Effects of protein reduction in lamb fattening concentrate on in vivo digestibility, nitrogen balance and meat quality
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Date
2026-01-27
Authors
Lobón Ascaso, SandraBaila Bigne, Claudia
Alvarez Rodríguez, Javier
Blanco Alibés, Mireia
Casasús Pueyo, Isabel
Pelegrín Valls, Jonathan
Joy Torrens, Margalida
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Publisher
Elsevier B.V.
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texto , revista , artículo , artículo originalAbstract
Determining the optimal crude protein (CP) content in light lambs’ diets is crucial for reducing ammonia. This study assessed lowering CP in fattening concentrates and its effect on digestibility and meat quality (two experiments). Two phases were tested: growing (14–19 kg BW; 18 % vs. 20 % CP) and finishing (19–25 kg BW; 17 % vs. 19 % CP). Experiment 1 involved 24 Rasa Aragonesa lambs, 12 per phase (growing: 14.0 ± 0.87 kg BW; finishing: 18.9 ± 0.78 kg BW, n = 6 per treatment) to assess apparent digestibility, nitrogen balance, and blood metabolites. The adaptation period to the diets were 12 days, while the collection period was 5 days. Digestibility was measured by total faecal collection and acid-insoluble ash (AIA) as internal marker. Experiment 2 evaluated meat quality of 24 Ripollesa lambs, slaughtered at 24.6 ± 0.23 kg BW after 42 days of fattening. Lower CP tended to decrease the acid detergent fibre (ADF) digestibility using total faecal method (P = 0.06) and decreased organic and dry matter digestibility with AIA (P = 0.03) during the growing phase (P < 0.05). No differences were observed in the finishing phase (P > 0.10). Digestibility coefficients were consistently underestimated with AIA compared to total faecal collection (P < 0.001). Nitrogen balance was unaffected by CP level (P > 0.05). Plasma metabolites were similar between treatments, except for β-hydroxybutyrate, which tended to be lower in Low CP lambs during the finishing (P = 0.09). Meat quality was minimally affected, however, Low CP increased metmyoglobin after 6 days of oxygen exposure (P = 0.005) and modified minor fatty acids. A moderate reduction of 2 % in dietary CP of light lambs appears feasible and does not impair nutrient digestibility and meat quality.
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Bibliographic citation
Lobón, S., Baila, C., Álvarez-Rodríguez, J., Blanco, M., Casasús, I., Pelegrin-Valls, J., & Joy, M. (2026). Effects of protein reduction in lamb fattening concentrate on in vivo digestibility, nitrogen balance and meat quality. Animal Feed Science and Technology, 334, 116670. https://doi.org/10.1016/j.anifeedsci.2026.116670
AGROVOC subjects
CorderoCalidad de la carne
Proteina bruta
Ácido graso
Digestibilidad in vivo
Sponsorship
Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad de España con la subvención RTA2017–00008-C02; el Gobierno de Aragón con los fondos del Grupo de Investigación (Grupo A25_23R); y la AEI con la beca predoctoral PRE2018–086670. Pelegrin-Valls, J. recibió el apoyo de la subvención FI (2019FI_B_00376) de la Generalitat de Catalunya-Fondos Sociales Europeos.