Abstract This study aimed to evaluate the use of acidulated soybean soapstock in association with lecithin on productive performance, metabolic efficiency in the utilization of nutrientes, and the egg quality of Japanese quails. A total of 192 quails were used, distributed randomly in a 2×2×2 factorial scheme that included two types of oils, two levels of supplementation (4% and 8%) and two levels of lecithin (1% or 0%). At the end of the six-month experimental period, some double significant interactions were shown between the level of oil and lecithin for the performance variables (egg weight p=0.04, feed intake p<0.01 and feed conversion rate p=0.04). The feed conversion rate also was influenced by a double significant interaction between the type of oil and the level of oil (p<0.01). The nutrient digestibility showed that different interactions affected the results. The evaluation of egg quality, was verified that the use of acidulated soybean soapstock did not affect most variables of internal quality. The results showed that it is possible to use 8% acidulated soybean soapstock in combination with 1% lecithin in the diets of Japanese quails for a period of up to six months without a reduction in performance.

ABSTRACT The effects of increasing levels of soybean acid oil in diets of quails on the quality of eggs were evaluated over a period of 56 days. A completely randomized design with five treatment levels of soybean acid oil (0, 2, 4, 6, and 8%) as a replacer for soybean oil and eight replicates of two quails each were used. A total of 240 fresh eggs were used for quality analysis, and 400 eggs were stored at 23ºC over a period of 0, 7, 14, 21, and 28 days for analysis of shelf-life. Polynomial regression and ANOVA with repeated measurements and Tukey´s tests were used. Soybean acid oil linearly increased the intensity of red (a* = -5.26 + 0.14 x, R2 = 0.89, P = 0.01) and yellow (b* = 42.32 + 0.44 x, R2 = 0.88 P = 0.01). All other variables of egg quality were not affected by the treatments, with the exception of sensory attributes, such as odor and aftertaste, which were more pronounced with soybean acid oil. In conclusion, soybean acid oil affects the intensity of yellow and red color of the yolk. Trained assessors detected differences in odor and aftertaste of eggs when soybean acid oil was included in the quail diet.