Humic acid and enzymes inclusion in canola-based diets generate different responses in growth performance, protein utilization dynamics, and hemato-biochemical parameters in broiler chickens.

The current study was conducted to investigate the effect of a humic acid and enzymes on growth performance, protein utilization, and blood parameters in broilers fed canola-based diets. Canola meal (CM) is characterized as low protein compared to soybean meal. Two-hundred-twenty broiler chickens were randomly allotted to the following 5 dietary treatments: 1. Control (commercial broiler diet); 2. CM (17.5% canola meal inclusion); 3. CMEnz (CM + 0.3 g/kg enzymes [Axtra XAP]); 4. CMPh (CM + 1.5% potassium humate, PH) and 5. CMEnzPh (CM + 1.5% PH + 0.3 g/kg Axtra XAP). Each treatment was replicated 4 times with each pen holding 11 birds as the experimental unit. The feeding trial was conducted over a grower (15 to 28 d) and a finisher phase (29 to 42 d). Diet did not affect (P > 0.05) feed intake across either grower or finisher phase but affected average daily gain (ADG) in the grower phase. In the grower phase, broilers fed CM had the highest ADG (71± 1.08 g/d), while the control (63.75 ± 1.08 g/d) had the lowest. However, control chickens had the highest feed conversion ratio (FCR) (1.65), while those fed CM (1.47) had the lowest. Diet significantly affected total white blood cell and white blood cell differential, which were consistently high in broilers fed CMEnzPh. With regard to serum metabolites, CM had the highest levels (P < 0.05) of aspartate aminotransferase (AST) (406.86 ± 38.07 IU/L), while CMEnzPh (254.17 ± 41.11 IU/L) had the lowest levels. Additionally, broilers fed CMPh had the highest (P < 0.05) serum sodium content (150.57 ± 0.69 mmol/l). Overall, canola meal, in the presence of enzymes and humic acid, was shown to have great potential as an alternative replacement of soybean meal in broiler diets. The findings from the study can, therefore, contribute to the design of low-cost canola-based feed formulations that will improve growth performance and health status in poultry farming systems in the future.