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•Variant IBDV (varIBDV)-SK 11 was the least immunogenic and antibody titer declined faster overtime.•varIBDV SK 09 elicited higher antibody response in breeder hen compared to other varIBDV strains.•varIBDV SK 10 specific maternal antibodies provided heterologous protection against varIBDV SK 09.•Challenge virus replicated more in chicks that gained maternal antibodies via commercial vaccines. The majority of infectious bursal disease virus (IBDV) strains circulating in the broiler chicken industry in Canada are variant strains (varIBDV). Despite high levels of maternally derived antibodies (MtAb), the circulating varIBDVs can establish infection and cause severe immunosuppression in broiler chicks. The objective of this study was to evaluate circulating varIBDVs as broiler breeder vaccine candidates and investigate their protective efficacy against varIBDV challenge in their progeny chicks. Six groups of breeders (20 females/group) were vaccinated with varIBDV strains, SK09, SK10, SK11, SK12, and SK13 or saline at the age of 13 weeks and antibody response was determined by ELISA at 3–7-, and 20- weeks post-vaccination. We also included commercial chicks for the comparison. Results showed that SK-09 is the most antigenic strain, followed by SK-10, SK-12, and SK-13. In contrast, SK-11 showed the lowest antibody response, and over time, antibody titers steadily decreased. Eggs from breeders were collected at 21-week post-vaccination and incubated to produce their respective progenies. The serum antibody titer in day-old chicks showed a successful MtAb transfer. Progeny chicks (n = 40/group) were orally challenged with varIBDV-SK-09 strain at 6 days of age and serum antibody titer (19 d and 35 d of age), bursa to body weight ratio (19 d and 35 d of age), bursal viral load (9 d and 19 d of age) was examined to assess the protection against IBDV. Following the challenge, we found a significant increase in the antibody titers in MtAb-free and commercial vaccine groups than in the varIBDV groups, both at 19 d and 35 d of age. The BBW ratio and viral load data indicated a significant homologous and heterologous protection against varIBDV-SK-09 challenge by SK-09 and SK-10 MtAbs, respectively. Overall, this study demonstrated the feasibility of developing breeder vaccines using circulating varIBDV as candidate vaccine antigens.

Currently, the poultry industry worldwide is facing an emerging trend of fowl adenovirus (FAdV)-associated diseases with a significant economic impact, especially in meat-type chickens. Vertical transmission is an important feature of all FAdVs; hence, preventive measures mostly revolve around breeding stocks. However, knowledge about temporal development of FAdV infections in modern commercial settings is rare or even nonexistent. In the present study, longitudinal monitoring for FAdV was conducted in broiler breeder flocks located in a confined geographical region with intensive poultry production in Iran. For this, the antibody status of birds from 4 to 32 wk of age was monitored with a commercial FAdV-ELISA and virus neutralization test (VNT). In parallel, fecal shedding of FAdV was determined at the peak of egg production with real-time PCR and virus isolation. Overall, the commercial ELISA showed seroconversion of flocks before onset of production. VNT resolved in detail infection patterns of individual serotypes with a primordial FAdV-D (FAdV-2/-11) infection, frequently followed by FAdV-E (FAdV-8a, -8b) superinfection. FAdV-A (FAdV-1) was traced in half of the investigated flocks, while no evidence of infection with FAdV-C (FAdV-4, -10) was noted. Common serological profiles between different houses of the same farm indicate an overarching biosecurity. Serological profiles coupled with virological findings at the peak of egg production indicated that higher antibody levels, determined by ELISA, correlated with lower amounts of viral DNA in fecal excretion. Simultaneously, the number of isolated FAdVs belonging to distinct serotypes declined in accordance with a rise of neutralizing antibodies in birds, underlining the significance of serotype-specific antibodies in the epidemiology of FAdV in breeders. Investigations in breeders were complemented with screening of FAdV-associated diseases in local broilers over a 3-yr period; 26 cases of inclusion body hepatitis with dominant involvement of FAdV-11/FAdV-8b, one outbreak of adenoviral gizzard erosion related to FAdV-1, and no evidence of hepatitis-hydropericardium syndrome suggest that identical serotypes are maintained in the local poultry industry.

•Bivalent (FAdV-8b-Sk + FAdV-11-1047) live FAdV is safe as a broiler breeder vaccine.•Live and inactivated bivalent vaccines both induce neutralizing antibodies (NAb).•Transferred MtAb protects the progeny against lethal challenge.•Bivalent live and inactivated FAdV vaccines are equally effective and have the potential for IBH control. Fowl adenovirus (FAdV) is comprised of five species (A to E) and 12 serotypes (1–7, 8a, 8b, 9–11). Inclusion body hepatitis (IBH) is caused by FAdV-7, 8a, 8b (species E) and FAdV-2 and 11 (species D). Commercial vaccines against IBH are not available in Canada. Autogenous FAdV broiler breeder vaccines are now used in some areas where outbreaks of IBH are occurring. The objective of this study was to evaluate the efficacy of a bivalent (species D and E) live and an inactivated FAdV broiler breeder vaccine in protecting broiler chicks against IBH through maternal antibody (MtAb) transfer. FAdV seronegative broiler breeders (n = 300/group) received either a live or inactivated bivalent (FAdV-8b-SK + FAdV-11-1047) vaccine. The live vaccine (1 × 104 TCID50 of each virus/bird) was given orally once at 16 weeks of age and the inactivated vaccine (1 × 106TCID50 of each virus + 20% Emulsigen D) was given intramuscularly at 16 and 19 weeks of age. Controls (n = 150) were given saline orally. The inactivated vaccine group was boosted 3 weeks later with the same vaccine. Neutralizing antibodies (NAb) in sera (n = 10) were detected at 19, 22, 30 and 48 weeks of age. NAb were able to neutralize various FAdV serotypes within species D and E. Mean NAb were similar in the both live and killed vaccine groups at 19, 30 and 48 weeks and ranged from 2.4 to 3.7 log10. Approximately 26 ± 7% of MtAbs were passively transferred through eggs to day-old chicks. Progeny challenged with a lethal dose (1 × 107 TCID50/bird intramuscularly) of FAdV-8b-SK, FAdV-11-1047, or FAdV-2-685 (n = 90/group) at 14 days post-hatch (dph) showed 98–100% protection in broiler chicks to homologous or heterologous FAdV challenges. Our data suggests that a bivalent live and an inactivated FAdV vaccine are equally effective and have the potential for the control of IBH.

A surge in fowl adenovirus (FAdV) causing inclusion body hepatitis (IBH) outbreaks has occurred in several countries in the last two decades. In Spain, a sharp increase in case numbers in broilers and broiler breeder pullets arose since 2011, which prompted the vaccination of breeders in some regions. Our retrospective study of IBH cases in Spain from 2011 to 2021 revealed that most cases were reported in broilers (92.21%) and were caused by serotypes FAdV-8b and -11, while cases in broiler breeder pullets were caused by serotypes FAdV-2, -11, and -8b. Vertical transmission was the main route of infection, although horizontal transmission likely happened in some broiler cases. Despite the inconsistent and heterogeneous use of vaccines among regions and over time, the number of cases mirrored the use of vaccines in the country. While IBH outbreaks were recorded year-long, significantly more cases occurred during the cooler and rainier months. The geographic distribution suggested a widespread incidence of IBH and revealed the importance of a highly integrated system. Our findings contribute to a better understanding of FAdV infection dynamics under field conditions and reiterate the importance of surveillance, serological monitoring of breeders, and vaccination of breeders against circulating serotypes to protect progenies.

This study investigated the effects of replacement of inorganic trace minerals (ITMs) by organic trace minerals (OTMs) on tissue mineral retention and fecal excretion in “Zhen Ning” yellow feather broiler breeders. Six hundred hens (initial BW: 1.70 ± 0.07 kg) aged 40 weeks were randomly divided into five treatments, with four replicates of 30 broiler breeders each. Experimental treatments were as follows: (1) ITM (Cu, Zn, Fe, Mn, Se providing commercially recommended concentrations), (2) L-ITM (50% of the ITM, except for Se), (3) VL-OTM (37.5% of the ITM, except for Se), (4) L-OTM (equivalent to L-ITM), and (5) OTM (62.5% of the ITM, except for Se). The duration of the study was 10 weeks including 2 weeks for adaptation. Compared with the L-ITM treatment, high-level supplementation of minerals in ITM and OTM increased the concentration of serum Mn and Se, pectoral Fe and pancreas Cu, and Fe ( P  < 0.05). Birds fed with OTM dietary exhibited comparable mineral retention in muscle compared with ITM. Differences were observed between L-ITM and L-OTM in serum Mn and Se, pectoral Fe, Zn, and Se, and heart Se with L-OTM retaining higher mineral concentrations than L-ITM ( P  < 0.05). L-OTM retained identical concentration with ITM treatment, except for the pancreatic Fe. All three organic diets reduced the Zn in excreta compared with the two inorganic diets ( P  < 0.05). This study indicates that replacement of dietary ITMs by OTMs improved mineral deposition in tissues and reduced fecal mineral excretion in broiler breeders under the conditions of this study.

This experiment was conducted in order to investigate the effect of the chelated form of trace elements in diet on the production traits, immunity, and blood parameters of Ross 308 broiler breeder chickens. Treatments included Treatment 1 (Negative control): Mn, Se, Cu, Fe and Zn provided as non-chelated form; Treatment 2 (Positive control): Mn, Se, Cu, Fe and Zn provided as chelated form; Treatment 3: Mn, Se, Cu, Fe and Zn provided as 50% chelated form and 50% non-chelated form; Treatment 4: Zn provided as chelated form; Treatment 5: Cu provided as chelated form; Treatment 6: Fe provided as chelated form; Treatment 7: Mn provided as chelated form; Treatment 8: Se provided as chelated form. The results showed that over the entire production period egg production and egg mass were affected by the experimental treatments (p < 0.05) and that the highest levels were observed in treatments 2 and 3. The chelated form of trace elements had a significant effect, increasing the number of settable eggs and decreasing the unsettable eggs over the entire production period (p < 0.05). Average egg weight over the entire period was not significantly changed (p > 0.05). The highest percentage of 2-yolk, thin shell, broken and small eggs was observed in 61st week of age significantly (p < 0.05). The experimental treatments had a significant effect on the immunity and the antibody titre against Newcastle disease showed a significant increase in treatments 2 and 8 (p < 0.05). The concentration of glucose, triglyceride, progesterone, AST and ALT were affected by the experimental treatments (p < 0.05). In conclusion, the use of a basic diet containing Zn, Fe, Cu, Se and Mn in the chelated form or the use of a basic diet containing mineral elements of Zn, Fe, Cu, Se and Mn with 50% non-chelated form and 50% in the chelated form improves the performance of production traits, immunity and blood parameters of Ross 308 broiler breeder chickens. Highlights Chelated form of trace elements in the diet led to improvement in productive traits, immune response and blood parameters compared to the mineral form Basic diet containing mineral elements of Zn, Fe, Cu, Se, and Mn, 50% in the non-chelated form and 50% in the chelated form led to a significant improvement in egg production, egg mass, egg weight and egg specific gravity Chelated form of trace elements in the diet led to a decrease in the number of abnormal eggs including double-yolk, thin shell, broken, deformed, and small eggs

The objective of this study was to evaluate, by means of RNA sequencing, the direct and transgenerational effect of a reduced balanced protein (RP) diet on broiler breeder metabolism. Chickens of the F0 generation were fed a control (C) or RP diet, and their F1 progeny was fed a C or RP diet as well, resulting in four groups of chickens: C/C, C/RP, RP/C and RP/RP. While both direct and maternal effects were seen on body weight, breast muscle weight and abdominal fat weight in the F1 generation, the direct effect was the most dominant one. The liver transcriptome in the F1 generation showed that amino acid metabolism was up-regulated in chickens that received the control feed when compared with their respective contemporaries that received the reduced protein diet. Interestingly, chickens hatched from control-fed hens but reared on the reduced protein diet (C/RP group) activated a fatty acid metabolism, expressing more fatty acid desaturase 1 gene, fatty acid desaturase 2 gene and elongation of very long-chain fatty acids protein 2 gene, when compared with control-fed chickens hatched from control-fed hens (C/C group), while chickens hatched from reduced protein-fed hens that received themselves the same reduced protein diet (RP/RP group) triggered their glucose metabolism more, showing elevated levels of phosphofructokinase gene, 6-phosphofructo-2-kinase/fructose-2,6-biphospatase 4 and fructose-biphosphate aldolase C mRNA compared with the chickens hatched from reduced protein-fed hens but reared on a control diet (RP/C group). This suggests that the maternal protein diet has an impact on the metabolism of broilers when they are reared on a RP diet.

Staphylococcus species are widespread in poultry environments and can cause various infections, often when the host’s defences are compromised. This manuscript reports on a co-infection of chickens with Staphylococcus lentus and Staphylococcus aureus associated with an outbreak of arthritis, synovitis, and osteomyelitis in an organic broiler breeder flock in Austria. Clinically, the affected flock showed weakness, lethargy, lameness, and increased mortality. Post-mortem examinations identified purulent arthritis and femoral head necrosis. Bacteriological analysis using MALDI-TOF MS identified both S. aureus and S. lentus in the affected joints. Antibiotic resistance testing revealed significant resistance, particularly in S. lentus. Histological analysis showed severe inflammation and bacterial colonies in the joints. While S. aureus is a common pathogen in poultry, S. lentus is less frequently reported. This study emphasises the need for detailed bacterial characterisation in outbreaks to better understand the role of less common pathogens like S. lentus. Further research is necessary to elucidate the impact of S. lentus on poultry health and its role in causing arthritis and synovitis, highlighting the importance of comprehensive investigation in such outbreaks.

The purpose of this study was to investigate the effects of different levels of single and double interspiking on reproductive performance, some body welfare, and blood parameters of broiler breeder flock. The study was carried out on a total of 3840 female and 384 male (with average weight 4706.07 ± 307.9 g) Ross 308 broiler breeders having age between 28 to 59 weeks in a broiler breeder house (40°13′16.3″N, 28°48′19.8″E) of a private commercial poultry company. A single interspiking was applied at the age of 45 weeks, and a double interspiking was applied at the age of 53 weeks with the ratio 75, 50, and 25% of the males in the trial groups were changed. The age was affected fertility ratio, hatchability of total eggs, and hatchability of fertile eggs in the single and double interspiking groups (P < 0.0001). While the spiking ratio was affected hatchability of fertile eggs in the single interspiking group (P < 0.0001), it was affected the fertility ratio, hatchability of fertile eggs in the double interspiking group (P = 0.015 and P = 0.024). The spiking type was affected fertility ratio and hatchability of total eggs (P = 0.002 and P = 0.001). The age and spiking ratio interaction was affected fertility ratio, hatchability of total eggs, and hatchability of fertile eggs in the single (P < 0.0001, P < 0.0001, and P = 0.053; respectively), and double interspiking groups (P = 0.015, P = 0.009, and P = 0.008; respectively). The age and spiking ratio and age- and spiking-type interaction were not affected body feather score and vent score in single and double interspiking group (P > 0.05). The age, spiking ratio, and type were not affected blood heterophil, lymphocyte, and heterophil/lymphocyte (H/L) ratio in the single and double interspiking group (P > 0.05). In conclusion, spiking program can be applied to the flocks which have poor management conditions and/or have less fertility traits.

Waste oil from olive oil extraction industry was used, instead of soybean oil, in heavy roosters’ diet in order to evaluate birds’ reproductive parameters. A total of forty roosters were housed individually in boxes with 1.2 m². Two experimental diets were used: control diet, based on corn, soybean meal, and soybean oil; and test diet, where soybean oil was totally replaced by waste oil. In order to verify weight gain and feed intake, animals were individually weighed weekly. Seven semen collections were performed with fifteen-day interval. Reproductive variables analyzed sperm volume, motility, concentration, and morphology. No statistical difference (p > 0.05) was observed between treatments at the different collection periods for the variables sperm volume, motility, and concentration. There was a statistically significant difference between treatments for body weight in periods three (p = 0.04), and seven (p = 0.04). Statistical differences (p = 0.01) were also observed between treatments for abnormal sperm morphology. Among collection periods, statistical difference was observed for motility (p = 0.00), and sperm concentration (p = 0.01). Total replacement of soybean oil by waste oil from olive oil extraction in young heavy roosters’ diets does not affect sperm volume, motility, and concentration; reduces defects in sperm tail, and promotes better weight gain control.