China Animal Husbandry and Veterinary Medicine ›› 2022, Vol. 49 ›› Issue (3): 913-923.doi: 10.16431/j.cnki.1671-7236.2022.03.013

• Nutrition and Feed • Previous Articles     Next Articles

Effects of Dietary Methionine on Growth Performance, Antioxidant Capacity and Stress Tolerance of Broilers Under High-density Feeding

WU Yuan1, QIN Xin1, DONG Yuanyang1, HAN Miaomiao1, MIAO Zhiqiang1, WEI Qingyu1, SONG Xianyi1, SHEN Liyan1, FENG Yan2, LI Huifeng2, LI Jianghui1   

  1. 1. College of Animal Science, Shanxi Agricultural University, Taigu 030801, China;
    2. College of Life Sciences, Shanxi Agricultural University, Taigu 030801, China
  • Received:2021-09-01 Online:2022-03-05 Published:2022-03-03

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Abstract: 【Objective】 The purpose of this experiment was to explore the effects of dietary methionine on performance, antioxidant and stress responses of broilers under high-stocking density.【Method】 396 1-day-old AA broilers were selected and fed uniformly at the age of 1-21 days.At the end of 21 days, broilers with similar body weights were selected and divided into 5 groups, with 6 replicates in each group.The feeding density of broilers in control group was 14 birds/m2, and the methionine level was 0.40%;the test groups were set at 20 birds/m2 stocking density, with methionine level at 0.35%, 0.40%, 0.45% and 0.50% in the diet, respectively.At the end of the experiment (42 d), blood and liver samples were collected to measure the stress level and antioxidant capacity.【Result】 ① Compared with normal-density feeding group, high-density rearing significantly reduced the final body weight, average daily feed intake and the average daily body weight gain of broilers during 22-42 days (P<0.05), and significantly increased broiler mortality rate (P<0.05).In the case of high-density feeding, the weight gain ratio of feed consumption was the highest when the methionine level was 0.35%, and it decreased linearly with the increase of the methionine level of the diet (P<0.05).The mortality rate could be reduced by 0.45% and 0.50% methionine diets, compared with 0.35% methionine level (P<0.05).② Compared with normal-density feeding group, T-AOC of high-density feeding group was significantly reduced (P<0.05), while SOD activity and PCO level were significantly increased (P<0.05).In high-density feeding groups, blood PCO level was significantly decreased as methionine level was increasing (P<0.05).③Compared with normal-density feeding group, high-density rearing significantly reduced TP concentration (P<0.05) and increased ALT activity (P<0.05) in plasma.In the case of high-density feeding, the plasma TP concentration and AST activity was significantly higher at 0.50% methionine level than that of the 0.35% and 0.40% methionine groups (P<0.05).The ALT activities of 0.40% and 0.45% methionine groups were significantly lower than that of 0.35% methionine group (P<0.05).④ Compared with normal-density feeding group, high-density rearing significantly increased HSP70 mRNA expression in liver (P<0.05).In the high-density feeding groups, HSP70 was significantly higher in 0.35% and 0.50% methionine groups than 0.45% level group (P<0.05).Compared with normal density feeding group, HMGCR mRNA expression was increased significantly when methionine level was 0.35% and 0.50% (P<0.05).【Conclusion】 The stocking density and the level of methionine addition had a certain impact on broiler's growth performance, stress level, and antioxidant capacity.High-density breeding could cause broiler stress and cause damage to liver function.Under high-density feeding, methionine restriction could increase mortality rate of broilers, and relatively higher methionine also could impair liver health.When methionine level was 0.45%, it had better anti-stress and antioxidant effects, which was beneficial to the growth of broilers.

Key words: methionine; stocking density; broiler; growth performance; antioxidant capacity; stress torerance

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