We describe a genetic variation map for the chicken genome containing 2.8 million single-nucleotide polymorphisms (SNPs). This map is based on a comparison of the sequences of three domestic chicken ...breeds (a broiler, a layer and a Chinese silkie) with that of their wild ancestor, red jungle fowl. Subsequent experiments indicate that at least 90% of the variant sites are true SNPs, and at least 70% are common SNPs that segregate in many domestic breeds. Mean nucleotide diversity is about five SNPs per kilobase for almost every possible comparison between red jungle fowl and domestic lines, between two different domestic lines, and within domestic linesin contrast to the notion that domestic animals are highly inbred relative to their wild ancestors. In fact, most of the SNPs originated before domestication, and there is little evidence of selective sweeps for adaptive alleles on length scales greater than 100 kilobases.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Gut microbial colonization and development of immune competence are intertwined and are influenced by early-life nutritional, environmental, and management factors. Perturbation of the gut microbiome ...at young age affects the crosstalk between intestinal bacteria and host cells of the intestinal mucosa.
We investigated the effect of a perturbation of the normal early life microbial colonization of the jejunum in 1-day old chickens. Perturbation was induced by administering 0.8 mg amoxicillin per bird per day) via the drinking water for a period of 24 h. Effects of the perturbation were measured by 16S rRNA profiling of the microbiome and whole genome gene expression analysis. In parallel to what has been observed for other animal species, we hypothesized that such an intervention may have negative impact on immune development. Trends were observed in changes of the composition and diversity of the microbiome when comparing antibiotic treated birds with their controls. in the jejunum, the expression of numerous genes changed, which potentially leads to changes in biological activities of the small intestinal mucosa. Validation of the predicted functional changes was performed by staining immune cells in the small intestinal mucosa and a reduction in the number of macrophage-like (KUL01
) cells was observed due to a direct or indirect effect of the antibiotic treatment. We provide evidence that a short, early life antibiotic treatment affects both the intestinal microbiota (temporarily) and mucosal gene expression over a period of 2 weeks.
These results underscore the importance of early life microbial colonization of the gut in relation to immune development and the necessity to explore the capabilities of a variety of early life dietary and/or environmental factors to modulate the programming for immune competence in broilers.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Circular RNA (circRNA) is a type of noncoding RNA involved in a variety of biological processes, especially in post-transcriptional regulation. The granulosa cells of follicles play a determining ...role in ovarian development. However, the function of circRNA in chicken follicles is unclear. To better understand the molecular mechanism underlying follicular development and granulosa cell function, we performed a strategy of second-generation sequencing and linear RNA depletion for granulosa cells from small yellow follicles (SYF, 5-8 mm), the smallest hierarchal follicles (F6, 9-12 mm), and the largest hierarchal follicles (F1, ~ 40 mm).
We predicted a total of 11,642 circRNAs that distributed on almost all chromosomes. The majority of the splice lengths of circRNAs were 200-500 nt and mainly produced from intron and CDS regions. During follicle growth, differentially expressed (DE) circRNAs showed dynamic changes which were tissue- and stage-specific. The host genes of DE circRNAs were functionally enriched in GTPase activity and several pathways involved in reproduction. Moreover, bioinformatic prediction analysis for circRalGPS2 demonstrated that circRNAs from the same genes may share common miRNA to act as a sponge. The predicted target genes were enriched in various biological processes including cognition, cell communication, and regulation of signaling, and several pathways related to reproduction such as tight junction, oocyte meiosis, progesterone-mediated oocyte maturation, and GnRH signaling.
This study provides a starting point for further experimental investigations into chicken circRNAs and casts a light on the understanding of follicle development.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The aim of this study was to investigate effects of L-threonine (L-Thr) supplementation on the growth performance, immunity, antioxidant status, and intestinal health of broilers at the early age. ...One hundred and forty-four 1-day-old male broiler chicks (Arbor Acres Plus) were allocated into 3 treatments with 6 replicates of 8 birds each, and fed a basal diet (analyzed Thr content, 7.87 g/kg) supplemented with 0 (control diet), 1 and 3 g/kg L-Thr for 21 d, respectively. Treatments did not alter growth performance of broilers. Compared with control, 1 g/kg Thr supplementation increased relative weight of spleen (P = 0.013). A higher level of Thr (3 g/kg) increased relative weight of thymus (P = 0.003). The supplementation of 3 g/kg Thr reduced Escherichia coli (P = 0.040) and Salmonella colonies (P = 0.015), whereas increased Lactobacillus colonies (P < 0.001) in the cecal contents. Thr supplementation increased intestinal villus height (P < 0.05), and the ratio of villus height to crypt depth (P < 0.001), and the values for these parameters were intermediate with 1 g/kg Thr. Goblet cell density was increased by Thr supplementation (P < 0.001). The jejunal immunoglobulin G content was increased by the inclusion of Thr (P = 0.002). Broilers fed diet supplemented with 1 g/kg Thr exhibited increased concentrations of jejunal immunoglobulin M (P = 0.037) and secretory immunoglobulin A (P = 0.018). Likewise, 3 g/kg Thr inclusion increased ileal secretory immunoglobulin A content (P = 0.023). The jejunal malondialdehyde accumulation was reduced by Thr inclusion (P = 0.012). A higher level of Thr inclusion also reduced malondialdehyde content in the serum (P = 0.029). The high level of Thr inclusion (3 g/kg) upregulated mucin-2 mRNA expression (P = 0.034), whereas downregulated the mRNA abundances of interferon-γ (P = 0.036) and interleukin-1β (P = 0.031) in the ileum. In conclusion, L-Thr supplementation can improve immunity, antioxidant capacity, and intestinal health of broilers at an early age.
Domesticated animals share a unique set of morphological and behavioral traits, jointly referred to as the domesticated phenotype. Striking similarities amongst a range of unrelated domesticated ...species suggest that similar regulatory mechanisms may underlie the domesticated phenotype. These include color pattern, growth, reproduction, development and stress response. Although previous studies have focused on the brain to find mechanisms underlying domestication, the potential role of the pituitary gland as a target of domestication is highly overlooked. Here, we study gene expression in the pituitary gland of the domesticated White Leghorn chicken and its wild ancestor, the Red Junglefowl. By overlapping differentially expressed genes with a previously published list of functionally important genes in the pituitary gland, we narrowed down to 34 genes. Amongst them, expression levels of genes with inhibitory function on pigmentation (ASIP), main stimulators of metabolism and sexual maturity (TSHB and DIO2), and a potential inhibitor of broodiness (PRLR), were higher in the domesticated breed. Additionally, expression of 2 key inhibitors of the stress response (NR3C1, CRHR2) was higher in the domesticated breed. We suggest that changes in the transcription of important modulatory genes in the pituitary gland can account not only for domestication of the stress response in domestic chickens, but also for changes in pigmentation, development, and reproduction. Given the pivotal role of the pituitary gland in the regulation of multiple shared domesticated traits, we suggest that similar changes in pituitary transcriptome may contribute to the domesticated phenotype in other species as well.
An experiment was conducted to investigate the supplementation of direct-fed microbials (DFM) as an alternative to antibiotics on growth performance, immune response, cecal microbial population, and ...ileal morphology of broiler chickens. A total of 800 one-day-old male broiler chicks (Ross × Ross) were randomly allotted to 4 dietary treatments with 4 replicate pens per treatment (50 birds/replicate pen). The 4 dietary treatments fed for 35 d were a corn-soybean meal basal diet (control); control plus 0.1% virginiamycin, as an antibiotic growth promoter (AGP); control plus 0.1% direct-fed microbials that contained Lactobacillus reuteri (DFM 1); and control plus 0.1% direct-fed microbials that contained a mixture of L. reuteri, Bacillus subtilis, and Saccharomyces cerevisiae (DFM 2). Results showed that dietary AGP and DFM supplementation significantly increased (P < 0.05) the BW gain of broilers during 0 to 21 d. The feed intake was reduced, whereas the feed conversion was improved significantly when birds were fed DFM 2 at 0 to 7 d of age. The white blood cell and monocyte levels were significantly higher in the DFM 2 group compared with the control. In addition, feeding DFM significantly (P < 0.05) increased the plasma immunoglobulin levels where a higher level was observed in DFM 2 compared with those of the other treatments. Neither DFM nor AGP treatments affected the cecal Lactobacillus and Salmonella content; however, cecal Escherichia coli content significantly decreased in broiler chickens fed DFM and AGP. The ileal villus height, and width and total thickness of muscularis externa were significantly increased when birds were fed DFM compared with AGP and control. These results indicate that the dietary supplementation of DFM increases the growth performance of birds at an early age, stimulates the immune response, decreases the number of E. coli, and improves the ileal morphology of broiler chickens. Thus, DFM that contained a mixture of several beneficial microorganisms could be a viable alternative to antibiotics in the broiler diets.
•ND vaccines without biosecurity may not control ND, especially in endemic countries.•Better understanding of the reasons for “vaccine failure” is needed.•A regular review of field vaccination ...protocols is necessary to ensure adequate application and response to emerging strains.•Vaccines that provide antigens matched to circulating strains induce more specific humoral responses.•Antigenically matched vaccines are more effective in decreasing viral shedding.
Newcastle disease (ND) has been defined by the World Organisation for Animal Health as infection of poultry with virulent strains of Newcastle disease virus (NDV). Lesions affecting the neurological, gastrointestinal, respiratory, and reproductive systems are most often observed. The control of ND must include strict biosecurity that prevents virulent NDV from contacting poultry, and also proper administration of efficacious vaccines. When administered correctly to healthy birds, ND vaccines formulated with NDV of low virulence or viral-vectored vaccines that express the NDV fusion protein are able to prevent clinical disease and mortality in chickens upon infection with virulent NDV. Live and inactivated vaccines have been widely used since the 1950’s. Recombinant and antigenically matched vaccines have been adopted recently in some countries, and many other vaccine approaches have been only evaluated experimentally. Despite decades of research and development towards formulation of an optimal ND vaccine, improvements are still needed. Impediments to prevent outbreaks include uneven vaccine application when using mass administration techniques in larger commercial settings, the difficulties associated with vaccinating free-roaming, multi-age birds of village flocks, and difficulties maintaining the cold chain to preserve the thermo-labile antigens in the vaccines. Incomplete or improper immunization often results in the disease and death of poultry after infection with virulent NDV. Another cause of decreased vaccine efficacy is the existence of antibodies (including maternal) in birds, which can neutralize the vaccine and thereby reduce the effectiveness of ND vaccines. In this review, a historical perspective, summary of the current situation for ND and NDV strains, and a review of traditional and experimental ND vaccines are presented.
Chicken intramuscular fat (IMF) content is closely related to meat quality and performance, such as tenderness and flavor. Abdominal fat (AF) in chickens is one of the main waste products at ...slaughter. Excessive AF reduces feed efficiency and carcass quality.
To analyze the differential deposition of IMF and AF in chickens, gene expression profiles in the breast muscle (BM) and AF tissues of 18 animals were analyzed by differential expression analysis and weighted co-expression network analysis. The results showed that IMF deposition in BM was associated with pyruvate and citric acid metabolism through GAPDH, LDHA, GPX1, GBE1, and other genes. In contrast, AF deposition was related to acetyl CoA and glycerol metabolism through FABP1, ELOVL6, SCD, ADIPOQ, and other genes. Carbohydrate metabolism plays an essential role in IMF deposition, and fatty acid and glycerol metabolism regulate AF deposition.
This study elucidated the molecular mechanism governing IMF and AF deposition through crucial genes and signaling pathways and provided a theoretical basis for producing high-quality broilers.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This study aimed to investigate the supplemental effects of probiotic Bacillus subtilis fmbJ (BS fmbJ) on growth performance, antioxidant capacity, and meat quality of broiler chickens. A total of ...240 day-old male Arbor Acres (AA) broiler chickens were randomly allotted to 4 treatments and raised for 6 wk. Each treatment had 6 replicate pens with ten birds per replicate. Birds in the control group (CON) were fed diets without BS fmbJ and antibiotics. The BS groups were fed the basal diets with BS fmbJ at 2 × 10
cfu/kg (BS-1 group), BS fmbJ at 3 × 10
cfu/kg (BS-2 group), BS fmbJ at 4 × 10
cfu/kg (BS-3 group) without antibiotics for 42 d. In the study, dietary supplementation with BS fmbJ significantly improved (P < 0.05) the average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) of broilers from 21 to 42 d and 1 to 42 d. At 42 d, the final body weight was increased (P < 0.05) in BS-2 group compared with that in CON. Dietary BS fmbJ significantly increased (P < 0.05) serum IgA and IgG concentrations of broilers after 42 days raising. The glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) activity of serum and liver were increased (P < 0.05), and methane dicarboxylic aldehyde (MDA) contents in serum and liver were decreased (P < 0.05) by BS fmbJ added into the broiler diets. Dietary supplementation with BS fmbJ significantly decreased (P < 0.05) reactive oxygen species (ROS) contents in liver mitochondria of broilers. Additionally, the expression of antioxidant enzyme gene including nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were improved (P < 0.05) by BS fmbJ added into the broiler diets. Among measuring items of chicken breast meat quality, the drip loss, cooking loss, shear force, L*
, a*
b*
and b*
values were influenced (P < 0.05) by BS fmbJ provided in the diet. Based on these results, Bacillus subtilis fmbJ could be acted as a beneficial feed additive with antioxidant capacity in broiler diets.
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