Effects of dietary garlic on cholesterol metabolism in laying hens

Abstract

Experiments were conducted to evaluate the potential for dietary garlic to influence egg yolk cholesterol concentrations and overall performance in different layer strains. Thirty-six, 28-wk-old, Hisex Brown,Isa Brown, Lohmann, Starcross, Babcock, and Starcross-579 strains (six hens per strain) were fed diets supplemented with 0 (control), 2, 4, 6, 8, or 10% sun-dried garlic paste for 6 wk. There were no differences (P > 0.05) among diets or strains in egg weight, egg mass, feed consumption, feed efficiency, and BW gain as averaged over 6 wk. Yolk weight, however, responded quadratically with increasing levels of dietary garlic and differed among strains (P < 0.05). Egg production and yolk weights were significantly higher in the Babcock strain in comparison with other strains. Serum and egg yolk cholesterol concentrations decreased linearly (P < 0.05) with increasing levels of dietary garlic. Serum and egg yolk cholesterol concentrations also differed among different strains (P < 0.05). It was concluded that garlic paste in the diets of laying hens reduced serum and yolk cholesterol concentrations. It was also concluded that dietary garlic paste had no adverse effects on layer performance.

The effects of dietary garlic powder on performance, egg yolk and serum cholesterol concentrations in laying quails

“…The supplementation of garlic powder had no significant effect (P > 0.05) on egg weight and body weight. In agreement with the present study, Khan et al (2008) and Chowdhury et al (2002) reported that egg weight was not affected by 0, 2, 6 or 8% garlic powder (P > 0.05) or by 0, 2, 4, 6, 8 or 10% garlic paste (P > 0.05) as averaged over the six-week period respectively. In contrast, Yalcin et al (2006) found that egg weight increased (P < 0.01) when laying hens were fed 5 and 10 g/kg garlic powder supplementation.…”

“…In agreement with the present study, Khan et al (2007) reported that egg production and feed consumption were affected during the six weeks in which 0, 2, 6 or 8% garlic powder was fed to the laying hens. In contrast, Chowdhury et al (2002) and Reddy et al (1991) reported that feed consumption, feed efficiency and egg production were not affected by supplements of 0, 2, 4, 6, 8 or 10% garlic paste (P > 0.05) as averaged over the 6-week period or by supplements of 0.02% garlic oil over eight weeks. The reason for this difference might be the duration of the experiment and the fact that different garlic products were used.…”

“…Chowdhury et al (2002) also reported that yolk weight responded quadratically (P < 0.05) in weeks three and four to increasing levels of sun-dried dietary garlic paste.…”

“…These results indicate that, compared with the control diet, mean egg yolk cholesterol levels dropped by 19.37, 29.58 and 46.40% in the 1, 2 or 4% garlic powder supplemented diets, respectively. Chowdhury et al (2002) reported that cholesterol concentration per gram of yolk decreased linearly (P < 0.01) with increasing levels of sun-dried dietary garlic paste. Dietary garlic paste at 2, 4, 6, 8 or 10% reduced egg yolk cholesterol on average by 5, 9, 14, 20 and 24%, respectively.…”

“…Similarly, Qureshi et al (1983b) also reported that the serum cholesterol concentration in White Leghorn pullets was reduced from 20 to 25% by supplementations of garlic paste, solvent extracted garlic paste and commercial garlic oil. The reduction of serum and egg yolk cholesterol observed when garlic paste was fed might be due to the reduction of synthetic enzyme activity (Chowdhury et al, 2002). Qureshi et al (1983a) reported a dose-dependent inhibition of hepatic HMG-CoA reductase, cholesterol 7α-hydroxylase and fatty acid synthetase when chickens were fed polar fractions of garlic powder equivalent to 1, 2, 4, 6 and 8% of fresh garlic paste.…”