RESUMO
A study was conducted to evaluate the production performance of Dahlem Red chicken over three consecutive generations maintained in intensive system. Dahlem Red birds were initially procured from CPDO Chandigarh and further produced through selective breeding. Performance traits evaluated were growth (day old chick weight, 4th week body weight (BW), 8th week BW, 12th week BW, 20th week BW and 40th week BW), age at sexual maturity, hen housed egg production (HHEP), hen day egg production (HDEP) and survivor egg production (SEP) at 40, 52 and 72 weeks of age and egg weight at 28, 40 and 52 weeks of age. Analysis revealed positive phenotypic trend in 4 week (17.58 g), 8 week (56.35 g), 12 week body weight (133.5 g), age at first egg (5.5 days) and age at 25% HHEP (2.0 days). The hen housed and hen day egg production at 40, 52 and 72 weeks revealed positive phenotypic trend of 4.79 and 1.93, 15.83 and 8.31, 31.6 and 13.98 eggs respectively. Further, survivor egg production also showed positive trend estimates at 40 and 52 weeks. Declining trends were observed in SEP at 72 week, day old chick weight (-0.89 g), 20 week BW (-37.99 g), 40 week BW (-141.2 g) and egg weight at 28 week (-1.7 g), 40 week (-3.3 g) and 52 week (-2.3 g). The results indicated the effectiveness of the selection along with improved management for bringing improvement in production traits in successive generations
RESUMO
Screening of trait-associated molecular markers can be used to enhance the efficiency of selective breeding. Previously, we produced the first high-density genetic linkage map for the mandarin fish (Siniperca chuatsi) and identified 11 quantitative-trait loci significantly associated with growth, of which one is located within the growth hormone (GH) gene. To investigate the GH gene polymorphisms and their correlation with growth, the complete sequence was cloned and 32 single-nucleotide polymorphisms (SNPs) and one simple-sequence repeat (SSR)were identified. Of which, eight SNPs (G1–G8) and the SSR (GH-AG)were selected for genotyping and correlation analysis with growth traits in a random population. The results showed that the four novel polymorphicloci (G1, G2, G3 and GH-AG) were significantly correlated with growth traits of mandarin fish (P < 0.05). Of these, G1, G3 and GH-AG showed highly significant correlations with multiple growth traits (P < 0.01) and the combined SNP analysis showed that G1–G3 formed four effective diplotypes (D1–D4), among which D1 was highly significantly greater than D4 (P < 0.01) for some important growth traits. In conclusion, our results show that the four polymorphic loci G1–G3 and GH-AG within the mandarin fish GH gene are significantly correlated with growth traits and could be used as candidate molecular markers for selective breedingof superior varieties of mandarin fish.
RESUMO
To explore the impact of Salmonella on Enterococcusfaecalis isolate N41 under the coexisting,the growth traits and the transcription of 26 virulence genes of N41 at various growth phases were detected.Salmonella and/or N41 were inoculated and done plate counting,then growth curves were drawn and bacterial total RNA were extracted at given time points,quantitive realtime PCR was used to analyze the RNA transcription levels of 26 virulence genes of N41.The result showed that comparison with single incubation,the bacteria concentration of N41 dropped about 3.9 times,and Salmonella dropped about 110-times.Among 26 virulence genes of N41,the RNA transcription levels of 12 virulence genes such as ebpA,ebpC,rnjB,ace,ebpR,psr and so on were promoted at the four growth phases,but the RNA transcription levels of SlyA and sprE were dropped.Except that the RNA transcription levels of CylL-S,CylL-L,efaA and AS had no significant changes at the four growth phases,the mostly rest genes increased dramatically at post-log phase.This indicated that when incubated together,N41 inhibited the growth of Salmonella significantly,and Salmonella promoted the transcription levels of virulence genes of N41 as a whole.The results lay a foundation for further research on the interaction between bacteria species and the pathogenicity mechanism of Enterococci.