China Animal Husbandry & Veterinary Medicine ›› 2026, Vol. 53 ›› Issue (1): 136-150.doi: 10.16431/j.cnki.1671-7236.2026.01.013

• Nutrition and Feed • Previous Articles     Next Articles

Effects of Eucalyptus globulus Essential Oil on Growth Performance, Serum Biochemical Indicators, Antioxidant Capacity and Intestinal Health of Broilers Under Heat Stress

JI Zhenzhen1,2(), CHENG Pu1, XI Lei1,2, LIU Tongshuai1, WANG Yongfen3()   

  1. 1.College of Animal Science & Technology,Henan University of Animal Husbandry and Economy,Zhengzhou 450046,China
    2.Henan Engineering Research Center on Animal Healthy Environment and Intelligent Equipment,Zhengzhou 450046,China
    3.College of Food and Biological Engineering,Henan University of Animal Husbandry and Economy,Zhengzhou 450046,China
  • Received:2025-04-28 Online:2026-01-05 Published:2025-12-26
  • Contact: WANG Yongfen E-mail:80117@hnuahe.edu.cn;yongfwang@163.com

Abstract:

Objective This study aimed to investigate the effects of dietary supplementation with Eucalyptus globulus essential oil (EGO) on the growth performance, serum biochemical indicators, antioxidant capacity and intestinal health of broilers under heat stress. Method A total of 100 healthy 21-day-old Cobb male broilers with similar body weights were randomly divided into 5 groups with 3 replicates per group and 15 broilers per replicate. Broilers in control group (CON) was housed at (24±1)℃ throughout the day and fed a basal diet, and broilers in the other groups were subjected to heat stress ((32±1)℃ from 09:00 to 17:00 daily and (24±1)℃ otherwise) and fed basal diets supplemented with 0 (HS group), 100 (HS+EGO-L group), 200 (HS+EGO-M group), and 300 (HS+EGO-H group) mg/kg EGO. The experiment lasted 21 d. During the trial period, the growth performance was statistically analyzed. At the end of the trial, subwing vein blood, intestinal tissues and cecal contents of broilers were collected to determine serum biochemical indicators, intestinal tissue morphology, and cecal microflora, respectively. Result ①Compared with CON group, the final body weight (FBW), average daily feed intake (ADFI), and average daily gain (ADG) of broilers in HS group were significantly decreased (P<0.05), and the F/G was significantly increased (P<0.05). The total bilirubin (TBIL) content and alkaline phosphatase (ALP) activity in serum of broilers in HS group were significantly increased (P<0.05), while the calcium and phosphorus levels in serum were significantly decreased (P<0.05). Serum superoxide dismutase (SOD) activity of broilers in HS group was significantly decreased (P<0.05), and malondialdehyde (MDA) content was significantly increased (P<0.05). Heat stress significantly reduced the villus height (VH) in duodenum and jejunum of broilers in HS group (P<0.05). Cecal microflora analysis revealed a significant decrease in Simpson index (P<0.05) and a significant increase in Shannon index (P<0.05), along with altered Beta diversity. The relative abundance of Firmicutes of broilers in HS group increased, the relative abundance of Bacteroidetes decreased, the ratio of Firmicutes to Bacteroidetes (F/B) increased, and the relative abundance of Eisenbergiella and Butyricicoccus of broilers in HS group were specifically proliferated. ②Compared with HS group, FBW and ADG of broilers in HS+EGO-M and HS+EGO-H groups were significantly increased (P<0.05), and F/G in HS+EGO-H group was significantly decreased (P<0.05). Serum ALP activity of broilers in HS+EGO-H group was significantly decreased (P<0.05), while serum phosphorus level in HS+EGO-M and HS+EGO-H groups was significantly increased (P<0.05). Serum calcium level in each EGO group was significantly increased and MDA content was significantly decreased (P<0.05). VH in duodenum of HS+EGO-L and HS+EGO-M groups and jejunum of HS+EGO-H group was significantly increased (P<0.05). The relative abundance of Firmicutes in cecum of broilers in each EGO group was decreased, and the relative abundance of Bacteroidetes in HS+EGO-M and HS+EGO-H groups was increased, with a decrease in F/B ratio. The relative abundance of Christensenellaceae_R-7_group, FaecalibacteriumBlautia, and norank_o_RF39 in cecum of broilers in HS+EGO-H group were specifically proliferated. ③The Tuzzerella, norank_f_Oscillospiraceae, and Escherichia-Shigella showed significant or extremely significant positive correlation with serum MDA content (P<0.05 or P<0.01), and Christensenellaceae_R-7_group, Lachnoclostridium, norank_o_Clostridia_UCG-014 and Akkermansia showed significant or extremely significant negative correlation with serum MDA content (P<0.05 or P<0.01). Conclusion Under the experiment conditions, addition of EGO to feed could alleviate liver damage and oxidative stress in broilers under heat stress, improve the antioxidant capacity of the body, improve intestinal morphology, and modulate gut microbiota balance, and then improve the growth performance of broilers. A dosage of 300 mg/kg EGO was recommended for optimal efficacy.

Key words: heat stress; Eucalyptus globulus essential oil; growth performance; antioxidant capacity; intestinal health

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