Effect of gradual substitution of soyabean meal by Nigella sativa meal on growth performance, carcass traits and blood lipid profile of growing Japanese quail

The aim of the study was to evaluate the effect of different inclusion levels of Nigella sativa meal (NSM) on growth performance, carcass yield and blood lipid profile of 300 unsexed one-week old Japanese quails. The experimental diets contained four levels of NSM replacing 0 (control), 20, 30 and 40% of soyabean meal (SBM) in growing Japanese quail diets. Live body weight was linearly (P = 0.017) and quadratically (P = 0.024) increased at week 3 of age and only quadratically (P > 0.001) at week 6 of age due to 30% SBM substitution. Birds fed diets with 20 and 30% SBM replaced by NSM consumed more feed in comparison with other animals during 3-6 and 1-6 week of age. The substitution of 20% SBM for the same percent of NSM resulted in a significant (P < 0.001) linear increase in both dressing and carcass percentages in comparison with the control and other treatment groups, giblets yield was also significantly (linearly P = 0.011 and quadratically P = 0.021) affected. A gradual reduction in serum total lipids, total cholesterol and HDL-cholesterol was observed along with the increasing level of NSM in the diet, except HDL which was elevated when 40% of SBM was replaced. It could be concluded that NSM could partially replace SBM up to 30% in growing Japanese quail diets without any harmful hazards regarding performance, feed utilization and carcass traits. Moreover, the blood lipid parameters are decreased with increasing NSM content in the diet.