ABSTRACT In order to explore the effect of estrogen receptor (ESR) gene polymorphism on the egg production performance of quails, the polymorphisms of exon 1, exon 4 and exon 8 of the ESR gene in three Laying Quail Populations of Chinese Yellow quail, Korean quail and Beijing white quail were detected by PCR-RFLP, and their association with the egg production performance of quails was analyzed. The results showed that three genotypes were detected in exon 1, exon 4 and exon 8 of the ESR gene in three quail populations, namely TT, CC and CT genotypes. Among them, the frequency of CC genotype in exon 1 of the ESR gene was the highest in Chinese Yellow quail, Beijing white quail and Korean quail (0.515, 0.600 and 0.723); Exon 4 of the ESR gene had the highest frequency of TT genotype (0.409, 0.617) in Chinese yellow and Korean quails, while CC genotype was the highest in Beijing white quails (0.667).The frequency of TT genotype in exon 8 of the ESR gene was the highest in Beijing white quail and Korean quail (0.708, 0.500), while the frequency of CT gene was the highest in Chinese yellow quail (0.521). The results of association analysis showed that there was no correlation between exon 1 of the ESR gene and quail egg production performance (p>0.05). Exon 4 of the ESR gene was significantly correlated with laying traits such as feed-egg ratio, egg laying number, laying rate and starting weight of quails (p<0.05). Exon 8 of the ESR gene was significantly correlated with feed-egg ratio, egg laying number and egg laying rate of quails (p<0.05).In conclusion, the research shows that the ESR gene can be used as a candidate gene for marker assisted selection of egg production performance of Laying Quails, which provides a theoretical basis for cultivating new egg laying quail lines with better egg production performance.

ABSTRACT This study investigated SNP mutation sites of Gonadotrophin releasing hormone (GnRH) gene in China yellow quail, Beijing white quail and Korean quail through PCR amplification and DNA sequencing technologies. Moreover, polymorphism of GnRH gene and its association with growth traits of quail were analyzed, aiming to get molecular markers associated to growth traits of quail, which could provide references for breeding of new quail species. According to research results, a total of 14 SNP mutation sites of GnRH were detected in China yellow quail, Beijing white quail and Korean quail, which were C71T, C108T, C168T, C178T, A184G, C206T, A209C, C215T, A252G, A279T, C281T, C293G, C339T and C458T. Except that only 2 genotypes were detected for A209C and C281T in China yellow quail and Beijing white quail, 3 genotypes were detected for all of the remaining 12 SNP mutation sites in three quail species. Of the 14 SNP sites, C71T, A209C, C215T, C281T, C293G, C339T and C458T were significantly associated with body weight (p<0.05), C71T, C108T, C168T, C178T, A184G, C206T, C215T, A252G, C293G, C339T and C458T were significantly associated with shank length (p<0.05), C71T, C215T, C293G and C458T were significantly associated with breastbone length (p<0.05), A209C and C281T were significantly associated with shank circumference (p<0.05).

ABSTRACT The feasibility of Laminaria japonica powder (LJP) combined with cecropin as a dietary supplement to enhance broiler growth performance and immune function was evaluated in this study. In total, 648 one-day-old Arbor Acres broiler chicks were randomly distributed into nine numerically-equal treatment groups: T1 (control group; fed a basal diet); T2 (fed the basal diet supplemented with 1% LJP);T3 (fed the basal diet supplemented with 300mg cecropin/kg); and T4,T5,T6,T7,T8 and T9, individually fed with the dietary supplemented with varying levels of LJP and cecropin). Compared with the control, dietary of LJP or cecropin supplementation slightly improved feed conversion ratio (FCR). However, the dietary supplementation of LJP combined with cecropin significantly improved broiler growth performance during the periods of 1-21,21-42, and 1-42 days (p<0.05).The dietary supplementation of 3% LJP combined with 300 mg/kg cecropin significantly increased FCR, and serum Newcastle disease antibody titers and lymphocyte numbers during the periods of 1-21, 21-42, and 1-42 days (p<0.05). Cecal microorganisms were cultivated and the number of Escherichia coli and Lactobacillus colonies were counted. The dietary supplementation of LJP combined with cecropin remarkably inhibited E. coli growth and increased Lactobacillus growth. The results of this study demonstrate the feasibility of using LJP and cecropin as feed supplement for improving the growth performance and enhancing the immune function of broilers.

This study evaluates the efficiency of using mechanochemical reduction to assist the extraction of zinc from zinc ferrites by alkaline leaching. The transition of zinc ferrite into a metastable state after mechanochemical reduction with metallic iron contributes to the ready dissolution of zinc from the activated zinc ferrites in alkaline solution. Zinc ferrites were mechanochemically reduced under conditions of Fe:ZnFe2O4 mole ratio of 2:1, using 5 mm diameter stainless steel balls as the activation medium at a mass ratio of balls to raw materials of 25:1. Subsequent leaching in 6 mol/L NaOH solution at 90°C resulted in more than 70% Zn extraction. These results may be used to further develop a hydrometallurgical process for recovering zinc from zinc ferrites in alkaline solution.

This study proposes a methodology for evaluating the risk of coal bumps in multiple-seam longwall mining. Both the stress field and the total energy release (TER) during retreat were evaluated in the specified case involving multiple-seam mining using the LaModel program. The results of numerical simulations indicated that both the peak vertical stresses on the panel edges and the peak TERs in the outby longwalls increased significantly as the horizontal offsets were reduced from 60 m to zero. With the comprehensive consideration of the stress field and TERs, a conservative offset of 60 m was ultimately adopted when developing the gateroads of the lower panel in the field. The field measurements indicated that coal bumps were avoided completely by employing the proposed design, and the maximum roof-to-floor and rib-to-rib convergences of the tailgate during retreat were only 360 mm and 576 mm, respectively.