Streaming Potential Experiment on Sandstone Core Samples Based on Current Source Model under Different Sodium Chloride Solutions.

The streaming potential effect has a wide range of applications in geophysics. The core streaming potential experiment requires that there is no external circuit at both ends of the core, but a measurement circuit must be introduced to measure the voltage between both ends of the core which will cause an external circuit. In order to analyze the effect of measurement circuits on the streaming potential experiment, this paper proposes a core current source model, i.e., the core in the streaming potential experiment is regarded as a circuit composed of a current source whose output current is equal to the seepage current and the core resistance. By changing the resistance value of the external circuit, it is found that the seepage current is not affected by the external resistance but by the excitation pressure. Experiments on the streaming potential of 20 sandstone cores under distilled water, 0.01 mol/L, 0.02 mol/L, 0.05 mol/L, 0.1 mol/L, 0.2 mol/L, 0.4 mol/L, and 0.6 mol/L sodium chloride solutions revealed that the effect of the external circuit on the streaming potential signal increased with decreasing mineralization. For distilled water-saturated sandstone cores, the effect of the external circuit was about 2%.

Experimental Study of Electroosmosis in Rock Cores Based on the Dual Pressure Sensor Method.

Electroosmotic experiments obtain the electroosmotic pressure coefficient of a rock sample by measuring the excitation voltage at both ends of the sample and the pressure difference caused by the excitation voltage. The electroosmotic pressure is very weak and buried in the background noise, which is the most difficult signal to measure in the dynamic-electric coupling experiment, so it is necessary to improve its signal-to-noise ratio. In this paper, for the low signal-to-noise ratio of electroosmotic pressure, the dual pressure sensor method is proposed, i.e., two pressure sensors of the same type are used to measure electroosmotic pressure. Two different data extraction methods, Fast Fourier Transform and Locked Amplification, are utilized to compare the dual pressure sensor method of this paper with the existing single pressure sensor method. The relationship between the electroosmotic pressure coefficient and the excitation frequency, mineralization, permeability, and porosity is analyzed and discussed.

Fucoidan Supplementation Improves Antioxidant Capacity via Regulating the Keap1/Nrf2 Signaling Pathway and Mitochondrial Function in Low-Weaning Weight Piglets.

Fucoidan (FC) is known for its antioxidant properties, but it has unclear effects and mechanisms on weaned piglets. Two experiments were conducted to determine the optimal FC dosage in piglet diets and its protective effect against lipopolysaccharide (LPS)-induced oxidative stress. In experiment one, 24 low weight weaned piglets were randomly assigned to four dietary treatments: a basal diet (FC 0), or a diet supplemented with 150 (FC 150), 300 (FC 300), or 600 mg/kg FC (FC 600). In experiment two, 72 low-weaning weight piglets were randomly allocated into four treatments: a basal diet (CON), or 300 mg/kg of fucoidan added to a basal diet challenged with LPS (100 µg LPS/kg body weight) or not. The results showed that FC treatments increased the G:F ratio, and dietary FC 300 reduced the diarrhea incidence and increased the plasma IGF-1 concentrations. In addition, FC 300 and FC 600 supplementation increased the plasma SOD activity and reduced the plasma MDA concentration. LPS challenge triggered a strong systemic redox imbalance and mitochondrial dysfunction. However, dietary FC (300 mg/kg) supplementation increased the activity of antioxidant enzymes, including SOD, decreased the MDA concentration in the plasma and liver, down-regulated Keap1 gene expression, and up-regulated Nrf2, CAT, MFN2, SDHA, and UQCRB gene expression in the liver. These results indicated that dietary fucoidan (300 mg/kg) supplementation improved the growth performance and antioxidant capacity of low-weaning weight piglets, which might be attributed to the modulation of the Keap1/Nrf2 signaling pathway and the mitochondrial function in the liver.

Porous Zinc Oxide and Plant Polyphenols as a Replacement for High-Dose Zinc Oxide on Growth Performance, Diarrhea Incidence, Intestinal Morphology and Microbial Diversity of Weaned Piglets.

The aim of this experiment is to evaluate the effects of adding porous zinc oxide, plant polyphenols, and their combination to diets without antibiotics and high-dose zinc oxide on the growth performance, diarrhea incidence, intestinal morphology, and microbial diversity of weaned piglets. A total of 150 Duroc × Landrace × Large White weaned piglets were allocated to one of five diets in a randomized complete block design with six replicates and five piglets per replicate. The experimental period was 42 d, divided into two feeding stages: pre-starter (0-14 d) and starter (14-42 d). In the pre-starter stage, the negative control group (NC) was fed a basal diet, the positive control group (PC) was fed a basal diet with 2000 mg/kg of zinc oxide, the porous zinc oxide group (PZ) was fed a basal diet with 500 mg/kg of porous zinc oxide, the plant polyphenol group (PP) was fed a basal diet with 1500 mg/kg of plant polyphenols, and the combination group (PZ + PP) was fed a basal diet with 500 mg/kg of porous zinc oxide and 1500 mg/kg of plant polyphenols. In the starter stage, the NC, PC, and PZ groups were fed a basal diet, while the PP and PZ + PP groups were fed a basal diet with 1000 mg/kg of plant polyphenols. The results showed that, (1) compared with the PZ group, adding plant polyphenols to the diet showed a trend of increasing the ADFI of weaned piglets from 14 to 28 d (p = 0.099). From days 28 to 42 and days 0 to 42, porous zinc oxide and the combination of porous zinc oxide and plant polyphenols added to the control diet improved the FCR to the level observed in pigs fed the PC diet. (2) Dietary PZ + PP tended to increase the jejunal villus height (VH) of weaned piglets (p = 0.055), and significantly increased the villus-height-to-crypt-depth ratio compared to the NC group (p < 0.05). (3) Compared with the NC group, PZ supplementation decreased the relative abundance of Firmicutes and increased the relative abundance of Bacteroidetes, and the relative abundance of Lactobacillus in the PZ and PZ + PP groups were both increased. In conclusion, porous zinc oxide and plant polyphenols may have synergistic effects in modulating intestinal health in weaned piglets and be a potential alternative to high-dose zinc oxide.

The Effects of Dietary Silybin Supplementation on the Growth Performance and Regulation of Intestinal Oxidative Injury and Microflora Dysbiosis in Weaned Piglets.

Oxidative stress is the major incentive for intestinal dysfunction in weaned piglets, which usually leads to growth retardation or even death. Silybin has caught extensive attention due to its antioxidant properties. Herein, we investigated the effect of dietary silybin supplementation on growth performance and determined its protective effect on paraquat (PQ)-induced intestinal oxidative damage and microflora dysbiosis in weaned piglets. In trial 1, a total of one hundred twenty healthy weaned piglets were randomly assigned into five treatments with six replicate pens per treatment and four piglets per pen, where they were fed basal diets supplemented with silybin at 0, 50, 100, 200, or 400 mg/kg for 42 days. In trial 2, a total of 24 piglets were randomly allocated to two dietary treatments with 12 replicates per treatment and 1 piglet per pen: a basal diet or adding 400 mg/kg silybin to a basal diet. One-half piglets in each treatment were given an intraperitoneal injection of paraquat (4 mg/kg of body weight) or sterile saline on day 18. All piglets were euthanized on day 21 for sample collection. The results showed that dietary supplementation with 400 mg/kg silybin resulted in a lower feed conversion ratio, diarrhea incidence, and greater antioxidant capacity in weaned piglets. Dietary silybin enhanced intestinal antioxidant capacity and mitochondrial function in oxidative stress piglets induced by PQ. Silybin inhibited mitochondria-associated endogenous apoptotic procedures and then improved the intestinal barrier function and morphology of PQ-challenged piglets. Moreover, silybin improved intestinal microbiota dysbiosis induced by the PQ challenge by enriching short-chain fatty-acid-producing bacteria, which augmented the production of acetate and propionate. Collectively, these findings indicated that dietary silybin supplementation linearly decreased feed conversion ratio and reduced diarrhea incidence in normal conditions, and effectively alleviated oxidative stress-induced mitochondrial dysfunction, intestinal damage, and microflora dysbiosis in weaned piglets.

Stimbiotics Supplementation Promotes Growth Performance by Improving Plasma Immunoglobulin and IGF-1 Levels and Regulating Gut Microbiota Composition in Weaned Piglets.

This study was conducted to investigate the effects of dietary supplementation with stimbiotics (STB) on growth performance, diarrhoea incidence, plasma antioxidant capacity, immunoglobulin concentration and hormone levels, and faecal microorganisms in weaned piglets. Compared with the control (CT) group, the addition of STB improved the body weight (BW) of piglets on days 28 and 42 (p < 0.05) and increased daily weight gain and daily feed intake from days 14-28 and throughout the trial period (p < 0.05). Correspondingly, the plasma insulin-like growth factor 1 (IGF-1) level on day 42 was significantly improved by STB (p < 0.05). VistaPros (VP) group levels of immunoglobulin (Ig) A and G were significantly higher on days 14 and 42 (p < 0.05) than the CT group levels. In addition, the activity of plasma catalase tended to be increased on day 14 (p = 0.053) in the VP group, as for superoxide dismutase, glutathione peroxidase, and malondialdehyde, STB did not significantly affect their levels (p > 0.05). Moreover, dietary STB increased the relative abundance of beneficial bacteria, including norank_f_Muribaculaceae, Rikenellaceae_RC9_gut_group, Parabacteroides, and unclassified_f__Oscillospiraceae. In summary, STB improved the immunity and IGF-1 levels in the plasma of weaned piglets and consequently promoted the growth performance of weaned piglets.

Live Yeast Supplementation in Gestating and Lactating Primiparous Sows Improves Immune Response in Dams and Their Progeny.

The present study determined the effects of live yeast (LY) supplementation during middle-late gestation and the lactation period in primiparous sows on reproductive parameters, lactation performance, and immunity, and also explores the carryover effects in their offspring. On day (d) 60 of gestation, 16 crossbred primiparous sows were randomly assigned to two dietary treatments (with or without supplementation of 425 mg/kg of live yeast; LYT and CT, respectively) homogeneous for body weight (BW) and backfat thickness. Experimental diets were applied from day 60 of gestation to the end of lactation. At weaning, 60 piglets with an average BW of each treatment were selected based on their source litter and assigned to two groups corresponding to the original treatments received by their mothers. Each group had five replicates of six piglets each and was fed a basal diet for 42 days. The results showed that LY supplementation significantly increased the serum IgA and IgG concentrations of sows at farrowing and weaning stages, and of piglets on day 14 and 28 post weaning. No significant differences were found in reproductive and lactation performance, while minor effects were observed on antioxidant capacity. In conclusion, live yeast addition during middle-late gestation and the whole lactation period resulted in enhanced immunity of primiparous sows and their offspring, therefore, improving maternal and progeny health.