Radiotelemetry recording of electroencephalogram in piglets during rest

A wireless recording system was developed to study the electroencephalogram (EEG) in unrestrained, male Landrace piglets. Under general anesthesia, ball-tipped silver/silver chloride electrodes for EEG recording were implanted onto the dura matter of the parietal and frontal cortex of the piglets. A pair of miniature preamplifiers and transmitters was then mounted on the surface of the skull. To examine whether other bioelectrical activities interfere with the EEG measurements, an electrocardiogram (ECG) or electromyogram (EMG) of the neck was simultaneously recorded with the EEG. Next, wire electrodes for recording movement of the eyelid were implanted with EEG electrodes, and EEG and eyelid movements were simultaneously measured. Power spectral analysis using a Fast Fourier Transformation (FFT) algorithm indicates that EEG was successfully recorded in unrestrained piglets, at rest, during the daytime in the absence of interference from ECG, EMG or eyelid movements. These data indicate the feasibility of using our radiotelemetry system for measurement of EEG under these conditions.     

State of nonspecific resistance in germfree and Escherichia coli contaminated miniature piglets

The phagocytic activity of the leukocytes and the serum complement, properdin, and lysozyme levels were studied in germfree miniature piglets and similar animals ocntaiminated withEscherichia coli 055 andE. coli 083. In the presence of autologous serum and complement phagocytosis ofE. coli 055 cells was inhibited, but it was considerably intensified under the influence of specific opsonins (antibodies againstE. coli 055). Lowered levels of complement, properdin, and lysozyme were found in the germfree animals. After peroral monocontamination withE. coli the formation of properdin and complement was stimulated the most, and that of lysozyme the least. Antibodies againstE. coli 055 were not found in the monocontaminated piglets. The highest lysozyme levels were found in the previously germfree animals, which points to the role of other contamination factors thanE. coli cells in the stimulation of lysozyme. It is concluded that microbial contamination plays an important role in the development of the cellular and humoral factors of resistance.Research Laboratory of Experimental Biological Models, Academy of Sciences of the USSR, Moscow Region. (Presented by Academician of the Academy of Medical Sciences of the USSR, N. N. Zhukov-Verezhnikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 9, pp. 341–344, September, 1978.     

Antibody repertoire development in fetal and neonatal piglets. XV. Porcine circovirus type 2 infection differentially affects serum IgG levels and antibodies to ORF2 in piglets free from other environmental factors

Porcine circovirus type 2 (PCV2) is an important pathogen in the porcine respiratory disease complex (PRDC) and its persistence may be due to dysregulation of systemic immunity. We examined this contention using isolator piglets. We present data on Ig levels in serum and bronchio-alveolar lavage (BAL), on antibody response to PCV2 and to TNP conjugates used as model antigens in 48 PCV2-infected isolator piglets. We compared these to data from TNP-immunized isolator piglets colonized with a probiotic flora, those infected with swine influenza (S-FLU) and those infected with porcine respiratory and reproductive syndrome virus (PRRSV). We found that PCV2 infection does not cause generalized hypergammaglobulinemia that characterizes PRRSV infections, but causes an unexplained increase in serum IgA. All animals had serum IgG to the ORF2 gene product of PCR2, but neither IgA nor IgG anti-ORF2 responses in BAL. PCV2 infection is a poor adjuvant since only natural anti-TNP antibodies were found. Unexpectedly, immunization appeared to result in lower Ig levels and lower anti-ORF2 responses. There was extreme variation in serum Ig levels in response to infection that could in part be traced to genetic and gender differences. These data suggest that non-replicating vaccines are unlikely to result in a significant primary antibody response but may prime the system for a secondary antibody and cytotoxic response following actual infection. In any case, developers may have to contend with significant genetic differences in the response of piglets to PCV2.     

低聚甘露糖醛酸对断奶仔猪的安全性评价*

目的试验旨在研究饲粮中添加高剂量低聚甘露糖醛酸(PM)对断奶仔猪的生长性能、血液生化指标、血常规指标和脏器指数的影响,从而确定PM对断奶仔猪的生物安全性。方法试验选用24头28日龄、健康的杜长大三元杂交断奶仔猪,按体重区组,随机分为4个处理,每个处理6个重复,每个重复1头猪,单笼饲养。对照组饲喂玉米-豆粕型基础日粮,试验组饲喂在基础日粮的基础上分别添加0.3%(推荐有效剂量)、1.5%(5倍推荐有效剂量)、3.0%(10倍推荐有效剂量)PM的试验饲粮,试验期28d。结果各处理组间不同生长阶段的平均日采食量差异均不显著(P>0.05)。与对照组相比,饲料中添加PM极显著增加了断奶仔猪的饲料转化效率(P≤0.01);饲料中添加PM对断奶仔猪死亡率、血清生化指标、血常规指标和脏器指数没有显著影响(P>0.05)。结论断奶仔猪饲料中PM的推荐添加量定为0.3%,饲料中PM为3.0%(10倍推荐添加量)对断奶仔猪饲用是安全的。     

Achyranthes bidentata polysaccharide enhances immune response in weaned piglets

The acquired immunity is underdeveloped at 3–4 weeks of age when piglets are usually weaned on commercial farms, and weaning is associated with compromised immunity. Dietary supplementation with immunomodulatory phytochemicals may enhance immune responses in the weaned piglets. This study is conducted to investigate the effects of dietary supplemental achyranthes bidentata polysaccharide (ABP) on proliferation activity of lymphocytes, and production of antibodies, complements and cytokines in weaned piglets. Results showed that lymphocyte proliferation activity in piglets fed diets supplementing with 1000 and 1500?mg/kg ABP increased (P?<?0.05) on days 14 and 28 compared with the non-additive piglets, as well as serum contents of IgG, IgA, IgM, C₃, C₄, IL (interleukin)-2 and IFN (interferon)-γ. The ABP had dose-dependent immunomodulatory activity and the dose of 1500?mg/kg presented the strongest stimulating activity in vivo. In addition, the ABP increased (P?<?0.05) the proliferation activity and production of IL-2 and IFN-γ of cultured lymphocytes in dose- or time-dependent manner. The proliferation activity of peripheral T cells and splenic lymphocytes in 400?μg/ml of ABP group arrived at their peak values, as well as the production of IL-2 and IFN-γ at 72 and 12?h after the treatment, respectively. Collectively, these findings suggested that dietary supplementation with ABP to weaned piglets enhances cellular and humoral immune responses, and ABP addition to culture medium also increases the proliferation activity and cytokine production of lymphocytes cultured in vitro, which indicate that dietary supplementation with the herbal polysaccharide may offer an effective alternative to antibiotics for weaned piglets.     

The Mechanism of PEDV-Carrying CD3+ T Cells Migrate into the Intestinal Mucosa of Neonatal Piglets

Porcine epidemic diarrhea virus (PEDV) can cause intestinal infection in neonatal piglets through the nasal cavity. A process in which CD3⁺ T cells carry PEDV plays a key role. However, the modes through which PEDV bridles CD3⁺ T cells as a vehicle for migration to the intestinal epithelium have not been clarified. In this study, we first demonstrated that PEDV could survive in blood-derived CD3⁺ T cells for several hours, depending on the multiplicity of infection. In addition, PEDV preferentially survived in CD4⁺ T cells over CD8⁺ T cells. Moreover, viral transmission was mediated by cell-to-cell contact between mesenteric lymph-node-derived CD3⁺ T cells, but did not occur in blood-derived CD3⁺ T cells. Following an increase in gut-homing integrin α4β7, blood-derived CD3⁺ T cells carrying PEDV migrated to the intestines via blood circulation and transferred the virus to intestinal epithelial cells through cell-to-cell contact in neonatal piglets. Our findings have significant implications for understanding PEDV pathogenesis in neonatal piglets, which is essential for developing innovative therapies to prevent PEDV infection.     

The Contribution of the Left Phrenic Nerve to Innervation of the Esophagogastric Junction

The contribution of the left phrenic nerve to innervation of the esophagogastric junction. The esophagogastric junction is part of the barrier preventing gastroesophageal reflux. We have investigated the contribution of the phrenic nerves to innervation of the esophagogastric junction in humans and piglets by dissecting 30 embalmed human specimens and 14 piglets. Samples were microdissected and nerves were stained and examined by light and electron microscopy. In 76.6% of the human specimens, the left phrenic nerve participated in the innervation of the esophagogastric junction by forming a neural network together with the celiac plexus (46.6%) or by sending off a distinct phrenic branch, which joined the anterior vagal trunk (20%). Distinct left phrenic branches were always accompanied by small branches of the left inferior phrenic artery. In 10% there were indirect connections with a distinct phrenic nerve branch joining the celiac ganglion, from which celiac plexus branches to the esophagogastric junction emerged. Morphological examination of phrenic branches revealed strong similarities to autonomic celiac plexus branches. There was no contribution of the left phrenic nerve or accompanying arteries from the caudal phrenic artery in any of the piglets. The right phrenic nerve made no contribution in any of the human or piglet samples. We conclude that the left phrenic nerve in humans contributes to the innervation of the esophagogastric junction by providing ancillary autonomic nerve fibers. Experimental studies of the innervation in pigs should consider that neither of the phrenic nerves was found to contribute. Clin. Anat. 33:265–274, 2020. © 2019 Wiley Periodicals, Inc.     

Achyranthes bidentata polysaccharide enhances growth performance and health status in weaned piglets

This study is conducted to investigate the effects of Achyranthes bidentata polysaccharide (ABP) as a dietary additive on growth performance, plasma parametre profile and the mRNA abundances of IGF-1 and IL-1β in liver, jejunal mucosa and mesentery lymph node. A total of 200 three-hybreded (Landrace×Yorkshire×Duroc) piglets weaned at 28 days of age were allocated into five dietary treatment groups on the basis of body weight and litter of origin in a complete randomised design. Five diets were tested for 35 days, including the basal control diet, the antibiotic treatment diet (basal control diet+500 mg/kg flavomycin), and three ABP treatment diets, in which ABP were added to basal control diet with 500, 1000 and 1500 mg/kg, respectively. There was higher average daily feed intake (ADFI) in animals fed with 500 mg/kg ABP when compared with animals in other groups (P<0.05). However, there was no significant deference in ADFI among animals in control group, antibiotics group (500 mg/kg flavomycin), high dose ABP supplementation group (1000 and 1500 mg/kg ABP) (P>0.05). Flavomycin (500 mg/kg) and different dose of ABP supplementation significantly increased average daily gain (P<0.05). Compared with animals in control group, there was low FiG in animals fed with 500 mg/kg flavomycin, 500, 1000 and 1500 mg/kg ABP, respectively (P<0.05). Flavomycin (500 mg/kg) and different dose of ABP supplementation significantly decreased the diarrhoea frequency of weaned piglets (P<0.05). Moreover, there was lower diarrhoea frequency in animals fed with different dose of ABP compared with animals fed 500 mg/kg flavomycin (P<0.05). Supplementation of ABP increased plasma concentrations of hormones, antibodies, and alkaline phosphatase (P<0.05) and IL-1β mRNA abundance in liver, jejunal mucosa and lymph nodes. These findings indicate that ABP is effective in improving growth performance and defending capacity, which suggests that ABP can be used as a diet additive for weanling piglets.