The study was conducted on 48 healthy Jabalpur color birds (pure line developed by the inter-se mating of 3^rd generation among the selected stock of Krishna J. Commercial Broiler/Breeder and one color line from Poultry Breeding Farm, Adhartal, Jabalpur) of 40 weeks age. Birds were procured from All India Coordinated Research Project (AICRP) on Poultry Breeding, Adhartal, Jabalpur, MP, India. They were kept separately in individual cages and maintained under similar hygienic conditions at Poultry Farm Adhartal, Jabalpur. The birds were randomly divided into 8 groups having 6 birds each. These groups were fed with diets supplemented with garlic and black cumin oil @ 0, 250, 500 and 750 mg kg^-1. The basal diet consisted of 2700 Kcal ME kg^-1 and 17% protein. Six eggs were collected from each group on 0^th, 14^th, 28^th, 42^th and 56^th days of feeding. Egg-yolk total lipids were extracted as per Folch et al. (1957) and estimated as per Frings et al. (1972). The egg yolk cholesterol and triglycerides were estimated by standard diagnostic kits (Erba).

The data obtained was analyzed using hierarchical analysis of variance (Steel and Torrie, 1992). Comparisons among the treatment means were made by Duncan’s (Duncan, 1955) multiple range test.

The variations in egg-yolk total lipids and cholesterol between groups and between intervals within treatments were highly significant (P<0.01) whereas those between treatments within groups were significant (P<0.05) except for egg-yolk triglycerides. The reduction in egg yolk total lipids was 22.96% in birds fed with 250 mg garlic oil kg^-1 diet on 56^th day of experiment whereas it was 31.15 and 42.12% in birds fed with 500 and 750 mg garlic oil kg^-1 diet, respectively and 16.04% in group T₂, 20.23% in group T₃ and 31.22% in group T₄ of black cumin oil on day 56 of the experiment (Table 1). No significant change was observed in control. Similar pattern of reduction in egg-yolk total lipids has been reported by Hebbar (2010) on dietary supplementations consisting of five plants, A. sativum, Cuminum cyminum, Terminalia arjuna, cinnamon and Tinospora cordifolia in the ratio of 3:2:2:2:1 @ 4500 mg kg^-1 feed in adult layer birds. Similar pattern of reduction (14%) in egg yolk total lipids was reported by Bagir et al. (2006) on dietary supplementations of black cumin seed of feed in adult White Leghorn birds.

The egg-yolk cholesterol was reduced by 22.75, 29.60 and 35.61% in birds fed with 250, 500 and 750 mg garlic oil kg^-1 diet, respectively and 11.97 in group T₂, 21.73 in group T₃ and 27.36 in group T₄ in the black cumin oil fed group on day 56 of the experiment (Table 2). Chowdhury et al. (2002) observed 5-24% reduction in yolk cholesterol of laying hens when fed on diets supplemented with garlic paste. Khan et al. (2008) observed a significant reduction in egg yolk cholesterol concentration with increasing level of oven-dried garlic powder from 0 to 8% in native desilayers for 6 weeks. Yalcin et al. (2009) reported significant reduction (p<0.01) in egg yolk cholesterol levels in Lohmann Brown laying hens 36 weeks of age after administration of black cumin seed. Significant (p<0.05) decrease in egg cholesterol was also reported by Akhtar et al. (2003) and Aydin et al. (2008).

Like egg-yolk total lipids and cholesterol, triglyceride values were reduced in birds fed with all the preparations in all the treatments in a dose-dependent manner (Table 3). The reduction was 16.76, 17.94 and 22.13% in birds fed with 250, 500 and 750 mg garlic oil kg^-1 diet, respectively, whereas the reduction was 10.75, 15.99 and 19.46 % in black cumin oil fed group respectively on day 56 of the experiment. Hebbar (2010) reported 19.19% reduction in egg yolk triglyceride values on supplementing the diet by a polyherbal preparation. Bagir et al. (2006) observed reduction of 21% and 23% in egg yolk triglycerides in White Leghorns on supplementation of black cumin.

The study revealed that garlic and black cumin oil supplementation @ 750 mg kg^-1 diet significantly reduced egg yolk lipid level in birds on 56th day of feeding, but on comparison between these two, garlic oil shows better results than the black cumin oil. Garlic oil can be effectively used for reducing total lipids, cholesterol and triglyceride contents in egg-yolk of poultry birds and these eggs can be consumed safely without the risk of cardiovascular diseases. We can also conclude that both the oils can be used in prevention of cardiovascular diseases.