Differential expression of L-FABP and L-BABP between fat and lean chickens

Supplemental L-arginine promotes hepatocyte proliferation and alters liver fatty acid metabolism in the late embryonic phase: an RNA-seq analysis

The in ovo feeding (IOF) of L-arginine (L-Arg) to chick embryos is a viable method for improving early intestinal development, subsequently leading to an acceleration in growth rate during the posthatch stage. However, the liver, being the pivotal organ for energy metabolism in poultry, the precise effects and mechanisms of L-Arg on the liver development and metabolism remain unclear. To elucidate these, the present study injected 2 doses of L-Arg (10 mg/egg and 15 mg/egg) into the embryos of Hongyao chickens at 17.5 d of incubation, subsequently incubating them until d 19 for further analysis. IOF of 15 mg L-Arg/egg significantly increased the organ indices of liver and small intestine, as well as the duodenal villus height/crypt depth. RNA-Seq analysis of liver tissues showed that the metabolism of xenobiotics, amino acid metabolism, and the fatty acid metabolism were significantly enriched in L-Arg injection group. The core differentially expressed genes (DEGs) were primarily involved in cell proliferation and fatty acid metabolism. The CCK8 assays revealed that supplemental L-Arg significantly enhanced the proliferation of primary embryo hepatocytes and leghorn male hepatoma (LMH) cells. Upregulation of core DEGs, including HBEGF, HES4, NEK3, EGR1, and USP2, significantly promoted the proliferation of liver cells. Additionally, analysis of triglyceride and total cholesterol content, as well as oil red O staining, indicated that supplemental L-Arg effectively reduced lipid accumulation. Overall, L-Arg supplementation in late chick embryos may promote early liver and small intestine development by reducing liver lipid deposition and enhancing energy efficiency, necessitating further experimental validation. This study provides profound insights into the molecular regulatory network of L-Arg in promoting the development of chicken embryos. The identified DEGs that promote cell proliferation and lipid metabolism can serve as novel targets for further developing methods to enhance early development of chicken embryos.

Effects of different breeds/strains on fatty acid composition and lipid metabolism-related genes expression in breast muscle of ducks

Fatty acid composition contributes greatly to the nutritional value of meat, and breeds/strains are important factors affecting the composition of fatty acid. Recently, few studies have focused on the fatty acid composition in breast muscle of different duck breeds. Therefore, the objective of the present study was to compare the fatty acid composition and lipid metabolism-related genes expression in breast muscle of Jianchang duck (J), Cherry Verry duck (CV) and 3 crossbred strains (BH1, BH2 and MC♂ × (BGF2♂  × GF2♀)♀ (MBG)). Our results showed that the breast muscle of J had the highest contents of C22:1(n−9) but the lowest ratios of Ʃ-omega 6 (Ʃn−6)/Ʃ-omega 3 (Ʃn−3), Ʃ-mono-unsaturated fatty acid (ƩMUFA)/Ʃ-saturated fatty acid (ƩSFA) and Ʃ-polyunsaturated fatty acid (ƩPUFA)/ƩSFA. The ƩPUFA/ƩSFA ratio was higher in breast muscle of MBG than in that of BH2 and CV, and the contents of C22:1(n-9), ƩMUFA and ƩPUFA were higher in BH1 than in BH2 and CV. Furthermore, the mRNA levels of SCD1, FADS2, ELOVL2, and ELOVL5 were significantly higher in MBG (P < 0.05), while those of FASD1 and ACACA were significantly higher in BH1 than in BH2 and CV (P < 0.05). Principal component analysis showed that fatty acids variation exhibited extensive positive loading on principal components (PCs). Correlation analysis showed that PC1 and PC3 of BH1, as well as PC1 of MBG were correlated with the mRNA levels of ACACA and FABP3, respectively. Thus, it could be concluded that the breast muscles of MBG and BH1 have better fatty acid composition, which was closely related to the increased expression levels of SCD1, FADS2, ELOVL2, and ELOVL5 genes in MBG but FADS1 and ACACA in BH1. Moreover, these results also showed that crossbreeding could optimize the composition of fatty acid in breast muscle of ducks.

Comparative Effects of Flaxseed Sources on the Egg ALA Deposition and Hepatic Gene Expression in Hy-Line Brown Hens

Healthy diets are necessary for both humans and animals, including poultry. These diets contain various nutrients for maintenance and production in laying hens. Therefore, research was undertaken to explore the efficiency of various dietary flaxseed sources on the n-3 deposition in the egg yolk and gene expression in laying hens. Five dietary groups were analyzed, i.e., (i) a corn-based diet with no flaxseed (FS) as a negative control (NC), (ii) a wheat-based diet supplemented with 10% whole FS without multi-carbohydrase enzymes (MCE) as a positive control (PC), (iii) ground FS supplemented with MCE (FS), (iv) extruded flaxseed meal was supplemented with MCE (EFM), (v) flaxseed oil supplemented with MCE (FSO). Results indicated that egg weight was highest in the NC, FS, EFM, and FSO groups as compared to PC in the 12th week. Egg mass was higher in enzyme supplemented groups as compared to the PC group, but lower than NC. In the 12th week, the HDEP (hen day egg production) was highest in the FS and EFM groups as compared to FSO, PC, and NC. The FCR (feed conversion ratio) was better in enzyme supplemented groups as compared to the PC group. Enzyme addition enhanced the egg quality as compared to PC in the 12th week. The HDL-C (high-density lipoprotein cholesterol) was increased, while LDL-C (low-density lipoprotein cholesterol), VLDL-C (very-low-density lipoprotein cholesterol), TC (total cholesterol), and TG (total triglycerides) were reduced in the enzyme supplemented groups as compared to PC and NC. The FSO deposit more n-3 PUFA and docosahexaenoic acid (DHA) in the egg yolk as compared to FS and EFM groups. The expression of ACOX1, LCPT1, FADS1, FADS2, and ELOV2 genes were upregulated, while PPAR-α was downregulated in the FSO group. The LPL mRNA expression was upregulated in the FS, EFM, and FSO groups as compared to the PC and NC groups. It was inferred that FSO with enzymes at 2.5% is cost-effective, improves the hen performances, upregulated the fatty acid metabolism and β-oxidation genes expression, and efficiently deposits optimal n-3 PUFA in the egg as per consumer’s demand.

Effects of different rearing systems on intramuscular fat content, fatty acid composition, and lipid metabolism-related genes expression in breast and thigh muscles of Nonghua ducks

Rearing system is a critical nongenetic factor influencing meat quality of ducks. In this study, a total of 360 birds were randomly allocated into floor rearing system (FRS) and net rearing system (NRS) to compare their effects on intramuscular fat (IMF) deposition, fatty acid composition, and related gene expression in muscles of Nonghua ducks. Sawdust bedding and stainless mesh bed were equipped in FRS and NRS, respectively. At the eighth week (8w) and 13th week (13w), the breast and thigh muscles of ducks were collected to determine the profiles of lipids composition and the expressions of lipid metabolism-related genes. The IMF content was higher in 13w-FRS than 8w-FRS and 8w-NRS in breast muscle, whereas it was higher in 13w-NRS than other groups in thigh muscle (P < 0.05). C16:1, C20:5(n-3) of muscles were higher in 8w-NRS than 8w-FRS, whereas C18:1(n-9)c, C18:2(n-6)c, Ʃ monounsaturated fatty acid (MUFA), and ƩMUFA/Ʃsaturated fatty acid (SFA) ratio of muscles were higher in 13w-NRS than 8w-FRS and 8w-NRS (P < 0.05). C22:6(n-3), C20:4(n-6) of breast muscle and C20:3(n-6) of thigh muscle were higher in 13w-NRS than 13w-FRS (P < 0.05). Fatty acids variation was studied by principal component analysis, exhibiting extensive positive loadings on principal components. SREBP1, ACADL, and FABP3 were downregulated in breast muscle, whereas PPARα and ELOVL5 were upregulated in thigh muscle of NRS ducks at 13w. Principal components were extensively correlated with lipids composition parameters, and principal components of breast muscle 1 and principal components of thigh muscle 1 were correlated with SREBP1 and PPARα, respectively (P < 0.05). In conclusion, with increasing age, FRS enhanced IMF deposition in breast muscle, and the same promotion in thigh muscle was because of NRS. The variation of fatty acids in muscles was uniform, and the change of single fatty acid was unable to distinguish NRS and FRS. However, as NRS downregulated SREBP1, ACADL and FABP3 in breast muscle and upregulated PPARα and ELOVL5 in thigh muscle, NRS could improve nutrient value and meat quality by increasing ƩMUFA, ƩMUFA/ƩSFA ratio, and important PUFA levels. Therefore, NRS was more recommended than FRS for Nonghua ducks during week 8 to 13 posthatching.

Genomic Insights Into the Multiple Factors Controlling Abdominal Fat Deposition in a Chicken Model

Genetic selection for an increased growth rate in meat-type chickens has been accompanied by excessive fat accumulation particularly in abdominal cavity. These progressed to indirect and often unhealthy effects on meat quality properties and increased feed cost. Advances in genomics technology over recent years have led to the surprising discoveries that the genome is more complex than previously thought. Studies have identified multiple-genetic factors associated with abdominal fat deposition. Meanwhile, the obesity epidemic has focused attention on adipose tissue and the development of adipocytes. The aim of this review is to summarize the current understanding of genetic/epigenetic factors associated with abdominal fat deposition, or as it relates to the proliferation and differentiation of preadipocytes in chicken. The results discussed here have been identified by different genomic approaches, such as QTL-based studies, the candidate gene approach, epistatic interaction, copy number variation, single-nucleotide polymorphism screening, selection signature analysis, genome-wide association studies, RNA sequencing, and bisulfite sequencing. The studies mentioned in this review have described multiple-genetic factors involved in an abdominal fat deposition. Therefore, it is inevitable to further study the multiple-genetic factors in-depth to develop novel molecular markers or potential targets, which will provide promising applications for reducing abdominal fat deposition in meat-type chicken.

Immediate and long-term transcriptional response of hind muscle tissue to transient variation of incubation temperature in broilers

Background

In oviparous species accidental variation of incubation temperatures may occur under natural conditions and mechanisms may have evolved by natural selection that facilitate coping with these stressors. However, under controlled artificial incubation modification of egg incubation temperature has been shown to have a wide-ranging impact on post-hatch development in several poultry species. Because developmental changes initiated in-ovo can affect poultry production, understanding the molecular routes and epigenetic alterations induced by incubation temperature differences may allow targeted modification of phenotypes.

Results

In order to identify molecular pathways responsive to variable incubation temperature, broiler eggs were incubated at a lower or higher temperature (36.8 °C, 38.8 °C) relative to control (37.8 °C) over two developmental intervals, embryonic days (E) 7–10 and 10–13. Global gene expression of M. gastrocnemius was assayed at E10, E13, and slaughter age [post-hatch day (D) 35] (6 groups; 3 time points; 8 animals each) by microarray analysis and treated samples were compared to controls within each time point. Transcript abundance differed for between 113 and 738 genes, depending on treatment group, compared to the respective control. In particular, higher incubation temperature during E7-10 immediately affected pathways involved in energy and lipid metabolism, cell signaling, and muscle development more so than did other conditions. But lower incubation temperature during E10-13 affected pathways related to cellular function and growth, and development of organ, tissue, and muscle as well as nutrient metabolism pathways at D35.

Conclusion

Shifts in incubation temperature provoke specific immediate and long-term transcriptional responses. Further, the transcriptional response to lower incubation temperature, which did not affect the phenotypes, mediates compensatory effects reflecting adaptability. In contrast, higher incubation temperature triggers gene expression and has long-term effects on the phenotype, reflecting considerable phenotypic plasticity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2671-9) contains supplementary material, which is available to authorized users.

Structural and biochemical characterization and evolutionary relationships of the fatty acid-binding protein 10 (Fabp10) of hake (Merluccius hubbsi)

A fatty acid-binding protein (FABP) from the liver of Argentine hake (Merluccius hubbsi) was isolated and characterized and its expression analyzed. The determination of its partial primary structures (72%) showed that it presents highest identity with Fabp10, commonly termed liver basic-type FABP. The evolutionary tree showed greater relationship between the Fabp10 of hake (Me Fabp10) and the Fabp10 and the Fabp10a of teleost fish. Me Fabp10 had low affinity for palmitic, oleic and palmitoleic acid and high affinity for bilirubin, lysophosphatidylcholine and lysophosphatidylethanolamine, all of them important in the metabolic functions of the liver. Me Fabp10 was able to bind only one cis-parinaric acid molecule and was found to be expressed only in the liver.

Identification of Potential Biomarkers for Gut Barrier Failure in Broiler Chickens

The objective of the present study was to identify potential biomarkers for gut barrier failure in chickens. A total of 144 day-of-hatch Ross 308 male broiler chickens were housed in 24 battery cages with six chicks per cage. Cages were randomly assigned to either a control group (CON) or gut barrier failure (GBF) group. During the first 13 days, birds in CON or GBF groups were fed a common corn–soy starter diet. On day 14, CON chickens were switched to a corn grower diet, and GBF chickens were switched to rye–wheat–barley grower diet. In addition, on day 21, GBF chickens were orally challenged with a coccidiosis vaccine. At days 21 and 28, birds were weighed by cage and feed intake was recorded to calculate feed conversion ratio. At day 28, one chicken from each cage was euthanized to collect intestinal samples for morphometric analysis, blood for serum, and intestinal mucosa scrapings for gene expression. Overall performance and feed efficiency was severely affected (P < 0.05) by a GBF model when compared with CON group at days 21 and 28. Duodenum of GBF birds had wider villi, longer crypt depth, and higher crypt depth/villi height ratio than CON birds. Similarly, GBF birds had longer crypt depth in jejunum and ileum when compared with CON birds. Protein levels of endotoxin and α1-acid glycoprotein (AGP) in serum, as well as mRNA levels of interleukin (IL)-8, IL-1β, transforming growth factor (TGF)-β4, and fatty acid-binding protein (FABP) 6 were increased (P < 0.05) in GBF birds compared to CON birds; however, mRNA levels of FABP2, occludin, and mucin 2 (MUC2) were reduced by 34% (P < 0.05), 24% (P = 0.107), and 29% (P = 0.088), respectively, in GBF birds compared to CON birds. The results from the present study suggest that serum endotoxin and AGP, as well as, gene expression of FABP2, FABP6, IL-8, IL-1β, TGF-β4, occludin, and MUC2 in mucosa may work as potential biomarkers for gut barrier health in chickens.