Phosphorus equivalency of phytase with various evaluation indicators of duck in starter.

This study was conducted to evaluate phosphorus (P) equivalency of phytase with various evaluation indicators of ducks in starter (0-14 days). Three hundred and twenty 1-day-old Cherry Valley ducks were randomly assigned to eight groups. The dietary treatments were four levels of available phosphorus (aP) with 0.25%, 0.32%, 0.39%, and 0.46% (treatments I-IV) and four levels of phytase added to low-aP basal diet (treatment I) with 300, 600, 900, and 1200 units (U) per kg (treatments V-VIII). The results were that compared to treatment I, increasing aP and supplementary phytase significantly (p < 0.05) improved body weight (BW), BW gain (BWG), feed intake (FI), live BW, carcass weight, semieviscerated weight, eviscerated weight, leg muscle weight, and decreased feed conversion ratio (FCR). Treatments V and VI did not significantly increase tibia ash, tibia calcium, and tibia P of 14-day-old ducks (p > 0.05). Following the increase of aP level (treatments I-IV), apparent utilization of Ca and P of ducks increased with varying degrees. With the increase of dietary phytase level (treatments V-VIII), the apparent utilization of Ca and P showed no significant difference (p > 0.05) but an increasing trend. Serum P reached the highest level when adding 600 U/kg phytase (treatment VI). Serum Ca and serum alkaline phosphatase activity showed no significant difference among treatments V-VIII (p > 0.05). Based on corn-soybean-rapeseed meal diet, with the evaluation indexes of FI, BWG, tibia ash, tibia Ca, tibia P, and apparent utilization of Ca and P, the addition of 500 U/kg phytase could release aP of 0.03%, 0.04%, 0.02%, 0.01%, 0.02%, 0.08%, and 0.07%, respectively. On the same way, the addition of 1000 U/kg phytase could release aP of 0.07%, 0.09%, 0.06%, 0.02%, 0.07%, 0.09%, and 0.09%, respectively.

Salidroside Activates the AMP-Activated Protein Kinase Pathway to Suppress Nonalcoholic Steatohepatitis in Mice.

BACKGROUND AND AIMS: NASH is becoming a leading cause of liver cirrhosis and HCC. Salidroside (p-hydroxyphenethyl-ß-D-glucoside; SAL) has various biological and pharmacological activities, including anti-inflammatory, -oxidant, and -cancer activities. However, the therapeutic effect and underlying molecular mechanism of SAL in NASH remain to be further clarified. METHODS AND RESULTS: In this study, we found that SAL alleviated lipid accumulation and inflammatory response in primary hepatocytes after palmitic acid/oleic acid (PO) stimulation. In addition, SAL effectively prevented high-fat/high-cholesterol (HFHC)-diet-induced NASH progression by regulating glucose metabolism dysregulation, insulin resistance, lipid accumulation, inflammation, and fibrosis. Mechanistically, integrated RNA-sequencing and bioinformatic analysis showed that SAL promoted AMPK-signaling pathway activation in vitro and in vivo, and this finding was further verified by determining the phosphorylation levels of AMPK. Furthermore, the protective effects of SAL on lipid accumulation and inflammation in hepatocytes and livers induced by PO or HFHC stimulation were blocked by AMPK interruption. CONCLUSIONS: Our studies demonstrate that SAL protects against metabolic-stress-induced NASH progression through activation of AMPK signaling, indicating that SAL could be a potential drug component for NASH therapy.

Effect of seasonal thermal stress on oxidative status, immune response and stress hormones of lactating dairy cows.

This study aimed to assess the impact of seasonal thermal stress on oxidative stress, immune response, and stress hormones of lactating dairy cows in subtropical regions with different levels of temperature-humidity index (THI). A total of 32 healthy lactating Holstein dairy cows experienced 4 seasons (8 cows/season). The physiological parameters were categorized into low THI (LTHI, THI = 42.97 ± 0.95) in winter, moderate THI (MTHI, THI = 61.84 ± 0.42) in spring and autumn, and high THI period (HTHI, THI = 86.09 ± 0.23) in summer. The blood samples were collected twice in each season to measure oxidative stress, inflammatory and hormonal parameters. Our results showed THI had a positive correlation with the rectal temperature (R 2 = 0.821, P < 0.001) and respiratory rate (R 2 = 0.816, P < 0.001). Dry matter intake, milk yield and fat percentage also significantly differed among groups (P < 0.05). Compared with the MTHI group, the LTHI group exhibited a significant increase in malondialdehyde (MDA) level (P < 0.001), and the HTHI group displayed a significant increase in levels of cortisol, interleukin (IL)-10, IL-1ß and tumor necrosis factor-α (P < 0.001). Opposite changes in serum endotoxin and immunoglobulin G levels were observed with the increasing THI (P < 0.001). LTHI notably increased the triiodothyronine level, although the thyroxine level was reduced by LTHI and HTHI compared with the MTHI group. In conclusion, LTHI and HTHI conditions may induce different degrees of oxidative stress, inflammation response, and stress hormone imbalances on lactating dairy cows, therefore environmental management is necessary for the health of dairy cows in extreme weather conditions.

Relationships among bedding materials, bedding bacterial composition and lameness in dairy cows.

OBJECTIVE: Bedding materials directly contact hooves of dairy cows and they may serve as environmental sources of lameness-associated pathogen. However, the specific composition of bacteria hidden in bedding materials is still not clear. The aim of this study was to determine the effect bedding material and its bacterial composition has on lameness of Holstein heifers. METHODS: Forty-eight Holstein heifers with similar body weights were randomly assigned into three groups including sand bedding (SB), concrete floor (CF), and compost bedding (CB). Hock injuries severity and gait performance of dairy cows were scored individually once a week. Blood samples were collected at the end of the experiment and bedding material samples were collected once a week for Illumina sequencing. RESULTS: The CF increased visible hock injuries severity and serum biomarkers of joint damage in comparison to SB and CB groups. Besides, Illumina sequencing and analysis showed that the bacterial community of CB samples had higher similarity to that of SB samples than CF samples. Bacteria in three bedding materials were dominated by gastrointestinal bacteria and organic matter-degrading bacteria, such as Actinobacteria, Firmicutes, and norank JG30-KF-cM45. Lameness-associated Spirochaetaceae and Treponeme were only detected in SB and CB samples with a very low relative abundance (0% to 0.08%). CONCLUSION: The bacterial communities differed among bedding materials. However, the treponemes pathogens involved in the pathogenesis of lameness may not be a part of microbiota in bedding materials of dairy cows.

Impact of yeast and lactic acid bacteria on mastitis and milk microbiota composition of dairy cows.

This experiment was conducted to evaluate the impact of yeast and lactic acid bacteria (LAB) on mastitis and milk microbiota composition of dairy cows. Thirty lactating Holstein cows with similar parity, days in milk were randomly assigned to five treatments, including: (1) Health cows with milk SCC < 500,000 cells/mL, no clinical signs of mastitis were found, fed basal total mixed ration (TMR) without supplementation (H); (2) Mastitis cows with milk SCC > 500,000 cells/mL, fed basal TMR without supplementation (M); (3) Mastitis cows fed basal TMR supplemented with 8 g day-1 yeast (M + Y); (4) Mastitis cows fed basal TMR supplemented with 8 g day-1 LAB (M + L); (5) Mastitis cows (milk SCC > 500,000 cells/mL) fed basal TMR supplemented with 4 g day-1 yeast and 4 g day-1 LAB (M + Y + L). Blood and milk sample were collected at day 0, day 20 and day 40. The results showed efficacy of probiotic: On day 20 and day 40, milk SCC in H, M + Y, M + L, M + Y + L was significantly lower than that of M (P < 0.05). Milk concentration of TNF-α, IL-6 and IL-1ß in M + Y + L were significantly reduced compared with that of M on day 40 (P < 0.05). Milk Myeloperoxidase (MPO) and N-Acetyl-ß-D-Glucosaminidase (NAG) activity of M + Y, M + L, M + L + Y were lower than that of M on day 40 (P < 0.05). At genus level, Staphylococcus, Chryseobacterium and Lactococcus were dominant. Supplementation of LAB decreased abundance of Enterococcus and Streptococcus, identified as mastitis-causing pathogen. The results suggested the potential of LAB to prevent mastitis by relieving mammary gland inflammation and regulating milk microorganisms.