Layla Al-Mitib

This experiment compared 14-day and 28-day inclusion schedules of 1,25(OH)₂D₃-glycosides in the broiler feed on the reduction of experimental clinical bacterial chondronecrosis with osteomyelitis (BCO) lameness, using the aerosol transmission induction model. Eight hundred and forty Cobb 500 chicks were randomly allocated to each of the following treatments at 60 chicks/pen as the initial stocking density and reared over 56 d: T1 (Positive Control-PC, 2 wire-flooring pens)—Basal diet (7166 IU/kg Vit-D3); T2 (Negative Control-NC, 4 litter pens)—Basal; T3 (4 litter pens)—Basal + 14d 1,25(OH)₂D₃-glycosides (1 µg/kg feed); and T4 (4 litter pens)—Basal + 28d 1,25(OH)₂D₃-glycosides (1 µg/kg feed). There were three feeding phases: Starter (d0–21), Grower (d22–42), and Finisher (d43–56). Clinical lameness assessment was conducted daily from d21, followed by euthanasia and necropsy of clinically lame birds to determine BCO lesion severity. Cumulative lameness incidence rates between treatments were assessed using binomial logistic regression analysis in a generalized linear mixed model. All statistical significance was determined at p < 0.05. Cumulatively, T4 (55.5%) was significantly lower in clinical lameness incidence compared to T2 (85.0%, relative decrease of 34.71%; p < 0.0001), while T3 (85.5%) was not significantly different (p = 0.89). These results further affirm efficacy of the 28-day inclusion period and the rate of 1,25(OH)₂D₃-glycosides against experimental clinical BCO lameness incidence.

Enterococcus cecorum has been identified as causing early sepsis in commercial broilers. We hypothesized that vertical transmission may contribute to the spread of the pathogen. Sampling of 360 commercial broiler eggs from a previously infected flock detected Enterococcus gallinarum and Enterococcus faecalis in yolks of 18-day incubated eggs. Enterococcus avium was recovered by enrichment from 1 of 31 unincubated yolks. Direct sampling without enrichment of 297 egg yolks from a previously infected broiler breeder flock detected E. faecalis, Escherichia coli, Globicatella sanguinis, and E. gallinarum, often in high numbers, or in coinfections. Microbiological sampling of day-of-hatch chicks suggested only the yolk sac was likely to yield bacterial growth, and that yolks could be sampled directly using swabs streaked onto growth medium. The most common isolate from sampling 30 day-of-hatch broiler chicks was E. faecalis from 16 different chicks. Further, E. coli was recovered as a mixed infection with E. faecalis in 3 of those 16 residual yolk sacs. From swab-sampling of residual yolk sacs from 40 day-of-hatch broiler breeder chicks, E. faecalis was recovered from 7 chicks. Thus, yolk infections by Enterococcus species were the primary isolates cultured from commercial broilers and broiler breeders in Arkansas. Identification of these species at high numbers in yolks is likely contributing to reduced hatchability, early chick death, and transmission of bacteria to subsequent flocks. Therefore, the broiler industry needs to pursue methods to identify infected laying hens and management strategies to mitigate vertical transmission. Importance: We were unable to identify E. cecorum being spread from flock to flock via vertical transmission. We did identify specific bacterial species infecting and reproducing within the yolks of developing embryos and day-old chicks of commercial, meat-type chickens. These particular species were detected at low and high levels, indicating growth within the yolk. The implication is that these species colonized the yolk within the hen’s reproductive tract and were vertically transmitted to the chicks and subsequent flocks. Some infections represent only a single species, while others involve two species that may represent cooperative infections. With the removal of the use of antibiotic growth promoters during early development, these species may be reducing chicken reproduction through embryo death or early chick mortality.

Chicken embryo mortality has been attributed to bacterial infections resulting in a decline in hatchability, and significant losses in the broiler industry. The aim of this study was to investigate the vertical transmission of specific bacterial pathogens from breeder hens to subsequent broiler flocks. In our sampling of 360 commercial broiler eggs, we isolated Enterococcus gallinarum and Enterococcus faecalis, from yolks of 17-day incubated eggs. Enterococcus avium was recovered by culture enrichment from 1 of 31 unincubated yolks. From 297 eggs yolks from broiler breeders incubated for 17 days we isolated E. faecalis, Globicatella sanuinis, and E. gallinarum, in some cases in high numbers. We then performed microbiological sampling of day-of-hatch chicks for broilers from a commercial hatchery. Culture enrichment and sampling of intestine and residual yolk sac suggested only yolk sac was likely to yield bacterial growth, and could be sampled directly by swabs onto growth medium. The most common isolate from sampling 30 newly hatched broiler chicks was E. faecalis from 16 different chicks. However, E. coli was recovered as a mixed infection with E. faecalis in 3 of those 16. Residual yolk sacs were then swab-sampled from day-of-hatch broiler breeder chicks. E. faecalis was recovered from 7 out of 40 chicks. Thus, yolk infections by Enterococcus species should be of concern in the broiler industry, and could be contributing to reduced hatchability, early chick death, and transmission of bacteria from hens to subsequent flocks.

Our prior research demonstrated a 20% to 25% reduction in bacterial chondronecrosis with osteomyelitis (BCO) lameness in broilers with organic Zn, Mn, and Cu (Availa^® ZMC) supplementation. Expanding on this, we investigated the optimal timing for Availa^® ZMC feeding to mitigate BCO lameness and reduce feed additive costs in the poultry industry. In this study, we compared the application of 0.15% Availa^® ZMC for 56 days, the first 28 days, and the last 28 days. The experimental design was a randomized block design involving 1560 one-day-old chicks distributed across two wire-floor pens as BCO source infection and four treatment groups with six replicates. The source of BCO infection exhibited a cumulative lameness incidence of 83%, whereas the negative control group showed a 77% cumulative incidence of lameness (p = 0.125). Administering 0.15% of Availa^® ZMC during the initial 28 d resulted in a 41.3% reduction in BCO incidence, significantly different from the supplementation during the last 28 d (p < 0.05). However, this reduction did not differ substantially (p > 0.05) from the 56d application period. Hence, administering 0.15% Availa^® ZMC during the first four weeks emerges as the optimal timing protocol, providing a defense against lameness comparable to the continuous supplementation throughout the complete production duration. Implementing this feeding approach reduces the cost of feed additive, promotes the health of skeletal bones, and effectively protects against BCO lameness in broilers, offering a valuable consideration for producers seeking optimal outcomes in the poultry industry.