Transcriptomic analysis of the liver in aged laying hens with different eggshell strength

High albumen height by expression of GALNT9 and thin eggshell by decreased Ca2+ transportation caused high hatchability in Huainan partridge chicken

Hatchability could be quite different among individuals of indigenous chicken breed which might be affected by the egg quality. In this study, hatchability was individually recorded among 800 forty-wk-old Huainan partridge chickens. The chickens were then divided into high and low hatchability groups (HH and LH group) with 50 birds in each group. Egg quality was further determined in the 2 groups. Eight birds from each group were selected for slaughtering and tissue, responsible for egg formation, collection for structure observation by staining and candidate gene expression by transcriptome analysis. The hatchability in HH was 100% and 61.18% in LH. The eggshell thickness and shell strength were significantly lower, while the albumen height and Haugh unit were significantly higher in HH group than those in LH group (P < 0.05). The magnum weight and index, and the expression of polypeptide N-acetylgalactosaminyltransferase 9 (GALNT9), which responsible for thick albumen synthesis, in HH group were also significantly higher than that of LH group (P < 0.05). Compared with the LH group, there were 702 differentially expressed genes (DEGs) in HH group, of which 402 were up-regulated and 300 were down-regulated. Candidate genes of calbindin 1 (CALB1) and solute carrier family 26 member 9 (SLC26A9), which regulate calcium signaling pathway so as to affect Ca2+ transportation, exhibited significant high and low expression, respectively, in HH group compared to those in LH group (P < 0.05). Therefore, indigenous chicken with high expression of GALNT9 in magnum to form thick albumen to provide more protein for embryo, while high CALB1 and low expression of SLC26A9 to decrease Ca2+ transportation so as to form a thinner eggshell and provide better gas exchange during embryo development.

Quantitative lipidomics reveals the changes of lipids and antioxidant capacity in egg yolk from laying hens with fatty liver hemorrhagic syndrome

In laying hens, fatty liver hemorrhagic syndrome (FLHS) is a common metabolic disorder, which can affect egg production and nutritional value. However, the impact of FLHS on the lipid content in egg yolks was not clear. In this study, FLHS model was induced by using high-energy low-protein diet, and the egg quality was evaluated. Egg yolk lipids were quantitatively analyzed by using ultra-performance liquid chromatography-mass spectrometry combined with multivariate statistical analysis. Gene expressions of the lipoprotein were determined by qRT-PCR and antioxidant capacity of the egg yolk were determined by kits. The elevated blood lipids and extensive lipid droplets observed indicated successful establishment of the FLHS model in laying hens. Measurements of egg quality showed that egg yolk weight was increased in the FLHS group. Lipidomics revealed that 1,401 lipids, comprising 27 lipid subclasses in the egg yolk. According to score plots of principal component analysis and orthogonal partial least squares discriminant analysis, different lipid profile was observed between the control and FLHS groups. A total of 97 different lipid species were screen out. Sphingolipid and glycerophospholipid metabolism were identified as key pathways. Free polyunsaturated fatty acids (PUFA) exhibited an increase in the FLHS group (P < 0.05). Notably, the form of PUFAs was changed that the FLHS group showed an increase in triacylglycerol-docosahexenoic acid and triacylglycerol-arachidonic acid in the egg yolk, while triacylglycerol-α-linolenic acid was decreased (P < 0.05). Total superoxide dismutase was decreased in the egg yolks affected by FLHS. Gene expressions of vitellogenin 2 (VTG2), VTG3, very low-density apolipoprotein II and apolipoprotein B were increased in the liver of laying hens with FLHS (P < 0.05). In conclusion, FLHS promoted the lipid transport from the liver to the yolk by upregulating lipoprotein expression, which altered lipid profile, and reduced antioxidant capacity in the yolk. This study provided a foundation for understanding the changes in lipids, lipid transport and lipid antioxidation capacity in egg yolk from laying hens with FLHS.

A Comprehensive Exploration of the Fatty Acids Profile, Cholesterol, and Tocopherols Levels in Liver from Laying Hens Fed Diets Containing Nonindustrial Hemp Seed

This study investigates the impact of dietary nonindustrial Moroccan hemp seed (HS) on the fatty acid profile, cholesterol, and tocopherol levels, in the liver of 120 Lohmann brown laying hens aged 22 weeks during 12 weeks of treatment. The hens are randomly allocated into four treatment groups, each subdivided into six replicates with five birds in each replicate. The dietary treatments consist of 0% HS (control), 10% HS, 20% HS, and 30% HS. Results indicate a substantial increase (p < 0.01) in polyunsaturated fatty acids, including omega 3 (n-3) and omega 6 (n-6) types, with the inclusion of HS in the diet. The n-6/n-3 ratio is significantly reduced (p < 0.01), and there is a significant reduction (p < 0.01) in saturated fatty acids only for the 30% HS treatment, indicating a more favorable fatty acid composition. Cholesterol levels remain largely unaffected by HS inclusion, except for the 10% HS group, which shows a significant decrease (p < 0.05). Moreover, hepatic tocopherol levels are significantly elevated (p < 0.01) in subjects receiving the HS diet, with the 30% HS group exhibiting the highest tocopherol content. In summary, incorporating HS into the diet up to 30% appears to offer promising benefits for hepatic lipid composition, particularly in terms of n-3 polyunsaturated fatty acids, the n-6/n-3 ratio, and tocopherol levels, while having minimal impact on cholesterol levels.