Dietary curcumin supplementation effects on blood immunological profile and liver enzymatic activity of laying hens after exposure to high temperature conditions

Various environmental factors affect livestock production but heat stress is a major challenge in the poultry farming. Poultry exposes to high temperature alters blood immunological parameters and liver enzymatic function which in turn, suppress the immunity and disease resistance of chickens. Thus, the purpose of present study was to explore the effect of dietary curcumin supplementation on blood immunological biomarker and liver enzymatic activity of laying hens under heat stress conditions. Experimental groups contained two control groups (normal temperature control (NC) and heat stress control (HC) and 3 heat stress curcumin treatment groups (HT100, HT200 and HT300). Hens in HC group with basal diet and heat stress curcumin treatment groups were exposed 6 h/day heat stress (32 ± 1 °C) from 10:00 a.m. to 16:00 p.m. for 9 week. The results of present study showed that heat stressed curcumin treatment group had improved liver weight, WBC values and immunoglobulin level as compared to untreated HC and NC groups. The available results also indicated that laying hens supplemented with curcumin under high temperature conditions had reduced H/L ratio, serum corticosterone levels, inflammatory cytokines response and liver enzymatic activity (ALT) which enhanced the immunity of laying hens under hot climatic conditions. Therefore, it is concluded that curcumin has ability to combat harsh environmental conditions which can be used as anti-inflammatory and immune booster feed additive in the poultry nutrition.

Alterations in cecal microbiota and intestinal barrier function of laying hens fed on fluoride supplemented diets

The objective of this study was to investigate the effects of fluorine at levels of 31, 431, 1237 mg/kg feed on cecum microbe, short-chain fatty acids (SCFAs) and intestinal barrier function of laying hens. The results showed that the intestinal morphology and ultrastructure were damaged by dietary high F intake. The mRNA expression levels of zonula occludens-1, zonula occludens-2, claudin-1, and claudin-4 were decreased in jejunum and ileum. However, the concentrations of serum diamine oxidase, and D-lactic acid and intestinal contents of interleukin 1 beta, interleukin 6, and Tumor necrosis factor-alpha were increased. Consistent with this, dietary high F intake altered the cecum microbiota, with increasing the concentration of pathogens, such as Proteobacteria and Escherichia-Shigella, as well as, decreasing the contents of beneficial bacteria, such as Lactobacillus, and expectedly, reduced the SCFAs concentrations. In conclusion, the actual results confirmed that (1) high dietary F intake could damage the intestinal structure and function, with impaired intestinal barrier and intestinal inflammation, and (2) destroy the cecum microbial homeostasis, and decrease the concentrations of SCFAs, which aggravate the incidence of intestinal inflammation in laying hens.

Metabolic activity of Bacillus coagulans R11 and the health benefits of and potential pathogen inhibition by this species in the intestines of laying hens under lead exposure

Probiotics are widely used in agricultural breeding for care and maintenance of animal health, especially Bacillus coagulans, a new and popular species that could replace Lactobacillus. However, lead contamination in feed might influence the beneficial function. In the present study, Bacillus coagulans R11 was used as a model bacterium to investigate the effect of lead on changes in metabolites and genes, which could influence the beneficial function on laying hen. At the laboratory scale, transcriptomics and metabolomics were used to screen the main metabolites and related genes under lead exposure. The results showed that 4-acetamidobutanoic acid, dodecanoic acid, L-3-phenyllactic acid, apigenin and daidzein, which are antioxidants and antibacterial agents, were the main metabolites, even in the 100 ppm lead exposure group (the levels of these metabolites were 1.17-, 1.10-, 4.80-, 1.43- and 1.67-fold higher in the 100 ppm group than in pure culture medium). Twenty-three genes associated with the syntheses of the above 5 main metabolites were identified. Further animal experiments showed that B. coagulans R11 feeding of laying hens under lead exposure could prevent oxidative damage by increasing T-AOC and T-SOD activity and reducing the MDA concentration in serum and reducing the abundances of potential pathogens (Escherichia coli, Pseudomonas aeruginosa and Salmonella). Further analysis also showed that the inhibition of pathogen growth was due to the regulation of gene expression, as observed by transcriptomics, and these genes were associated with the abovementioned 5 main metabolites. However, the laying rate decreased by 10.53% compared with that of the control group when the lead exposure concentration was 100 mg/kg. The present study suggested that Bacillus coagulans R11 could help prevent oxidative damage and inhibit pathogen growth in laying hens to maintain a healthy intestinal environment for daily breeding, but under high-lead conditions, Bacillus coagulans R11 feeding could decrease the laying rate.

Reliability of genomic evaluation for egg quality traits in layers

Background

Genomic evaluation, based on the use of thousands of genetic markers in addition to pedigree and phenotype information, has become the standard evaluation methodology in dairy cattle breeding programmes over the past several years. Despite the many differences between dairy cattle breeding and poultry breeding, genomic selection seems very promising for the avian sector, and studies are currently being conducted to optimize avian selection schemes. In this optimization perspective, one of the key parameters is to properly predict the accuracy of genomic evaluation in pure line layers.

Results

It was observed that genomic evaluation, whether performed on males or females, always proved more accurate than genetic evaluation. The gain was higher when phenotypic information was narrowed, and an augmentation of the size of the reference population led to an increase in accuracy prediction with regard to genomic evaluation. By taking into account the increase of selection intensity and the decrease of the generation interval induced by genomic selection, the expected annual genetic gain would be higher with ancestry-based genomic evaluation of male candidates than with genetic evaluation based on collaterals. This advantage of genomic selection over genetic selection requires more detailed further study for female candidates.

Conclusions

In conclusion, in the population studied, the genomic evaluation of egg quality traits of breeding birds at birth seems to be a promising strategy, at least for the selection of males.

The paradoxical effects of progesterone on the eggshell quality of laying hens

This study demonstrates the effects of progesterone on eggshell quality and ultrastructure by injecting progesterone into laying hens 2 and 5 h post-oviposition, respectively. Progesterone injected 2 h post-oviposition (P₄-2 h) improved eggshell quality with a significant decrease (P < 0.01) in the thickness of the mammillary layer and a significant increase (P < 0.01) in the thickness of the effective layer in the eggshell ultrastructure compared to the control. Progesterone injected 5 h post-oviposition (P₄-5 h) damaged the eggshell quality by significantly reducing (P < 0.01) the effective layer thickness. Progesterone injected delayed obviously (P < 0.01) the following oviposition. Moreover, the concentrations of Thr, Cys, Leu, Lys, and His in the eggshell membranes were significantly higher (P < 0.05) in the P₄-2 h treated hens whereas Val and Lys were significantly lower (P < 0.05) in P₄-5 h treated hens compared to the control. Therefore, progesterone shows paradoxical effects on eggshell quality depending on the injection time-points post-oviposition, which could explain the contradictions in previous related reports. P₄ injected affected the content of amino acids in eggshell membranes, especially lysine which contributed to eggshell quality. In addition, P₄ injected 2 h after oviposition improved eggshell quality by promoting the premature fusion of mammillary knobs. This work contributed to a novel insight to understanding the mechanism of improving eggshell quality.

Characteristics of the fecal microbiota of high- and low-yield hens and effects of fecal microbiota transplantation on egg production performance

The microbiota that resides in the digestive tract plays pivotal role in maintaining intestinal environmental stability by promoting nutrition digestion and intestinal mucosal immunity. However, whether the intestinal microbiota in laying hens affects egg laying- performance is not known. In this study, 16S rDNA gene sequencing and fecal microbiota transplantation were used to determine the structure of the intestinal microbiota and the effect of the intestinal microbiota on egg production. The results revealed that Firmicutes were dominant in both the H (high egg laying rates) and L (low egg laying rates) groups, while Bacteroides, Actinobacteria and Proteobacteria were significantly enriched in the L group compared to the H group. The laying rates were weakly affected in H hens transplanted with the fecal microbiota from L hens, except for temporary fluctuation, while the egg laying rates were significantly increased in L hens transplanted with the fecal microbiota from H hens. Therefore, we concluded that the population structure of the intestinal microbiota varied between the H and L groups, and the intestinal microbiota of high-yield laying hens had significant effects on low-yield laying hens performance.

Interactions Between Different Selenium Compounds and Essential Trace Elements Involved in the Antioxidant System of Laying Hens

The purpose of this study was to investigate the interactions between different selenium (Se) compounds including sodium selenite (SS), selenium-enriched yeast (SY), and nano-selenium (NS) and various essential trace elements involved in the antioxidant systems, and to evaluate the effects on laying performance and egg quality. A total of 288 21-week-old Hyline Sophie hens were allotted to four dietary treatments: (1) basal diet without Se supplementation; (2) basal diet supplemented with 0.3 mg/kg Se of SS; (3) basal diet supplemented with 0.3 mg/kg Se of SY; (4) basal diet supplemented with 0.3 mg/kg Se of NS. Each treatment had eight replicates with nine hens per replicate. The trial lasted for 35 days. Results demonstrated that NS supplementation decreased the egg production (EP) and increased the feed conversion rate (FCR) and eggshell thickness and that SY changed the egg shape index (p < 0.05). Supplementation with three Se compounds significantly increased serum Se concentration and glutathione peroxidase (GSH-Px) activity in all treatment groups, as well as total superoxide dismutase (T-SOD) activity in the SY and NS groups. Yolk iron (Fe) and copper (Cu) concentrations in the NS group were also increased with Se supplementation. While the serum zinc (Zn) concentration decreased in the NS and SY groups, as well as the yolk manganese (Mn) concentration in the SY group. And the total antioxidant capability (T-AOC) of yolk with 3 days of storage in the SY and NS groups, malondialdehyde (MDA) value in the NS group, and the T-SOD activity and MDA value of yolk with 10 days of storage in the SY group also decreased. Thus, the source of Se compounds may influence the balance between Se and other trace elements including Zn, Mn, Fe, and Cu, which is important for proper antioxidant defense in blood and egg yolk of laying hens.

Effects of Dietary Different Levels of Nano, Organic and Inorganic Zinc Sources on Performance, Eggshell Quality, Bone Mechanical Parameters and Mineral Contents of the Tibia, Liver, Serum and Excreta in Laying Hens

This study was conducted to determine the effect of dietary zinc (Zn) sources and their levels on the performance, egg quality, tissue mineral concentrations and bone mechanical traits of laying hens. Two hundred seventy, 44-week-old, Super Nick white laying hens were randomly distributed to 15 experimental groups in a 3 (sources of Zn) × 5 (levels of Zn) factorial arrangement, using groups of 18 birds with 6 replicates. The 15 experimental diets consisted of three sources of Zn (zinc-oxide as an inorganic form, zinc-proteinate as an organic form and nano zinc-oxide powder as a nano form) and five different levels of Zn (20, 40, 60, 80 and 100 mg Zn/kg diet). The experiment lasted 12 weeks. Dietary Zn sources, Zn levels and their interactions had no significant effect on the performance parameters between the treatment groups, nor a significant effect on eggshell weight and eggshell breaking strength. Eggshell thickness and eggshell Ca and P contents were significantly affected by the different dietary Zn sources. Dietary Zn sources, Zn levels and their interactions had no significant effect on tibia Ca and P contents, and also had no significant effect on tibia Zn content. Liver Zn content was significantly affected by the dietary Zn sources. Serum Zn content was not affected by the dietary treatments. Dietary Zn sources, Zn levels and their interactions had no significant effect on tibia weight, tibia stress and tibia breaking strength, as tibia mechanical parameters. Excreta Zn content decreased linearly when hens were fed nano Zn compared to organic and inorganic Zn, and excreta Zn content also linearly increased with increasing dietary Zn levels. In conclusion, 20 mg/kg of supplemental Zn is optimal for sustaining performance, good eggshell quality and bone status, while also reducing Zn excretion and soil pollution, with organic (Zn-proteinate) and nano (ZnO) Zn as the preferred forms in laying hen diets.

Molecular detection of avian spirochete Borrelia anserina in Argas persicus ticks in Algeria

Argasid ticks are one of the most important poultry ectoparasites. They affect poultry directly through blood meal and indirectly through the transmission of pathogens essentially Borrelia anserina, agent of avian borreliosis, one of the most widespread poultry diseases in the world, and is of great economic importance. This study was conducted between April 2014 and March 2015 in the region of Ksar El Boukhari, Algeria, in order to investigate the presence of soft ticks in laying hen farms and to detect B. anserina bacteria using molecular tools. DNA was extracted and screened for the presence of Borrelia spp. DNA by real-time polymerase chain reaction (qPCR). Borrelia spp. screening was performed using primers and probe targeting the 16S rRNA gene. A total of 83 traditional laying hen farms were visited, of which 39 (46.98 %) were found infested with A. persicus tick. Molecular analysis revealed that 2/34 (5.88 %) of ticks were infected by B. anserina. None of the ticks tested were positive for Rickettsia spp., and Coxiella burnetii. These results constitute the first report in Algeria of A. persicus harboring B. anserina.

Production performance, egg quality, blood biochemical constituents, egg yolk lipid profile and lipid peroxidation of laying hens fed sugar beet pulp

The effect of including sugar beet pulp (SBP) in laying hen diets on performance, egg quality, blood chemistry and egg lipid peroxidation was studied. A total of 200 laying hens were randomly assigned into 4 groups and were offered diets containing SBP at the level of 0%, 3%, 5%, and 7%. The dietary inclusion of SBP linearly (P < 0.01) increased feed intake, egg production, egg weight and mass, and improved feed conversion ratio, yolk color core and Haugh unit. Eggs laid by hens receiving SBP had linearly (P < 0.01) greater protein and lower ether extract. Dietary inclusion of SBP linearly (P < 0.01) decreased egg yolk malondialdehyde, cholesterol, and triglyceride, while increased glutathione peroxidase. Laying hens fed SBP had lower (P < 0.01) serum total lipids, cholesterol, alanine aminotransferase, aspartate aminotransferase, and creatinine. Dietary inclusion of SBP could improve hen performance, health, egg quality, and egg shelf life.

Unravelling fatty liver haemorrhagic syndrome: 2. Inflammation and pathophysiology

To study the role of inflammation in the pathophysiology of the fatty liver haemorrhagic syndrome (FLHS), mature laying hens were treated with oestrogen (β-oestradiol-17-dipropionate or E₂) and challenged with lipopolysaccharide (LPS). Oestrogen injections induced FLHS, but the incidence and severity of the condition was increased with a combination of E₂ & LPS. Hepatic mRNA levels of the genes encoding key regulators of inflammation, such as interleukin-1β (IL-1β), interleukin-6 (IL-6) and interleukin-18 (IL-18), were evaluated. The expression of IL-6 mRNA in hepatocytes of all treated groups (E₂, LPS and E₂ & LPS hens) was elevated from 6-fold to 56-fold (P < 0.01), when compared to baseline and control values, with the highest fold change at 3 h post-treatment. The mRNA levels for IL-1β were better expressed at 24 h post-treatments with E₂, LPS and E₂ & LPS. The expression of IL-18 mRNA in the liver tissue was lower than IL-1β and IL-6 mRNA in all treated birds. At 24 h post-treatment, total white blood cell (WBC) counts and fibrinogen levels were elevated (P < 0.05) in E₂-, LPS- and E₂- & LPS-treated hens. Histologically, livers of hens from E₂- and E₂- & LPS-treated groups revealed inflammatory alterations with areas showing mononuclear aggregations, vacuolar fatty degeneration of hepatocytes, and increased sinusoidal congestion and haemorrhages. It was concluded that liver lipid accumulation and injury were associated with incidences of local (hepatic) and systemic inflammation, which could have initiated liver blood vessel and capsule rupture and, subsequently, the onset of FLHS.

Risk factors of Salmonella infection in laying hens in Menoua Division, Western region of Cameroon (Central Africa)

Salmonella infections in poultry farms are overlooked in many African countries; yet these infections are mostly zoonotic with impact on both poultry industry and public health. Considering the impact of Salmonella in laying hens, and the role of laying hens as a source of Salmonella outbreak in human, knowledge of the status of Salmonella on laying hen farms as well as the factors influencing the presence of Salmonella is important. In a cross sectional study, cloacal swabs were collected from 270 commercial laying hens on 27 farms located in Menoua Division. These samples were cultured on standard media. A questionnaire was used to collect information on animals, farms and farmer's characteristics. The prevalence of Salmonella was 93.34%; three zoonotic isolates namely S. Enteritidis (75.90%), S. Paratyphi (11.90%), and S. Typhimurium (5.60%) were identified. The location of farms was significantly associated with presence of Salmonella, and the risk of infection was 10-fold higher in Nkong-ni than Santchou (p < 0.05). Other potential risk factors such as flock size, age of the farm (infrastructure), or water source were not associated with Salmonella infection. The prophylactic measures against avian diseases in the country must include measures against Salmonella to protect poultry industry and public health.

Unravelling fatty liver haemorrhagic syndrome: 1. Oestrogen and inflammation

Previous studies have implicated oestrogen as a factor in the induction of fatty liver haemorrhagic syndrome (FLHS). In this study, a refined laying hen model was employed to permit further investigations. Intramuscular (i.m.) injections of exogenous oestrogen as β-estradiol-17-dipropionate (E₂) (5 mg/kg BW) were given every 4 days for 20 days to 30-week-old hens fed either ad libitum or with restricted feed intake. Elevated (P < 0.01) plasma oestrogen concentrations produced significant macroscopic and microscopic hepatic alterations. Hens in the E₂-treated ad libitum fed (EAL) group experienced a higher incidence of FLHS than hens in the E₂-treated restricted feed intake group, showing that birds with a higher feed intake are more at risk of developing FLHS. Histological examination of livers revealed that hens in the E₂-treated ad libitum fed group had consistent and severe fat infiltration in the liver, and fat vacuolization within hepatocytes. Fat accumulation and fat droplets were found not only in the cytoplasm of hepatocytes but also in liver sinusoids. White blood cell counts and fibrinogen concentrations were altered (P < 0.01) in hens treated with E₂ when compared with controls. Plasma fibrinogen concentrations were altered over time, and correlated with white blood cell counts (Pearson's correlation r = 0.96; P = 0.001). Hens treated with E₂ had increased (P < 0.01) levels of cholesterol and triglycerides, confirming that E₂ induced hypercholesterolaemia and hypertriglyceridaemia. It was concluded that E₂ successfully induced FLHS in hens, with typical systemic and hepatic events resulting from a disturbance in lipid metabolism and chronic low-grade inflammation.

A survey of free-range egg farmers in the United Kingdom: Knowledge, attitudes and practices surrounding antimicrobial use and resistance

Antimicrobial resistance (AMR) is a significant global challenge affecting human health and attention has been drawn to practices of all stakeholders involved in antimicrobial prescription and administration, including in the livestock sector. This survey of free-range egg farmers (n = 117) was conducted to investigate knowledge, attitudes and practices surrounding antimicrobial use, and identify farmer-led solutions towards responsible antimicrobial use. Most participants proved knowledgeable of AMR and selected treatments based on principles of responsible medicine use. 'Worms' and 'infectious diseases' were the most common reasons for medicine use. Farms with a higher number of poultry houses, younger flock ages at depopulation and farms visited by a vet less than once a year or 3-4 times a year (compared to annually or twice a year) were more likely to select 'ANTIBIOTICS ONLY', as opposed to 'BOTH ANTIBIOTICS AND ANTIPARASITICS' or 'ANTIPARASITICS ONLY' as their most frequently used medicines. Participants from farms with a younger flock age at depopulation, from company-owned farms, and participants purchasing medicines from agricultural merchants instead of veterinary practices were less likely to be taking measures to reduce or replace antimicrobial use. Participants from larger farms and those that had less contact with their vet were less likely to think that they could reduce or replace the amount of antibiotics used. Survey results provided evidence for the important role of veterinarians in guiding antimicrobial stewardship through engagement, collaboration and education. Discussion groups in which farmers share best practices could assist the free-range egg industry in further promoting responsible antimicrobial use.

Feather pecking in laying hens housed in free-range or furnished-cage systems on French farms

1. Beak trimming is currently used in France to avoid the negative consequences of severe feather pecking (SFP). However, this practice is controversial in terms of animal welfare, and forbidden in some European countries.2. This study aimed to assess the prevalence of SFP in French laying hen farms, to describe how farmers manage this behavioural disorder and to better understand the risk factors involved.3. A study was carried out from April 2015 to June 2016. Visits were paid to 79 flocks kept in furnished cages (FC) and 80 flocks in a free-range (FR) system. All the hens had trimmed beaks and were genotypically brown. The information collected included feather cover, skin damage, beak condition, farm and poultry house characteristics, livestock performance and management.4. The prevalence of SFP in FC flocks was estimated at 32.9% (IC = 95%, [22.5; 43.3]) and the prevalence of cannibalism as 2.5% (IC = 95%, [0.7; 8.8]) at 70 weeks of age. The prevalence of SFP in FR flocks was estimated to be 23.8% (IC = 95%, [14.5; 31.1]) and the prevalence of cannibalism was 8.8% (IC = 95%, [4.3; 17.0]) at 61 weeks of age.5. In FC flocks, SFP was associated with the combination of genotype, type and length of perches, cage area per hen, type of lighting, number of hens per cage and farm location. In FR flocks, feather cover was associated with use of the outdoor run, lighting programme, genotype, farm location and date of house construction.

Nutrient stability in mould-infested feed and mitigating effect of dietary supplemental vitamins in brown laying hens

A 10-week study was conducted to assess the impact of mould infestation on nutrient stability of feed and the mitigating effect of supplemental tocopherol, retinol or a multivitamin on performance and hepatic histology of ISA Brown laying chickens. Two batches of corn were obtained: the aflasafe corn used in preparing control diet and corn with physical evidence of mould used in preparing diets 2 to 5 containing no supplemental vitamin, tocopherol, retinol or a branded multivitamin supplementations respectively. One hundred and fifty (150) laying chickens used were completely randomized into five dietary treatments with three replicates of 10 birds each. Results showed that there was gross instability in the nutrients of mouldy maize. The activities of the fungi depleted both protein and lipid contents by 11.54% and 12.72% respectively while crude fibre content rose by 31.7%. There was substantial drop in both retinol and tocopherol while aflatoxin content rose to 267 μg in mouldy corn and 118 μg in the mouldy diets. Feed intake was significantly (P < 0.05) reduced and consequently depressed (P < 0.05) egg production and feed efficiency. Egg quality differs (P < 0.05) in shell thickness and yolk colour. Proliferation of biliary duct epithelium, hepatic degeneration, cellular infiltration, hyper-cellularity or dilation of the sinusoidal spaces characterized livers of birds on mouldy corn diets while supplementation with vitamins subverted mycosis and aflatoxicosis as evidenced by normal-to-mild congestion of hepatocytes. It was concluded that mould contamination in feed compromised feed nutritive values, reduced bird performance and adversely impaired the liver of the experimental birds while tocopherol, retinol or a multivitamin supplementation relapses the damaging potential of mould and mycotoxin differently.

Effects of Different Selenium Sources on Laying Performance, Egg Selenium Concentration, and Antioxidant Capacity in Laying Hens

Supplementation of selenium (Se) is a common practice in the poultry industry via sodium selenite (SS) and selenium yeast (SY), while the effects of nano-selenium (NS) on laying hens are poorly known. This study aimed to compare the effects of NS, SS, and SY on productivity; selenium (Se) deposition in eggs; and antioxidant capacity in laying hens. A total of 288 30-week-old Brown Hy-line laying hens were randomly assigned into four dietary treatments, which included corn-soybean meal basal diet (Con) without Se sources and basal diets supplemented with 0.3 mg Se/kg as SS, SY, or NS, respectively. The results exhibited that Se-supplemented treatments achieved greater egg production, egg weight, and daily egg mass, also better feed conversion ratio than Con group (p < 0.05). Se supplementation significant increased egg Se concentration and decreased the egg Se deposition efficiency (p < 0.05), while SY or NS supplementation had higher Se deposition efficiency than SS group at 35 days (p < 0.05). Moreover, serum glutathione peroxidase (GSH-Px) activity increased in SS or NS group compared to Con group (p < 0.05). The glutathione peroxidase 4 (GPX-4) mRNA levels in liver were significantly higher (p < 0.05) in SS or SY group than in NS group, and mRNA levels of the methionine (Met) metabolism gene glycine N-methyltranserfase (GNMT) were markedly upregulated (p < 0.05) in SY group compared to SS or NS group. Taken together, the results revealed Se from SY is deposited into eggs more efficiently than Se from NS or SS, probably via enhancing the route of Met metabolism. Meanwhile, it might be concluded that SS or SY supplementation directly regulated GSH-Px activity via enhancing GPx4 level, whereas NS via GPx1, thus affecting body oxidation and development.

A non-targeted LC-HRMS approach for detecting exposure to illegal veterinary treatments: The case of cephalosporins in commercial laying Hens

Cephalosporins are of particular importance in human medicine and should be reserved for second-line curative treatment in the veterinary field to avoid any emerging antimicrobial resistance. Due to misuse of ceftiofur in the poultry sector in France, it is now recommended to completely stop using cephalosporins in this sector. Methods currently used for the control of veterinary practices are mostly based on liquid chromatography coupled to mass spectrometry in a targeted mode, including parent compounds and any major metabolites. The aim of the present study was to evaluate the relevance of untargeted metabolomic approaches to highlight a possible exposure of laying hens to cephalosporins using a predictive model including selected treatment biomarkers. An experimentation carried out on living animals involved the administration of cefquinome and ceftiofur. Three biological matrices-droppings, eggs and liver-were investigated. Metabolites were extracted and analysed by liquid chromatography coupled to high resolution mass spectrometry in a full scan mode. Metabolites impacted by the treatment were selected by using univariate and multivariate statistical analyses. Predictive models built from the potential biomarkers selected in the "droppings" matrix were validated and able to classify "treated" and "control" hens. PLS-DA and logistic regression models were compared and both models gave satisfactory results in terms of prediction. Results were of less interest for other matrices in which only biomarkers of exposure to cefquinome were detected.

Integrating miRNA and mRNA expression profiles in plasma of laying hens associated with heat stress

High temperature is one of the most common environmental stressors plaguing animal husbandry worldwide. Little is known about the regulatory roles of miRNAs in response to heat stress in laying hens. To systematically identify heat stress-responsive miRNAs and their targets in laying hens, the differential expression of miRNAs and mRNAs was compared under heat stress and normal temperature. We identified 16 miRNAs and 502 genes that were significantly changed in heat-stressed laying hens. By comparing the differentially expressed genes (DEGs) and the putative targets of the altered miRNAs based on bioinformatics prediction, 82 coordinated genes were identified. Gene ontology classification analyses of the 82 putative target genes showed that the biological category 'cellular response to stress' was prominently annotated. Notably, the response-related gene autophagy-related protein 9A was most likely controlled by the upregulated miRNAs gga-miR-92-5p, gga-miR-1618-5p, gga-miR-1737, and gga-miR-6557 in response to heat stress. Analysis of DEGs also revealed an increase in lipid metabolism in heat-stressed laying hens. Some of these genes were negatively correlated with the altered miRNAs, suggesting that they are potential targets of the miRNAs. Taken together, our results advance our understanding of the regulatory mechanism of heat-stress-induced injury in laying hens, specifically with regard to miRNAs.

Role of genome-wide mRNA-seq profiling in understanding the long-term sperm maintenance in the storage tubules of laying hens

Sperm storage function of the sperm storage tubules (SSTs) is directly correlated with the fertility of laying hens. SSTs are located at the utero-vaginal junction (UVJ) and infundibulum of the hen oviduct. However, little is known about the cellular and molecular mechanisms responsible for long-term sperm maintenance in the lumen of the SSTs. In this study, we profiled transcriptomes to detect the different gene expressions between infundibulum and UVJ using RNA-seq. As a result, we identified a total of 1382 differentially expressed genes (DEGs). GO analysis showed that fat acid metabolism, regulation of cell differentiation, regulation of transport, and immune response were enriched for these DEGs, and many of the pH-regulatory functions genes such as CAIV and SLC4A4 were highly expressed in UVJ, which inferred that SSTs could preserve sperm by regulating physiological functions in UVJ. Our results provide new insight to understand the specific function for SSTs to extend sperm life span in the oviduct of laying hens.

Effect of supplementing layer hen diet with phytogenic feed additives on laying performance, egg quality, egg lipid peroxidation and blood biochemical constituents

This study was conducted to evaluate the effects of supplementing laying hen diet with phytogenic additives on laying performance, egg quality, blood constituents and egg lipid peroxidation. Two hundred Lohmann Brown Lite laying hens were randomly allotted to 4 dietary treatments: control (without phytogenic additive), fennel seeds (5 g/kg), black cumin seeds (5 g/kg) and hot red pepper (5 g/kg). Each of the 4 diets was fed to 5 replicates of 10 hens for 8 weeks. No significant differences were observed in body weight or feed intake between the groups. Dietary inclusion of fennel followed by red pepper improved (P < 0.05) egg weight, egg production, egg mass and feed conversion ratio compared with control. Higher yolk shape index, shell and albumen weight percentages and Haugh unit (P < 0.05) were recorded in the fennel supplemented group compared with control. The egg yolk color score increased by the addition of fennel or hot red pepper in laying hen diets compared with control. The inclusion of black cumin or hot red pepper decreased serum and egg yolk cholesterol and malondialdehyde concentrations (P < 0.05) compared with control. Serum aspartate aminotransferase concentration was lower in black cumin group (P < 0.05) than in other treatments. In conclusion, the best laying performance and egg quality were obtained by dietary inclusion of fennel, followed by hot red pepper and black cumin. Dietary supplementation of black cumin or red pepper may lead to the development of low-cholesterol concentration and better antioxidant capacity of eggs.

Circadian calcium feeding regime in laying hens related to zinc concentration, gene expression of circadian clock, calcium transporters and oxidative status

The study was conducted to investigate the effects of different circadian calcium feeding regimes on parameters of Zn status and gene expression of circadian clock, calcium transporters and oxidative status in laying hens. In total, 180 of 41-weeks Brown Hy-line laying hens were assigned randomly into three groups, 1-CON group (Control Ca, diets contained 3.4% Ca at both 0730 and 1530 h), 2-HL group (High-low Ca, diets contained 3.6%-3.2% Ca respectively) and 3-LH group (Low-high Ca, diets contained 3.2%-3.6% Ca respectively), which were fed a certain amount of control diet at 0730 h and 1530 h. Blood, tibia, jejunum and kidney samples were collected at 4 h intervals with initial starting at 0800 h after 10 weeks of experiment. Compared with the CON group: 1) the serum zinc in HL group increased at 2000 h, but lower at 1600 h in LH group (P < 0.05). 2) in jejunum, circadian clock genes including CLOCK and BMAL1 expression of HL group were down-regulated at 0000 h and 1600 h, as well as CLOCK, BMAL1, Cry2, Per3 and calcium transporter gene NCX1 in LH group at 2000 h (P < 0.05). 3) in kidney, CLOCK, Cry1, Cry2 and Per3 of LH group were up-regulated at 0400 h, CLOCK at 0000 h as well, while CLOCK at 2000 h were down-regulated (P < 0.05). 4) in kidney, the calcium transporters including PMCA, CaBP and CA of LH group were up-regulated at 0000 h, but PMCA and CaBP of LH group were down-regulated at 0800 h, 1200 h and 1600 h, as well as CA at 1600 h and PMCA at 2000 h of LH group (P < 0.05), and the oxidative gene SOD of the LH group was up-regulated at 0400 h, as well as CAT at 0400 h, SOD and GPX1 at 1200 h in HL group, but SOD at 1600 h and 2000 h, and GPX1 at 1600 h were down-regulated in LH group (P < 0.05). These results demonstrated that the dynamic circadian calcium feeding regime affected circadian rhythms of serum zinc concentration as well as the expression of certain genes related to the circadian clock, calcium transport and antioxidative capacity, and circadian calcium feeding regimes may therefore be considered with regard to improving the calcium usability.

Effects of Modified Palygorskite Supplementation on Egg Quality and Mineral Element Content, and Intestinal Integrity and Barrier Function of Laying Hens

This study was conducted to investigate effects of modified palygorskite (MPal) supplementation on the laying performance, egg quality and mineral element content, immunity, oxidative status, and intestinal integrity and barrier function of laying hens. A total of 360 52-week-old Hyline Brown hens were randomly assigned into four dietary treatments for a 7-week feeding trial. The birds were fed a basal diet supplemented with 0 (control group), 0.25, 0.5, and 1 g/kg MPal, respectively. The supplementation of MPal did not alter laying performance and egg quality among groups. Compared with the control group, MPal inclusion decreased lead (Pb) content in yolks at 49 days, and either 0.5- or 1-g/kg MPal supplementation decreased Pb accumulation in yolks at 25 days and manganese (Mn) accumulation in yolks at 25 and 49 days. The contents of jejunal secretory immunoglobulin A (SIgA), ileal SIgA, and immunoglobulin G were decreased by the dietary 0.5-g/kg MPal supplementation. The supplementation of MPal also decreased malondialdehyde content in jejunum and ileum, and decreased serum diamine oxidase activity of the laying hens at 25 and 49 days. The inclusion of 0.5 and 1 g/kg MPal enhanced villus height in jejunum and ileum, and also increased the ratio of villus height to crypt depth in ileum. In conclusion, MPal supplementation decreased Pb and Mn contents in yolks, and exhibited beneficial effects on the intestinal immunity, oxidative status, and intestinal integrity and barrier function of laying hens and its optimal dosage was 0.5 g/kg.

Fatty liver haemorrhagic syndrome occurrence in laying hens: impact of production system

Surveys were conducted with cage and alternative layer production systems to assess the prevalence of fatty liver haemorrhagic syndrome (FLHS). Commercial caged laying hens of different ages from three farms in Queensland were monitored for three months. The mortality rate of flocks ranged from 0.8% (the youngest flock) to 11.6% (the oldest flock). Six hundred and fifty-one birds were necropsied, and approximately 40% of hens died due to FLHS. Hens kept in cages in a controlled environment shed, were at a similar risk of developing FLHS to hens kept in naturally controlled sheds, however, the heavier birds in a flock were more likely to have the condition than lighter birds. In another study, layer flocks kept in cage, barn and free-range housing systems at the University of Queensland facility, were monitored for 50 weeks. Data from necropsies and performance records showed no significant differences in mortality rates between the housing systems (6.1%, 6.4% and 5.8%, for cages, barns and free-range, respectively), but the cause of mortality was different. In cages, 74% of necropsied hens died due to FLHS. In the other systems, only 0-5% of dead hens were diagnosed with the condition. These results are in agreement with previous Australian and overseas findings which have shown that FLHS is one of the main causes of hen death in caged flocks. Factors associated with husbandry practices in different production systems, such as restricted movement, increased production and temperature variations, influence hepatic lipid metabolism and predispose hens to FLHS.

Toxicological Effects of Mercury Chloride on Laying Performance, Egg Quality, Serum Biochemistry, and Histopathology of Liver and Kidney in Laying Hens

The objective of this study was to determine the effects of mercury chloride (HgCl₂) on laying performance, egg quality, hepatic and renal histopathology, and serum biochemical profiles in laying hens. A total of 768 Hy-line brown laying hens aged 40 weeks were randomly allocated to four groups (8 pens per group and 24 hens per pen). The concentrations of mercury (Hg) in four groups were 0.280, 3.325, 9.415, and 27.240 mg/kg. Results revealed that dietary Hg could significantly reduce laying performance (P < 0.05) and egg quality (P < 0.05) and was dose-dependently deposited in albumen, yolk, eggshell, and whole egg. Meanwhile, the thicknesses of palisade layer, mammillary layer, and total layer, and the percent of palisade layer were significantly decreased (P < 0.05), while the percent of mammillary layer was sharply increased (P < 0.05) in eggshell. In addition, with increasing dietary dosage of Hg, accumulation of Hg in viscera was significantly increased (P < 0.05), and histopathological damages in liver and kidney were more and more severe. Serum alanine aminotransferase, aspartate aminotransferase, and globulin were significantly increased (P < 0.05), while serum albumin and albumin to globulin ratio were significantly decreased (P < 0.05) in 27.240 mg/kg Hg group. Blood urea nitrogen, uric acid, and creatinine were significantly increased (P < 0.05) in 3.325, 9.415, and 27.240 mg/kg Hg groups. These results suggested that dietary HgCl₂ could reduce laying performance and egg quality with hepatic and renal function disorders in laying hens.