ABSTRACT:The effects of humic acid on feed consumption, egg production, feed efficiency, egg weight and external and internal egg quality of laying hens were studied during feeding periods. A total of 180 (Hysex Brown) layers (36 weeks of age) were used in this experiment. There was one control and two experimental groups, each containing 60 hens and 4 subgroups. The experimental period lasted 16 weeks. At the end of the experiment, the supplementation of humic acid had a significant effect on feed consumption and feed efficiency. An increase in egg production was determined when humic acid was added to the diets at 30 g/t of feeds (91.70%) and 60 g/t of feeds (91.32%). There were no significant differences between the groups in egg shell thickness, egg shell breaking strength, yolk index, albumen index and Haugh unit. It can be therefore concluded that the dietary supplementation of humic acid at doses of 30 and 60 g/t feed can be used to improve egg production, egg weight and feed efficiency.

This study was conducted to investigate the effects of garlic powder on the performance, egg traits and blood parameters of laying hens. One hundred and sixty-two SHSY-type brown layers aged 21 weeks were chosen at random from a large flock. They were allocated to three dietary treatments. Each treatment comprised six replicates of nine layers in groups of three. The diets were supplemented with 0, 5 and 10 g kg −1 garlic powder. The experimental period lasted 22 weeks. Garlic powder addition did not significantly affect body weight, egg production, feed consumption, feed efficiency, egg shell index, egg breaking strength, egg shell thickness, egg albumen index, egg yolk index, egg Haugh unit, egg yolk weight and serum protein concentration. Egg weight increased (P < 0.01) with garlic powder supplementation. There was a significant (P < 0.01) reduction in egg cholesterol concentration as mg g −1 yolk when the dietary level of garlic powder was increased from 0 to 10 g kg −1 . Hen serum triglyceride (P < 0.05) and total cholesterol (P < 0.01) concentrations decreased with garlic powder supplementation. This study demonstrated that garlic powder addition increased egg weight and decreased egg yolk cholesterol concentration (mg g −1 yolk) and serum triglyceride and cholesterol concentrations without adverse effects on performance and egg traits. INTRODUCTIONGarlic (Allium sativum) and its products are known to have potential hypolipidemic/hypocholesterolemic, hypotensive, hypoglycemic, hypothrombotic and hypoatherogenic properties. 1 -4 Garlic contains a variety of organosulfur compounds such as allicin, ajoene, S-allylcysteine, diallyl disulfide, S-methylcysteine sulfoxide and S-allylcysteine sulfoxide. 5 Despite the fact that the mechanisms primarily responsible for the hypocholesterolemic action of garlic are uncertain at present, the composition and quantity of the sulfur components of different garlic preparations used in various studies could account in part for the inconsistent findings. 6 Other contributing factors may include subject recruitment, duration of experiment, dietary control, lifestyle and methods of lipid analysis. 3,4 S-Methylcysteine sulfoxide 7,8 and S-allylcysteine sulfoxide 8 had a potent antihypercholesterolemic effect on cholesterol-fed rats. However, previous studies with laying hens and broilers showed controversial results on the hypocholesterolemic effect of garlic. 9 -13 In experiments with diets containing garlic paste at 38 g kg −1 or solvent fractions or garlic oil equivalent to 38 g kg −1 garlic paste, the activity of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase decreased by 50-69% in 12-week-old