Comparative transcriptomic analysis of ovaries from high and low egg-laying Lingyun black-bone chickens.

Egg-laying rate is mainly determined by ovarian function and regulated by the hypothalamic-pituitary-gonadal axis; however, the mechanism by which the ovary regulates the egg-laying rate is still poorly understood. The purpose of this study was to compare the differences in the transcriptomes of the ovary of Lingyun black-bone chickens with relatively high and low egg-laying rates and screen candidate genes related to the egg-laying rate. RNA-sequencing (RNA-Seq) was conducted to explore the chicken transcriptome from the ovarian tissue of six Lingyun black-bone chickens with high (group G, n = 3) and low (group D, n = 3) egg-laying rates. The results showed that 235 differentially expressed genes (DEGs) were identified between the chickens with high and low egg-laying rates; among them, 209 DEGs were up-regulated and 26 DEGs were down-regulated. Gene Ontology analysis showed that the up-regulated 209 DEGs were enriched in 50 GO terms and the down-regulated 26 DEGs were enriched in 40 GO terms. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that up-regulated DEGs were significantly enriched in 25 pathways and down-regulated DEGs were significantly enriched in three pathways. Among the pathways, we found the longevity regulating pathway-multiple species pathway, Estrogen signalling pathway and PPAR signalling pathway may have an essential function in regulating the egg-laying rate. The results highlighted DEGs in the ovarian tissues of relatively high and low laying Lingyun black-bone chicken and identified essential candidate genes related to the egg-laying rate, thereby providing a theoretical basis for improving the egg-laying rate of Lingyun black-bone chicken.

Effects of Soy Protein Concentrate in Starter Phase Diet on Growth Performance, Blood Biochemical Indices, Carcass Traits, Immune Organ Indices and Meat Quality of Broilers.

Soybean meal (SBM) is high in antinutritional factors (ANFs), which is not conducive to the starter growth of broilers. The purpose of this study was to investigate the effects of soy protein concentrate (SPC) in starter diet on growth performance, carcass traits, meat quality, immune organ indices and blood biochemical indices of broilers. A total of 384 1-day-old Arbor Acres (AA) male broilers (46.05 ± 0.37 g) with similar body weight were randomly divided into 4 groups with 8 replicates in each group and 12 broilers in each replicate. The experiment was divided into three phases: in starter phase (1-10 d), birds were fed a corn-SBM-based basal mash diet (control) and the basal diet was supplemented with SPC at 4% (SPC4), 8% (SPC8), 12% (SPC12). In the grower phase (11-21 d) and the finisher phase (22-42 d), the birds in all four treatment groups were fed the same diets. The results showed that the body weight was significantly increased in the SPC8 and SPC12 groups of broilers at 10 d and 42 d (p < 0.05). The average daily gain was significantly increased in the SPC12 group of broilers at 1-10 d and 1-42 d (p < 0.05). The average daily feed intake was significantly increased in the SPC8 and SPC12 groups of broilers at 1-10 d (p < 0.05). The feed conversion rates at 1-42 d (p = 0.055) tended to decline in the SPC12 group. The carcass yield and the thymus indices were significantly increased in the SPC12 group of broilers at 42 d (p < 0.05). Alanine aminotransferase (ALT)/ aspartate aminotransferase (AST) tended to decline in SPC12 group at 10 d (p = 0.055) and total protein (TP) tended to increase in the SPC12 group at 42 d (p = 0.080). The contents of total cholesterol (T-CHO) and high-density lipoprotein (HDL) were significantly elevated in the SPC12 group of broilers at 42 d (p < 0.05). In conclusion, dietary inclusion of 12% SPC as a starter diet can be recommended due to the positive effects on broilers.