Oregano essential oil in the diet of laying hens in winter reduces lipid peroxidation in yolks and increases shelf life in eggs.

We evaluated the effects of oregano essential oil (OEO) added to the feed of semi-heavy laying hens during winter. We measured performance as well as physical and chemical quality of fresh and 21-day stored eggs. A total of 240 semi-heavy laying hens were distributed into six treatments and five replicates (n = 8 each). Treatments consisted of five groups of hens fed diets supplemented with 0, 50, 100, 150 and 200 mg OEO/kg. We measured the average of three productive cycles (1st: week 1-4, 2nd: week 5-8 and 3rd: week 9-12), and found that feed consumption increased in hens in the control group and those in the group treated with 200 mg OEO/kg; other zootechnical variables did not differ between treatments. When we analyzed each individual production cycle individually, we did not observe differences between treatments for the performance variables in the first or second cycles. However, in the third cycle, when the animals were exposed to a greater number of days to cold stress, we recorded improved conversion rate/dozen eggs, conversion rate/daily feed consumed and egg production at T50 (50 mg OEO/kg). Stored eggs from hens supplemented with 50 mg OEO/kg showed lower eggshell percentages and higher yolk pHs. The intensity of the yellow was higher in yolks of the control group and in those from hens supplemented with 200 mg OEO/kg. Lipid peroxidation was lower in fresh egg yolks from hens that received 200 mg OEO/kg and stored eggs of T150. The reduction of lipid peroxidation in egg yolk is beneficial to consumer health by reducing levels of free radicals consumed. Reduction of lipid peroxidation associated with 150 mg OEO/kg in laying hens in winter might be useful for maintaining egg quality and for prolonging shelf life; productive efficiency was improving even at 39.8 mg OEO/kg if we consider feed conversion (kg/kg).

Oregano essential oil (Origanum vulgare) to feed laying hens and its effects on animal health.

This study evaluated the effect of oregano essential oil added to the feed of commercial laying hens. This research was focused on the analysis of biochemical changes linked to hepatic function, and protein and lipid metabolism. It was used 240 laying hens (59 weeks-old) distributed in a completely randomized design of six treatments (five repetitions with eight birds each). The experiments were constituted by a control treatment (CT) with the inclusion of zinc bacitracin and five treatments of oregano essential oil (OEO: 0, 50, 100, 150, and 200 mg.kg-1), respectively. After 28 days of feeding, an increase on serum levels of total proteins and globulins was observed on groups T150 and T200, as well as an increase on albumin levels on group CT. After 84 days of feeding, a significant reduction on total proteins and albumin was observed on group T200, as well as an increase in serum triglycerides. OEO at 200 mg.kg-1 increased globulin levels on day 28, which may be considered an effect in the inflammatory response, which increases serum immunoglobulins and proteins.

Feed addition of curcumin to laying hens showed anticoccidial effect, and improved egg quality and animal health.

The aim of this study was to evaluate whether the addition of curcumin in the diet of commercial laying hens could have an anticoccidial action and improve egg quality. For this, 60 laying hens were divided into three groups: T0 (the control group); T30 and T50 (30 and 50 mg/kg of curcumin in the feed, respectively). Eggs recently laid were collected on days 14 and 21 of the experiment, and stored for 21 days. It was observed increased specific gravity and yolk index in stored eggs of the groups T30 and T50 compared to T0. The yolk color reduced in the eggs stored from groups T30 and T50 compared to T0. Moreover, TBARS levels were lower in fresh and stored eggs from groups T30 and T50. It was observed increased TAC levels in fresh eggs from groups T30 and T50 and in stored eggs from the group T50. The presence of curcumin was not detected by HPLC in the yolk and albumen. Seric levels of albumin and uric acid did not differ between groups, while seric levels of total proteins increased on day 21 on groups T30 and T50. Finally, it was observed a significant reduction on the number of oocysts in fecal samples on days 14 and 21 of T30 and T50 compared to T0. Based on these evidences, it is possible to conclude that the addition of curcumin in the diet of laying hens has an anticoccidial effect and improves egg quality.