Search

SUMMARY: Spirulina platensis is an emerging poultry diet source due to its essential nutrition and bioactive ingredients. Spirulina microalgae confers beneficial effects on broiler's growth performance, immune response, and antioxidant activity. We investigated the effect of Spirulina platensis on BCO lameness, one of the most driving factors for economic and animal well-being concerns in the poultry industry. Additionally, supplementation of Availa ZMC containing organic trace minerals – zinc, manganese, and copper – was shown to alleviate lameness by 20 to 25%. We hypothesized that pairing microalgae and organic trace minerals might confer a synergistic effect in reducing BCO. A 2 × 2 factorial study, with microalgae (5% Spirulina platensis and 5% Spirulina platensis plus 0.15% Availa ZMC) and without microalgae (0.15% Availa ZMC and a negative control diet), plus one BCO source group were applied to 1,320 one-day-old chicks with 5 replicates of 60 chicks per treatment for lameness assessment. No significant difference in lameness was observed between the negative control and BCO source group (60.0% vs. 54.5%, P = 0.56). Compared to the negative control, Availa ZMC significantly reduced lameness by 51.2% (60.0% vs. 29.3%, P < 0.001), while microalgae slightly increased lameness by 6.3% (60.0% vs. 63.8%, P = 0.1). Availa ZMC plus microalgae alleviated lameness by 16.7% (50.0% vs. 60.0%, P = 0.005) compared to the negative control, which was statistically lower than microalgae alone and higher than Availa ZMC alone. These findings suggested the inclusion of 5% Spirulina platensis did not reduce BCO lameness, while Availa ZMC significantly alleviated lameness. When combined, there was no significant interaction between Availa ZMC and microalgae in mitigating broiler lameness.

ABSTRACT: Bacterial chondronecrosis with osteomyelitis (BCO) lameness is the most critical animal health and welfare issue facing the broiler industry worldwide. It is estimated that 1 to 2% of bird condemnation at marketing age is caused by BCO lameness, resulting in tens of millions of dollars in annual losses. Fast-growing broilers are prone to mechanical stress that triggers bacterial translocation across epithelial barriers into the bloodstream, followed by bacterial colonization in the growth plate of long bones, and eventually, bone necrosis and lameness. Mycotoxins (MTX) are secondary metabolites produced naturally by microfungi, of which deoxynivalenol (DON), fumonisin (FUM), and zearalenone are the most prevalent in corn and soybean-meal-based diets. The presence of these mycotoxins in feed has been proven to reduce the barrier strength of the intestinal tracts and trigger immunosuppressive effects. In this study, we investigated the effects of the DON and FUM-contaminated feeds on the incidence of BCO lameness in broilers reared in both wire- and litter-floors. 720 one-day-old broiler chicks were assigned to the 2 × 2 factorial design: 2 MTX diets containing DON and FUM on wire flooring (MTX-W) and litter flooring (MTX-L), and 2 diets without MTX contamination on control wire flooring (CW) and control litter flooring (CL). Throughout the trial, the cumulative incidence of lameness per treatment was assessed by necropsying the lame birds. Birds in the MTX-W group had a higher incidence of lameness compared to those in CW (73.3% vs. 62.0%) (P < 0.05), and birds in the MTX-L group had a higher incidence of lameness compared to birds in CL (54.0% vs. 34.0%) (P < 0.05). MTX elicited net increases in BCO to a greater degree on litter (+20%) than on wire flooring (+12%). The increased incidence of BCO lameness in the MTX-W coincided with increased intestinal permeability supporting a correlation between intestinal barrier integrity and BCO lameness. To conclude, DON and FUM are predisposing factors for increasing BCO. However, no significant interaction exists between the diet and floor types in inducing lameness in broilers.

Bacterial chondronecrosis with osteomyelitis (BCO) lameness is a major welfare issue for broiler production worldwide affecting approximately 1.5% of broilers over 42 days old. Excessive body weight gain causes mechanical stress on long bones, leading to micro-fractures. This condition induces a bacterial infection of fractures, resulting in bone necrosis and eventual BCO lameness. Increasing gut integrity and supporting Calcium metabolism contribute to the optimal bone structure and subsequently reduce BCO lameness. Probiotics thus provide an excellent strategy for alleviating BCO due to the improvement of intestinal integrity and barrier function. Accordingly, the present study investigated the lameness reduction through the feed supplementation of a selected probiotic. Broiler chickens were assigned to three treatments, including a control litter group (FL), a PoultryStar®Bro probiotic fed group (BRO), and a control wire-flooring group (CW) designed to induce BCO lameness. The probiotic significantly decreased lameness by 46% compared to the control group (p < 0.05). The most predominant bacteria identified from the BCO lesions were Staphylococcus cohnii and Staphylococcus lentus. Moreover, significant increments of tight junction gene expression in jejunum and ileum, plus numerical improvements of body weight gain (BW; +360 g) and feed conversion ratio (FCR; −12 pts) were observed in BRO-supplemented birds.

This report demonstrates that high levels of lameness can be induced by a limited bacterial challenge in drinking water for birds raised on litter flooring, comparable with lameness induced by the gold standard for inducing lameness, growth on suspended wire flooring. The bacterium used in the challenge was cultured from lesions in birds induced for bacterial chondronecrosis with osteomyelitis (BCO) in the wire-flooring model so the epidemiology appears similar. The litter-flooring model could better approximate broiler operations. Furthermore, the work demonstrates that 2 commercial probiotics (GalliProTect and GalliProMax) can reduce lameness in the bacterial challenge litter-flooring model. Lameness attributable to BCO is one of the most significant animal welfare issues for broiler production. The wire-flooring and litter-flooring models afford alternatives for understanding the etiology, and epidemiology of BCO, and development of management strategies to reduce lameness. Probiotics afford a promising management strategy. The results suggest that the probiotic protection may extend beyond just intestinal health and intestinal barrier function.

The feed additive Availa-ZMC was investigated for the ability to reduce lameness in broilers using 2 alternative models for inducing lameness. The mixture of organic trace minerals was effective in reducing lameness by 20% in the wire flooring model and 25% in the litter flooring model with the bacterial challenge. Lameness in both models is overwhelmingly attributable to bacterial chondronecrosis with osteomyelitis. The reduction in lameness was associated, at least in part, with enhanced intestinal barrier integrity mediated by elevated expression of tight junction proteins and stimulation of bactericidal killing of adherent peripheral blood monocytes obtained from the birds treated with Availa-ZMC. Lameness is a major animal welfare concern in broiler production. The wire flooring model and litter flooring model with the bacterial challenge are effective models for evaluation of management strategies for mitigating infectious causes of lameness.

ABSTRACT: We used an embryo lethality assay (ELA) to assess virulence for different isolates from cases of bacterial chondronecrosis with osteomyelitis (BCO) in broilers. Lameness is among the most significant animal welfare issues in the poultry industry. Bacterial infections are a major cause of lameness and different bacterial species have been obtained from lame broilers. Reliable lab-based assays are required to assess relative virulence of bacteria obtained from lame broilers. ELA has been used to assess lethal dosage of Enterococcus faecalis and Enterococcus cecorum. We hypothesized that ELA could substitute for more laborious and costly assessments of BCO isolate pathogenicity using live birds. We evaluated 2 different levels of bacteria injected into eggs from layer and commercial broiler embryos. Significant findings include 1) Escherichia coli from neighboring farms operated by the same integrator had very different embryo lethality, 2) isolate Staphylococcus agnetis 908 had low virulence in ELA, even though this isolate can induce more than 50% BCO lameness, 3) Enterococcus cecorum 1415 also had low pathogenicity; even though it was recovered from severe bilateral tibial dyschondroplasia, 4) human and chicken BCO isolates of S. aureus had significant pathogenicity, 5) virulence for some isolates was highly variable possibly corresponding with quality of the embryos/fertile eggs used, and 6) ELA pathogenicity was much lower for our BCO isolates than previous reports which may reflect maternal environment. Overall, ELA virulence and BCO virulence are not always concordant indicating that ELA may not be an effective measure for assessing virulence with respect to BCO.