Low pathogenic Avian Influenza (AI) virus has the ability to evolve to high pathogenic viruses resulting in significant economic losses in the poultry sector. This study aims at assessing the impact of H9N2 viral pass...Low pathogenic Avian Influenza (AI) virus has the ability to evolve to high pathogenic viruses resulting in significant economic losses in the poultry sector. This study aims at assessing the impact of H9N2 viral passaging in broilers and its relatedness to pathogenicity and amino acid (a.a) sequences of the hemagglutinin (HA) cleavage site and neuraminidase (NA) stalk. The original H9N2 AI virus (P0) was used to challenge ten-21 days old broilers. Individual recovery of H9N2 virus from homogenates of trachea, lungs and airsacs was attempted in 9 days old chicken embryos, as a conclusion of the first passage (P1). Tracheal isolates of H9N2 were passaged for a second (P2) and a third (P3) time in broilers, followed by a similar embryonic recovery procedure. The a.a. sequence of a part of HA1 cleavage site and Neuraminidase stalk were compared among the differently passaged viruses;an assessement of the relatedness of the determined a.a. sequences to the pathogenicity in broilers, based on frequency of mortality, morbidity signs, gross and microscopic lesions at 3 days post challenge with the P1, P2, and P3-H9N2, is concluded. An increase in certain morbidity signs and specific lesions was observed in P2- and P3-H9N2 challenged broilers compared to birds challenged with P1-H9N2. A conserved R-S-S-R amino acid sequence at the HA1 cleavage site was observed in the differently passaged H9N2, associated with a variability in the NA stalk-a.a sequences. The passaging of the low pathogenic H9N2 virus in broilers leads to a trend of increase in pathogenicity, manifested in higher frequency of morbidity signs, and of specific gross and microscopic lesions of the examined organs. This passaging was associated with a conserved a.a. sequence of the hemaglutinin cleavage site and a variability in the sequence of the neuraminidase stalk. A detailed study of the potential of the detected variability in the neuraminidase stalk of H9N2 in induction of a higher pathogenicity in broilers will be the subject of future investigations.展开更多
The purpose of this study was to investigate the effects of methionine deficiency on cellular immune function by determining morphological and ultrastructural changes of thymus, thymic cell cycle and apoptosis, periph...The purpose of this study was to investigate the effects of methionine deficiency on cellular immune function by determining morphological and ultrastructural changes of thymus, thymic cell cycle and apoptosis, peripheral blood T-cell subsets, T- cell proliferation function and the serum interleukin-2 （IL-2） contents. 120 1-d-old broilers were randomly divided into two groups （6 replicates in each group and l0 broilers in each replicate） and fed on a control diet or methionine deficient diet for 42 d. Lesions were observed in experiment. Histopathologically, lymphopenia and congestion were observed in the medulla of thymic lobule. Ultrastructurally, there were more apoptosis lymphocytes, and the mitochondria of lymphocytes were swelled in thymus of methionine deficiency. The G0/G~ phase of the cell cycle of the thymus was much higher （P〈0.01）, and the S, G2＋M phases and proliferating index （PI） were lower （P〈0.01） in methionine deficiency than in control group. And the percentage of apoptotic cells in the thymus was significantly increased in methionine deficiency （P〈0.01）. The percentage of CD4＋ and CD8~ T-cells was decreased in methionine deficiency compared with control group. Meanwhile, the proliferation function of peripheral blood T-cell was decreased in methionine deficiency. Also, the serum IL-2 contents were decreased in methionine deficiency. It was concluded that methionine deficiency could cause pathological and ultrastructural changes of thymus, reduce the T-cell population, serum IL-2 contents and the proliferation function of T- cells, and induce increased percentage of apoptotic cells. The cellular immune function was finally impaired in broilers.展开更多
Background: Meat color and lipid peroxidation are important traits related to meat quality. CO_2 concentration is a critical factor that can affect meat quality in the commercial use of gas stunning(GS). However, the ...Background: Meat color and lipid peroxidation are important traits related to meat quality. CO_2 concentration is a critical factor that can affect meat quality in the commercial use of gas stunning(GS). However, the effect and mechanism of CO_2 stunning on meat color and lipid peroxidation during long-term storage remain poorly studied. We aimed to study the effects of GS methods, especial y CO_2 concentration, on meat color and meat lipid peroxidation in broilers during long-term storage at 4 °C and to explore the potential mechanism of meat color change via lipid peroxidation and the inner lipid peroxide scavenging system.Methods: Eighteen broilers were sacrificed after exposure to one of the following gas mixtures for 90 s: 40% CO_2+21% O_2+ 39% N2(G40%), 79% CO_2+ 21% O_2(G79%), or no stunning(0% CO_2, control). Meat color, serum variables,enzyme activities, and the gene expression of mitogen-activated protein kinase(MAPK), nuclear factor-erythroid2-related factor 2(Nrf2), glutathione S-transferase(GST) and superoxide dismutase(SOD) were determined.(Continued on next page)Results: The concentrations of serum triiodothyronine(T3, P = 0.03) and the ratio of serum free triiodothyronine/free thyroxine(FT3/FT4, P < 0.01) were decreased, whereas levels of serum cortisol(P < 0.01) were increased in the 40%CO_2 group compared with the control group. Additionally, the thiobarbituric acid-reactive substances(TBARS)3 d(P < 0.01) and TBARS6 d(P = 0.01) in breast meat and the TBARS3 din thigh meat(P < 0.01) were increased in the40% CO_2 group compared with the control group. Serum T3 was negatively correlated with TBARS6 dboth in the breast and thigh meat(r =-0.63, P < 0.01 and r =-0.47, P = 0.05 respectively). T3/T4 was negatively correlated with TBARS6 din the breast meat and in the thigh meat(r =-0.57, P = 0.01; and r =-0.53, P = 0.03 respectively). Compared with the control group, Lightness(L*)1 d(P = 0.03) and L*9 d(P < 0.01) were increased, whereas total chromatic aberration(E*)1 d(P = 0.05) and E*3 d(P < 0.01) were decreased in the breast meat of both the G40% and G79% groups. The values of yel owness(b*)3 d(P = 0.01), b*6 d(P < 0.01) and E*6 d(P < 0.01) in the thigh meat were lower in both the G40% and G79% groups than in the control group. In the breast muscle, the m RNA levels of c-Jun N-terminal kinase 2(JNK2, P = 0.03),GSTT1(P = 0.04), and SOD1(P = 0.05) were decreased, and the m RNA levels of JNK1(P = 0.07), Nrf2(P = 0.09), and GSTA3(P = 0.06) were slightly lower in both the G40% and G79% groups compared with the control group. However, among these genes, only the m RNA level of JNK1 was decreased in the G40% group compared with the control group and the G79% group(P = 0.03) in the thigh muscle.Conclusions: Compared with the control group, meat color quality in the breast meat was decreased, and the expression of genes in the MAPK/Nrf2/ARE(antioxidant responsive element) antioxidant pathway in breast muscle was partly suppressed by GS of both 40% and 79% CO_2. However, oxidative stress and meat lipid peroxidation during storage were aggravated by GS with 40% CO_2 compared to GS with 79% CO_2 and no GS.展开更多
Background： Insulin-like factor 2（IGF2） plays an important role in embryonic growth process by modulating intermediary metabolism and cell proliferation. Folic acid is involved in one carbon metabolism and contribu...Background： Insulin-like factor 2（IGF2） plays an important role in embryonic growth process by modulating intermediary metabolism and cell proliferation. Folic acid is involved in one carbon metabolism and contributes to DNA methylation which is related to gene expression. The purpose of this study was to explore whether folic acid could regulate IGF2 expression via epigenetic mechanism and further promote embryonic growth of new-hatched broilers.Methods： In the present study, 360 fertile eggs were selected and randomly assigned to four treatments. On11 embryonic day of incubation（E11）, 0, 50, 100 and 150 μg folic acid were injected into eggs respectively.After hatched, growth performance of broilers were calculated. Hepatic IGF2 expression, methylation level and chromatin structure of promoter region were analyzed.Results： Results have showed that IGF2 expression was up-regulated in 150 μg folic acid group（P 〈 0.05） and other two dose of folic acid did not affect gene expression（P 〉 0.05）. Meanwhile, methylation level of IGF2 promoter were lower in 100 and 150 μg groups, which was consistent with lower expression of DNA methyltransferase1（DNMT1）（P 〈 0.05）. What＇s more, chromatin looseness of IGF2 promoter was higher in 150 μg group than control group（P 〈 0.05）. Further, birth weight（BW）, liver and bursa index of new-hatched chickens in 150 μg folic acid group were higher than the other groups（P 〈 0.05）. There were positive correlations between hepatic IGF2 expression and BW and organs index（P 〈 0.05）.Conclusion： In conclusion, our data have demonstrated that 150 μg folic acid injection on E11 could up-regulate IGF2 expression by modulating DNA hypomethylation and improving chromatin accessibility in the gene promoter region,and ulteriorly facilitate embryonic growth and organ development of broilers.展开更多
Background: Lysine is used widely in livestock production due to the shortage of feed protein resources.Llysine·H2SO4 contains L-lysine sulphate as well as fermentation co-products which contain other amino acids...Background: Lysine is used widely in livestock production due to the shortage of feed protein resources.Llysine·H2SO4 contains L-lysine sulphate as well as fermentation co-products which contain other amino acids and phosphorus.However,there are few articles about L-lysine·H2SO4 product regarding intestinal morphology and liver pathology of broiler chickens.In this article,we focus on the absorption and metabolism of L-lysine·H2SO4 revealed in the variation of intestinal morphology and liver pathology to determine the tolerance of chicks for L-lysine·H2SO4.Methods: To evaluate the tolerance of broilers for L-lysine·H2SO4,240 one day old broilers were allocated randomly to one of five dietary treatments which included corn-soybean diets containing 0,1%,4%,7% or 10% L-lysine·H2SO4(L-lysine content = 55%).Results: Supplementation of 1% L-lysine·H2SO4 in the diet had no negative effects.However,4%,7% or 10% Llysine·H2SO4 supplementation produced negative responses on broiler performance,carcass characteristics,blood biochemistry,and particularly on intestinal morphology and liver pathology compared with broilers fed the control diet.Conclusion: Our results show that supplementation with 1% L-lysine·H2SO4 had no negative effects on performance,carcass characteristics,blood biochemistry,intestinal morphology and liver pathology in broilers,but supplementation with 4%,7% or 10% L-lysine·H2SO4 produced a negative response,particularly with respect to intestinal morphology and liver pathology.展开更多
The purpose of this research was to study the effect of hypoxia on the Ca^2＋ concentration in broiler＇s cardiac muscle cells （CMCs）. The concentration of Ca^2＋ in the CMC was observed using a laser scanning confo...The purpose of this research was to study the effect of hypoxia on the Ca^2＋ concentration in broiler＇s cardiac muscle cells （CMCs）. The concentration of Ca^2＋ in the CMC was observed using a laser scanning confocal microscope （LSCM）. The results showed that hypoxia could significantly increase intracellular Ca^2＋（normal oxygen, 99.3 ＋_ 13.1; hypoxia, 129.4 ＋_ 24.3, P 〈 0.01） in CMCs. The Ca^2＋ antagonist （nifedipine, verapamil） could significantly restrain the Ca^2＋ influx across the cell membrane of CMC treated by hypoxia （CMC： hypoxia ＋ verapamil, 100.9± 28.2; hypoxia ＋ nifedipine, 107.6± 27.7; P 〈 0.01）. The results showed hypoxia could increase intracellular Ca^2＋ concentration of CMC, and the Ca^2＋ antagonist could restrain the Ca^2＋ influx across the cell membrane of CMC treated by hypoxia.展开更多
文摘Low pathogenic Avian Influenza (AI) virus has the ability to evolve to high pathogenic viruses resulting in significant economic losses in the poultry sector. This study aims at assessing the impact of H9N2 viral passaging in broilers and its relatedness to pathogenicity and amino acid (a.a) sequences of the hemagglutinin (HA) cleavage site and neuraminidase (NA) stalk. The original H9N2 AI virus (P0) was used to challenge ten-21 days old broilers. Individual recovery of H9N2 virus from homogenates of trachea, lungs and airsacs was attempted in 9 days old chicken embryos, as a conclusion of the first passage (P1). Tracheal isolates of H9N2 were passaged for a second (P2) and a third (P3) time in broilers, followed by a similar embryonic recovery procedure. The a.a. sequence of a part of HA1 cleavage site and Neuraminidase stalk were compared among the differently passaged viruses;an assessement of the relatedness of the determined a.a. sequences to the pathogenicity in broilers, based on frequency of mortality, morbidity signs, gross and microscopic lesions at 3 days post challenge with the P1, P2, and P3-H9N2, is concluded. An increase in certain morbidity signs and specific lesions was observed in P2- and P3-H9N2 challenged broilers compared to birds challenged with P1-H9N2. A conserved R-S-S-R amino acid sequence at the HA1 cleavage site was observed in the differently passaged H9N2, associated with a variability in the NA stalk-a.a sequences. The passaging of the low pathogenic H9N2 virus in broilers leads to a trend of increase in pathogenicity, manifested in higher frequency of morbidity signs, and of specific gross and microscopic lesions of the examined organs. This passaging was associated with a conserved a.a. sequence of the hemaglutinin cleavage site and a variability in the sequence of the neuraminidase stalk. A detailed study of the potential of the detected variability in the neuraminidase stalk of H9N2 in induction of a higher pathogenicity in broilers will be the subject of future investigations.
基金supported by the program for Changjiang Scholars and Innovative Research Team in University,China (IRT0848)the Education Department of Sichuan Province, China (09ZZ017)
文摘The purpose of this study was to investigate the effects of methionine deficiency on cellular immune function by determining morphological and ultrastructural changes of thymus, thymic cell cycle and apoptosis, peripheral blood T-cell subsets, T- cell proliferation function and the serum interleukin-2 （IL-2） contents. 120 1-d-old broilers were randomly divided into two groups （6 replicates in each group and l0 broilers in each replicate） and fed on a control diet or methionine deficient diet for 42 d. Lesions were observed in experiment. Histopathologically, lymphopenia and congestion were observed in the medulla of thymic lobule. Ultrastructurally, there were more apoptosis lymphocytes, and the mitochondria of lymphocytes were swelled in thymus of methionine deficiency. The G0/G~ phase of the cell cycle of the thymus was much higher （P〈0.01）, and the S, G2＋M phases and proliferating index （PI） were lower （P〈0.01） in methionine deficiency than in control group. And the percentage of apoptotic cells in the thymus was significantly increased in methionine deficiency （P〈0.01）. The percentage of CD4＋ and CD8~ T-cells was decreased in methionine deficiency compared with control group. Meanwhile, the proliferation function of peripheral blood T-cell was decreased in methionine deficiency. Also, the serum IL-2 contents were decreased in methionine deficiency. It was concluded that methionine deficiency could cause pathological and ultrastructural changes of thymus, reduce the T-cell population, serum IL-2 contents and the proliferation function of T- cells, and induce increased percentage of apoptotic cells. The cellular immune function was finally impaired in broilers.
基金financed by the National Natural Science Foundation of China(NSFC)(31601978)the China Agriculture Research System-Beijing Team for Poultry Industrythe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Background: Meat color and lipid peroxidation are important traits related to meat quality. CO_2 concentration is a critical factor that can affect meat quality in the commercial use of gas stunning(GS). However, the effect and mechanism of CO_2 stunning on meat color and lipid peroxidation during long-term storage remain poorly studied. We aimed to study the effects of GS methods, especial y CO_2 concentration, on meat color and meat lipid peroxidation in broilers during long-term storage at 4 °C and to explore the potential mechanism of meat color change via lipid peroxidation and the inner lipid peroxide scavenging system.Methods: Eighteen broilers were sacrificed after exposure to one of the following gas mixtures for 90 s: 40% CO_2+21% O_2+ 39% N2(G40%), 79% CO_2+ 21% O_2(G79%), or no stunning(0% CO_2, control). Meat color, serum variables,enzyme activities, and the gene expression of mitogen-activated protein kinase(MAPK), nuclear factor-erythroid2-related factor 2(Nrf2), glutathione S-transferase(GST) and superoxide dismutase(SOD) were determined.(Continued on next page)Results: The concentrations of serum triiodothyronine(T3, P = 0.03) and the ratio of serum free triiodothyronine/free thyroxine(FT3/FT4, P < 0.01) were decreased, whereas levels of serum cortisol(P < 0.01) were increased in the 40%CO_2 group compared with the control group. Additionally, the thiobarbituric acid-reactive substances(TBARS)3 d(P < 0.01) and TBARS6 d(P = 0.01) in breast meat and the TBARS3 din thigh meat(P < 0.01) were increased in the40% CO_2 group compared with the control group. Serum T3 was negatively correlated with TBARS6 dboth in the breast and thigh meat(r =-0.63, P < 0.01 and r =-0.47, P = 0.05 respectively). T3/T4 was negatively correlated with TBARS6 din the breast meat and in the thigh meat(r =-0.57, P = 0.01; and r =-0.53, P = 0.03 respectively). Compared with the control group, Lightness(L*)1 d(P = 0.03) and L*9 d(P < 0.01) were increased, whereas total chromatic aberration(E*)1 d(P = 0.05) and E*3 d(P < 0.01) were decreased in the breast meat of both the G40% and G79% groups. The values of yel owness(b*)3 d(P = 0.01), b*6 d(P < 0.01) and E*6 d(P < 0.01) in the thigh meat were lower in both the G40% and G79% groups than in the control group. In the breast muscle, the m RNA levels of c-Jun N-terminal kinase 2(JNK2, P = 0.03),GSTT1(P = 0.04), and SOD1(P = 0.05) were decreased, and the m RNA levels of JNK1(P = 0.07), Nrf2(P = 0.09), and GSTA3(P = 0.06) were slightly lower in both the G40% and G79% groups compared with the control group. However, among these genes, only the m RNA level of JNK1 was decreased in the G40% group compared with the control group and the G79% group(P = 0.03) in the thigh muscle.Conclusions: Compared with the control group, meat color quality in the breast meat was decreased, and the expression of genes in the MAPK/Nrf2/ARE(antioxidant responsive element) antioxidant pathway in breast muscle was partly suppressed by GS of both 40% and 79% CO_2. However, oxidative stress and meat lipid peroxidation during storage were aggravated by GS with 40% CO_2 compared to GS with 79% CO_2 and no GS.
基金supported by the Natural Science Foundation of China (No. 31272464)the Program for New Century Excellent Talents (NCET-12-0476)the Program for Shaanxi Science & Technology (2014 K01-18-02, 2015NY149, 2015KTCQ02-19)
文摘Background： Insulin-like factor 2（IGF2） plays an important role in embryonic growth process by modulating intermediary metabolism and cell proliferation. Folic acid is involved in one carbon metabolism and contributes to DNA methylation which is related to gene expression. The purpose of this study was to explore whether folic acid could regulate IGF2 expression via epigenetic mechanism and further promote embryonic growth of new-hatched broilers.Methods： In the present study, 360 fertile eggs were selected and randomly assigned to four treatments. On11 embryonic day of incubation（E11）, 0, 50, 100 and 150 μg folic acid were injected into eggs respectively.After hatched, growth performance of broilers were calculated. Hepatic IGF2 expression, methylation level and chromatin structure of promoter region were analyzed.Results： Results have showed that IGF2 expression was up-regulated in 150 μg folic acid group（P 〈 0.05） and other two dose of folic acid did not affect gene expression（P 〉 0.05）. Meanwhile, methylation level of IGF2 promoter were lower in 100 and 150 μg groups, which was consistent with lower expression of DNA methyltransferase1（DNMT1）（P 〈 0.05）. What＇s more, chromatin looseness of IGF2 promoter was higher in 150 μg group than control group（P 〈 0.05）. Further, birth weight（BW）, liver and bursa index of new-hatched chickens in 150 μg folic acid group were higher than the other groups（P 〈 0.05）. There were positive correlations between hepatic IGF2 expression and BW and organs index（P 〈 0.05）.Conclusion： In conclusion, our data have demonstrated that 150 μg folic acid injection on E11 could up-regulate IGF2 expression by modulating DNA hypomethylation and improving chromatin accessibility in the gene promoter region,and ulteriorly facilitate embryonic growth and organ development of broilers.
基金The present study was supported by the 111 Project(B16044)of China
文摘Background: Lysine is used widely in livestock production due to the shortage of feed protein resources.Llysine·H2SO4 contains L-lysine sulphate as well as fermentation co-products which contain other amino acids and phosphorus.However,there are few articles about L-lysine·H2SO4 product regarding intestinal morphology and liver pathology of broiler chickens.In this article,we focus on the absorption and metabolism of L-lysine·H2SO4 revealed in the variation of intestinal morphology and liver pathology to determine the tolerance of chicks for L-lysine·H2SO4.Methods: To evaluate the tolerance of broilers for L-lysine·H2SO4,240 one day old broilers were allocated randomly to one of five dietary treatments which included corn-soybean diets containing 0,1%,4%,7% or 10% L-lysine·H2SO4(L-lysine content = 55%).Results: Supplementation of 1% L-lysine·H2SO4 in the diet had no negative effects.However,4%,7% or 10% Llysine·H2SO4 supplementation produced negative responses on broiler performance,carcass characteristics,blood biochemistry,and particularly on intestinal morphology and liver pathology compared with broilers fed the control diet.Conclusion: Our results show that supplementation with 1% L-lysine·H2SO4 had no negative effects on performance,carcass characteristics,blood biochemistry,intestinal morphology and liver pathology in broilers,but supplementation with 4%,7% or 10% L-lysine·H2SO4 produced a negative response,particularly with respect to intestinal morphology and liver pathology.
基金This work was supported by National Natural Science Foundation of China （30371063） Natural Science Foundation of Hebei Province, China （302432）.
文摘The purpose of this research was to study the effect of hypoxia on the Ca^2＋ concentration in broiler＇s cardiac muscle cells （CMCs）. The concentration of Ca^2＋ in the CMC was observed using a laser scanning confocal microscope （LSCM）. The results showed that hypoxia could significantly increase intracellular Ca^2＋（normal oxygen, 99.3 ＋_ 13.1; hypoxia, 129.4 ＋_ 24.3, P 〈 0.01） in CMCs. The Ca^2＋ antagonist （nifedipine, verapamil） could significantly restrain the Ca^2＋ influx across the cell membrane of CMC treated by hypoxia （CMC： hypoxia ＋ verapamil, 100.9± 28.2; hypoxia ＋ nifedipine, 107.6± 27.7; P 〈 0.01）. The results showed hypoxia could increase intracellular Ca^2＋ concentration of CMC, and the Ca^2＋ antagonist could restrain the Ca^2＋ influx across the cell membrane of CMC treated by hypoxia.
