6: 331-3471. https://doi.org/10.1093/ecam/nem137Abdel-Wahhab M.A., Nada S.A., Khalil F.A.2002. Physiological and toxicological responses in rats fed aflatoxin-contaminated diet with or without sorbent materials. Animal Feed Sci. 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Latent Abnormal Pathology Affects Long-Term Graft Function in Elder Living Renal Allograft Recipients

Objective. This study evaluated the long-term effects and clinical significance of latent abnormal pathology on elder living donor kidney graft function after renal transplantation in China. Methods. One-hundred and thirty-eight living donor renal transplantations have been carried out at our hospital in recent years. Of these, 72 Time-Zero biopsies were performed and used in this analysis. Clinical data were retrospectively measured at 3, 6, 12, and 24 months after renal transplants. Relationships and effects from biopsy results taken from implanted donor kidney grafts were analyzed. Results. Time-Zero biopsy pathology results from donor kidneys showed that 48.61% of donor kidneys had latent abnormal changes; arterial lesions of donor kidneys had significant effects on the renal function of grafts after 2 years' transplantation; correlations between donor age and arterial lesions were significant; and Time-Zero biopsy pathology results could help predict the long-term function of a renal graft. Conclusions. Existing latent pathological changes of an elder living donor kidney before transplantation could affect long-term renal function. Whether a senior donor is used should be very carefully considered

Dandelion Extract Alleviated Lipopolysaccharide-Induced Oxidative Stress through the Nrf2 Pathway in Bovine Mammary Epithelial Cells

In practical dairy production, cows are frequently subjected to inflammatory diseases, such as high-grain diet-induced subacute ruminal acidosis (SARA) as well as mastitis and metritis. Under the circumstances, lipopolysaccharide (LPS) induces oxidative stress within the cow and in the mammary epithelial cells. It has implications in practical production to alleviate oxidative stress and to optimize the lactational function of the mammary epithelial cells. This study thus aimed to investigate the antioxidative effects of dandelion aqueous extract (DAE) on LPS-induced oxidative stress and the mechanism of DAE as an antioxidant to alleviate oxidative stress through the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the bovine mammary epithelial cell line MAC-T cells. The cells were cultured for 48 h in six treatments including control (without LPS and DAE), LPS (100 ng/mL), DAE10 (100 ng/mL LPS and 10 &mu;g/mL DAE), DAE50 (100 ng/mL LPS and 50 &mu;g/mL DAE), DAE100 (100 ng/mL LPS and 100 &mu;g/mL DAE), and DAE200 (100 ng/mL LPS and 200 &mu;g/mL DAE), respectively. The results showed that cell viability was reduced by LPS, and the adverse effect of LPS was suppressed with the supplementation of DAE. Lipopolysaccharide-induced oxidative stress through enhancing reactive oxygen species (ROS) production, resulted in increases in oxidative damage marker concentrations, while 10 and 50 &mu;g/mL DAE alleviated the LPS-induced oxidative stress via scavenging cellular ROS and improving antioxidant enzyme activity. The upregulation of antioxidative gene expression in DAE treatments was promoted through activating the Nrf2 signaling pathway, with DAE at a concentration of 50 &mu;g/mL exhibiting the highest effect. Overall, DAE acted as an effective antioxidant to inhibit LPS-induced oxidative stress and as a potential inducer of the Nrf2 signaling pathway

Intestinal challenge with enterotoxigenic Escherichia coli in pigs, and nutritional intervention to prevent postweaning diarrhea

Gut health of nursery pigs immediately after weaning is tightly associated with their growth performance and economic values. Postweaning diarrhea (PWD) is one of the major concerns related to gut health of nursery pigs which often is caused by infections of enterotoxigenic Escherichia coli (ETEC), mainly including F4 (K88)+ and F18+ E. coli. The main virulence factors of ETEC are adhesins (fimbriae or pili) and enterotoxins. The common types of fimbriae on ETEC from PWD pigs are F18+ and F4+. Typically, PWD in pigs is associated with both F18+ and F4+ ETEC infections whereas pre-weaning diarrhea in pigs is associated with F4+ ETEC infection. Enterotoxins including heat-labile enterotoxins (LT) and heat-stable peptide toxins (ST) are associated with causing diarrhea in pigs. At least 109 to 1010 ETEC are required to induce diarrhea in nursery pigs typically lasting 1 to 5 days after ETEC infection. Antibiotics used to be the most effective way to prevent PWD, however, with the increased bacterial resistance to antibiotics, alternatives to the use of antibiotics are urgently needed to prevent PWD. Immunopropylaxis and nutritional intervention of antimicrobial minerals (such as zinc oxide and copper sulfate), organic acids, functional feedstuffs (such as blood plasma and egg yolk antibodies), direct fed microbials, phytobiotics, and bacteriophage can potentially prevent PWD associated with ETEC. Some other feed additives such as nucleotides, feed enzymes, prebiotic oligosaccharides, and clay minerals can enhance intestinal health and thus indirectly help with preventing PWD. Numerous papers show that nutritional intervention using selected feed additives can effectively prevent PWD

Impacts of low level aflatoxin in feed and the use of modified yeast cell wall extract on growth and health of nursery pigs

This study was to investigate the effect of corn naturally contaminated with aflatoxins (AF) under the regulatory level on the growth performance and health of nursery pigs, and the efficiency of yeast cell wall based feed additive (YC) mainly composed of β-glucans and mannan oligosaccharide (MOS) (Integral A+, Alltech, Lexington, KY) in prevention of mycotoxicosis. Pigs (60 barrows and 60 gilts at 6.02 ± 0.83 kg BW) were randomly allotted to 4 treatments in a randomized complete block design based on a 2 × 2 factorial arrangement with 10 pens (5 barrow and 5 gilt pens) per treatment and 3 pigs per pen. Pigs were fed experimental diets for 5 wk. First factor was AF (0 or 20 µg/kg in feed) and the second factor was YC (0 or 2 g/kg in feed). Feed intake and body weight were measured weekly, and blood samples were used to measure blood cell counts, immunoglobulin G (IgG), tumor necrosis factor-a (TNF-a), oxidative damage status, and serological evaluation related to liver health. Aflatoxin decreased (P < 0.05) the number of platelet count (247.4 to 193.5 × 103/µL), and it also tended to increase the level of albumin (P = 0.055, 3.46 to 3.63 g/dL), albumin:globulin ratio (P = 0.050, 2.09 to 2.37), and Ca (P = 0.080, 10.79 to 10.97 mg/dL). Yeast cell wall based feed additive increased (P < 0.05) ADG (493 to 524 g/d), and ADFI (796 to 846 g/d) of pigs whereas G:F was not affected, and it also tended to increase (P = 0.055) albumin level (3.46 to 3.63 g/dL). Interactions (P < 0.05) on hemoglobin, hematocrit, and platelet count indicated that YC further increased their levels when pigs were eating AF contaminated feed. Interactions (P < 0.05) on urea nitrogen and blood urea N to creatinine ratio indicated that YC further decreased their levels when feed were contaminated with AF. In conclusion, low level of 20 µg AF/kg under the regulatory level had minor effects on hematology without affecting growth performance, however the supplementation of 2 g/kg YC as a source of β-glucans and MOS in feed can improve feed intake and therefore the growth of pigs. Keywords: Aflatoxin, β-glucans, Health, MOS, Nursery pigs, modified yeast cell wall extrac

PGN and LTA from Staphylococcus aureus Induced Inflammation and Decreased Lactation through Regulating DNA Methylation and Histone H3 Acetylation in Bovine Mammary Epithelial Cells

Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) are the most common pathogens of mastitis, and S. aureus generally causes subclinical mastitis which is more persistent and resistant to treatment. Peptidoglycan (PGN) and lipoteichoic acid (LTA) are cell wall components of S. aureus. Although the roles of PGN and LTA in causing inflammation are well studied, the epigenetic mechanisms of the effects of PGN and LTA on the inflammation and lactation remain poorly understood. This study characterized the gene expression profiling by RNA sequencing and investigated DNA methylation and histone acetylation in relation to inflammation and lactation in the immortalized bovine mammary epithelial cell line (MAC-T). The cells were cultured for 24 h with neither PGN nor LTA (CON), PGN (30 &mu;g/mL), LTA (30 &mu;g/mL), and PGN (30 &mu;g/mL) + LTA (30 &mu;g/mL), respectively. The number of differentially expressed genes (DEGs) and the expression of proinflammatory factors including interleukin (IL)-1&beta;, IL-6, IL-8, chemokine (C-X-C motif) ligand (CXCL)1, and CXCL6 of the treatments increased in the following order: CON &lt; PGN &lt; LTA &lt; PGN + LTA, and the DEGs mainly enriched on the cytokine-cytokine receptor interaction and chemokine signaling pathway. LTA and PGN + LTA induced hypomethylation of global DNA by suppressing DNA methyltransferase (DNMT) activity. PGN and LTA, alone or combined, decreased the mRNA expression of casein genes (CSN1S1, CSN2, and CSN3) and the expression of two caseins (CSN2 and CSN3), and reduced histone H3 acetylation by suppressing histone acetyltransferase (HAT) activity and promoting histone deacetylase (HDAC) activity. Collectively, this study revealed that PGN and LTA induced inflammation probably due to decreasing DNA methylation through regulating DNMT activity, and decreased lactation possibly through reducing histone H3 acetylation by regulating HAT and HDAC activity in bovine mammary epithelial cells

Bacterial Lipopolysaccharide Induced Alterations of Genome-Wide DNA Methylation and Promoter Methylation of Lactation-Related Genes in Bovine Mammary Epithelial Cells

Bacterial lipopolysaccharide (LPS) could result in poor lactation performance in dairy cows. High methylation of DNA is associated with gene repression. However, it is unclear whether LPS could suppress the expression of lactation-related genes by inducing DNA methylation. Therefore, the objective of this study was to investigate the impact of LPS on genome-wide DNA methylation, using methylated DNA immunoprecipitation with high-throughput sequencing (MeDIP-seq) and on the promoter methylation of lactation-related genes using MassArray analysis in bovine mammary epithelial cells. The bovine mammary epithelial cell line MAC-T cells were treated for 48 h with LPS at different doses of 0, 1, 10, 100, and 1000 endotoxin units (EU)/mL (1 EU = 0.1 ng). The results showed that the genomic methylation levels and the number of methylated genes in the genome as well as the promoter methylation levels of milk genes increased when the LPS dose was raised from 0 to 10 EU/mL, but decreased after further increasing the LPS dose. The milk gene mRNA expression levels of the 10 EU/mL LPS treatment were significantly lower than these of untreated cells. The results also showed that the number of hypermethylated genes was greater than that of hypomethylated genes in lipid and amino acid metabolic pathways following 1 and 10 EU/mL LPS treatments as compared with control. By contrast, in the immune response pathway the number of hypomethylated genes increased with increasing LPS doses. The results indicate LPS at lower doses induced hypermethylation of the genome and promoters of lactation-related genes, affecting milk gene mRNA expression. However, LPS at higher doses induced hypomethylation of genes involved in the immune response pathway probably in favor of immune responses