Abstract
The type of dietary lipids consumed by laying hens affects the fatty acid (FA) profile of the eggs. This work analyzed the available scientific publications that examined the use of hempseed products (Cannabis sativa L. varieties with low concentration of tetrahydrocannabinol) on the fatty acid profiles of eggs produced by laying hens. The literature search was performed to identify publications that reported experiments, in which laying hens were fed hemp products (seeds, cakes, or oils). Fourteen eligible publications (49 dietary treatments) were identified that were published in international journals from 2005 to 2019. Most of the experimental diets (24 treatments) used whole hempseeds, about one-third of the diets examined low levels of hempseed oils, and 3 studies (7 treatments) examined hempseed cakes and meal. To summarize the results of the different experiments, the inclusions of hempseed products were converted into hempseed equivalents based on total fat concentration. The inclusion of hempseed products in the diet did not affect the total saturated FA concentration of the eggs, but it did decrease the monounsaturated FA content (R2 = 0.47) by about 115 mg/yolk for each 10% inclusion in the diet of hempseed products. Dietary hempseed also increased several polyunsaturated FA (PUFA) content of yolk. A 10% increase in the dietary hempseeds led to eggs that had 46 mg/yolk of α-linolenic acid (ALA, R2 = 0.86), 25% greater than the control diet (36 mg/yolk). The same inclusion rate of dietary hempseeds increased the γ-linolenic acid content by 1.7 mg/yolk (+28% relative to the basal level, R2 = 0.85), and increased the linoleic acid (LA) content by about 6%. The other ω-3 PUFA also increased (docosahexaenoic acid, R2 = 0.62, +33%; docosapentaenoic acid, R2 = 0.81, +51%; eicosapentaenoic acid, R2 = 0.60, +41%). For each 10% increase in the diet of hempseeds, the egg yolks had greater increases of ALA than LA, leading to a reduction in the ω-6:ω-3 (R2 = 0.66). In conclusion, diets for laying hens containing hemp products led to eggs that had increased PUFA and a reduction in the ω-6:ω-3.
