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Acta Prataculturae Sinica ›› 2023, Vol. 32 ›› Issue (4): 173-182.DOI: 10.11686/cyxb2022249

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Impact of heat stress on growth rate, serum antioxidant properties, and rumen flora in weaned lambs

Ai-yu LIU1(), Chao WANG1(), Zhan-jun WU2, Shou-pei ZHAO1, Li-chen ZHAO1, Xiao-yu LI1, Wei-tao ZHANG3, Le-tian WANG4, Yu-hong GAO1()   

  1. 1.College of Animal Science and Technology,Hebei Agricultural University,Baoding 071000,China
    2.Institute of Grain and Oil Crops,Hebei Academy of Agriculture and Forestry Science,Shijiazhuang 050000,China
    3.Hebei Animal Husbandry Station,Shijiazhuang 050000,China
    4.Heilongjiang Sanjiang Art Vocational College,Jiamusi 154013,China
  • Received:2022-06-07 Revised:2022-09-07 Online:2023-04-20 Published:2023-01-29
  • Contact: Yu-hong GAO

Abstract:

Heat stress (HS) has affected the efficiency and development of the sheep industry. This study investigated the growth performance, serum antioxidant properties, and rumen microbiota in weaned lambs under HS conditions using an environmental control chamber. Twelve weaned lambs were randomly allocated into two groups and raised in two chambers with one lamb per pen. The chamber of the control group was maintained at 21.5 ℃ and 60% humidity, while the HS chamber was maintained at 33.5 ℃ and 60% humidity. The entire experiment lasted for 14 days, and the growth rate, serum antioxidant enzyme activities, heat stress proteins (HSP), and rumen flora diversity were measured at the end of the experiment. It was found that: 1) Under HS conditions, the daily feed intake and daily weight gain of lambs decreased (P<0.05) by 28.38% and 41.12%, respectively, compared with those in control group, while the feed/gain (F/G) increased by 33.13%. 2) The serum antioxidant properties of lambs decreased under HS conditions. The total antioxidant capacity, catalase, or superoxide dismutase (SOD) activity decreased ( P<0.05) under HS, while the levels of malondialdehyde increased (P≤0.05). Moreover, compared with the control group, the serum HSP content in the HS group increased (P<0.05) by 1.19 times for HSP60, 1.47 times for HSP70, and 1.39 times for HSP90. 3) The diversity and abundance of rumen flora were affected by the HS conditions; The Shannon index and Simpson index both decreased (P<0.05), while the relative abundance of Bacteroidetes or Proteobacteria increased (P<0.05). In particular, Bacteroidetes abundance increased by 76.47% compared with the control group. However, the abundance of Actinobacteria or Firmicutes decreased (P<0.05). In addition, under HS, the abundance of Prevotella_1 in the rumen increased by 326.28% (P<0.05), and the abundance of Selemonas_1 decreased by 84.21% (P<0.05), compared with the control. In summary, HS affected growth rate, serum antioxidant properties, and rumen microbe community structure of the lambs. The results from this study provide data to help understand and relieve sheep affected by HS in commercial production.

Key words: lamb, heat stress, growth performance, antioxidant performance, flora