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Meta-Analysis
. 2020 Nov;99(11):6205-6211.
doi: 10.1016/j.psj.2020.08.019. Epub 2020 Aug 26.

Heat stress impacts on broiler performance: a systematic review and meta-analysis

Lili Liu  1 , Mengya Ren  2 , Kui Ren  2 , Yuanchang Jin  2 , Mingli Yan  2
Affiliations
Meta-Analysis

Heat stress impacts on broiler performance: a systematic review and meta-analysis

Lili Liu et al. Poult Sci. 2020 Nov.

Abstract

Heat stress (HS) is a major problem in poultry business which affects chickens' performance and may trigger large economic losses. This study intends to analyze the impact of HS on broiler chickens' performance compared with those under normal condition. A literature search was performed on PubMed, Web of Science, and Cochrane Library for studies published in English up to January 17, 2020. Outcomes of body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), and mortality were calculated by weighted difference (WMD) or odds ratio (OR) with 95% confidence interval (CI). A total of 12 studies with 470 broiler chickens were included. HS significantly decreased FI (11 trials: WMD = -97.95, 95% CI: -141.70, -54.20) and BWG (7 trials: WMD = -151.40, 95% CI: -198.59, -104.21) and significantly increased FCR (9 trials: WMD = 0.17, 95% CI: 0.04, 0.29) and mortality (8 trials: OR = 3.74, 95% CI: 1.39, 10.12) compared with the control. In conclusion, HS significantly affected broiler chickens' BWG, FI, FCR, and mortality, indicating the importance to control housing temperature to avoid unnecessary costs.

Keywords: broiler chicken; feed intake; heat stress; meta-analysis; thermal condition.

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Figures

Figure 1
Figure 1
Study selection process. A total of 4,107 studies were retrieved from the electronic databases (PubMed, Web of Science, and Cochrane Library), and 3 studies were identified through manual search. Finally, a total of 12 studies were included in the study.
Figure 2
Figure 2
The forest plot of feed intake between the broiler chickens exposed to heat stress and thermoneutral condition. Feed intake was significantly decreased in the chickens exposed to heat stress compared with the normal control (WMD = −97.95, 95% CI: −141.70, −54.20).
Figure 3
Figure 3
The forest plot of body weight gain between the broiler chickens exposed to heat stress and thermoneutral condition. Heat stress significantly decreased chickens' birth weight gain compared with the control (WMD = −151.40, 95% CI: −198.59, −104.21).
Figure 4
Figure 4
The forest plot of feed conversion ratio between the broiler chickens exposed to heat stress and thermoneutral condition. No significantly difference was observed between groups (A), while feed conversion ratio was significantly increased in heat stress group if omitted Alhenaky 2017(2) and Quinteiro 2012 (B).
Figure 5
Figure 5
The forest plot of mortality between the broiler chickens exposed to heat stress and thermoneutral condition. Heat stress significantly increased mortality compared with the control.
See this image and copyright information in PMC

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