Aflatoxin B1 (AFB1) has potent hepatotoxic, carcinogenic, genotoxic, immunotoxic and other adverse effects in human and animals. The aim of this study was to investigate the molecular mechanism of G2/M cell cycle arrest induced by AFB1 in the jejunum of broilers. Broilers, as experimental animals, were fed 0.6 mg/kg AFB1 diet for 3 weeks. Our results showed that AFB1 reduced the jejunal villus height, villus height/crypt ratio and caused G2/M cell cycle arrest. The G2/M cell cycle was accompanied by the increase of ataxia telangiectasia mutated (ATM), p53, Chk2, p21 protein and mRNA expression, and the decrease of Mdm2, cdc25C, cdc2, cyclin B and proliferating cell nuclear antigen protein and mRNA expression. In conclusion, AFB1 blocked G2/M cell cycle by ATM pathway in the jejunum of broilers.

Weanling pigs, with an underdeveloped intestine and immature immune system, are usually subjected to depressed feed intake, growth retardation, and postweaning diarrhea. The aim of this study was to determine 1) the growth response of weaned pigs to supplemental tributyrin (TB) and 2) the potential effects and mechanisms of TB in modulating immune responses of lipopolysaccharide (LPS)-challenged piglets. A total of 240 piglets (Duroc × Large White × Landrace) were weaned at 21 d of age to a control (basal diet), supplemented with antibiotics (AB; +AB), supplemented with TB (+TB), or with supplemental AB and TB (+AB+TB) diets, with 10 replicate pens (6 piglets/pen) per diet. At 49 d of age, male pigs from the control and +TB groups were intraperitoneally injected with LPS (25 μg/kg BW) or saline ( = 6) and sacrificed at 4 h after injection to collect blood, intestine, and digesta samples for biochemical analysis. There were higher ( < 0.05) feed intake and lower ( < 0.05) percentage of negative growth piglets in the +TB groups than in the control group during the first week after weaning. For piglets without LPS challenge, there were higher ( < 0.05) ileal fibroblast growth factor 19 () mRNA abundance and total bile acid concentrations in the +TB groups than in the control group, whereas downregulated ( < 0.05) expression was observed in the +TB groups after LPS challenge. Lipopolysaccharide challenge in the control group increased ( < 0.05) plasma tumor necrosis factor α and IL-6 concentrations and colonic amount and decreased ( < 0.05) colonic goblet cells and colonic and cecal acetate concentrations, with no differences ( > 0.05) observed between +TB groups following LPS challenge. Taken together, dietary supplementation with TB prevented growth retardation through stimulating the appetite of weaned pigs and protected piglets against lethal infection via modulation of inflammatory cytokines production, ileal expression, and intestinal acetate fermentation.

No abstract

Copper (Cu) is a necessary micronutrient at lower concentration, while excessive Cu exposure or Cu homeostasis disorders can lead to toxicity. The mechanism of male reproductive toxicity induced by Cu is still unknown. This study aims to investigate whether autophagy plays an important role in copper-induced spermatogenesis disorder in vivo and vitro. The present study showed that copper sulfate (CuSO 4 ) might significantly promote autophagy level in the testis and mouse-derived spermatogonia cell line GC-1 spg cells. Concurrently, CuSO 4 could induce autophagy via AMPK-mTOR pathway that downregulated p -mTOR/mTOR and subsequently upregulated p -AMPKα/AMPKα as well as p -ULK1/ULK1. In the meanwhile, CuSO 4 treatment could also increase expression levels of the autophagy-related proteins. Then, the role of oxidative stress in CuSO 4 -induced autophagy was investigated. The findings demonstrated that oxidative stress inhibitor (NAC) attenuated CuSO 4 -induced autophagy in vivo and vitro , reversing the activation for AMPK-mTOR pathway. Additionally, the study also investigated how autophagy worked under the spermatogenesis disorder induced by CuSO 4 . Inhibition of autophagy could decrease cell viability, and enhance the ROS accumulation and apoptosis in the GC-1 cells, meanwhile, the spermatogenesis disorder, oxidative stress and histopathological changes were increased in the testis. Furthermore, co-treatment with the apoptosis inhibitor (Z-VAD-FMK) could decrease the spermatogenesis disorder but not influence autophagy. Besides, the crosslink between autophagy and ferroptosis were also measured, the data showed that inhibition of autophagy could suppress CuSO 4 -induced ferroptosis in in vivo and vitro . Altogether, abovementioned results indicated that CuSO 4 induced autophagy via oxidative stress-dependent AMPK-mTOR pathway in the GC-1 cells and testis, and autophagy activation possibly led to the generation of protection mechanism through oxidative damage and apoptosis inhibition, however, autophagy also aggravate CuSO 4 toxicology through promoting ferroptosis. Overall, autophagy plays a positive role for attenuating CuSO 4 -induced testicular damage and spermatogenesis disorder. Our study provides a possible targeted therapy for Cu overload-induced reproduction toxicology.

No abstract

Aflatoxin B1 (AFB1) is a common contaminant of poultry feeds in tropical and subtropical climates. Early researches have well established the hepatotoxic, carcinogenic, and immunotoxic effects of AFB1 on humans and animals. Recently, it has been shown that AFB1 could cause the up- or down-alteration of mitochondrial pathway molecule expression. However, the information on the expression of death receptor and endoplasmic reticulum molecules in the jejunal apoptosis induced by AFB1 were unavailable. So the present study was conducted to explore the expression of apoptotic molecules related to death receptor and endoplasmic reticulum in the jejunal cells of chickens exposed to AFB1 diet for 3 weeks. Total of 144 one-day-old chickens was randomly divided into two groups, namely control group (containing 0 mg/kg AFB1) and AFB1 group (containing 0.6 mg/kg AFB1). Histopathological observation and microscopic quantitative analysis revealed morphological changes in the jejunum such as the shedding of the mucosal epithelial cells in the apical region of villi along with the decrease of villus height, villus area and villus/crypt ratio in the AFB1 group. Both TUNEL and flow cytometry assays showed that AFB1 intake induced excessive apoptosis of jejunal cells. Quantitative real-time PCR test displayed the general upregulation of death receptors (FAS, FASL, TNF-α and TNF-R1), endoplasmic reticulum signals (GRP78 and GRP94) as well as initiator and executioner caspases (CASPASE-10, CASPASE-8 and CASPASE-3) in the jejunum of AFB1-intoxicated chickens. It's the first study demonstrating that AFB1 induced apoptosis of chickens’ jejunum accompanied by the alteration of death receptor and endoplasmic reticulum molecule expression.

The effects of dietary β-hydroxy-β-methylbutyrate (HMB) supplementation during gestation on reproductive performance of sows and the mRNA expression of myogenic markers in skeletal muscle of neonatal pigs were determined. At day 35 of gestation, a total of 20 sows (Landrace × Yorkshire, at third parity) were randomly assigned to two groups, with each group receiving either a basal diet or the same diet supplemented with 4 g/day β-hydroxy-β-methylbutyrate calcium (HMB-Ca) until parturition. At parturition, the total and live litter size were not markedly different between treatments, however, the sows fed HMB diet had a decreased rate of stillborn piglets compared with the sows fed the control (CON) diets (p < 0.05). In addition, piglets from the sows fed HMB diet tended to have an increased birth weight (p = 0.08), and a reduced rate of low birth weight piglets (p = 0.05) compared with piglets from the CON sows. Nevertheless, lower feed intake during lactation was observed in the sows fed the HMB diet compared with those on the CON diet (p < 0.01). The relative weights of the longissimus dorsi (LD) and semitendinosus (ST) muscle were higher (p < 0.05) in neonatal pigs from the HMB than the CON sows. Furthermore, maternal HMB treatment increased the mRNA levels of the myogenic genes, including muscle regulatory factor-4 (MRF4, p < 0.05), myogenic differentiation factor (MyoD) and insulin-like growth factor-1 (IGF-1, p < 0.01). In conclusion, dietary HMB supplementation to sows at 4 g/day from day 35 of gestation to term significantly improves pregnancy outcomes and increases the expression of myogenic genes in skeletal muscle of neonatal piglets, but reduces feed intake of sows during lactation.

Mechanistic target of rapamycin complex1 (mTORC1) activation and protein synthesis varied with methionine sources; however, the related mechanisms are largely unknown. Porcine mammary epithelial cells (PMEC) and mammary tissue slices (MTS) were used to test whether methionine precursors differ in providing the available methionine and thus differ in mTORC1 signaling-associated protein synthesis. PMEC with methionine deprivation for 8 h and MTS from lactating sows were cultured for 24 and 2 h, respectively, with treatment media without methionine (negative control, NC) or supplemented with 0.6 mM (for PMEC) and 0.1 mM (for MTS) of L-methionine (L-MET), D-methionine (D-MET), DL-2-hydroxy-4-(methylthio) butyric acid (HMTBA), or keto-methyl(thio)butanoic acid (KMB). The measurements included: phosphorylation of mTORC1 signaling, fractional protein synthesis rate (FSR), amino acids (AA) profile, and enzyme activities. Compared with the NC treatment, activated mTORC1 signaling as manifested by higher (P < 0.05) protein abundance of phosphorylated-S6 Kinase 1 (P-S6K1) and phosphorylated-4E-binding Protein 1 (P-4E-BP1) in PMEC and MTS, and increased protein synthesis as indicated by higher (P < 0.05) FSR in MTS occurred in L-MET and HMTBA treatments rather than in D-MET treatment. Compared with the NC treatment, methionine concentration and ratio of methionine to lysine in MTS increased (P < 0.05) in L-MET and HMTBA treatments but not in D-MET treatment, and activities of enzymes responsible for conversion of D-MET and HMTBA to keto-methionine in mammary tissues were about 10 and 50%, respectively, of that in liver. Taken together, mTORC1 signaling-associated protein synthesis in porcine mammary glands was regulated by the local available methionine depending on methionine sources.