Dietary silymarin improves performance by altering hepatic lipid metabolism and cecal microbiota function and its metabolites in late laying hens.

BACKGROUND: Liver lipid dysregulation is one of the major factors in the decline of production performance in late-stage laying hens. Silymarin (SIL), a natural flavonolignan extracted from milk thistle, is known for its hepatoprotective and lipid-lowering properties in humans. This study evaluates whether SIL can provide similar benefits to late-stage laying hens. A total of 480 68-week-old Lohmann Pink laying hens were randomly assigned into 5 groups, each group consisting of 6 replicates with 16 hens each. The birds received a basal diet either without silymarin (control) or supplemented with silymarin at concentrations of 250, 500, 750, or 1,000 mg/kg (SIL250, SIL500, SIL750, SIL1000) over a 12-week period. RESULTS: The CON group exhibited a significant decline in laying rates from weeks 9 to 12 compared to the initial 4 weeks (P = 0.042), while SIL supplementation maintained consistent laying rates throughout the study (P > 0.05). Notably, the SIL500 and SIL750 groups showed higher average egg weight than the CON group during weeks 5 to 8 (P = 0.049). The SIL750 group had a significantly higher average daily feed intake across the study period (P < 0.05), and the SIL500 group saw a marked decrease in the feed-to-egg ratio from weeks 5 to 8 (P = 0.003). Furthermore, the SIL500 group demonstrated significant reductions in serum ALT and AST levels (P < 0.05) and a significant decrease in serum triglycerides and total cholesterol at week 12 with increasing doses of SIL (P < 0.05). SIL also positively influenced liver enzyme expression (FASN, ACC, Apo-VLDL II, FXR, and CYP7A1; P < 0.05) and altered the cecal microbiota composition, enhancing species linked to secondary bile acid synthesis. Targeted metabolomics identified 9 metabolites predominantly involved in thiamin metabolism that were significantly different in the SIL groups (P < 0.05). CONCLUSIONS: Our study demonstrated that dietary SIL supplementation could ameliorate egg production rate in late stage laying hens, mechanistically, this effect was via improving hepatic lipid metabolism and cecal microbiota function to achieve. Revealed the potentially of SIL as a feed supplementation to regulate hepatic lipid metabolism dysregulation. Overall, dietary 500 mg/kg SIL had the best effects.

Transfer of Caffeine and Its Major Metabolites to Chicken Eggs.

This study aimed to determine whether the eggs of laying hens fed caffeine contain this compound and its primary metabolites (theophylline, theobromine, and paraxanthine). Laying hens were distributed into four experimental groups fed rations containing 0 (control), 150, 300, or 450 µg/g of caffeine. For residual analysis, six eggs per group were collected after 4, 8, and 12 weeks. The concentrations of caffeine, theophylline, theobromine, and paraxanthine were determined in the white and yolk of each egg by a high-performance liquid chromatography with photodiode array detector (HPLC-PDA) method. All four compounds were detected in the white and yolk of eggs produced by hens fed caffeine, but their levels in the egg white were approximately twice those in the yolk. The major metabolite found in eggs was theophylline (57.5% of caffeine metabolites in the egg white and 58.5% in the yolk), followed by theobromine (39.9% in the egg white and 41.5% in the yolk), and paraxanthine (2.64% in the egg white and non-detected in the yolk). In summary, caffeine and its metabolites, theophylline, theobromine, and paraxanthine, are transferred to the chicken eggs.

Effect of Bile Acids Supplementation in Fatty Liver Hemorrhagic Syndrome, Production Performance, Physiological and Quality Characteristics of Laying Hen Eggs.

This study aimed to investigate the effects of bile acids (BAs) supplementation on fatty liver hemorrhagic syndrome (FLHS), production performance, and physiological and quality characteristics of laying hen eggs. Sixty Sanhuang laying hens, aged 28 weeks, were randomly allocated to six dietary treatments over a 4-week period, including the control (CON) group (feeding basal diet), the high-fat diet (HFD)-treated group (basal diet containing 10% soybean oil), and HFD supplemented with 0.01% and 0.02% of chenodeoxycholic acid (CDCA) or hyodeoxycholic acid (HDCA) groups. Production performance, egg quality, liver morphology, serum biochemical indexes, antioxidant capacity, proinflammatory cytokines, and intestinal microbiota were evaluated. The average body weight in 0.01% CDCA was larger than in the HFD group (p < 0.05). Eggshell Thickness in the CON group was greater than in the HFD, 0.01% CDCA, and HDCA groups (p < 0.05). Albumen height in the 0.02% HDCA group was higher than the HFD group (p < 0.05). Eggshell weight in the HFD group was less than the CON group (p < 0.05). Haugh unit (HU) in the HDCA group was larger than the HFD group (p < 0.05). Albumen weight in the 0.02% HDCA group was greater than the CON and HFD groups (p < 0.05). In the HFD group, the levels of triglyceride (TG), total cholesterol (TC), and low-density lipo-protein cholesterol (LDL-C) were surpassing the other groups (p < 0.05). The levels of catalase (CAT) and total superoxide dismutase (T-SOD) in the HFD group was smaller than the other groups (p < 0.05). The level of malondialdehyde (MDA) in the HFD group was higher than in the other groups (p < 0.05). Tumor necrosis factor-α (TNF-α) levels were larger in the HFD group than in the other groups (p < 0.05). The 16S rRNA sequencing analysis indicated significant variations in the relative abundance of specific bacterial populations among the different treatment groups. The treatment and CON groups exhibited a higher presence of bacteria that inhibit host energy absorption or promote intestinal health such as Firmicutes, Bacteroidetes, and Ruminococcus, whereas the HFD group showed an increased prevalence of potentially pathogenic or deleterious bacteria, such as Desulfovibrio spp. In conclusion, the supplementation of BAs in poultry feed has been demonstrated to effectively mitigate the detrimental effects of FLHS in laying hens. This intervention regulates lipid metabolism, bolsters antioxidant defenses, reduces inflammation, and modulates the gut microbiota, offering a novel perspective on the application of BAs in the poultry industry.

The Influence of Male Biostimulation on Cloacal Anatomy and Egg-Laying Behavior in Young Female Muscovy Ducks (Cairina moschata forma domestica).

The importance of Muscovy ducks in industrial poultry production is growing; however, little is known about the physiology of their reproductive cycles. This study investigated the influence of male biostimulation on female ducks before the commencement of the laying phase. A total of 30 muscovy ducks, hatched in the same year at 289-341 days of age, were divided into two groups of 15 birds each and kept with and without contact with a male duck until the day of first egg-laying-319 ± 14 and 335 ± 13, respectively. Before reaching egg-laying maturity, the cloacae of 29 adult ducks were subjected to daily clinical assessments. The evaluations yielded four unique categories of outcomes, determined by assessing factors such as the degree of redness and protrusion of the mucous membrane, the moisture level, and swelling of the cloacal sphincter muscle. The results of this study on biostimulation revealed that, on average, female ducks that had contact with males laid their first egg 16 days earlier, weighing 78.7 ± 3.0 g, compared to the isolated female ducks, weighing 79.1 ± 7.0 g. Furthermore, there was no significant difference observed in the mean initial egg weight between the groups (p = 0.841). The cloacal morphology indicated significant morphological changes 25-26 days before laying. Efforts to improve Muscovy production and develop biotechnological techniques to modify these ducks' reproductive cycle will benefit from these advancements.

Sequence variations and accessory proteins adapt TMC functions to distinct sensory modalities.

Transmembrane channel-like (TMC) proteins are expressed throughout the animal kingdom and are thought to encode components of ion channels. Mammals express eight TMCs (mTMC1-8), two of which (mTMC1 and mTMC2) are subunits of mechanotransduction channels. C. elegans expresses two TMCs (TMC-1 and TMC-2), which mediate mechanosensation, egg laying, and alkaline sensing. The mechanisms by which nematode TMCs contribute to such diverse physiological processes and their functional relationship to mammalian mTMCs is unclear. Here, we show that association with accessory proteins tunes nematode TMC-1 to divergent sensory functions. In addition, distinct TMC-1 domains enable touch and alkaline sensing. Strikingly, these domains are segregated in mammals between mTMC1 and mTMC3. Consistent with these findings, mammalian mTMC1 can mediate mechanosensation in nematodes, while mTMC3 can mediate alkaline sensation. We conclude that sequence diversification and association with accessory proteins has led to the emergence of TMC protein complexes with diverse properties and physiological functions.

Effects of graded levels of dietary microbial 6-phytase on performance, intestinal histomorphology, caecal microbial population and short-chain fatty acid composition of Lohmann white-classics.

1. This study was conducted to determine the effects of graded levels of phytase on the performance, egg quality and gut health of white laying hens.2. Treatments consisted of a negative control (NC) diet containing 0.14% available phosphorus (avP), positive control (PC) diet containing 0.35% avP provided via dicalcium phosphate (DCP) and DCP replaced in the PC by with three graded levels of phytase derived from Komagataella phaffii at 500 (PC-500), 750 (PC-750) and 1000 (PC-1000) FTU/kg which provided 0.176%, 0.188% and 0.200% of avP, respectively.3. Egg production, feed intake, feed conversion ratio and jejunal morphometry were negatively affected in NC-fed birds (p < 0.05). Considering the whole period, birds fed a diet supplemented with graded levels of phytase shared the same egg production and feed intake levels with PC birds (p < 0.05). Feed conversion ratio was significantly lowered by 4.9%, 1.6% and 7.6% in hens fed on diets PC-500, PC-750 and PC-1000, respectively compared to those fed the PC (p < 0.05).4. Neither of the dietary treatments affected cracked eggs, dirty eggs, eggshell breaking strength and eggshell thickness. Dietary supplementation of phytase significantly increased villus surface area by 15%, 36% and 40% in PC-500, PC-750 and PC-1000 birds, respectively compared to PC (p < 0.05).5. A significant increase in lactobacillus count was observed in line with increasing the level of phytase (p < 0.05). Dietary treatments had no effect on the caecal coliform or aerobic populations. Furthermore, phytase supplementation significantly increased the concentrations of total caecal short-chain fatty acid (SCFA; p < 0.01).6. In conclusion, along with improving performance parameters, the inclusion of phytase in laying hen diets can ameliorate intestinal morphology and stimulate caecal microflora and increase SCFA concentrations.

Fermented Aronia melanocarpa pomace improves the nutritive value of eggs, enhances ovarian function, and reshapes microbiota abundance in aged laying hens.

Introduction: There is a decline in the quality and nutritive value of eggs in aged laying hens. Fruit pomaces with high nutritional and functional values have gained interest in poultry production to improve the performance. Methods: The performance, egg nutritive value, lipid metabolism, ovarian health, and cecal microbiota abundance were evaluated in aged laying hens (320 laying hens, 345-day-old) fed on a basal diet (control), and a basal diet inclusion of 0.25%, 0.5%, or 1.0% fermented Aronia melanocarpa pomace (FAMP) for eight weeks. Results: The results show that 0.5% FAMP reduced the saturated fatty acids (such as C16:0) and improved the healthy lipid indices in egg yolks by decreasing the atherogenicity index, thrombogenic index, and hypocholesterolemia/hypercholesterolemia ratio and increasing health promotion index and desirable fatty acids (P < 0.05). Additionally, FAMP supplementation (0.25%-1.0%) increased (P < 0.05) the ovarian follicle-stimulating hormone, luteinizing hormone, and estrogen 2 levels, while 1.0% FAMP upregulated the HSD3B1 expression. The expression of VTG II and ApoVLDL II in the 0.25% and 0.5% FAMP groups, APOB in the 0.5% FAMP group, and ESR2 in the 1% FAMP group were upregulated (P < 0.05) in the liver. The ovarian total antioxidant capacity was increased (P < 0.05) by supplementation with 0.25%-1.0% FAMP. Dietary 0.5% and 1.0% FAMP downregulated (P < 0.05) the Keap1 expression, while 1.0% FAMP upregulated (P < 0.05) the Nrf2 expression in the ovary. Furthermore, 1.0% FAMP increased cecal acetate, butyrate, and valerate concentrations and Firmicutes while decreasing Proteobacteria (P < 0.05). Conclusion: Overall, FAMP improved the nutritive value of eggs in aged laying hens by improving the liver-blood-ovary function and cecal microbial and metabolite composition, which might help to enhance economic benefits.

Influence of rosehip (Rosa canina L.) leaves as feed additive during first stage of laying hens on performances and egg quality characteristics.

This study aimed to evaluate the effects of rosehip leaves (RL) supplementation on the production performances and egg quality of laying hens during the first stage of laying. For that, 90 Lohmann Brown Classic hens, aged 26 wk, were randomly assigned to 3 dietary treatments as follows: a control diet (RL0), an experimental diet containing 0.5% rosehip leaves (RL0.5), and an experimental diet containing 1% rosehip leaves (RL1). The laying hens were accommodated in an experimental hall with identical pens (3.96 m2), and controlled microclimate conditions. The dietary treatments were administered for a 6-wk experimental period (26-32 d of age). During this time, production performance of hens was recorded. To assess the impact of RL on egg weight and its components evolution, egg yolk and albumen color, and primary chemical composition of egg constituents were determined every 2 wk. The effect on egg yolk fatty acids profile was determined only at the end of the trial. The results showed that RL0.5 and RL1 dietary treatments significantly improved laying rate, feed conversion ratio and egg mass compared with RL0 group. A significant effect on egg weight and its components was observed only over time, showing that RL has no effect on these parameters. Significant changes in egg yolk coloration were observed over time, with significant increases in L*, a* and b* chromomeric parameters in both RL0.5 and RL1 compared to RL0. Significant alterations were obtained from the sum of egg yolk fatty acids. The RL1 egg yolk presented significantly higher n-3, and significantly lower n-6 fatty acids, compared with both RL0 and RL0.5. Further research is warranted to explore the long-term effects of rosehip leaf supplementation on laying hens performance and egg quality.

CircRNAs involved in the red light of effect on follicle selection in pigeons.

Red light (RL) can enhance egg production in poultry. CircRNAs play a crucial role by serving as transcriptional regulators. However, their role in influencing follicle development in White King pigeons remains unexplored. In this study, 54 paired White King pigeons were chosen and divided into RL and white light (WL) groups, each with 3 subgroups. The egg production of paired pigeons in each replicate was recorded for 45 d, and the characteristics of follicle development were monitored during the laying interval (LI). The granulosa cell layer from follicles of the second-largest follicle (F2) was collected, and high-throughput sequencing was performed to elucidate the molecular mechanism of follicle development in pigeons. The study confirmed that RL enhances egg production in pigeons. Additionally, under RL, the F2 follicle was selected, while under WL, small follicles were kept on the third day (LI3). A total of 5,510 circRNAs were identified across all samples, revealing differentially expressed circRNAs (DECs) in various comparisons: 627 in RF1 vs. WF1, 900 in RF2 vs. WF2, 606 in RF1 vs. RF2, and 937 in WF1 vs. WF2. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that host genes of DECs were enriched in pathways like steroid hormone biosynthesis, oocyte meiosis, GnRH signaling pathway, and apoptosis pathway. Moreover, circRNA_5497, circRNA_2016, and circRNA_3328 were common DECs across 4 groups, sharing miRNA binding sites with follicle selection-associated genes. In conclusion, our findings suggest that RL promotes egg production by stimulating follicle selection during LI, offering insights into the regulatory mechanisms of circRNAs in follicle selection under RL. This knowledge can help enhance the reproductive performance of pigeons.

Effects of different energy levels in low-protein diet on liver lipid metabolism in the late-phase laying hens through the gut-liver axis.

BACKGROUND: The energy/protein imbalance in a low-protein diet induces lipid metabolism disorders in late-phase laying hens. Reducing energy levels in the low-protein diet to adjust the energy-to-protein ratio may improve fat deposition, but this also decreases the laying performance of hens. This study investigated the mechanism by which different energy levels in the low-protein diet influences liver lipid metabolism in late-phase laying hens through the enterohepatic axis to guide feed optimization and nutrition strategies. A total of 288 laying hens were randomly allocated to the normal-energy and normal-protein diet group (positive control: CK) or 1 of 3 groups: low-energy and low-protein diet (LL), normal-energy and low-protein diet (NL), and high-energy and low-protein diet (HL) groups. The energy-to-protein ratios of the CK, LL, NL, and HL diets were 0.67, 0.74, 0.77, and 0.80, respectively. RESULTS: Compared with the CK group, egg quality deteriorated with increasing energy intake in late-phase laying hens fed low-protein diet. Hens fed LL, NL, and HL diets had significantly higher triglyceride, total cholesterol, acetyl-CoA carboxylase, and fatty acid synthase levels, but significantly lower hepatic lipase levels compared with the CK group. Liver transcriptome sequencing revealed that genes involved in fatty acid beta-oxidation (ACOX1, HADHA, EHHADH, and ACAA1) were downregulated, whereas genes related to fatty acid synthesis (SCD, FASN, and ACACA) were upregulated in LL group compared with the CK group. Comparison of the cecal microbiome showed that in hens fed an LL diet, Lactobacillus and Desulfovibrio were enriched, whereas riboflavin metabolism was suppressed. Cecal metabolites that were most significantly affected by the LL diet included several vitamins, such as riboflavin (vitamin B2), pantethine (vitamin B5 derivative), pyridoxine (vitamin B6), and 4-pyridoxic acid. CONCLUSION: A lipid metabolism disorder due to deficiencies of vitamin B2 and pantethine originating from the metabolism of the cecal microbiome may be the underlying reason for fat accumulation in the liver of late-phase laying hens fed an LL diet. Based on the present study, we propose that targeting vitamin B2 and pantethine (vitamin B5 derivative) might be an effective strategy for improving lipid metabolism in late-phase laying hens fed a low-protein diet.

Nutritional and physiological responses to dietary phosphorus levels and phytase in pullets and laying hens.

The objective of this study was to determine the effects of dietary available phosphorus (P) levels and dietary phytase added into the very low-P diet on the performance, mineral balance, odor emission, and stress responses in growing pullets and laying hens during 13 to 32 wk of age. One hundred sixty-eight pullets (Hy-Line Brown) were randomly assigned into 1 of 4 dietary treatments with 7 replicates of 6 birds each. Experimental diets were formulated to contain 3 graded P levels at 0.25, 0.35, and 0.45% during 13 to 15 wk (phase 1), 0.25, 0.35, and 0.45% during 16 to 18 wk (phase 2), and 0.20, 0.30, and 0.40% during 19 to 32 wk (phase 3). In addition, dietary phytase (500 FTU/kg matrix values) was added into the very low-P diets (0.20% during 13-15 wk, 0.25% during 16-18 wk, and 0.20% during 19-32 wk) to meet the nutritional adequacy with standard P diets. In all phases, decreasing dietary P levels did not affect (P > 0.05) growth, laying performance, and egg qualities. Decreasing dietary P levels linearly increased the relative duodenal and oviduct weights (P < 0.05), and quadratically increased the relative ovary weight in pullets (P = 0.016). Dietary phytase lowered (P = 0.021) the relative duodenal weight compared with the very low-P diet. Tibia breaking strength and tibia Mg contents in pullets were linearly lowered (P < 0.05) as dietary P levels decreased. Dietary phytase tended to increase (P = 0.091) tibia breaking strength and significantly increased (P = 0.025) tibia Mg content compared with the very low-P diet. Dietary P levels and dietary phytase affected (P < 0.05) ileal crypt depth and ileal villus height: crypt depth ratio in pullets. Decreasing dietary P levels linearly decreased (P < 0.01) crude fat digestibility and P excretion in both pullets and laying hens. Dietary phytase reversed (P < 0.05) the very low-P diet-mediated decrease of crude fat digestibility in pullets and laying hens. Dietary P levels and dietary phytase affected (P < 0.05) odor emission including ammonia in pullets and total volatile fatty acids in laying hens. Finally, lowering dietary P levels increased (P < 0.01) yolk corticosterone concentrations and the increased corticosterone concentration by the very low-P diet was reversed by dietary phytase. Collectively, our study shows that decreasing dietary P levels induced nutritional and physiological responses in pullets and laying hens and these P-mediated negative effects were mitigated by dietary phytase.

Carotenoid deposition in yolks of laying hens fed with corn diets differing in grain hardness and supplemented with rapeseed oil and emulsifier.

This study investigated the effects of supplementing diets consisting of two dent corn hybrids (soft- and hard-type) with different amounts of rapeseed oil (2, 3, and 4%) and with (0.05%) or without emulsifier (Lysoforte Extended, Kemin) on the content and deposition of carotenoids in egg yolk. The feeding trial was conducted with 216 Lohmann Brown laying hens which were by 3 located in 72 cages. The cages were randomly assigned to 12 dietary treatments (2 hybrids × 3 rapeseed oil levels × 2 emulsifier levels), resulting in 6 cages (replicates) per each dietary treatment. After depletion, hens were fed treatment diets without added pigment for 7 wk. After stabilization of the carotenoid profile (lutein, zeaxanthin, α- and ß-cryptoxanthin and ß-carotene and total carotenoids), eggs were collected once a week until the end of the experiment and deposition efficiency was calculated based on carotenoid content in yolk and diets, yolk weight, egg production and diet intake. Corn hybrid and rapeseed oil affected (P < 0.05) the yolk content and deposition efficiency of most carotenoids. Moreover, a significant (P < 0.05) hybrid × rapeseed oil level interaction for all carotenoids indicated hybrid-specific responses to rapeseed oil supplementation. In the soft-type hybrid, the addition of 3% rapeseed oil enhanced the carotenoid content compared to 2% of rapeseed oil, whereas for the hard-type hybrid, 2 and 3% of rapeseed oil resulted in similar contents. Supplementation of 4% rapeseed oil reduced the content regardless of the hybrid. Emulsifier addition positively affected (P < 0.05) the deposition efficiency of all carotenoids except ß-carotene. In conclusion, supplementing corn diets with rapeseed oil and emulsifier affected carotenoid utilization and these responses varied in hybrids differing in grain hardness, which should be considered when using corn as the sole source of carotenoids in hen diets.

Effect of monosodium glutamate supplementation in diet on fatty acid profiles, genes expression related to lipid metabolism and egg yolk cholesterol in late phase of production in laying hens.

In an experiment with four treatments and five replicates, the effects of adding monosodium glutamate (MSG) to the diet in late phase of egg production was studied on performance, and lipid metabolism in laying hens. Dietary treatments included the control basal diet without MSG and the other treatments adding 0.4%, 0.8% and 1.2% MSG in the control diet respectively. The effect of supplementation of MSG on egg weight, egg production, feed conversion ratio and egg mass was insignificant (p < 0.05). Adding MSG to the diet significantly increased feed intake and blood polyunsaturated fatty acids concentration (p < 0.05). Intake of 0.8% and 1.2% MSG in the diet up regulated the mRNA expression of acetyl-coenzyme A carboxylase, fatty acid synthase and lipoprotein lipase in the abdominal and liver tissues in comparison to the control group. Blood very low-density lipoprotein-cholesterol, triglycerides and cholesterol concentration were increased in treatment fed with a diet containing 0.8% MSG compared to the control group (p < 0.05). The effect of MSG on total egg yolk cholesterol concentration was not significant. In conclusion, the results of the present experiment indicated that adding MSG increased feed intake and blood polyunsaturated fatty acid concentration.

Partial budget analysis of laying hens' transition from cages to production systems of improved welfare: a case study in Greece.

1. In recent years, public concern regarding animal welfare has increased while, at the same time, cage systems for animal production have been greatly criticised by EU citizens. In addition, large food retailers promote food products that are made with eggs produced in cage-free systems.2. The objective of this study was to evaluate the economic viability of the transition of laying hens' to production systems; from conventional to alternative systems with improved welfare. Three independent scenarios were assumed as follows: transition from enriched colony cages to barn (S1), transition from barn to free-range (S2), and transition from free-range to organic (S3). Economic assessments of each transition was applied to a model farm in Greece with 12 000 hens, through partial budget analysis and net benefits and costs were estimated.3. The results showed a positive economic impact in all transitions to a production system of improved animal welfare (€12,044 in S1, €18,957 in S2 and €7,977 in S3) which indicated that they are economically sustainable. In all scenarios, unit cost increased by 19% in S1, 12% in S2, and 85% in S3.4. In conclusion, transitioning towards improved animal welfare production systems in laying hen farms could be an economically viable option for egg producers in compliance with societal demands and market trends.

The effect of thermostable and enteric-coated multi-protease on the performance and digestibility of laying hen fed low-protein diets.

This study evaluated the efficacy of a multi-protease on the performance, egg quality and digestibility of laying hen. The study had four treatments: Control (without multi-protease, CON), Pro 1.2 (CON + 0.1% multi-protease), Pro 2.4 (CON + 0.2% multi-protease) and Pro 3.6 (CON + 0.3% multi-protease). Each treatment was replicated six times (replicate = experimental unit = one pen with 15 hens) to give a total of 360 layer hens of the Hy-line breed. The study lasted for a total of 3 months (14 day adaptation period + 84 days experimental period). The effects of the additive were assessed on: the performance variables, egg quality and ileal amino acid (AA) digestibility. At the end of the study, dietary supplementation with Pro 2.4 and Pro 3.6 improved (p < 0.05) hen-day egg production, egg mass and eggshell thickness compared with CON at the peak phase. Further improvements (p < 0.05) were observed in the digestibility of crude protein and AAs such as isoleucine, lysine, threonine and cysteine at Pro 2.4 and Pro 3.6 protease supplementation levels compared with CON, while arginine and alanine were higher (p < 0.05) at Pro 3.6 compared with CON. No differences were reported for other performances such as body weight, average daily feed intake, average egg weight, feed conversion ratio, eggshell hardness and all the egg qualities measured. Overall, the results from this study showed better efficacy at Pro 2.4 and Pro 3.6 on the performance of laying hen during the peak phase.

Egg Quality, Sensory Attributes, and Protein Metabolites of Laying Hens Fed Whole Flaxseed, Fish Oil, and Different Sources of Trace Elements.

This study evaluated the effects of whole flaxseed (WFS), fish oil (FO), and different sources of Se, Zn, and Fe (inorganic, organic, and nano-source) on egg production, quality, sensory attributes, and serum protein metabolites in laying hens. A total of 144 hens were divided into six groups with six replicates of four hens each. Hens were fed six diets as follows: 1) control diet; 2) 7.5%WFS+1.5%FO; 3) 7.5%WFS+1.5%FO+175 mg/kg vitamin E (VE); 4) 7.5%WFS+1.5%FO+175 mg/kg VE + inorganic sources of Se, Zn, and Fe (ISeZnFe); 5) 7.5%WFS+1.5%FO+175 mg/kg VE + organic sources of Se, Zn, and Fe (OSeZnFe); 6) 7.5%WFS+1.5%FO+175 mg/kg VE + nano-source of Se, Zn, and Fe (NSeZnFe) from 40-50 weeks of age. Laying hens fed 7.5% WFS, 1.5% FO, and different sources of trace elements in their diets had no negative effects on laying rate, egg weight, egg mass, feed intake, feed conversion ratio, body weight change, or survival rate compared to that of hens fed the control diet. Dietary treatments did not negatively affect the external and internal egg characteristics or egg sensory attributes. Feeding 7.5%WFS+1.5%FO+VE+ISeZnFe positively influenced yolk color in fresh eggs. Dietary treatments had a significant impact on egg nutritional composition, with the highest levels of macronutrients found in eggs from hens fed the 7.5%WFS+1.5%FO+VE+NSeZnFe treatment. The highest plasma globulin concentrations were observed in hens fed organic and nano-source trace elements. The same diets reduced plasma uric acid levels. Based on these findings, the inclusion of organic or nano-source trace minerals in diets containing WFS and FO positively affected egg quality and hen protein metabolites.

Chicken ovarian follicular atresia: interaction network at organic, cellular, and molecular levels.

Most of follicles undergo a degenerative process called follicular atresia. This process directly affects the egg production of laying hens and is regulated by external and internal factors. External factors primarily include nutrition and environmental factors. In follicular atresia, internal factors are predominantly regulated at 3 levels; organic, cellular and molecular levels. At the organic level, the hypothalamic-pituitary-ovary (HPO) axis plays an essential role in controlling follicular development. At the cellular level, gonadotropins and cytokines, as well as estrogens, bind to their receptors and activate different signaling pathways, thereby suppressing follicular atresia. By contrast, oxidative stress induces follicular atresia by increasing ROS levels. At the molecular level, granulosa cell (GC) apoptosis is not the only factor triggering follicular atresia. Autophagy is also known to give rise to atresia. Epigenetics also plays a pivotal role in regulating gene expression in processes that seem to be related to follicular atresia, such as apoptosis, autophagy, proliferation, and steroidogenesis. Among these processes, the miRNA regulation mechanism is well-studied. The current review focuses on factors that regulate follicular atresia at organic, cellular and molecular levels and evaluates the interaction network among these levels. Additionally, this review summarizes atretic follicle characteristics, in vitro modeling methods, and factors preventing follicular atresia in laying hens.

Hypothalamic transcriptome profile from laying period to incubation period of Changshun green-shell laying hens.

Incubation behavior in chickens is closely associated with hypothalamus. Here, RNA sequencing of hypothalamus from Changshun green-shell laying hens, an indigenous chicken breed from China, in egg-laying period (LP) and incubation period (BP) was conducted to identify critical pathways and candidate genes involved in controlling the incubation behavior in hypothalamus. A total of 637 up-regulated and 305 down-regulated differently expressed genes (DEGs) were identified in chicken hypothalamus between LP and BP groups. Gene ontology term (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis further revealed that neuroactive ligand-receptor interaction, hippo signaling pathway, and focal adhesion were significantly enriched. Five candidate genes (POMC, IGF1R, CHAD, VCL, and MYL9) were suggested to play crucial roles in the regulation of chicken incubation behavior. Our results further indicated the complexity of reproductive behavior of different chicken breeds.

Pathogenicity of two different genotypes avian hepatitis E strains in laying hens and silkie fowl.

To determine the pathogenicity of two different genotypes of avian hepatitis E strains in two species of birds, a total of thirty healthy 12-week-old birds were used. After inoculation, fecal virus shedding, viremia, seroconversion, serum alanine aminotransferase (ALT) increases and liver lesions were evaluated. The results revealed that CHN-GS-aHEV and CaHEV could both infect Hy-Line hens and silkie fowls, respectively. Compared to the original avian HEV strain, the cross-infected virus exhibited a delay of 2 weeks and 1 week in emerged seroconversion, viremia, fecal virus shedding, and increased ALT level, and also showed mild liver lesions. These findings suggested that CHN-GS-aHEV may have circulated in chickens. Overall, these two different genotypes of avian HEV showed some variant pathogenicity in different bird species. This study provides valuable data for further analysis of the epidemic conditions of two avian HEVs in Hy-Line hens and silkie fowls.

Effect of energy level of pullet diet and age on laying performance and expression of hypothalamus-pituitary-gonadal related genes in laying hens.

Dietary energy density influences feed intake (FI) and development of layer-type pullets. A total of 384 nine-wk-old Hy-Line Brown pullets were randomly assigned to one of 3 dietary treatments: fed a diet with 2,600, 2,750, and 2,900 Kcal metabolizable energy/kg (ME/kg) from 10 to 21 wk of age. The results showed that the 2,900 and 2,600 ME groups had lower feed and ME intake (P < 0.01) from 10 to 21 wk of age. The 2,600 ME pullets had heavier body weight (BW) and longer shank length (P < 0.05) at 21 wk of age than the 2,750 ME group. The eggshell percentage was increased by the 2,600 and 2,900 kcal/kg treatments (P = 0.002). Serum concentration of 17-ß-estradiol (E2), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) decreased at 70 wk of age (P < 0.05). Pullet diet and its interaction with age had a significant influence (P < 0.001) on the expression of gonadotropin-releasing hormone 1 (GnRH-1) and gonadotropin-inhibitory hormone (GnIH) in the hypothalamus and of gonadotropin releasing hormone 1 receptor (GnRH-1R) and gonadotropin-inhibitory hormone receptor (GnIHR) in the pituitary. In the hypothalamus, GnRH-1 expression increased from 9 to 40 wk of age and then decreased; however, GnIH expression was highest at 70 wk of age. Follicle-stimulating hormone receptor (FSHR) expression increased (P < 0.001) at wk 40 and decreased at wk 70 compared to wk 21 at various follicular stages. In conclusion, the energy level of pullet diet had no unfavorable influence on feed intake, laying rate, egg mass, and FCR, whereas change egg weight and mortality during the laying period from 21 to 70 wk of age. during the laying period. These results suggest that pullet dietary energy can activate the expression of genes related to reproduction in the hypothalamus, whereas it plays a minor role in the regulation of genes in the pituitary and ovary. Age-induced gene expression in the hypothalamus-pituitary-gonadal (HPG) axis is associated with laying performance in hens.