Effects of different rearing systems on meat production traits and meat fiber microstructure of Beijing-you chicken.

Beijing-you is a Chinese local chicken which is raised for both meat and eggs. In the present study, we detected the effects of different rearing systems on growth, slaughtering performances and meat quality of Beijing-you chickens at 26-40 weeks of age. Six hundred Beijing-you hens were randomly allocated into two groups at 16 weeks of age and raised in free range or battery cage systems. The body weight, slaughtering performance and meat quality were measured for each group at the ages of 26, 30, 35 and 40 weeks. Some of the traits were dramatically influenced by the two systems, although most of them did not show significant changes. For the meat fiber microstructure, we found that the diameter of thigh and breast muscle fiber in the free range group were significantly increased than in the cage group (P < 0.05) at 26 weeks of age. The ratio of fast muscle fiber in thigh muscle samples of the free range group was significantly reduced compared to that of cage group at both 35 (P < 0.01) and 40 (P < 0.01) weeks of age, indicating that the free range system could promote the transforming of fast muscle fiber to slow muscle fiber.

Partial antiviral activities detection of chicken Mx jointing with neuraminidase gene (NA) against Newcastle disease virus.

As an attempt to increase the resistance to Newcastle Disease Virus (NDV) and so further reduction of its risk on the poultry industry. This work aimed to build the eukaryotic gene co-expression plasmid of neuraminidase (NA) gene and myxo-virus resistance (Mx) and detect the gene expression in transfected mouse fibroblasts (NIH-3T3) cells, it is most important to investigate the influence of the recombinant plasmid on the chicken embryonic fibroblasts (CEF) cells. cDNA fragment of NA and mutant Mx gene were derived from pcDNA3.0-NA and pcDNA3.0-Mx plasmid via PCR, respectively, then NA and Mx cDNA fragment were inserted into the multiple cloning sites of pVITRO2 to generate the eukaryotic co-expression plasmid pVITRO2-Mx-NA. The recombinant plasmid was confirmed by restriction endonuclease treatment and sequencing, and it was transfected into the mouse fibroblasts (NIH-3T3) cells. The expression of genes in pVITRO2-Mx-NA were measured by RT-PCR and indirect immunofluorescence assay (IFA). The recombinant plasmid was transfected into CEF cells then RT-PCR and the micro-cell inhibition tests were used to test the antiviral activity for NDV. Our results showed that co-expression vector pVITRO2-Mx-NA was constructed successfully; the expression of Mx and NA could be detected in both NIH-3T3 and CEF cells. The recombinant proteins of Mx and NA protect CEF cells from NDV infection until after 72 h of incubation but the individually mutagenic Mx protein or NA protein protects CEF cells from NDV infection till 48 h post-infection, and co-transfection group decreased significantly NDV infection compared with single-gene transfection group (P<0. 05), indicating that Mx-NA jointing contributed to delaying the infection of NDV in single-cell level and the co-transfection of the jointed genes was more powerful than single one due to their synergistic effects.

Ontogenic expression of the amino acid transporter b(0,+)AT in suckling Huanjiang piglets: effect of intra-uterine growth restriction.

Intestinal amino acid (AA) transport is critical for the supply of AA to other tissues. Few studies regarding AA intestinal transport systems during the period from postnatal intense development of piglets until weaning are available. In the present study, we measured the intestinal expression of b(0,+)AT according to developmental stage using the suckling Huanjiang piglet model, and documented the effect of intra-uterine growth restriction (IUGR) on such expression using real-time PCR and Western blot analysis. Suckling piglets that recovered after IUGR and those with normal body weights (NBW) were used after birth or at 7, 14 and 21 d of age. Blood samples were used for the measurement of plasma AA concentrations, and the jejunum was collected for the measurement of b(0,+)AT expression. In NBW piglets, b(0,+)AT expression was markedly decreased from days 0 to 21 (P< 0.01) and remained at a low level during all the suckling periods. In IUGR piglets, there was a marked decrease in b(0,+)AT expression at birth, which remained lower, when compared with NBW piglets, during the suckling period. These results coincided with decreased plasma arginine concentration at birth and decreased lysine concentration in 21-d-old piglets (P< 0.05). It is concluded that the high expression of b(0,+)AT at birth decreases during the suckling period, and that IUGR is associated with decreased expression of this apical AA transporter. The possible causal relationship between decreased b(0,+)AT expression and lower body weight of IUGR piglets in the suckling period is discussed.

Molecular cloning and expression profiling of excitatory amino acid carrier 1 in suckling Huanjiang mini-piglets with large or small body weight at birth.

Dietary glutamate is extensively oxidized in enterocytes during its trans-cellular journey from the intestinal lumen to the blood. This corresponds to high energy requirement for the absorptive function and renewal of the epithelium. Excitatory amino acid carrier 1 (EAAC1) is known to be the major transporter of glutamate in the intestine. The present study was conducted in Huanjiang mini-piglets which represent a valuable agronomical model for pig production and also extrapolation to human intestinal physiology in order: (i) to determine the amino acid sequence of EAAC1; (ii) to measure the ontogenic expression profiles of jejunal EAAC1 during the suckling period and (iii) to evaluate the influence of low body weight at birth on the expression of EAAC1. For such a purpose, we cloned EAAC1 from Huanjiang mini-pig and used real-time RT-PCR method and Western blotting analysis. Our results show that EAAC1 in the mini-pig encoded a predicted 524-AA protein with eight putative trans-membrane domains. The expression in mRNA and protein of EAAC1 in jejunum was increasing from birth up to 14 days of age and then decreased at 21 days. Piglets with small BW had lower jejunal EAAC1 protein content between birth and after 7 days suckling. These findings indicate that the expression of the EAAC1 in jejunum is much depending on the stage of piglet development and that low BW at birth is associated with lower expression of this carrier in the early suckling period. Then, it can be hypothesized that lower expression of the intestinal glutamate carrier may decrease the availability of glutamate to enterocytes, thus challenging the optimal absorptive function of the small intestine and normal mucosal growth.

Impacts of birth weight on plasma, liver and skeletal muscle neutral amino acid profiles and intestinal amino acid transporters in suckling Huanjiang mini-piglets.

Genetic selection strategies towards increased prolificacy have resulted in more and more increased littler size and incidences of impaired fetal development. Low birth weight (LBW) piglets, with long-term alterations in structure, physiology and metabolism, have lower survival rates and poor growth performance. The aim of the study was to compare the plasma, liver and skeletal muscle contents of neutral amino acids (NAA) and the intestinal expression of NAA transporters between LBW and high birth weight (HBW) suckling Huanjiang mini-piglets. Forty piglets with either LBW or HBW (20 piglets per group) were sampled on day 0, 7, 14 and 21 of age to give 5 observations per day per group. The contents of NAA in plasma, liver and skeletal muscle were measured, and jejunal expression of transporters for NAA, including Slc6a19 (B(0)AT1) and Slc1a5 (ASCT2), were determined by real-time RT-PCR and Western Blot, respectively. Results showed that the suckling piglets with LBW had higher contents of Thr, Ser, Gly, Ala, Val, Met, Ile, Leu, Tyr, Phe and Pro in liver, and Gly in skeletal muscle, whereas lower contents of Met, Ser and Ala in plasma when compared with the HBW littermates. Consistent with the content differences in plasma NAA, the jejunal expression profiles of both Slc6a19 (B(0)AT1) and Slc1a5 (ASCT2) in the LBW piglets were lower in compared with the HBW littermates during the early suckling period. These findings suggested that intestinal dysfunction in the LBW piglets may be one of the reasons in altered physiology and metabolism states of other organs, which result in lower survival and growth rate.

Partial antiviral activities of the Asn631 chicken Mx against newcastle disease virus and vesicular stomatitis virus.

Conflicting data existed for the antiviral potential of the chicken Mx protein and the importance of the Asn631 polymorphism in determination of the antiviral activity. In this study we modified the chicken Mx cDNA from the Ser631 to Asn631 genotype and transfected them into COS-I cells, chicken embryonic fibroblast (CEF) or NIH 3T3 cells. The Mx protein was mainly located at the cytoplasm. The transfected cell cultures were challenged with newcastle disease virus (NDV) or vesicular stomatitis virus (VSV), cytopathic affect (CPE) inhibition assay showed that the times for development of visible and full CPE were significantly postponed by the Asn631 cDNA transfection at 48 h transfection, but not by the Ser631 cDNA transfection. Viral titration assay showed that the virus titers were significantly reduced before 72 h postinfection. CEF cells was incubated by the cell lysates extracted from the COS-I cells transfected with pcDNA-Mx/Asn631, could resist and delayed NDV infection. These data suggested the importance of the Asn631 polymorphism of the chicken Mx in determination of the antiviral activities against NDV and VSV at early stage of viral infection, which were relatively weak and not sufficient to inhibit the viral replication at late stage of viral infection.

Increased seed cytokinin levels in transgenic tobacco influence embryo and seedling development.

Seed-specific expression of a heterologous vicilin-isopentenyl transferase (ipt) gene has been determined in transgenic tobacco lines 7 and 16. Genetic analysis of self-fertilized progeny showed that a single copy of the vicilin-ipt gene had been integrated, and T2 progeny had become homozygous for the transgene. Stable inheritance of the vicilin-ipt gene in T3 progeny was verified by polymerase chain reaction analysis. Seed cytokinin levels were 2-3-fold higher than control levels. Cytological analyses revealed a significant increase in the number of plerome cell layers and enlargement of diameter in transgenic embryos compared with controls. Dry weight of mature seeds and subsequent seedling growth was increased significantly. This correlated with the level of vicilin-ipt overexpression and increased cytokinin levels in transgenic tobacco seeds. The results suggest a crucial role for cytokinins in regulation of tobacco embryo development.