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The objective of this experiment was to replace soya bean oil with glycerol in laying hen diets and assess the change's effect on performance, parameters of egg quality and the egg fatty acid profile. A total of 60 44-week-old Hy-Line W36 laying hens were distributed according to a completely randomised experimental design into four treatments consisting of glycerol substitutions for soya bean oil dietary at varying inclusion levels (0%, 25%, 50% and 75%), with five replicates of three birds each. Dietary treatments had no significant effect on BW change, egg production, feed intake, feed conversion ratio, egg weight and egg mass of laying hens. The inclusion of glycerol in the diet of laying hens had no significant effect on egg specific gravity, eggshell breaking strength, eggshell weight, eggshell thickness, egg shape index, albumen index, yolk index, haugh unit, albumen pH, yolk pH and egg yolk colour values. The inclusion of glycerol in the diet of laying hens had no significant effect on palmitic, palmitoleic, stearic, oleic and linolenic acid contents of the egg yolk. The linoleic acid and polyunsaturated fatty acid contents of the egg yolk significantly decreased with the higher levels of dietary glycerol supplementation ( P < 0.05). The results of this study show that it is possible to replace 75% of soya bean oil (4.5% in diet) with glycerol.Keywords: crude oil, glycerol, performance, egg quality, laying hens ImplicationsAlthough glycerol, as a by-product of biodiesel production, can be an attractive alternative energy source for poultry diets, there is a need to determine what level of glycerol could be used in laying hen diets. Its effect on performance, egg quality and egg yolk fatty acid composition should be investigated. According to the results of this study, 75% of soya bean oil can be replaced by glycerol without a negative effect on performance and egg quality in laying hens. However, high level glycerol in the diets potentially decrease PUFA and linoleic acid percentages in the egg yolk.

In this study, the performance, egg quality, egg yolk colour and fatty acids profile of quails fed on diets containing different fat sources were determined. During 8 weeks trial, a total of 75, 10-weeks-old laying quails were used. Three diets were formulated to contain soybean oil (SBO), sunflower oil (SFO) and hempseed oil (HSO), respectively. The performance parameters were not significantly influenced by the dietary different oil sources. Eggshell ratio, eggshell thickness, eggshell breaking strength, egg shape index, egg yolk index, albumen index and egg yolk colour values (except a*) were not influenced by the different dietary oil sources. The a* value was significantly affected and the highest a* value was the HSO of group. The different oil sources supplementation to the diets was effective on fatty acid composition of the egg yolk. The highest value in terms of α-linolenic acid, total polyunsaturated fatty acids and total n-3 fatty acids were found in the diet fed group with HSO added. As a result; supplementation of different sources of oil to quail diets without negatively affecting performance and egg quality can be used to change the egg yolk fatty acid composition. Hempseed oil may increase the amount of total polyunsaturated fatty acids and total n-3 fatty acid content of egg yolk.

In this study, the laying performance, external egg quality, egg yolk colour and fatty acids profile of quails (Coturnix coturnix japonica) fed on diets containing hemp seed meal (HSM) were determined. During 8 weeks trial, a total of 150, 10-weeks-old laying quails were used. Five diets were formulated to contain HSM at the level of 0 (control),5, 10, 15, and 20% that represented as 0 HSM, 5 HSM, 10 HSM, 15 HSM and 20 HSM, respectively.The performance parameters were not significantly (P>0.05)influenced by the dietary HSM contents. Eggshell ratio, eggshell breaking strength, egg shape index, egg yolk index and egg yolk colour values were not significantly (P>0.05) influenced by the dietary HSM, whereas eggshell thickness was significantly (P<0.05) affected. The albumen index has been significantly (P<0.05) increased by increasing in the HSM level in the diets. The HSM supplementation to the diets was effective on fatty acid composition and total saturated fatty acids, total mono unsaturated fatty acids and total polyunsaturated fatty acids content of the egg yolk depending on the addition level. In conclusion, HSM can be used to increase egg total monounsaturated fatty acids and especially omega-3 fatty acids without unfavourable effects on the performance and egg quality parameters.

Oil seeds are commonly used in cooking, frying and as salad oil and have commercial and economic importance. Since the seeds are roasted before pressing of the oil, changes occur in their composition; thus it is crucial to modify roasting process to minimise adverse effects. This study reflects the effects of different roasting temperatures (90, 150 and 210 °C for 10 min. in conventional oven) on the oil constituents and some chemical properties of oils from the seeds of sesame, sunflower, soybean, flaxseed and poppy along with comparison to those of unroasted corresponding seed oils. Lipids from roasted seeds of sesame, flax and soybean exhibited relatively higher viscosity and free fatty acids, than lipids from unroasted seeds. With an increase in roasting temperatures the colour of the oils were slightly darker even though the changes were not significant in most cases. The content of α-and γ-tocopherols in oils (except soybean oil) gradually decreased as roasting temperature increased. β-tocopherol was higher in the oils of roasted seeds, while the amount of δ-tocopherol showed different trends with roasting depending on the type of seeds. For sesame and poppy oils, after roasting at 210 °C, stearic and oleic acids showed higher percentages when compared to the levels in oils roasted at 90 and 150 °C.