Swine

The impact of a nitrogen- and phosphorus-reduced feeding strategy on bone-related traits in Landrace boars

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Abstract

Reducing the amount of nitrogen (N) and phosphorus (P) in animal feed aims to minimize environmental pollution, such as the accumulation of excess nutrients in bodies of water and soil degradation. In pigs, the main focus is on limiting the excretion of nitrogen (N) and phosphorus (P). This requires changes to the nutrient content of diets and to the efficiency of the nutrient utilization, without impairing the growth and health of the animals. An animal's genotype can affect its ability to adapt to dietary changes, potentially leading to genotype×feed interactions (G×F) within different pig populations. The study aimed to investigate the effects of N/P-restricted diets on the morphological bone structure, chemical bone composition, and bone density, as well as fundament conformation in pigs. In total, 1,082 purebred landrace (LR) boars were divided into two feeding groups. Animals were genotyped using a 77K Illumina SNP Chip. The diet of the control group was adapted based on the live weight of the pigs and contained crude protein and P in a range of 187 to 171 g/kg DM (CP) and 6 to 5.5 g/kg DM (P). The N/P-reduced diet contained ~10% less CP and ~7% less P following the recommendations by DLG. Before slaughter, the leg and body conformation of 835 boars were evaluated using a routine subjective linear scoring system. After slaughter, the right front foot of each animal was collected, and the 3rd (Mc3) and 4th (Mc4) metacarpal bones were extracted. The length, weight, and diameter of Mc3 and Mc4 bones were measured, and the bone density of Mc3 was determined by computer tomography. Afterwards, the content of ash, calcium, phosphorus, magnesium, and sodium of Mc3 was analyzed. The feeding group exhibited no substantial impact on bone density; however, four conformation traits demonstrated a significant response to the dietary regimen. The chemical analyses revealed significant differences for the magnesium content only. Variance component estimation was performed using ASReml to estimate heritabilities (h2) and genetic (rg) and phenotypic (rp) correlations via uni- and bivariate analyses. A bivariate analysis was then used to determine the importance of G×F by dividing traits according to the feeding group. A significant G×F was assumed for traits with rg 2 was observed for bone mass traits, ranging from 0.70 to 0.98, whereas lower h2 of 0.05 to 0.48 were estimated for all other traits. A significant relevance of G×F was identified for two traits (rg g, as described in the literature. In the next step, GWAS will be performed to investigate the impact of G×F on bone morphological and chemical traits.

Keywords: 2026

How to Cite:

Brà¼ggemann, D., Grosse-Brinkhaus, C., Hoffmann, M., Jonas, E., Lohmayer, R. & Tholen, E., (2026) “The impact of a nitrogen- and phosphorus-reduced feeding strategy on bone-related traits in Landrace boars”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2285872. doi: https://doi.org/10.31274/wcgalp.23813

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