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. 2025 Jan-Dec;96(1):e70077.
doi: 10.1111/asj.70077.

Reducing Protein Levels in Diets for Local Pig Breeds: A Case Study on Fat-Type Krškopolje Pig

Martin Škrlep  1 , Klavdija Poklukar  1 , Sam Millet  2 , Marjeta Čandek-Potokar  1   3
Affiliations

Reducing Protein Levels in Diets for Local Pig Breeds: A Case Study on Fat-Type Krškopolje Pig

Martin Škrlep et al. Anim Sci J. 2025 Jan-Dec.

Abstract

This study investigated the effects of reduced dietary protein levels in fat-type local breed Krškopolje pig in conventional indoor and organic outdoor systems. Two tests were conducted: one in conventional system (n = 28 pigs) and one in organic outdoor system (n = 24 pigs). Two dietary strategies varying in crude protein (CP) level were tested: control, high protein (HP) with phases of 15%, 12.5%, and 10% CP content and low protein (LP) with phases of 15% and 10% CP content. The ingredients used were identical, but in the organic diet, they came from organic agriculture. The feed was offered ad libitum. Feed distribution was recorded, pigs were weighed, and the thickness of the backfat and longissimus lumborum muscle was measured with ultrasound. After 228 days, pigs were slaughtered, and carcass and meat quality were assessed. Modeling growth data with InraPorc indicated that protein and essential amino acid requirements were generally met, except for lysine in the LP diets, which appeared with the transition to a 10% protein diet. Lysine deficiency was more pronounced in the organic than in conventional system. Overall growth rate was similar in LP and HP groups. There were no pertinent differences in carcass or meat quality.

Keywords: InraPorc; Krškopolje pig; modeling; nutrition; production system.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

FIGURE 1
FIGURE 1
Design of the multiphase feeding trial with high‐protein and low‐protein diets in Krškopolje pigs raised in outdoor organic and indoor conventional systems. CP, crude protein.
FIGURE 2
FIGURE 2
Daily feed intake estimated with InraPorc based on feed distribution and growth data. HP, high‐protein diet; LP, low‐protein diet.
FIGURE 3
FIGURE 3
Assumed lysine (expressed as standardized digestible lysine) requirements and supply for Krškopolje pigs. Lysine requirements are estimated based on the profile of HP animals in (a) conventional indoor and (b) organic outdoor rearing systems. HP, high‐protein diet; LP, low‐protein diet.
FIGURE 4
FIGURE 4
Retained energy (MJ) as protein or lipid or lipid in Krškopolje pig raised in outdoor organic and indoor conventional systems. HP, high‐protein diet; LP, low‐protein diet.
See this image and copyright information in PMC

References

    1. Alonso, V. , del Mar Campo M., Provincial L., Roncalés P., and Beltrán J. A.. 2010. “Effect of Protein Level in Commercial Diets on Pork Meat Quality.” Meat Science 85, no. 1: 7–14. 10.1016/j.meatsci.2009.11.015. - DOI - PubMed
    1. AOAC . 2000. “Association of Official Analytical Chemists 2000.” In Official Methods of Analysis of AOAC International, vol. 1, 17th ed. Gaithersburg, MD, USA: AOAC International.
    1. Bao, Y. , and Ertbjerg P.. 2018. “Effects of Protein Oxidation on the Texture and Water‐Holding of Meat: A Review.” Critical Reviews in Food Science and Nutrition 59: 1–50. 10.1080/10408398.2018.1498444. - DOI - PubMed
    1. Barea, R. , Nieto R., and Aguilera J. F.. 2007. “Effects of Dietary Protein Content and the Feeding Level on Protein and Energy Metabolism in Iberian Pigs Growing From 50 to 100 kg Body Weight.” Animal 1: 357–365. 10.1017/S1751731107666099. - DOI - PubMed
    1. Batorek Lukač, N. , Tomažin U., Škrlep M., Kastelic A., Poklukar K., and Čandek‐Potokar M.. 2019. “Krškopoljski prašič (Krškopolje Pig).” In European Local Pig Breeds – Diversity and Performance: A Study of Project TREASURE, edited by Candek‐Potokar M. and Nieto Liñan R., 141–154. IntechOpen. 10.5772/intechopen.83767. - DOI