Variations in soybean meal (SBM) quality can be caused by uneven cooking, undercooking, and overcooking which can result in antinutritional factors such as trypsin inhibitors and low-quality diets. The objective of this study was to determine if poor quality SBM would negatively impact growth performance and enteric permeability including bacterial translocation (BT), body weight (BW), and serum fluorescein isothiocyanate dextran (FITC-d) in broilers. To produce poor-quality SBM (pqSBM), a 1:1:1 mixture of raw SBM, normal SBM, and overcooked SBM replaced normal SBM in the treatment diets. Overcooked SBM was created by autoclaving SBM for 120 min. The trypsin inhibitor activity of pqSBM was 5.9mg/g, indicating a sufficient quantity of antinutritional factors to impair protein digestibility. The trial consisted of 3 treatments, Control, Rye + Meat and Bone Meal (MBM) + pqSBM, and MBM + pqSBM. Each treatment consisted of 4 replicate pens with 50 birds per pen (n = 200/trt). On day of hatch (DOH), E. cecorum (1 x 104 CFU/chick) was administered to all birds by oral gavage, and 15 birds per pen tagged to monitor BW throughout the experiment. On DOH, d15 and d35, tagged birds were weighed, and on d15 and d35, 3 randomly selected birds from each pen were orally administered FITC-d (4.17 mg/kg) 2h prior to sample collection. Free thoracic vertebrae (FTV) were aseptically collected for plating on TSA and CHROMagarTM to assess BT and presence of Enterococcus spp., and blood was collected from the femoral artery to quantify serum FITC-d recovery. All data were analyzed via ANOVA and significant differences amongst means were determined using Tukey›s HSD test (p<0.05). There were no differences for FITC-d recovery and BT at either time point. However, there were significant decreases in BW (p<0.001) of birds fed diets containing pqSBM. There was also a significantly higher level of Enterococcus spp. (p<0.001) in the FTV of birds fed pqSBM at d15, but no difference at d35.
Based on these results, pqSBM suppresses growth performance while also predisposing birds for increased translocation of Enterococcus spp. early in life. These results highlight that poor diet quality could predispose birds to opportunistic diseases that result in economic losses beyond lowered BW.