Effects of dietary Ca source and concentration, and vaccine dosage on d14 and d29 Broiler performance

Due to the absence of antimicrobial drugs within the feed, a better understanding regarding the mitigation of NE is necessary. Recent research has identified that dietary Ca levels could potentially induce NE pathogenesis, but the mechanism is unknown. In theory, the amount and availability of Ca in the lower intestine can provide an enriched environment for C. perfringens bacteria, resulting in an increased proliferation of the bacteria and toxin activity. The current study was to assess broiler performance when fed diets that differed in Ca source and concentration, as well as subjected to differing coccidia vaccine levels. Treatments were arranged in a 2x2x2 factorial, that varied in vaccine level of a 1X or 2X dosage of commercial coccidia vaccine (Coccivac B52), and dietary treatment consisting of Ca sources Calmin or limestone that was fed at a concentration of 1.05% or 1.25% of the diet. Diets were fed to 10 replicate floor pen of 30 male Cobb 500 broilers. Data were analyzed using a 2x2x2 factorial arrangement in a randomized complete block design. Broilers dosed with 1X vaccine exhibited improved BWG at d14(P=0.0401). Ca source and concentration at d14 interacted to affect BWG, at 1.05% concentration broilers that consumed diets with limestone had improved BWG compared to diets of Calmin(P=0.001). Broilers dosed with 1X vaccine exhibited improved FC at d14(P=0.0001). Broilers provided diets with the Ca source of limestone had improved FC at d14(P=0.0001). Broilers provided diets with concentrations of 1.05% had improved FCR at d14(P=0.0093). Broilers dosed with 1X vaccine exhibited improved FC at d29(P<0.0001). Broilers provided diets with the Ca source of limestone had improved FC(P= 0.0036). Ca source, Ca concentration and vaccine at d29 interacted to affect BWG(P=0.05). Birds provided limestone concentrations at 1.05% that received 1X or 2X dose of vaccine at d29 performed better than birds fed Calmin at concentrations of 1.05% or 1.25% with 1X or 2X dose of vaccine. This trial supports previous data indicating nutritionists should consider the interaction of Ca source, concentration, and vaccine to help mitigate the risk of NE through limiting the availability of excess Ca that could contribute to the occurrence of NE.

Key Words: Calcium, Necrotic Enteritis, Limestone, Coccidia Vaccine, Broiler.

Abstract presented at the International Poultry Scientific Forum during IPPE 2020.