Search Results (77)

The objective of this study was to evaluate the effect of two limestone granulometries (0.568 and 1.943 mm) and different levels of vitamin D3 (12.5 g and 25 g) on the thermoregulatory and behavioral responses of replacement pullets. Lohman brown lineage pullets (270 birds), with an average weight of 639.60 g ± 6.05 and an initial age of eight weeks, were used in this study. The experimental design adopted was completely randomized in a 2 × 2 × 2 + 1 factorial arrangement (2 limestone granulometries × 2 levels of vitamin D3 × 2 shifts). The respiratory rate (RR), cloaca temperature (CT), feather surface temperature (FST) and featherless surface temperature (FLST) were higher in the afternoon (p < 0.05), while the thermal gradient (TG) was higher in the morning (p < 0.05). Birds supplemented with different limestone granulometries and different levels of vitamin D3 showed similar thermoregulatory and behavioral responses. The “eating” activity was more frequent in the morning, while in the afternoon, the birds remained seated for longer (p < 0.05). The dietary supplementation with different limestone granulometries and vitamin levels did not impair thermoregulation even at higher temperatures. Regardless of the level of vitamin D3, they showed a better expression of welfare-related behavioral activities in the morning in the semiarid region. Full article

Venerupis corrugata (pullet carpet shell) is a premium native clam species in Portugal. This species is highly perishable, typically sold live within 3 or 4 days, posing a significant risk of loss. Therefore, efforts to extend its shelf-life are relevant. The impact of the storage temperature (3, 5, 8 and 12 °C) on clams in plastic net bags and the effect of modified atmosphere packaging (MAP) were investigated. The survival percentage and microbiological and chemical parameters were evaluated, as well as sensory characteristics. The survival percentage and sensory aspects results indicate that the longest time with 95% live clams was observed at 5 °C and 8 °C, but lower temperatures (3 and 5 °C) have lower death rates after the threshold. In the MAP tests, the clams were kept closed due to confinement in plastic trays applying a vacuum, before gas flushing that drew the lid film over the clams. However, a negative effect of CO₂ was observed for clams, with lower survival when packaged in 30% CO₂. The shelf-life increased by only 1–2 days under >70% O₂ with no CO₂. These results show that this species is very sensitive, and MAP is not commercially effective for this application. Full article

This research aimed to assess body weight (BW) at the end of the brooding period in affecting Hyline Brown laying hens aged 6 to 72 wks from the aspects of growth performance, egg quality, sexual maturity, and productive performance. Pullets (6 wk old, n = 640) were sorted into two groups according to BW: normal (460.75 ± 10.82 g) and light (347.96 ± 6.27 g, 75.52% of normal weight), with eight replicates of 40 pullets each. All the hens, when reaching 6–72 wks in age, took the same diets by stages ad libitum. The heavier BW in the normal weight group (NWG) at 6 wks of age compared to lighter weight group (LWG) birds continued until 22 wks (p < 0.05). Similarly, a smaller coefficient of variation (CV) for BW of chicks in the LWG was detected at 19 (p < 0.01), 20 (p < 0.01), and 21 (p < 0.05) wks of age compared with that in the NWG. The body slope length and the shank circumference of pullets in the LWG were smaller than in the NWG at the age of 15 wks (p < 0.01), but the difference gradually disappeared by 20 wks of age (p > 0.05). The LWG presented raised ages of hens when producing the first egg and 5% eggs (p < 0.01), while the CV for the age at first egg decreased, compared with the CV in the NWG (p < 0.05). The total egg number (p < 0.05), laying rate (p < 0.05), and egg mass (p < 0.01) of laying hens in the LWG decreased at the age of 18–72 wks, and the CV for individual egg numbers (p < 0.05) increased compared with the CV in the NWG. Compared with the normal weight hens, the proportion of lighter weight hens laying more than 250 eggs at the age of 18–72 wks was significantly reduced (p < 0.05, 69.52% vs. 87.38%), while the proportion of hens laying less than 200 eggs was significantly increased (p < 0.05, 24.97% vs. 3.76%). In summary, BW by the end of the brooding period can be a good indicator reflecting individual differences among laying hens and may serve as an important phenotypic indicator for evaluating laying performance and early elimination of unqualified laying hens in layer production. Therefore, it is recommended that pullets weighing 25% or more below the normal flock weight at the end of the brooding period should be culled at this time. Full article

The concerns regarding Fowl Adenoviruses have gained significance in the poultry industry due to their association with various diseases, including Inclusion Body Hepatitis, Hepatitis-Hydropericardium Syndrome, and Adenoviral Gizzard Erosion (AGE). AGE is an emerging disease reported in several countries, particularly in Asia and Europe, causing significant economic losses in the poultry industry. In 2001, Fowl Adenovirus Serotype 1 was identified as the etiological agent of AGE in Japan. Since then, it has been spreading to other countries due to its transmission mode. Although Adenoviral Gizzard Erosion has been mostly described in broilers, it has also been observed in layers and pullets. This review offers a comprehensive analysis of Fowl Adenovirus Serotype 1, encompassing various key aspects of the virus. We also examine the pathogenesis and epidemiology of the virus, providing an overview of its distribution and prevalence in avian populations worldwide. Highlighting the most recent developments in serological and molecular techniques for virus detection, quantification, and genotyping and comparing them to conventional tests, this review aims to contribute to the understanding of the diagnostic workflow for this virus. Lastly, this review sheds light on some vaccine strategies to prevent Adenoviral Gizzard Erosion. Full article

Selection for water consumption could impact broiler breeders’ immune capabilities. To assess these impacts of selection based on the water conversion ratio (WCR), three trials were conducted using broiler breeders from the modern random bred (MRB), low (L)WCR, and high (H)WCR lines. Ten- to 11-week-old male broilers received intradermal (i.d.) growing feather (GF)-pulp injections of LPS (Trial 1) or PGN (Trial 2), to assess local (GF-pulp) and systemic (blood) inflammatory responses over 24 h and 72 h p.i., respectively. Measurements included leukocyte profiles in GF-pulps and blood, GF cytokine mRNA expression and reactive oxygen species (ROS) generation, and plasma concentrations of α1-acid glycoprotein (AGP-1). In Trial 3, 14-week-old pullets were immunized by i.d. GF-pulp injection of SEV (10⁸ CFU/mL). Leukocyte profiles in the GF-pulp and blood were measured over 72 h and plasma levels of SEV-specific IgM, IgY(G), and IgA antibodies over 4 weeks p.i. Independent of the line, phagocytes infiltrated GF-pulps by 6 h post-LPS injection (p ≤ 0.05), while lymphocytes were the major leukocyte recruited in response to PGN (p ≤ 0.05). However, with both LPS and PGN, HWCR broilers were less effective in recruiting lymphocytes than MRB and LWCR broilers, which had similar lymphocyte infiltration levels. There were no line differences in GF-pulp cytokine mRNA expression and ROS generation, nor in blood leukocyte and AGP-1 concentrations, following LPS injections. Independent of the line, SEV immunization stimulated similar phagocyte recruitment profiles; however, the LWCR and MRB lines had a higher infiltration of lymphocytes (esp. B cells) than the HWCR line (p ≤ 0.05). Independent of the line, SEV immunization triggered a robust, high-quality, primary SE-specific antibody response (p ≤ 0.05). Collectively, selection for improved water efficiency in the LWCR broiler breeder lines did not negatively impact immune response capabilities to LPS, PGN, and a killed SEV. Full article

Background/Objectives: Commercial poultry flocks undergo Salmonella vaccinations to manage salmonellosis outbreaks. Due to reports of severe injection site reactions to Salmonella bacterins, assessment of local inflammatory responses is necessary. The objective was to assess local inflammatory and systemic humoral immune responses to commercial autogenous Salmonella bacterin vaccines (SV1 or SV2) following primary or secondary intradermal (i.d.) vaccination in Light-Brown Leghorns (LBLs). Methods: LBL pullets received primary (14 wks) or secondary (19 wks) vaccination by i.d. growing feather (GF) pulp injection of SV1, SV2, Salmonella Enteritidis (SE) lipopolysaccharide (LPS), or water–oil–water emulsion (V). Local leukocyte levels and relative cytokine mRNA expression were monitored before (0 d) and at 6 h, 1 d, 2 d, 3 d, 5 d, and 7 d post-GF pulp injection (p.i.). Blood was collected through 28 d post-primary or -secondary vaccination, and SE-specific antibodies were quantified via ELISA. Results: Primary vaccine administration increased local heterophil and macrophage levels and increased IL-6 and IL-8 mRNA expressions at 6 h p.i., independent of treatment. Secondary administration extended these local immune activities through 3 d p.i. and included prolonged IL-17A mRNA expression. Primary and secondary GF-pulp injection with V resulted in rapid lymphocyte recruitment by 6 h p.i., comprised primarily of CD4⁺ and γδ T cells. SV1 and SV2 also produced a T-dependent systemic humoral immune response, as indicated by the IgM-to-IgG isotype switch, along with a memory phenotype in the secondary response. Conclusions: These commercial-killed Salmonella vaccines, when prepared in water–oil–water emulsions, stimulated prolonged innate and T helper (Th) 17-type inflammatory responses at the injection site and produced a classic systemic humoral immune response after a second vaccination. Further research is needed to determine if extended inflammation influences adaptive immune responses in eliminating Salmonella infection. Full article

Background: Two high primary-immunization doses of a wild-type E. tenella strain were assessed in healthy pullets (5K versus 10K sporulated oocysts/bird) to understand the effects of coccidia infection. Methods: Acquired immunity was evaluated following primary immunization and two booster doses with the homologous strain. Total oocyst shedding, clinical signs, and viability of every bird/group after each immunization/booster were recorded. Indirect ELISA measured the time course of humoral responses from each immunization group against sporozoite and second-generation merozoite of E. tenella. Antigen pattern recognition on these two asexual zoite stages of E. tenella was analyzed using Western blotting with antibodies from each immunization program. Afterwards, antigen recognition of specific life-cycle stages was performed using individual pullet serums from the best immunization program. Results: A primary-immunization dose of 1 × 10⁴ oocysts/bird reduced the oocyst output; however, all pullets exhibited severe clinical signs and low specific antibodies titers, with decreased polypeptide recognition on both E. tenella asexual zoite stages. In contrast, immunization with 5 × 10³ oocysts/bird yielded the best outcomes regarding increased oocyst collection and early development of sterilizing immunity. After the first booster dosage, this group’s antisera revealed a strong pattern of specific antigen recognition on the two assayed E. tenella life-cycle stages. Conclusions: The E. tenella-specific antibodies from the 5 × 10³ oocysts/bird immunization program can aid in passive immunization trials and further research to identify B-cell immunoprotective antigens, which could help in the development of a genetically modified anticoccidial vaccine. Full article

Infectious bursal disease virus (IBDV) is an important pathogen affecting the poultry industry worldwide. IBDV serotype 1, including classical virulent strains (cvIBDV), variant strains (varIBDV), and very virulent strains (vvIBDV), is pathogenic for chickens. IBDV mainly infects immature B-lymphocytes in the bursa of Fabricius, weakening the humoral immune response and leading to secondary infections and increased morbidity and mortality. The Laboratory of Avian Pathology received ten live 8-week-old pullets from a laying hen operation experiencing increased mortality, prostration, diarrhea, and sudden death. Upon necropsy, the affected birds presented swollen, hemorrhagic, and edematous bursa of Fabricius, as well as hemorrhage in the breast and thigh muscles. RT-PCR confirmed that the samples from the bursa of Fabricius were positive for IBDV. Phylogenetic analysis of the VP1 and VP2 gene nucleotide sequences classified the strain, isolated in embryonated chicken eggs, as the A3B5 genotype. Amino acid sequence analysis of the VP2 hypervariable region revealed the presence of amino acid residues commonly found in vvIBDV. Additional studies are required to investigate the epidemiological situation of this genotype in Chile and to evaluate current vaccination plans and their effectiveness against new variants. Full article

The old Hungarian poultry breeds are the hidden reserves of the Carpathian Basin’s agriculture. The aim of this study was to examine the slaughter weight, carcass merit, and certain meat properties of two of them: the Partridge-colored Hungarian Chicken (PC) and the White Transylvanian Naked-neck Chicken (TN) under semi-intensive and traditional fattening conditions. Test slaughtering of chickens was conducted at 12th and 18th weeks of age. The eviscerated body weight (and the weight of cuts) of the PC (1140 g) and the cockerels of both breeds (1148 g) was larger than that of TN (878 g) and pullets (870 g). The farming system did not influence the carcass composition. At the same time, the pullets were characterized with larger values (p < 0.001) in regards to, for example, the breast–whole leg (0.81:1), breast fillet–thigh fillet (1.29:1), breast fillet–breast bone proportion (2.40:1) in comparison to the cockerels (0.7:1, 1.10:1 and 2.17:1, respectively). Examinations of meat quality revealed that the pH-value of the thigh (5.73 vs. 5.83) and breast meat (6.21 vs. 6.43) of the PC was significantly lower. However, the lightness (L*) of breast fillet was higher (55.2) than that in the TN (49.9). In addition, the yellowness (b*) value of the breast meat and breast skin was significantly higher in the PC, but the redness (a*) of the breast skin was higher in the TN. Results showed that the farming system affects these values, too. Accordingly, the yellowness (b*) of breast meat, breast skin, thigh meat, and thigh skin was significantly higher in the traditional group. The PC showed more satisfactory results in poultry production today. However, the reddish meat of the TN should be emphasized, which is excellent and appropriate in traditional agriculture. It is argued that the indigenous chicken breeds should be supported for the chicken meat trade regardless of their competitiveness. Full article

(1) Background: this study compared hydroxychloride and traditional oxide/sulfate sources of zinc (Zn), manganese (Mn), and copper (Cu) in ISA Brown pullet diets, focusing on growth, tibia strength, egg production, and eggshell quality. (2) Methods: in total, 120 pullets were divided into two groups, each with six replicates of 10 birds, receiving diets with hydroxychloride or oxide/sulfate sources of Mn, Zn, and Cu (65, 50, and 5 mg/kg, respectively) during rearing. At 16 weeks, 18 pullets per group transitioned to individual cages and were fed a standard diet with Mn-oxide, Zn-oxide, and Cu-sulfate until 50 weeks. (3) Results: pullets fed hydroxychloride minerals exhibited a higher feed conversion ratio (p = 0.023) and a trend toward higher average daily feed intake (p = 0.059) compared to those on oxide/sulfate sources during the rearing phase. During the laying phase, while no significant differences were observed in egg production until 24 weeks, hens previously fed hydroxychloride minerals demonstrated increased average daily feed intake and egg weight from 25 to 50 weeks of age (p < 0.05). (4) Conclusions: rearing diets supplemented with hydroxychloride minerals influenced feed intake and efficiency, with carryover effects that enhanced laying-phase performance. Full article

Changes in leukocyte populations and immune gene expression associated with attenuated vaccine (SA2) or field (Class 9) strains of infectious laryngotracheitis virus in chicken pullets were observed primarily in the trachea and conjunctiva, while no substantial changes were detected in the Harderian gland. Although there were no significant differences in cellular infiltration in the tissues exposed to Class 9 and SA2, Class 9 induced greater changes in immune gene expression than SA2 in the trachea and conjunctiva and significantly upregulated CD4, CD8A, IRF1, STAT4 and downregulated CXCL12 expression in the trachea. Meanwhile, SA2 significantly upregulated CD14 and downregulated MPO, CCR6 and RAG1 expression in the conjunctiva. In conclusion, gene expression in pullets infected with SA2 and Class 9 were mostly related to inflammatory and tissue-repairing responses in the trachea and conjunctiva. Compared to SA2, Class 9 inoculation was associated with a more robust gene expression of immune markers; however, a larger infiltration of Kul01+, Bu1+ and CD8a+ cells was observed in trachea and conjunctiva after SA2 inoculation. Full article

(a) Introduction: Zambia’s poultry industry comprises commercial chickens and small-scale producers of indigenous chickens (Gallus domesticus) (ICs). Large, integrated entities run the commercial chicken sector, while the indigenous chicken sector (IC sector) is predominantly run by small-scale farmers (SSFs). Increased costs and low access to formal markets for commercial chickens have motivated SSFs to enter the IC sector under the free-range system (FRS) and semi-intensive system (SIS). (b) Objective: This study aimed to highlight the price changes in poultry inputs and outputs and demonstrate that the IC sector has more potential to contribute to farm income than commercial chickens under family poultry production systems. (c) Method: We analysed the prices for inputs and outputs for Zambia’s poultry industry for the first quarter of 2016 to 2023 using data from the Poultry Association of Zambia (PAZ). We also analysed data from the 2021 Qualtrics survey to investigate the crops grown and crops used as feed and feed ingredients, the sources of feed, and the use of minerals and vitamins by SSFs for chickens. The gross profit (GP) and benefit–cost ratio (BCR) were analysed to compare the viability and profitability of ICs and broilers under SSFs. (d) Results: Our study shows that prices for day-old chicks (DOCs) and point-of-lay (POL) pullets increased by 57–125%, broiler and layer feeds increased by 67–96%, and soybean meal (SBM) and fishmeal rose by 143–229%. Prices for live ICs, commercial broilers, and ex-layers increased by 150%, 79%, and 71%, respectively. Egg prices rose by 100–124%. Farmers tried to look for local feed sources. Over 21% of the crops grown was maize, and nearly 43% was used for feed. (e) Conclusion: Our analysis and comparison between the ICs and broilers demonstrated that SSFs could achieve more farm income by producing ICs than commercial broilers. Full article

Vaccination strategies are used to manage Salmonella in chickens. Salmonella-killed vaccines are considered safer since they are inactivated. However, little is known regarding the cellular immune activities at the site of vaccine administration of Salmonella-killed vaccines. The growing feather (GF) cutaneous test has been shown to be an effective bioassay to monitor local tissue/cellular responses. We assessed local and systemic antibody responses initiated by intradermal injection of Salmonella-killed vaccines into GF-pulps of 14–15-week-old pullets. Treatments consisted of two autogenous Salmonella-killed vaccines (SV1 and SV2), S. Enteritidis (SE) lipopolysaccharide (SE-LPS), and the water-oil-water (WOW) emulsion vehicle. GF-pulps were collected before (0 h) and at 6, 24, 48, and 72 h post-GF-pulp injection for leukocyte population analysis, while heparinized blood samples were collected before (0 d) and at 3, 5, 7, 10, 14, 21, and 28 d after GF-pulp injections to assess plasma levels (a.u.) of SE-specific IgM, avian IgY (IgG), and IgA antibodies using an ELISA. Injection of GF-pulps with SV1, SV2, or SE-LPS, all in a WOW vehicle, initiated inflammatory responses characterized by the recruitment of heterophils, monocytes/macrophages, and a few lymphocytes. The WOW vehicle emulsion alone recruited more lymphocytes than vaccines or SE-LPS. The SV1 and SV2 vaccines stimulated Salmonella-specific IgM and IgA early, while IgG levels were greatly elevated later during the primary response. Overall, SV1 and SV2 stimulated a heterophil and macrophage-dominated local inflammatory- and SE-specific humoral response with an isotype switch from IgM to IgG, characteristic of a T-dependent primary antibody response. This study provides comprehensive information on innate and adaptive immune responses to autogenous Salmonella-killed vaccines and their components that will find application in the management of Salmonella in poultry. Full article

As hen body weight (BW) impacts egg weight (EW) and feed efficiency, egg producers prefer pullets of a specific size to enter the egg-laying cycle. Lighting and feeding programs were tested to achieve target Hy-Line Brown pullet BW. Three feeding programs were implemented: ad libitum (ad lib); feeding to achieve breed standard weight for age (BSW); and feeding to achieve 88% BSW (managed). The feeding programs were used with either control lighting (CL: 10 h light/d from 7 weeks of age (WOA)) or reduced lighting (RL: 9 h light/d from 4 WOA). One-hundred and fifty pullets were assigned to each feeding program by lighting treatment during rearing. At 16 WOA, 70 pullets from each treatment during rearing were moved to cages and onto ad libitum feeding under a step-up photoperiod reaching 16 h light/d at 33 WOA. The age and weight of the first egg, hen BW, feed intake (FI), egg production (EP), and EW were measured until 36 WOA. At 16 WOA, pullets reared with ad lib feeding under CL had higher BW and cumulative FI (CFI) compared to ad lib feeding under RL. The latter were the earliest to lay, and the managed pullets under CL were the last to lay. Control lighting and BSW independently generated the heaviest first eggs. At 36 WOA, BW, EW, CFI, and cumulative egg production (CEP) were highest following ad lib feeding during rearing, while rearing under CL generated higher BW and EW but lower CEP than RL. Hence, lighting and feeding programs throughout rearing can regulate pullet growth, FI, and hen performance throughout early lay. Full article

The food chain acts as an entry point for antibiotic resistance to reach humans and environment. Because of the importance of the poultry sector, we investigated the prevalence and evolution of antibiotic resistance in Escherichia coli isolates from a series of 14,500 breeding hens and their farm environment during the rearing period. Samples included meconium from one-day-old breeders and fecal samples and boot swabs from the breeding sheds of pullets and adult hens. All E. coli isolates from one-day-old chicks, 77% from feces and 61% from boot swabs, were resistant to at least one antibiotic. Cefotaxime and multi-drug resistance in fecal isolates decreased during the rearing period from 41.2% and 80.8% in one-day-old chicks to 3.8% and 33.8% in adults. All genes studied were detected in E. coli from feces and boot swabs, the most common being bla_TEM (75%), bla_SHV (72%), and qnrB (67%). bla_CMY-2 was detected in 100% of one-day-old breeders. The combination of at least one cephalosporin and one quinolone resistance gene was detected in 68.7% of fecal and boot swab isolates. Our results highlight the need to monitor the prevalence of antibiotic resistance on farms and to take appropriate measures to reduce the risk to public and environmental health. Full article