The objective of the present study was to evaluate the effects of an olive leaf extract obtained with an up-to-date laboratory method, when supplemented at different levels in laying hens’ diets, on egg quality, egg yolk antioxidant parameters, fatty acid content, and liver pathology characteristics. Thus, 96 laying hens of the ISA-Brown breed were allocated to 48 experimental cages with two hens in each cage, resulting in 12 replicates per treatment. Treatments were: T1 (Control: basal diet); T2 (1% olive leaf extract); T3 (2.5% olive leaf extract); T4 (Positive control: 0.1% encapsulated oregano oil). Eggshell weight and thickness were improved in all treatments compared to the control, with T2 being significantly higher till the end of the experiment (p < 0.001). Egg yolk MDA content was lower for the T2 and T4 groups, while total phenol content and Haugh units were greater in the T2. The most improved fatty acid profile was the one of T3 yolks. The α-tocopherol yolk content was higher in all groups compared to T1. No effect was observed on cholesterol content at any treatment. Based on the findings, it can be inferred that the inclusion of olive leaf extract at a concentration of 1% in the diet leads to enhancements in specific egg quality attributes, accompanied by an augmentation of the antioxidant capacity.

Pomegranate contains bioactive compounds in all its parts. In this study, two levels of pomegranate peel byproduct (PPB) with or without the inclusion of xylanase enzyme were used to supplement laying hens’ diet, in a 2 × 2 full factorial design. A total of 48 Isa brown laying hens were fed the following experimental diets for 8 weeks: T1 (2.5% PPB); T2 (2.5% PPB and xylanase); T3 (5% PPB); T4 (5% PPB and xylanase). Eggs collected were analyzed for egg quality parameters. Moreover, egg yolks were analyzed for Malondialdehyde content (MDA), fatty acid profile and total phenolic content. The T2 eggs showed enhanced yolk coloration and greater yolk total phenolic content. The T3 and T4 egg yolks showed lower MDA levels compared with T1, T2. Overall, results have shown that (a) xylanase inclusion affected egg yolk coloration and total phenolic content when combined with 2.5% PPB dietary supplementation; (b) dietary supplementation of 5% PPB resulted in eggs with reduced MDA levels.

Exogenous carbohydrases are commonly added to monogastric animal feed to degrade non-starch polysaccharides (NSP) to improve zootechnical performance and nutrient digestion. In the current study, the effects of dietary supplementation of a new, intrinsically thermostable, monocomponent xylanase on intestinal parameters, zootechnical performance and carcass traits of broilers were evaluated. A total of 720 1-day-old broilers were randomly allotted to four wheat-based diets with different levels of xylanase (T1: control; T2: 30,000 U/g; T3: 45,000 U/g; T4: 90,000 U/g) and fed from 1 to 35 days of age. The data showed that xylanase supplementation reduced the intestinal viscosity significantly, especially in the ileum. Duodenum and cecum pH was not influenced by xylanase supplementation, while T3 treatment showed the lowest pH value in jejunum and ileum. Xylanase supplementation reduced significantly feed conversion ratio (FCR) without affecting feed intake (FI). T2 treatment exhibited a higher body weight gain (BWG) compared the other treatments. Live weight, carcass weight, legs, and liver weight were significantly higher in T3 and T4 treatments compared to T1. No significant differences on foot pad lesions were observed among the four treatments. In conclusion, dietary supplementation of this new xylanase significantly improves intestinal tract viscosity and affects beneficially broilers’ performance and carcass traits.

Wheat is rich in non-starch polysaccharides (NSP) and their degradation in poultry diets is promoted by exogenous carbohydrases. The objective here was to evaluate the effect of adding an intrinsically thermostable xylanase on wheat-based diets for laying hens in yolk color, carotenoid and fatty acid profiles of eggs. A total of 128 laying hens were used for 12 weeks. They were randomly allocated to four dietary treatments with different levels of xylanase: T1: control (no xylanase), T2: 30,000 U/g, T3: 45,000 U/g and T4: 90,000 U/g, with 32 birds, 16 replicates per treatment (2 birds/replicate). At the end of the experimental period, egg yolk color index, redness (a*) and yellowness (b*) of egg yolks were found significantly higher in all the enzyme supplemented diet groups (T2, T3, T4) compared with the control (T1). Canthaxanthin levels were significantly higher in T3 than T1 (p < 0.05). Total n-3, n-6 and total polyunsaturated fatty acids (FAs) were significantly higher in T4 compared with the control (p < 0.01), while the reverse trend was evidenced for monounsaturated FAs. Additionally, total n-3 FAs were higher in the T2 than T1 (p < 0.005). Overall, the results showed that exogenous xylanase enzyme supplementation in wheat-based diets for laying hens contribute to maintaining egg yolk color. Overall, exogenous xylanase enzyme supplemented at all levels in wheat-based laying hens’ diets improved egg yolk color compared to the control diet. The enzyme supplemented at the higher level (90,000 U/g) improved polyunsaturated and reduced monounsaturated egg yolk fatty acid content.