Effect of lipid source and emulsifier on productive and physiological parameters of broilers

OBJECTIVE: This study aimed to evaluate the replacement of degummed soybean oil (DSO) by acid soybean oil (ASO) in diets with or without the inclusion of emulsifier on broiler performance, relative organ weight, lipase activity, intestinal morphometry, and nutrient digestibility. METHODS: A total of 704 1-day-old male broiler chicks were allotted to a 2×2 completely randomized factorial design (with or without emulsifier × two lipid sources [ASO and DSO]), with eight replicates and 22 birds each. The metabolizable energy level in diets with emulsifier was reduced by 40 kcal/kg from 1 to 21 d and 50 kcal/kg from 22 to 49 d. RESULTS: Broilers fed diets containing ASO without emulsifier had higher (p = 0.005) weight gain than DSO-fed animals and with the inclusion of emulsifier had worse (p = 0.018) feed conversion ratio (FCR). Birds fed diets with emulsifier worsened FCR regardless of lipid source from 1 to 21 days (p = 0.006) and from 1 to 49 days (p = 0.0002). There was an increase (p = 0.026) in the relative pancreas weight, at 14 days, in birds fed diets containing ASO. Lipase activity and morphometry of the duodenum and jejunum, at 14 and 21 days, were not affected (p>0.05). The dietary inclusion of emulsifier improved the digestible energy (p = 0.053) in the presence of ASO. For the digestibility coefficients (gross energy, crude protein, and mineral matter), no interference was observed (p>0.05). CONCLUSION: The inclusion of emulsifier to energy-restricted diet with ASO maintained broiler performance in the first week, but worsened FCR in subsequent phases. The ASO can be considered as an alternative lipid source to DSO and does not interfere with the morphophysiological characteristics and performance of broilers. The combination of ASO and emulsifier increased the digestible energy content by 6.2%.