Comprehensive metabolic profiling of dioxin-like compounds exposure in laying hens: Implications for toxicity assessment.

The evaluation of toxicity related to polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) is crucial for a comprehensive risk assessment in real-world exposure scenarios. This study employed a controlled feeding experiment to investigate the metabolic effects of dioxin-like compounds (DLCs) on laying hens via feed exposure. Diets enriched with two concentrations (1.17 and 5.13 pg toxic equivalents (TEQ)/g dry weight (dw)) were administered over 14 days, followed by 28 days of clean feed. Metabolomics analyses of blood samples revealed significant metabolic variations between PCDD/Fs and DL-PCBs exposed groups and controls, reflecting the induced metabolic disruption. Distinct changes were observed in sphingosine, palmitoleic acid, linoleate, linolenic acid, taurocholic acid, indole acrylic acid, and dibutyl phthalate levels, implying possible connections between PCDD/Fs and DL-PCBs toxic effects and energy-neuronal imbalances, along with lipid accumulation and anomalous amino acid metabolism, impacting taurine metabolism. Moreover, we identified three differential endogenous metabolites-L-tryptophan, indole-3-acetaldehyde, and indole acrylic acid-as potential ligands for the aryl hydrocarbon receptor (AhR), suggesting their role in mediating PCDD/Fs and DL-PCBs toxicity. This comprehensive investigation provides novel insights into the metabolic alterations induced by PCDD/Fs and DL-PCBs in laying hens, thereby enhancing our ability to assess risks associated with their exposure in human populations.

Dietary starch structure modulates nitrogen metabolism in laying hens via modifying glucose release rate.

The objective of this study was to investigate the effects of starch structure (Amylopectin/Amylose, AP/AM) in a low-protein diet on production performance, nitrogen utilization efficiency, and cecal flora in laying hens. Four hundred eighty 45-wk-age Hy-Line Gray laying hens were randomly allocated to five dietary groups and subjected to a 12-wk feeding trial. The AP/AM ratios of the five experiment diets were 1.0, 1.5, 2.0, 3.0, and 4.0. The results indicated that compared to other groups, laying hens fed with AP/AM 4.0 diets showed significantly improved average egg weight and feed conversion ratio (P < 0.05). Furthermore, as the AP/AM ratio increased, there was a significant linear enhancement in intestinal amino acids apparent digestibility, apparent metabolizable energy, and villus area (P < 0.05). Compared to the high AP groups, high-AM diets significantly increased eggshell thickness, crude protein digestibility, and reduced energy supply from amino acid oxidation in ileum (P < 0.05). Additionally, moderate-AM diets enriched with short-chain fatty acid-producing bacteria in the cecum, such as Lactobacillus, Rikenellaceae_RC9_gut_group, and Christensenellaceae_R-7_group, which are associated with the promoting nitrogen utilization. These findings may offer useful information on optimizing starch structure for the design of food products and relevant therapies due to the potential effects on nutrient metabolism and gut homeostasis.

Effects of Different Defatting Methods of Black Soldier Fly (Hermetia illucens) Larvae Meal on the Metabolic Energy and Nutrient Digestibility in Young Laying Hens.

This study aimed to investigate the effects of different defatting methods of black soldier fly (Hermetia illucens) larvae meal (BSFM) on the metabolic energy and nutrient digestibility in laying hens. Sixty young laying hens (Hy-Line W-36) aged 63 days were randomly divided into two groups (G1 and G2), each with five replicates of six hens housed in individual cages. Group G1 was fed 25% pressed black soldier fly meal (BSFMp) and 75% basal diet, and Group G2 was fed 25% extracted black soldier fly meal (BSFMe) and a 75% basal diet. Both diets included 5 g/kg chromium oxide as an external marker. A 7-day preliminary trial was followed by a 4-day experimental period. The results indicate that pressing and extracting significantly affected the digestibility of crude fat and total energy in BSFM, with BSFMp showing significantly higher crude fat digestibility than BSFMe. Similarly, total energy digestibility was also significantly higher in BSFMp. However, there were no significant differences in dry matter, organic matter, and crude protein digestibility between the two processing methods. The apparent metabolic energy values of BSFMp and BSFMe were 16.34 and 12.41 MJ/kg, respectively, showing a significant difference. The nitrogen-corrected metabolic energy values were 15.89 MJ/kg in BSFMp and 11.93 MJ/kg in BSFMe, indicating a highly significant difference. The digestibility of arginine and leucine in BSFMp was significantly higher than in BSFMe, while differences in lysine, cystine, threonine, tryptophan, and isoleucine were not significant. In conclusion, both defatting methods of BSFM had no adverse effects on the metabolic energy and nutrient digestibility in young laying hens, but BSFMp demonstrated better effects on the digestibility of metabolic energy and nutrients in the feed for young laying hens.

The Effects of Replacing Soybean Meal with Chlorella vulgaris in Laying Hen Diets on Performance and Physical Characteristics of Eggs.

Chlorella vulgaris (CV) is a microalga with considerable nutritional value, containing high levels of protein, carotenoids, and polyunsaturated fatty acids, which have the potential to positively influence the productive performance and egg quality of laying hens. CV emerges as a more sustainable ingredient than soybean meal (SBM) as it can be produced locally and with fewer inputs. In this regard, a study was conducted with 48 H&N Brown Nick strain laying hens, at 19 weeks of age, over a period of 16 weeks. The hens were divided into four treatments, with 12 replicates each. The treatments consisted of providing four different diets: a control diet based on corn and SBM without the inclusion of CV, and three other diets with partial substitution of SBM by 2.5, 5, and 10% of CV. The results showed that the inclusion of CV in the diets did not significantly affect feed intake, feed conversion ratio, or egg production (p > 0.05). In addition, moderate CV levels increased egg weight, while higher levels reduced it. Haugh units, yolk index, albumen index, egg surface area, specific density, and translucency were not affected (p > 0.05), while shell index and shell thickness were lower in the groups that received the CV (p < 0.0001). Yolk color improved significantly with increasing CV levels (p < 0.0001), with darker, more intensely colored yolks at higher CV concentrations. The results of this study suggest that the incorporation of CV in the diet of laying hens had a limited impact on performance parameters. In addition, CV supplementation can positively influence egg quality and yolk color, although careful consideration of optimal levels is necessary to avoid negative effects on other parameters.

Effects of relative humidity on physiology and behavior of laying hens exposed to high ambient temperatures.

This study investigated how different relative humidity (RH) would impact behavior and physiology of laying hens. One hundred-eighty laying hens (Hy-Line Brown), aged 68-week-old (1,908 ± 78 g), were exposed to daily ambient temperatures of 30 °C with RH set at 25% (RH25), 50% (RH50), or 75% (RH75) for 12 h a day (9:00 am to 9:00 pm) from 70 to 74 weeks of age. All hens had been raised at 24 °C and 50% RH during 2-week adaptation period. Each RH treatment consisted of 10 replicates with 6 hens each in a completely randomized design. Results indicated that rectal temperature, respiratory rate, and heart rate were increased (P ≤ 0.05) in the RH75 group compared with the RH25 and RH50 groups. Plasma malondialdehyde concentrations were elevated in the RH75 group compared RH50 at 3, 7, and 21 days (P ≤ 0.05) following the RH exposure. Plasma glutathione peroxidase activity was lowered (P ≤ 0.05) in the RH75 group compared with the RH25 and RH50 groups at 21 days. Increasing RH led to decreased feeding behavior but showed a tendency to increase drinking behavior. Wings elevated and panting behaviors were higher in the RH75 group compared with the RH25 and RH50 groups (P ≤ 0.05). In conclusion, these findings suggest that elevated RH at constant ambient temperature could negatively influence the behavior and physiology of laying hens.

Evaluating the therapeutic effect of different forms of silymarin on liver status and expression of some genes involved in fat metabolism, antioxidants and anti-inflammatory in older laying hens.

BACKGROUND: Silymarin, the predominant compound of milk thistle, is an extract took out from milk thistle (Silybum marianum) seeds, containing a mixture of flavonolignans with strong antioxidant capability. METHODS: The experiment was conducted using 70 Lohmann LSL-Lite hens at 80 weeks of age with 7 treatments each with 10 replicates. Treatments included: (1) control diet without silymarin, (2) daily intake of 100 mg silymarin powder/kg body weight (BW) (PSM100), (3) daily intake of 200 mg silymarin powder/kg BW (PSM200), (4) daily intake of 100 mg nano-silymarin/kg BW (NSM100), (5) daily intake of 200 mg nano-silymarin/kg BW (NSM200), (6) daily intake of 100 mg lecithinized silymarin/kg BW (LSM100) and (7) daily intake of 200 mg lecithinized silymarin/kg BW (LSM200). The birds were housed individually, and diets were fed for 12 weeks. RESULTS: Scanning electron microscopy showed that NSM was produced with the average particle size of 20.30 nm. Silymarin treatment improved serum antioxidant enzyme activity. All groups receiving silymarin showed a decrease in liver malondialdehyde content, expression of fatty acid synthase, tumour necrosis factor alpha, interleukin 6 (IL-6) genes in the liver, and hepatic steatosis than the control, except those fed the PSM100 diet. There were decreases in liver dry matter and fat contents, non-alcoholic fatty liver disease and hepatocyte ballooning, and an increase in glutathione peroxidase gene expression and a decrease in iNOS gene expression in birds fed the NSM100, NSM200, LSM100 and LSM200 diets compared to the control group. Moreover, all groups receiving silymarin showed a significant decrease in liver weight compare to the control group. CONCLUSIONS: Overall, the effects of silymarin when converted to NSM or LSM and offered at the level of 200 mg/kg BW were more pronounced on the hepatic variables and may be useful in the prevention of the liver disease in older laying hens.

Hepatoprotective effects of magnolol in fatty liver hemorrhagic syndrome hens through shaping gut microbiota and tryptophan metabolic profile.

BACKGROUND: Magnolol (MAG) exhibits hepatoprotective activity, however, whether and how MAG regulates the gut microbiota to alleviate fatty liver hemorrhagic syndrome (FLHS) remains unclear. Therefore, we investigated the mechanism of MAG in FLHS laying hens with an emphasis on alterations in the gut-liver axis. We randomly divided 540 56-week-old Hy-line white laying hens with FLSH into 4 groups. The birds were fed a high-fat low-protein (HFLP) diet (CON) or HELP diets supplemented with 200, 400, and 600 mg/kg of MAG (M1, M2, and M3, respectively) for 9 weeks. RESULTS: Magnolol supplementation increased the laying rate and ameliorated hepatic damage and dysfunction by regulating lipid metabolism, improving intestinal barrier function, and shaping the gut microbiota and tryptophan metabolic profiles. Dietary MAG supplementation downregulated the expression of lipid synthesis genes and upregulated the expression of lipid transport genes at varying degrees. The intestinal barrier function was improved by 200 and 400 mg/kg of MAG supplementation, as evidenced by the increased villus height and mRNA expression of tight junction related genes. Microbiological profile information revealed that MAG changed the gut microbiota, especially by elevating the abundances of Lactobacillus, Faecalibacterium, and Butyricicoccus. Moreover, non-targeted metabolomic analysis showed that MAG significantly promoted tryptophan metabolites, which was positively correlated with the MAG-enriched gut microbiota. The increased tryptophan metabolites could activate aryl hydrocarbon receptor (AhR) and relieved hepatic inflammation and immune response evidenced by the downregulated the gene expression levels of pro-inflammatory cytokines such as interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in the liver. The fecal microbiota transplantation (FMT) experiments further confirmed that the hepatoprotective effect is likely mediated by MAG-altered gut microbiota and their metabolites. CONCLUSIONS: Magnolol can be an outstanding supplement for the prevention and mitigation of FLHS in laying hens by positively regulating lipid synthesis and transport metabolism, improving the intestinal barrier function, and relieving hepatic inflammation by reshaping the gut microbiota and metabolite profiles through gut microbiota-indole metabolite-hepatic AhR crosstalk. These findings elucidate the mechanisms by which MAG alleviates FLHS and provide a promising method for preventing liver diseases by modulating gut microbiota and their metabolites.

Effects of different housing systems on the oxidative defence system, heterophil functions, cellular immune response and cytokines in laying hens.

1. This study investigated the effects of different housing systems on oxidative defence mechanisms, heterophil functions, cellular immune response and cytokine production in laying hens. One hundred and twenty laying hens were allocated into one of four groups: conventional cages, furnished cages, deep litter, and free range.2. Housing system did not affect malondialdehyde concentrations and enzymatic antioxidant status. Ascorbic acid values were higher in deep-litter hens than in those in conventional cages and free range.3. Phagocytic and chemotactic activities tended to rise in the deep-litter system, and oxidative burst was higher than in furnished cages. Cytotoxic T cells were decreased in furnished cages, both cytotoxic and helper T cells decreased in deep litter compared to free range.4. The IL-2 and IL-13 expression was higher in deep litter than in conventional cages, and IL-6 expression was higher in furnished cages than in free range.5. Housing system had no significant effects on the oxidative defence system; however, they affected heterophil functions, cellular defence mechanisms and cytokine production. The results suggested that breeders need to consider the housing system's potential effects on immune defence responses while applying a breeding strategy appropriate for animal welfare and consumer demand.

Meta-Analysis of Positive Effects of Dietary Turmeric (Curcuma longa L.) on Performance of Commercial Laying Hens.

Turmeric improves performance in nonruminants, but results in laying hens are not consistent. This meta-analysis assessed the performance of laying hens fed turmeric powder (TP)-based diets. Nineteen studies retrieved from Google Scholar, Scopus, ScienceDirect, PubMed, and Web of Science databases were used for the meta-analysis. The outcome variables analysed were productive indices (feed intake [FI], feed conversion ratio [FCR], hen day production [HDP], egg weight [EW], egg mass [EM]), egg quality (Haugh unit [HU], shell thickness [SHT], shell strength [SHS], yolk cholesterol [YC]), serum biochemical parameters (serum cholesterol [SC], alanine transferase [ALT], and aspartate transferase [AST]), and moderator variables (layer strains, inclusion level, feeding duration, and hen's age). All analyses were performed on OpenMEE software and the R package. A random-effects model (REM) was used and results were presented as standardised mean difference (SMD) at a 95% confidence interval (CI). The results showed that dietary TP improved FCR (SMD = -0.31; 95% CI: -0.61, -0.01; p = 0.046) and HDP (SMD = 0.49; 95% CI: 0.29, 0.69; p < 0.001), but not EW, EM, HU, SHT, SHS, YC, and serum AST in layers. On the other hand, dietary TP decreased FI (SMD = -0.15; 95% CI: -0.26, -0.05; p = 0.004), SC (SMD = -75.18; 95% CI: -102.55, -47.80; p < 0.001), and ALT (SMD = -3.55; 95% CI: -4.71, -2.40; p < 0.001) in laying hens with proof of significant heterogeneity. However, meta-regression showed that layer strains and feeding duration accounted for most of the sources of heterogeneity. In conclusion, results suggest that dietary TP increased HDP and reduced FI, FCR, SC, and ALT in laying hens.

Host genetics and gut microbiota synergistically regulate feed utilization in egg-type chickens.

BACKGROUND: Feed efficiency is a crucial economic trait in poultry industry. Both host genetics and gut microbiota influence feed efficiency. However, the associations between gut microbiota and host genetics, as well as their combined contributions to feed efficiency in laying hens during the late laying period, remain largely unclear. METHODS: In total, 686 laying hens were used for whole-genome resequencing and liver transcriptome sequencing. 16S rRNA gene sequencing was conducted on gut chyme (duodenum, jejunum, ileum, and cecum) and fecal samples from 705 individuals. Bioinformatic analysis was performed by integrating the genome, transcriptome, and microbiome to screen for key genetic variations, genes, and gut microbiota associated with feed efficiency. RESULTS: The heritability of feed conversion ratio (FCR) and residual feed intake (RFI) was determined to be 0.28 and 0.48, respectively. The ileal and fecal microbiota accounted for 15% and 10% of the FCR variance, while the jejunal, cecal, and fecal microbiota accounted for 20%, 11%, and 10% of the RFI variance. Through SMR analysis based on summary data from liver eQTL mapping and GWAS, we further identified four protein-coding genes, SUCLA2, TNFSF13B, SERTM1, and MARVELD3, that influence feed efficiency in laying hens. The SUCLA2 and TNFSF13B genes were significantly associated with SNP 1:25664581 and SNP rs312433097, respectively. SERTM1 showed significant associations with rs730958360 and 1:33542680 and is a potential causal gene associated with the abundance of Corynebacteriaceae in feces. MARVELD3 was significantly associated with the 1:135348198 and was significantly correlated with the abundance of Enterococcus in ileum. Specifically, a lower abundance of Enterococcus in ileum and a higher abundance of Corynebacteriaceae in feces were associated with better feed efficiency. CONCLUSIONS: This study confirms that both host genetics and gut microbiota can drive variations in feed efficiency. A small portion of the gut microbiota often interacts with host genes, collectively enhancing feed efficiency. Therefore, targeting both the gut microbiota and host genetic variation by supporting more efficient taxa and selective breeding could improve feed efficiency in laying hens during the late laying period.

Enhancing Laying Hens' Performance, Egg Quality, Shelf Life during Storage, and Blood Biochemistry with Spirulina platensis Supplementation.

Enhancing the sustainability of chicken farming involves improving health and productivity and product qualities. This study explores the influence of Spirulina platensis (SP) supplementation on the productivity, egg quality, shelf life during storage, and blood biochemistry of laying hens. A total of 192 thirty-nine-week-old White Leghorn hens were randomly divided into 4 dietary groups: a control group and 3 treatment groups receiving 2.5 g/kg, 5 g/kg, or 10 g/kg of SP, respectively. The study was conducted for six weeks with measuring feed intake, feed conversion ratio, egg production, egg quality, shelf life, and blood biochemistry. The results demonstrated significant enhancements in egg weight (p < 0.05) and egg mass (p < 0.05) in the treatment of SP groups. The SP treated hens showed significant improvements in yolk color (p < 0.05) and Haugh unit scores (p < 0.05). The SP supplementation showed a hepatoprotective effect, as indicated by significant reduction in Alanine aminotransferase (ALT) (p < 0.05) and alkaline phosphatase (ALP) (p < 0.05) levels; however, increases in total protein, albumin, and globulin levels were observed. Furthermore, the egg quality of stored eggs for 21 days linearly increased with increments in the SP levels. In conclusion, it can be speculated that adding SP at 2.5 g/kg and 5 g/kg can significantly improve the productivity of laying hens, eggs' quality, shelf life, and blood biochemistry, thereby contributing to a more sustainable and efficient chicken production.

Decreasing light exposure increases the abundance of antibiotic resistance genes in the cecum and feces of laying hens.

The gut microbiome plays a crucial role in maintaining animal health and is influenced by various factors, including light exposure; however, the response in laying hens of the gut microbiome to intermittent light regimes and the related impact on antibiotic resistance genes (ARGs) remain poorly understood. In this study, we divided 20-week-old laying hens into two groups. These groups were exposed to either continuous normal light or intermittent light for 8 weeks. The feces and cecal contents of laying hens were collected for analysis. Metagenomic analysis of both feces and cecal content samples revealed significant shifts in the microbial composition and abundance of ARGs under intermittent light exposure compared to normal light exposure (P < 0.05). Furthermore, metabolomic analysis of the cecal contents revealed substantial alterations in the abundance and composition of ARGs and mobile genetic elements (MGEs) in response to intermittent light exposure (P < 0.05). Network analysis revealed intricate co-occurrence patterns among bacterial communities, metabolites, and ARGs, highlighting correlations between Bacteroidetes species, ARGs, and metabolites. Although certain bacterial species showed differential associations, the dominant bacteria carrying ARGs or MGEs had relatively low numbers, suggesting that other bacterial communities may have had a greater influence on ARG dissemination. Moreover, our observations highlight the crucial role of metabolites as mediators between bacterial communities and ARGs, providing novel insights into the dynamics of antibiotic resistance development. Our findings underscore the impact of intermittent light exposure on ARG proliferation in poultry farming and emphasize interconnections among ARGs, bacterial communities, and metabolic pathways. The results underscore the importance of considering both microbial communities and metabolic processes to understand antibiotic resistance in agricultural settings.

Elimination patterns of dimetridazole in egg of laying hens and tissues of broiler after oral administration.

Dimetridazole (DMZ) is a broad-spectrum anti-anaerobic and antiprotozoal drug extensively used for the control of blackhead disease in poultry (especially turkeys). The presence of DMZ and its metabolites in animal food poses potential risks to human health. In this study, we developed a high-performance liquid chromatography tandem mass spectrometry (HPLC/MS-MS) method for the precise detection of DMZ and its metabolite 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI). Our results demonstrate a strong linear relationship (r2 > 0.99) between the concentrations of DMZ and HMMNI in tissues and egg within the range of 1~100 ng/g. The limits of detection (LOD) were determined to be 0.5 ng/g, with corresponding limits of quantification (LOQ) at 1.0 ng/g. Furthermore, average recoveries in tissues and egg fell within the range of 84.90% to 103.01%, with coefficients of variation below 15% for both intra-day and inter-day analyses. To investigate the residue elimination pattern of DMZ and HMMNI, diets containing 500 mg/kg DMZ were fed to healthy SanHuang chicken and Hy-line Gray laying hens for 10 consecutive days. The results indicated that the concentration of HMMNI consistently exceeded that of DMZ during the same period, in both broiler tissues and egg. Sebum showed the slowest elimination of DMZ and HMMNI, becoming undetectable after 168 h of withdrawal. In egg, residues of both substances peaked on the first day after drug withdrawal, followed by slow elimination with half-lives of 0.45 days for DMZ and 0.66 days for HMMNI. Based on these findings, WT1.4 software was used to calculate a withdrawal time of 11 days for broilers and an egg abandonment period of 14 days after withdrawal for laying hens, providing a scientific basis for the safe and rational use of DMZ in poultry farming.

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.

Assessment of the feed additive consisting of endo-1,4-beta-xylanase (produced with Trichoderma reesei MUCL 49755) and endo-1,3(4)-beta-glucanase (produced with T. reesei MUCL 49754) (AveMix® XG 10) for laying hens and minor poultry species for fattening and laying for the renewal of its authorisation (AVEVE BV).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the assessment of the feed additive consisting of endo-1,4-beta-xylanase (produced with Trichoderma reesei MUCL 49755) and endo-1,3(4)-beta-glucanase (produced with T. reesei MUCL 49754) (AveMix® XG 10/AveMix® XG 10 L) for the renewal of its authorisation as a zootechnical feed additive for laying hens and minor poultry species for fattening and laying. The applicant declared a change in the carrier material used in AveMix® XG 10 from soybean meal to calcium carbonate + wheat flour or calcium carbonate + sepiolite. The applicant provided evidence that the additive AveMix® XG 10 with calcium carbonate + wheat flour and AveMix® XG 10 L comply with the conditions of the authorisation. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) noted that no data were submitted to support compliance of the formulation of AveMix® XG 10 with calcium carbonate + sepiolite with the conditions of the authorisation. The FEEDAP Panel concluded that both formulations of the additive (powder and liquid) remain safe for laying hens and minor poultry species for fattening and laying, consumers and the environment. AveMix® XG 10 formulated with calcium carbonate + sepiolite and AveMix® XG 10 L are not irritant to skin and eyes. No conclusions on the irritation potential of AveMix® XG 10 formulated with calcium carbonate + wheat flour could be drawn. The additive in both formulations is considered a respiratory and skin sensitiser. There was no need for assessing the efficacy of the additive in the context of the renewal of the authorisation.

Effects of Yeast Culture on Laying Performance, Antioxidant Properties, Intestinal Morphology, and Intestinal Flora of Laying Hens.

Yeast culture (YC) plays a significant role in enhancing the performance and health of poultry breeding. This study investigated the impact of different YC supplementation concentrations (basal diet with 1.0 g/kg and 2.0 g/kg of YC, YC1.0, and YC2.0) on egg production performance, egg quality, antioxidant properties, intestinal mucosal structure, and intestinal flora of laying hens. Both YC1.0 and YC2.0 groups significantly enhanced the egg protein height, Haugh unit, and crude protein content of egg yolks compared to the control group (p < 0.05). The supplementation with YC2.0 notably increased the egg production rate, reduced feed-to-egg ratio, and decreased the broken egg rate compared to the control group (p < 0.05). Additionally, YC supplementation enhanced serum total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-PX) activity while reducing malondialdehyde (MDA) content (p < 0.05). Moreover, YC supplementation promoted duodenal villus height and villus ratio in the duodenum and jejunum (p < 0.05). Analysis of cecal microorganisms indicated a decrease in Simpson and Shannon indices with YC supplementation (p < 0.05). YC1.0 reduced the abundance of Proteobacteria, while YC2.0 increased the abundance of Bacteroidales (p < 0.05). Overall, supplementation with YC improved egg production, quality, antioxidant capacity, intestinal morphology, and cecal microbial composition in laying hens, with significant benefits observed at the 2.0 g/kg supplementation level.

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.

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.

Role of Nannochloropsis Oculata supplement in improving performance, antioxidant status, blood metabolites, and egg quality of laying hens under hot environmental conditions.

The increase in environmental temperature led to economic losses in the poultry industry, urging the use of feed supplements to mitigate the negative effects on chick's welfare and performance. Therefore, this study aimed to examine the effects of marine microalgae (Nannochloropsis Oculata, N. Oculata) additive on commercial Brown Lohmann laying hen's performance, blood metabolites, and antioxidant status under hot environmental conditions. One hundred and eighty birds (34 weeks old with an initial body weight of 1885 ± 23.5 g) were used till 47 weeks. The birds were divided into three equal groups (birds in each group were distributed into four equal replicates 15 hens/ replicate). The 1st group was the control (CON) and was fed the basal diet, while the 2nd (TR1) and 3rd (TR2) groups were fed the basal diet supplemented with 0.5 and 1.0% of N. Oculata, respectively. The results showed that total protein and globulin concentrations increased (P < 0.05) in treated groups compared with the control group, whereas, albumin concentration increased (P < 0.05) in TR2 compared to the control group. The concentration of ALT and AST decreased in hens fed N. Oculata. Supplementing with N. Oculata reduced serum cholesterol and creatinine concentrations, while glucose concentration increased (P < 0.05) in the treated groups compared to the control group. Serum calcium, total antioxidant capacity (TAC), Triiodothyronine (T3), and progesterone increased (P < 0.05) in hens fed N. Oculata. N. Oculata supplement improved production performance through a positive effect on egg number, egg weight, egg mass, feed conversion ratio, and mortality rate. In addition, the overall mean of shell thickness increased (P < 0.05) in hens fed N. Oculata. It can be concluded that the supplementation of 1.0% N. Oculata to the laying hens' diet enhanced productive performance, serum constituents, and antioxidant status under hot environmental conditions.