Effects of rapeseed meal on laying performance and egg quality in laying ducks

A genome-wide association study identified candidate genes associated with egg quality traits in Muscovy duck

BACKGROUND

Egg quality directly determines embryo development in meat-type poultry. However, it is difficult to directly select the egg quality of Muscovy duck. The genes and SNPs associated with egg quality screened by GWAS can be used for molecular breeding and accelerate the progress of selection in Muscovy duck.

RESULT

295 Muscovy ducks were used for whole genome sequencing, and a total of 6,131,623 SNPs were obtained for further analysis. The heritability of egg quality ranged from 0.01 to 0.41, in which egg weight (EW) was 0.19, albumen weight (AW) was 0.16 and the yolk weight (YW) was 0.27. The genetic correlation of EW and AW, EW and YW, and eggshell thickness (EST) and eggshell strength (ESS) were 0.65, 0.51, and 0.74, respectively. Phenotypic correlations between egg quality ranged from - 0.13 to 0.17. A total of 68 SNPs significantly associated with EW were located within the genes PSMG4, SLC22A23, DNAH5, FABP6, ADAMST17, IGF1R, NTRK3, and SCAI. The linkage disequilibrium (LD) analysis identified 2_75684453_C > G, 2_76305509_A > G, 2_76350118_T > A, 11_3834664_C > T, 11_4339778_C > T, and 11_8079686_C > T as tagSNPs to represent the significant SNPs. Fifty SNPs significantly associated with YW were located within the genes XKR6, DNAJC24, SNCB, UNC5A, MAD1L1, NOTCH1, and WDR7. The SNPs 14_9186714_C > T, 14_9199818_A > G, 15_5452098_C > T, and 18_9038052_C > T were selected as tagSNPs. Fifty-four SNPs significantly associated with albumen height were located within the genes LIN9 and NID1. The SNP 3_17718980_A > G was selected as the tagSNP. The significant SNPs associated with eggshell strength were located within the genes CLPX, EPHA5, ZBTB44, NOL6, and UBAP1. The SNPs 25_1996726_A > C and 25_2078328_A > G were selected as tagSNPs. Genes associated with egg quality were significantly enriched in the positive regulation of the BMP signaling pathway in the GO enrichment analysis of biological processes. The KEGG enrichment analysis suggested that the SNPs located genes were significantly enriched in Axon guidance, Endocrine resistance, and Progesterone-mediated oocyte maturation.

CONCLUSION

Some tagSNPs were identified that may be useful for molecular breeding of egg quality. RNF423, RNF220, IGF1R, SLC22A23, WDR7, and NTRK3 may be candidate genes for egg quality traits in Muscovy duck.

Lipidomics combined with random forest machine learning algorithms to reveal freshness markers for duck eggs during storage in different rearing systems

The differences in lipids in duck eggs between the 2 rearing systems during storage have not been fully studied. Herein, we propose untargeted lipidomics combined with a random forest (RF) algorithm to identify potential marker lipids based on ultra-performance liquid chromatography‒mass spectrometry (UPLPC-MS/MS). A total of 106 and 16 differential lipids (DL) were screened in egg yolk and white, respectively. In yolk, metabolic pathway analysis of DLs revealed that glycerophospholipid metabolism and sphingolipid metabolism were the key metabolic pathways in the traditional free-range system (TFS) during storage, glycosylphosphatidylinositol-anchored biosynthesis and glyceride metabolism were the key pathways in the floor-rearing system (FRS). In egg white, the key pathway in both systems is the biosynthesis of unsaturated fatty acids. Combined with RF algorithm, 12 marker lipids were screened during storage. Therefore, this study elucidates the changes in lipids in duck eggs during storage in 2 rearing systems and provides new ideas for screening marker lipids during storage. This approach is highly important for evaluating the quality of egg and egg products and provides guidance for duck egg production.

Mixed-Strain Fermentation Conditions Screening of Polypeptides from Rapeseed Meal and the Microbial Diversity Analysis by High-Throughput Sequencing

Conventional fermentation of rapeseed meal has disadvantages such as sterilization requirement, high energy consumption and low efficiency, as well as poor action of single bacteria. To overcome these drawbacks, mixed-strain fermentation of unsterilized rapeseed meal was investigated. Mixed-fermentation of unsterilized rapeseed meal (ratio of solid–liquid 1:1.2 g/mL) using Bacillus subtilis, Pediococcus acidilactici and Candida tropicalis (at 40 °C, for 3 days, with inoculation amount of 15% (w/w)) substantially increased the polypeptide content in rapeseed meal by 814.5% and decreased the glucosinolate content by 46.20%. The relationship between microbial diversity and physicochemical indicators showed that the improvement in polypeptide content was mainly caused by C. tropicalis (on the first day of fermentation) and B. subtilis (on the second day). Compared to raw rapeseed meal, the microbial diversity following the fermentation was significantly reduced, indicating that mixed-strain fermentation can inhibit the growth of miscellaneous bacteria. The study findings suggest that mixed-strain fermentation could be used to considerably increase the polypeptide content of unsterilized rapeseed meal, increasing the potential of rapeseed meal.

Biotransformation technology and high-value application of rapeseed meal: a review

Rapeseed meal (RSM) is an agro-industrial residue of increased functional biological value that contains high-quality proteins for animal feed. Due to the presence of antinutritional factors and immature development technology, RSM is currently used as a limited feed additive and in other relatively low-value applications. With increasing emphasis on green and sustainable industrial development and the added value of agro-industrial residues, considerable attention has been directed to the removal of antinutritional factors from RSM using high-efficiency, environment-friendly, and cost-effective biotechnology. Similarly, the high-value biotransformations of RSM have been the focus of research programmes to improve utilization rate. In this review, we introduce the sources, the nutrient and antinutrient content of RSM, and emphasize improvements on RSM feed quality using biological methods and its biotransformation applications.