Dietary Digestible Protein Requirement in Finishing Pigs: A Study for Experimental Determination and Verification

Crude protein, as a traditional standard for characterizing dietary nitrogen content, fails to reflect protein bioavailability. Digestible protein (DP) emphasizes the importance of total available proteins and offers better adaptability in low-protein diversified diets. The objective of this study w...

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Main Authors: Shengkai Li, Hui Ma, Jianliang Wu, Jihe Lu, Shiyan Qiao, Xiangfang Zeng, Junyan Zhou
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Agriculture
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Online Access:https://www.mdpi.com/2077-0472/15/12/1306
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author Shengkai Li
Hui Ma
Jianliang Wu
Jihe Lu
Shiyan Qiao
Xiangfang Zeng
Junyan Zhou
author_facet Shengkai Li
Hui Ma
Jianliang Wu
Jihe Lu
Shiyan Qiao
Xiangfang Zeng
Junyan Zhou
author_sort Shengkai Li
collection DOAJ
description Crude protein, as a traditional standard for characterizing dietary nitrogen content, fails to reflect protein bioavailability. Digestible protein (DP) emphasizes the importance of total available proteins and offers better adaptability in low-protein diversified diets. The objective of this study was to establish and validate the digestible protein (DP) requirement for 80–110 kg finishing pigs (Duroc × Yorkshire × Landrace). In Experiment 1, 450 pigs were fed diets with graded DP levels (8.82–11.26%). Linear and quadratic regression models identified 9.55% DP as the optimal level, optimizing average daily gain and feed efficiency (R<sup>2</sup> ≥ 0.94). Experiment 2 validated this requirement using three diet treatments and 270 pigs: high-protein traditional, low-protein traditional, and low-protein diversified. No significant differences were observed in growth performance, carcass traits, or meat quality among diets, confirming the robustness of 9.55% DP across formulations. Plasma urea nitrogen and total amino acids increased linearly with DP (<i>p</i> < 0.05), while hepatic transcriptomics revealed immune and metabolic partial impairments in high-protein traditional diet pigs, which may be linked to nitrogen overload. Muscle tissues from different treatment groups showed minimal transcriptional differences, emphasizing efficient protein utilization when amino acid requirements are met. This study demonstrates that 9.55% DP, combined with balanced amino acids, supports productivity in both traditional and diversified diets, reducing reliance on resource-intensive feed ingredients. These findings advocate for DP as a precise metric in swine production, thereby promoting sustainable development.
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spelling doaj-art-670b1e90d32e4e5c93ddfcb2650d31332025-08-20T03:30:28ZengMDPI AGAgriculture2077-04722025-06-011512130610.3390/agriculture15121306Dietary Digestible Protein Requirement in Finishing Pigs: A Study for Experimental Determination and VerificationShengkai Li0Hui Ma1Jianliang Wu2Jihe Lu3Shiyan Qiao4Xiangfang Zeng5Junyan Zhou6College of Animal Science and Technology, Beijing University of Agriculture, Beijing 102206, ChinaBeijing Sanyuan Seed Industry Technology Co., Ltd., Beijing 102600, ChinaBeijing Sanyuan Seed Industry Technology Co., Ltd., Beijing 102600, ChinaBeijing Zhongyu Breeding Pig Co., Ltd., Beijing 100194, ChinaCollege of Animal Science and Technology, China Agricultural University, Beijing 100193, ChinaCollege of Animal Science and Technology, China Agricultural University, Beijing 100193, ChinaCollege of Animal Science and Technology, Beijing University of Agriculture, Beijing 102206, ChinaCrude protein, as a traditional standard for characterizing dietary nitrogen content, fails to reflect protein bioavailability. Digestible protein (DP) emphasizes the importance of total available proteins and offers better adaptability in low-protein diversified diets. The objective of this study was to establish and validate the digestible protein (DP) requirement for 80–110 kg finishing pigs (Duroc × Yorkshire × Landrace). In Experiment 1, 450 pigs were fed diets with graded DP levels (8.82–11.26%). Linear and quadratic regression models identified 9.55% DP as the optimal level, optimizing average daily gain and feed efficiency (R<sup>2</sup> ≥ 0.94). Experiment 2 validated this requirement using three diet treatments and 270 pigs: high-protein traditional, low-protein traditional, and low-protein diversified. No significant differences were observed in growth performance, carcass traits, or meat quality among diets, confirming the robustness of 9.55% DP across formulations. Plasma urea nitrogen and total amino acids increased linearly with DP (<i>p</i> < 0.05), while hepatic transcriptomics revealed immune and metabolic partial impairments in high-protein traditional diet pigs, which may be linked to nitrogen overload. Muscle tissues from different treatment groups showed minimal transcriptional differences, emphasizing efficient protein utilization when amino acid requirements are met. This study demonstrates that 9.55% DP, combined with balanced amino acids, supports productivity in both traditional and diversified diets, reducing reliance on resource-intensive feed ingredients. These findings advocate for DP as a precise metric in swine production, thereby promoting sustainable development.https://www.mdpi.com/2077-0472/15/12/1306amino acidsdigestible proteinfeed ingredientfinishing pigslow-protein diets
spellingShingle Shengkai Li
Hui Ma
Jianliang Wu
Jihe Lu
Shiyan Qiao
Xiangfang Zeng
Junyan Zhou
Dietary Digestible Protein Requirement in Finishing Pigs: A Study for Experimental Determination and Verification
Agriculture
amino acids
digestible protein
feed ingredient
finishing pigs
low-protein diets
title Dietary Digestible Protein Requirement in Finishing Pigs: A Study for Experimental Determination and Verification
title_full Dietary Digestible Protein Requirement in Finishing Pigs: A Study for Experimental Determination and Verification
title_fullStr Dietary Digestible Protein Requirement in Finishing Pigs: A Study for Experimental Determination and Verification
title_full_unstemmed Dietary Digestible Protein Requirement in Finishing Pigs: A Study for Experimental Determination and Verification
title_short Dietary Digestible Protein Requirement in Finishing Pigs: A Study for Experimental Determination and Verification
title_sort dietary digestible protein requirement in finishing pigs a study for experimental determination and verification
topic amino acids
digestible protein
feed ingredient
finishing pigs
low-protein diets
url https://www.mdpi.com/2077-0472/15/12/1306
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