Nutritional and physiological evaluation of quercetin
as a phytogenic feed additive in laying hens

The objective of the current study was to evaluate the effect of dietary quercetin supplementation on productive and reproductive performance, intestinal bacterial count, and blood biochemical parameters of laying hens. A total of 200 hens at 28 weeks of age were randomly assigned to four treatments (10 hens per treatment, 5 replicates each), group 1 was treated as control (basal diet without any supplementation), group 2, 3 and 4 were fed diets supplemented with 300, 600 and 1200 mg quercetin/kg feed, respectively. Egg production and egg mass increased (P ≤ 0.001) as a result of dietary supplementation with 300 and 600 mg quercetin/kg feed, while egg weight and feed intake were not affected, but the feed conversion ratio improved. Shell thickness, Haugh unit and yolk colour score were improved by quercetin supplementation. The total count of aerobic, anaerobic and coliform bacteria in the intestine of laying hens was reduced (P ≤ 0.001) in all quercetin-supplemented groups, and the lowest bacterial count was recorded at 600 mg /kg feed. There was an increase in the total Lactobacillus count in the treated groups. Heterophil (H) % was not affected by quercetin addition, while lymphocyte (L) % increased (P ≤ 0.001) at 300 and 600 mg quercetin/kg feed, hence the H/L ratio was reduced at these doses as compared to the control diet. The inclusion of quercetin in the diet of laying hens increased total plasma antioxidant capacity, superoxide dismutase and high-density lipoprotein cholesterol, while reduced malondialdehyde, total cholesterol and low-density lipoprotein cholesterol levels compared to the control diet. Estradiol-17β and immunoglobulin (IgG and, IgM) levels increased (P ≤ 0.0001) in response to quercetin treatments, with the highest values recorded in the group supplemented with 600 mg/kg feed. In conclusion, dietary supplementation with quercetin at a dose of up to 600 mg/kg improved productivity and physiological parameters in peak-producing laying hens; Immunity and the count of intestinal bacteria were increased, which in turn translated into overall good health and welfare of chickens.

ACKNOWLEDGEMENTS

The Authors declare that there is no conflict of interest.

METADATA IN OTHER LANGUAGES:

Chinese

槲皮素作为蛋鸡植物源性饲料添加剂的营养与生理学评价

关键词：抗氧化剂；血液指标；蛋鸡；槲皮素

摘要: 本研究旨在评价日粮中添加槲皮素对蛋鸡生产性能、繁殖性能、肠道细菌数和血液生化指标的影响。试验选用28周龄蛋鸡200只，随机分为4组，每组10只，每个处理5个重复，第1组为对照组 (基础日粮不添加任何补充剂)，第2、3、4组日粮中分别添加300、600和1200 mg/kg的槲皮素。结果显示日粮中添加300 mg/kg 和600 mg/kg的槲皮素可提高蛋鸡的产蛋量和蛋重 (P ≤ 0.001)，虽然不影响蛋重和采食量，但提高了饲料转化率。添加槲皮素可提高蛋壳厚度、哈夫单位和蛋黄颜色评分。各剂量组均能降低产蛋鸡肠道中需氧菌、厌氧菌和大肠菌群总数 (P ≤ 0.001)，其中以600 mg/kg饲料组最低。治疗组乳酸菌总数增加。在饲料中添加300 mg/kg和600 mg/kg时，异嗜性细胞 (H) %不受影响，淋巴细胞 (L) %升高 (P ≤ 0.001)，H / L比降低。与对照日粮相比，蛋鸡日粮中添加槲皮素可提高血浆总抗氧化能力、超氧化物歧化酶和高密度脂蛋白胆固醇水平，降低丙二醛、总胆固醇和低密度脂蛋白胆固醇水平。雌二醇 - 17β和免疫球蛋白 (Ig G和Ig M) 水平随处理剂量的增加而升高 (P ≤ 0.001)，其中以添加600 mg/kg饲料组最高。综上所述，日粮中添加高达600 mg/kg的槲皮素可提高产蛋高峰期蛋鸡的生产性能和生理指标，提高免疫力和肠道细菌数量，进而促进鸡的整体健康和福利。

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