Lipopolysaccharide (LPS) was selected as a stimulus to investigate its effect on cell viability and oxidative stress in bovine mammary epithelial cells (BMEC) by detecting the cell relative growth rate (RGR), antioxidant indicators and inflammatory factors. This information was used to provide the theoretical basis for the establishment of a LPS-induced oxidative damage model. The experiment was divided into two parts. The first part used a two-factor experimental design to determine the appropriate incubation time of LPS by detecting the RGR. The third-passage BMEC were divided into 24 groups with six replicates in each group. The first factor was LPS concentration, which was 0 (control), 0.1, 1.0 and 10.0 μg/mL; the second factor was LPS incubation time (2, 4, 6, 8, 12 and 24 h). The optimum LPS incubation time was 6 h according to the results of the first part of the experiment. The second part of the experiment was conducted using a single-factor experimental design, and the third-passage cells were divided into four groups with six replicates in each group. The cells were incubated with culture medium containing different concentrations of LPS (0 [control], 0.1, 1.0 and 10.0 μg/mL) for 6 h to select the appropriate concentration of LPS to measure the antioxidant indicators and inflammatory factors. The results showed the RGR was significantly reduced as the concentration of LPS and the incubation time increased; the interaction between concentration and incubation time was also significant. The cells treated with 0.1 μg/mL of LPS for 6 h had no significant difference in the activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD) (P > 0.05) compared with the cells in the control group. On the contrary, catalase (CAT) activity and malondialdehyde (MDA) content were markedly lower and higher, respectively, in the 0.1 μg/mL LPS-treated group for 6 h compared with the control group (P < 0.05). The activities of GPx, CAT and SOD in the BMEC treated with 1.0 or 10.0 μg/mL of LPS were significantly lower compared with the cells treated with 0.1 μg/mL of LPS and cells in the control group after 6 h of incubation; however, the opposite trend was detected in MDA content. There was no significant (P > 0.05) difference between the 10.0 and 1.0 μg/mL LPS-treated groups. Compared with the control group, interleukin-1, interleukin-6 and nitric oxide concentrations and the activity of inducible nitric oxide synthase in the 0.1 μg/mL LPS-treated group significantly increased (P < 0.0001), but the levels of tumour necrosis factor did not significantly change (P > 0.05). All of observed indicators were higher in the 1.0 and 10.0 μg/mL LPS-treated groups (P < 0.0001) compared with the other groups, but there was no significant (P > 0.05) difference between the 1.0 and 10.0 μg/mL LPS-treated groups. The results indicated that a concentration of 1.0 μg/mL of LPS and an incubation time of 6 h were the optimum conditions necessary to induce oxidative stress in the BMEC and establish a model for oxidative damage.

Due to a series of problems, such as drug resistance and tissue residue caused by adding antibiotics to feed, this research aimed to study the effects of Artemisia annua L. aqueous extract (AAE) as an alternative to antibiotics on growth performance and antioxidant capacity of broilers. A total of 240 one-day-old mixed-sex Arbour Acres broilers were randomly allotted into six groups with five replicates of eight birds each. These six diets were formulated by adding 0, 500, 1000, 1500, 2000 mg/kg AAE and 50 mg/kg chlortetracycline (CTC) to the basal diet, respectively. Average daily body weight gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were measured. Total antioxidant capacity (T-AOC), the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and the concentrations of malondialdehyde (MDA) were determined, and the relative gene expression in tissues was measured. The polyphenol flavonoid contents and in vitro antioxidative results showed that: the total phenolic and flavonoid contents were 39.58 ± 6.01 mg GAE/g, 7.04 ± 0.55 mg RE/g, respectively. The inclusion of AAE increased ADG, the activities of T-AOC, CAT, SOD and GSH-Px, and the gene expression of antioxidant enzymes, the concentrations of MDA decreased in serum and tissues. In conclusion, AAE can be used as a feed additive due to its capability to improve growth performance, antioxidant function in broilers. Dietary inclusion of 1000–1500 mg/kg AAE can be used as an alternative for antibiotic growth promoter replacement without negative effect on broiler performance.

Objective: This research aimed to study the effects of Artemisia argyi flavonoids (AAF) supplemented in diets on the growth performance and immune function of broiler chickens challenged with lipopolysaccharide (LPS). Methods: A total of one hundred and ninety-two 1-d-old broiler chicks were assigned into 4 treatment groups, which were, respectively, fed a basal diet (control), fed a diet with 750 mg/kg AAF, fed a basal diet, and challenged with LPS, fed a diet with 750 mg/kg AAF, and challenged with LPS. Each treatment had six pens with 8 chicks per pen. On days 14, 16, 18, 20 (stress phase I) and 28, 30, 32, 34 (stress phase II), broilers were injected with LPS (500 μg/kg body weight) or an equivalent amount of saline. Results: The results demonstrated that dietary AAF significantly improved the body weight (d 21) and alleviated the decrease of average daily gain in broilers challenged with LPS on d 21 and d 35 (p<0.05). Dietary AAF increased bursa fabricius index, and dramatically attenuated the elevation of spleen index caused by LPS on d 35 (p<0.05). Furthermore, serum interleukin-6 (IL-6) concentration decreased with AAF supplementation on d 21 (p<0.05). Diet treatment and LPS challenge exhibited a significant interaction for the concentration of IL-1β (d 21) and IL-6 (d 35) in serum (p<0.05). Additionally, AAF supplementation mitigated the increase of IL-1β, IL-6 in liver and spleen induced by LPS on d 21 and 35 (p<0.05). This study also showed that AAF supplementation significantly reduced the expression of IL-1β (d 21) and nuclear transcription factor kappa-B p65 (d 21 and 35) in liver (p<0.05), and dietary AAF and LPS treatment exhibited significant interaction for the gene expression of IL-6 (d 21), toll like receptor 4 (d 35) and myeloid differentiation factor 88 (d 35) in spleen (p<0.05). Conclusion: In conclusion, AAF could be used as a potential natural immunomodulator to improve growth performance and alleviate immune stress in broilers challenged with LPS.

Acetate is a short-chain fatty acid (SFA) that is the major substrate for de novo fatty acid synthesis. The mammalian target of rapamycin/eukaryotic initiation factor 4E (mTOR/eIF4E) signaling pathway is involved in fat synthesis. However, the effect and mechanism of acetate on fatty acid synthesis by the mTOR/eIF4E signaling pathway is unclear in bovine mammary epithelial cells (BMECs). The objectives of this study were to investigate the effect of acetate on cell viability, triacylglycerol (TG), and mRNA expression of the genes related to lipid synthesis. The mechanism of acetate regulation milk fat synthesis through the mTOR/eIF4E signaling pathway was assessed by blocking the mTOR signaling pathway and silencing eIF4E in BMECs. Third-passage BMECs were allocated to 6 treatments including 0, 4, 6, 8, 10, and 12 mM acetate to evaluate the effect of acetate on lipid synthesis; the optimum concentration in the first study was selected for the subsequent study. Subsequently, cells were randomly allocated to 4 treatments, 1 control group and 3 treated groups, consisting of acetate (6 mM), rapamycin (100 nM), and acetate + rapamycin to test the role of mTOR signaling pathway response to acetate in milk lipid synthesis. Finally, eIF4E was silenced by small interfering RNA (siRNA) to detect the role of eIF4E in milk lipid synthesis. Treatments included control, eIF4E siRNA, acetate (6 mM), and acetate+ eIF4E siRNA. Results showed that acetate increased TG accumulation and the relative expression of fatty acid synthase (FASN), acetyl-coenzyme A carboxylase α (ACACA), fatty acid-binding protein 3 (FABP3), sterol regulatory element binding protein 1 (SREBP1), peroxisome proliferator-activated receptor gamma (PPARG), mTOR, eIF4E, P70 ribosomal protein S6 kinase-1 (S6K1), and 4E-binding protein-1 (4EBP1) in a dose-dependent manner. Rapamycin effectively inhibited the positive effect of acetate on the relative expression of mTOR, eIF4E, S6K1, 4EBP1, FASN, ACACA, FABP3, stearoyl-CoA desaturase (SCD1), SREBP1, and PPARG. The upregulation of acetate on the relative expressions of FASN, ACACA, SCD1, and SREBP1 was suppressed when eIF4E was knocked down. It suggested that acetate regulated milk fat synthesis through mTOR/eIF4E signaling pathway in BMECs.