The impact of dietary phosphorus levels on growth, slaughter, and digestive metabolism in growing sheep

Phosphorus (P) pollution from livestock farming poses significant environmental challenges, necessitating efficient P utilization. This study systematically investigated the effects of varying dietary P levels on growth, slaughter performance, nutrient digestion, and metabolism in Yunnan Semi-fine W...

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Main Authors: Shoupei Zhao, Xiaojun Ni, Jia Zhou, Xiaoqi Zhao, Xiao Wen, Xiaolin Wang, Mingyu Cao, Yanfei Zhao, Chong Shao, Lianghao Lu, Yuanyuan Chen, Bao Zhang, Huaming Yang, Bai Xue, Guobo Quan
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-02-01
Series:Frontiers in Veterinary Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fvets.2025.1489948/full
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Summary:Phosphorus (P) pollution from livestock farming poses significant environmental challenges, necessitating efficient P utilization. This study systematically investigated the effects of varying dietary P levels on growth, slaughter performance, nutrient digestion, and metabolism in Yunnan Semi-fine Wool Sheep during the growth phase. Forty-five sheep (30.33 ± 0.56 kg) were randomly assigned to five dietary P levels (0.40, 0.51, 0.68, 0.82, and 0.97%) over a 44-day trial, including a 14-day pre-feeding and 30-day formal trial period. Digestibility trials were conducted on days 22–27, and selected sheep were slaughtered for detailed analysis. Results showed no significant effects of dietary P on daily weight gain, feed-to-gain ratio, or organ indices (p > 0.05). However, dry matter intake, liver, and lung weights decreased linearly with increasing P levels (p < 0.05). Carcass traits such as left half carcass rate and net rib rate varied significantly (p < 0.05), showing quadratic trends. P levels also affected P, calcium, protein, and energy metabolism, as well as apparent digestibility of acid detergent fiber (p < 0.05). Using endogenous loss and comparative slaughter methods, the P maintenance requirement was determined as: Retained p = 0.5436 × Intake P – 0.0614 (R2 = 0.83, p < 0.01). P requirements for growth were modeled as: P (g/kg EBW) = 30.95772 × EBW – 0.5031. The recommended dietary P level was 0.40%, with maintenance and growth requirements of 0.06 g/EBW and 5.34–6.19 g/kg EBW, respectively, providing a foundation for P reduction strategies.
ISSN:2297-1769