The effects of varying dietary electrolyte balance levels in canola meal-based diets on growth performance, ascites susceptibility, and nutrient digestibility in cold-stressed broilers

This study investigated the effects of dietary electrolyte balance (DEB) supplementation in canola meal (CM)-based diets on the growth, ascites incidence, intestinal function, nutrient digestibility, stress, and thyroid function of cold-stressed broilers. A total of 360 one-day-old male Hubbard broilers were assigned to four dietary treatments: a soybean meal (SBM)-based diet and three CM-based diets formulated to have lower (CM-L), equal (CM-E), or higher DEB (CM-H) levels compared to the SBM diet. Each treatment consisted of six replicates of 15 birds, with the trial lasting 38 days. Birds fed CM- based diets exhibited lower body weight gain, reduced plasma nitric oxide (NO) concentration, diminished intestinal absorptive capacity, and decreased ileal digestibility of dry matter, energy, crude protein (CP), and ether extract (EE) relative to SBM- based diet fed birds. Furthermore, feed conversion ratio, the right ventricle-to-total ventricles (RV:TV) ratio, stress indicators, and relative thyroid weight were elevated, while plasma triiodothyronine was lower, all indicating a higher susceptibility to stress and ascites risk compared with SBM-based diet fed birds. However, the CM-H-based diet mitigated these negative effects when compared to the CM-l-based diet. The inclusion of the CM-H diet resulted in enhanced plasma NO and hemoglobin oxygen saturation ( SO2 ), improved jejunal absorptive capacity, and increased ileal digestibility of CP and EE. Furthermore, it led to a reduced RV:TV ratio and lower ascites mortality. Notably, concerning ascites-related mortality, blood oxygen pressure, and SO2 , the values observed in the CM-H group were comparable to those in the SBM group. In conclusion, although CM-based diets impaired growth and increased ascites risk under cold stress, elevating DEB effectively reduced ascites susceptibility and improved physiological status in broiler chickens.