Channel: ANIMAL SCIENCE·VETERINARY SCIENCE http://journals.caass.org.cn/zgnykx EN-US http://journals.caass.org.cn/zgnykx/EN/current.shtml http://journals.caass.org.cn/zgnykx 5 【Objective】 The objective of this study was to study the effects of ambient temperature on feeding and intestinal development of poultry, and to supplement the absent temperature parameters for laying hens rearing, so as to provide a certain scientific basis for the correct feeding of laying hens.【Method】 A total of 360 Issa brown laying hens aged 11 weeks were selected and divided into 5 treatment groups with 6 replicates per group and 12 hens per replicate. The experimental laying hens were transferred to 5 intelligent environmental control chicken houses for 1 week of pre-trial and 8 weeks of formal experiment, with 3 chickens per cage. The relative humidity in the chicken house was kept at 60%, and the light was kept for 8 h (9:00-17:00) every day during the prelay period. The temperature of the control group was kept unchanged at 22℃, and the four treatment groups were carried out in a manner of daily intermittent, including 24℃, 26℃, 28℃, and 30℃ at 10:00-18:00 every day, respectively, and changed to the base temperature 22℃ for the rest of the time, the heating and cooling time were within 1 h. The experiment lasted for 8 weeks. The experimental laying hens were free to eat and drink, the feed intake was counted weekly, and the samples were collected once every two weeks. Twelve hens in each group were randomly selected and weighed, and then killed by neck cutting. The weight of glandular stomach, the weight and length of duodenum, jejunum and ileum were weighed. Hypothalamus, glandular stomach and duodenum samples were frozen in liquid nitrogen and stored at -80℃. Feed intake was calculated in heat treatment period and non-heat treatment period for 3 days before the end of experiment.【Result】 Compared with T22 group, the feed intake in T30 group was significantly decreased at 13-16 week (P<0.05); the feed intake in T24 group was significantly higher than that in T28 and T30 groups at 17-20 week (P<0.05). During the heat treatment period, the feed intake of T30 group was significantly lower than that in T22 and T24 groups (P<0.05). The feed intake of T30 group was significantly lower than that in T22, T24 and T26 groups during the non-heat treatment period (P<0.05). The feed intake in the heat treatment period was significantly lower than that in the non-heat treatment period (P<0.05), and the highest feed intake was maintained in T24 group and the lowest in T30 group. Compared with T22 group, the glandular gastric index was significantly increased at 16 week (P<0.01). At 18 week, compared with T22 group, the jejunum index in T30 group was significantly lower than that in other groups (P<0.05). At 20 week, compared with T22 group, the glandular stomach index, jejunum index and ileum index in T24 group were significantly increased (P<0.05), and the jejunum index was significantly higher than that in T30 group (P<0.05). Compared with T22 group, the expression of NPY (Neuropeptide Y) in hypothalamus of all treatment groups was significantly increased at 14 week (P<0.05). The expression of AgRP (Agouti-related protein) in hypothalamus of T30 group was significantly decreased (P<0.05), and the expression of CCK (Cholecystokinin) in duodenum of T30 group was significantly increased (P<0.05). At 20 week, compared with T22 group, the expression of CART (amphetamine-regulated transcript) in hypothalamus of T24 group was significantly decreased (P<0.05), and the expression of ghrelin in glandular stomach of T24 group was significantly decreased (P<0.05).【Conclusion】 These results indicated that ambient temperature at 24℃ during the growing period could promote the development of gastrointestinal tract, increase the expression of NPY in hypothalamus, and inhibit the expression of CART and ghrelin in hypothalamus, which was beneficial to the growth and development of laying hens. However, the high temperature treatment at 30℃ damaged the intestinal tract of laying hens, inhibited the expression of hypothalamus feeding promoting factor AgRP, and promoted the expression of duodenal feeding inhibiting factor CCK, thus inhibiting feeding intake and reducing feed intake of laying hens.

]]> 【Background】 African swine fever (ASF) is an acute, highly contagious, and deadly infectious disease of pigs caused by ASF virus (ASFV), which is currently considered the biggest killer in global swine industry. To date, there is no effective vaccines or antiviral drugs for the prevention or treatment of ASF. As obligate intracellular parasites, the viruses are fully reliant on the host translation machinery to produce the polypeptides that are essential for viral replication. A central mechanism regulating translation initiation involves phosphorylation of the α subunit of eukaryotic initiation factor 2 (eIF2α), which directs host translational control and adaptation to cellular stress. The regulation of eIF2α phosphorylation has been regarded as a critical step for viral infection, with important effects on virulence, tissue tropism, pathogenicity, and immunoevasion. However, the molecular mechanisms by which most of the ASFV-encoded proteins affecting eIF2α phosphorylation have not been well studied. 【Objective】 The aim of this study was to explore the mechanism of ASFV MGF110-5L-6L protein on the host cell translation block and promote the formation of stress particles, so as to provide a scientific basis for further revealing the pathogenic mechanism of African swine fever virus.【Method】 The preliminary screening by luciferase reporter assays identified that ectopic expression of ASFV MGF110-5L-6L, a previously uncharacterized member of the multigene family 110, significantly increased eIF2α phosphorylation levels. To confirm and clarify the potential role of MGF110-5L-6L expression in mediating eIF2α phosphorylation and downstream of translation control, two continuous porcine cell lines, including 3D4/21 (porcine alveolar macrophage) and PK-15 (porcine kidney), were used for the plasmid transfection and/or drug treatment and subjected to immunoblotting or confocal immunofluorescence analysis. To investigate how the ectopic expression of MGF110-5L-6L triggers cellular stress, the structure, subcellular localization and function of the MGF110-5L-6L protein were further characterized by a combination of bioinformatic prediction, immunofluorescence and immunoblotting analysis.【Result】 Here, it was confirmed that ectopic expression of MGF110-5L-6L remarkably promoted eIF2α phosphorylation and the expression of ATF4, indicating that it functions in the integrated stress response. The subsequent analyses revealed that MGF110-5L-6L expression could trigger the ER stress and activate the unfolded protein response, and the phosphorylation of eIF2α was mediated via PERK and PKR, resulting in the suppression of host translation and stress granule formation. It was further observed that MGF110-5L-6L protein had two highly conserved central cysteine-rich domains and was mainly retained in the endoplasmic reticulum (ER), and also caused a significant reorganization of the subcellular distribution and morphological characteristics of the Golgi and peroxisome, suggesting that it might interfere with ER redox homeostasis, secretory pathway, and other membrane-bound organelles to trigger cellular stress.【Conclusion】 Together, these results demonstrated a previously uncharacterized role of ASFV MGF110-5L-6L and further defined several molecular interfaces by which ASFV MGF110-5L-6L hijacks the host cell translation, which expanded the view of ASFV in determining the fate of host-pathogen interactions.

]]> 【Background】 Meridian theory is the cornerstone of Traditional Chinese Medicine (TCM), and acupoints are the key sites on the meridian, which are the implementation location of the acupuncture. However, there are different opinions on the structural basis and morphological composition of acupoints, which cannot be scientifically clarified. As a newly found type of interstitial cells, Telocytes (TCs) were suggested to be the potential essence cells of the meridian by morphological study recently, but the characteristics and distribution of TCs at acupoints need to be further elucidated. 【Objective】 This study aimed to analyze the structural differences between acupoints and non-acupoints, and to explore the morphological characteristics of TCs at acupoints. The structural relations between TCs and its surrounding components were also analyzed, so as to provide theoretical support for the study of the cellular mechanism of TCM acupuncture treatment. 【Method】 The skin tissues of Baihui (Du₂₀), Quchi (LI₁₁), Sanyinjiao (Sp₆), Danzhong (Ren₁₇), Chengjiang (Ren₂₄), Erjian (EP₄) and non-acupoints on the back and abdomen were collected from five adult healthy Hu sheep. TCs and Tps (telopodes) were stained by specific markers CD34 and Vimentin, the mast cells were labeled by TPS, and nerves were identified by PGP9.5. Extracellular vesicles were marked by TSG101. The structure and fine composition of skin acupoints and non-acupoints were analyzed by H.E and immunohistochemical techniques (IHC), and the morphological quantitative analysis of the data was carried out by using ImageJ and Image-Pro Plus statistical software. The distribution differences of TCs and its related structures at acupoints and non-acupoints were analyzed. On this basis, the morphological characteristics and stereoscopic structure of TCs were observed by transmission electron microscope (TEM), scanning electron microscope (SEM) and immunofluorescence (IF) double labeling technique, and the morphological relationship between TCs and these structures was further analyzed, thus determining the ultramorphology and material basis of acupoints. 【Result】 There were such structures as hair follicles, sebaceous glands, sweat glands and arrector pili muscle, as well as nerves, blood vessels, mast cells, collagen fiber bundles at the acupoints and non-acupoints. However, the number of nerves, blood vessels and mast cells distribution at acupoints was significantly more than that at non-acupoints (P<0.05). More importantly, TCs with slender tubular processes (telopodes, Tps) were distributed in the skins, and the distribution of TCs at the acupoints was significantly different from that of non-acupoints (P<0.05). TCs could be used as the integrator of acupoints stroma. There were extensive relationships between TCs themselves or TCs and surrounding morphological structures (including gap junctions and extracellular vesicles, etc.), which could develop a structural network system. At the ultramicro level, it was observed that the Tps was a typical beaded appearance, which was composed of alternating arrangement of the inflated part (podom, Pd) and the slender stenotic part (podomer, P). The well-developed mitochondria in the cytoplasm of podom, the cellular connection between Tps and Tps, and a large number of extracellular vesicles on or around TCs (significantly more than non-acupoints (P<0.05)) ensured the core role of TCs in the structure of acupoints. Moreover, the structural connection between TCs and epidermal derivatives also verified the relationship between acupoints and epidermal derivatives in the classic book Huangdi Neijing (The Yellow Emperor’s Canon of Internal Medicine) at the cellular level. 【Conclusion】 Structural compositions at the acupoints and non-acupoints were basically the same, while the number of TCs and Tps, nerves, blood vessels, mast cells, extracellular vesicles at acupoints was significantly more than that at non-acupoints; TCs and Tps had the functional structures of connecting and integrating various morphological components, which might be mediators or integrators of different systems at the acupoints. The cell connections among TCs, developed mitochondria and extracellular vesicles had the structural basis for cell communication and energy generation, which corresponds to the “Qi-Xue” in TCM.

]]>