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International audience; In organic pig production systems, one of the main challenges is to meet the demand for resources rich in protein. Among the resources available, temperate green plants, such as forage legumes, are potential sources of energy and protein. The aim of the study was to determine the nutritional value of silages (S) from the whole plant of lucerne (L) and red clover (R) and protein pastes (PPs) obtained from L and R leaves. In a first trial, 30 pigs were used in a factorial design to determine the total tract digestibility (TTD) of dietary nutrients and energy in five dietary treatments. The control group was fed a control diet (C1). The lucerne silage (LS) and red clover silage (RS) groups were fed a 78%:22% mixture (on a DM basis) of the C1 diet and LS or RS. The lucerne protein paste (LPP) and the red clover protein paste (RPP) groups were fed an 81%:19% mixture (on a DM basis) of the C1 diet and LPP or RPP. In the second trial, five pigs were used in a 5 x 5 Latin square design to evaluate the standardised ileal digestibility (SID) of amino acids (AAs) in the four legume products. The control diet (C2) was formulated with casein as the sole protein source. The LS and RS groups were fed an 85%:15% mixture (on a DM basis) of the C2 diet and LS or RS. The LPP and RPP groups were fed an 80%:20% mixture (on a DM basis) of the C2 diet and LPP or RPP. Regardless of the plant species, silages obtained from L and R leaves contained less AA and more fibre than protein pastes. While the fresh forages contained the same percentage of protein N in total N (63.6%), lucerne lost more protein N during ensiling than red clover (-75.5 vs -33.8%). The calculated TTD coefficient of energy was higher in silages than in protein pastes and lower in R than in L products (72.8, 71.5, 67.7, and 61.3 for LS, RS, LPP and RPP, respectively). The SID of total essential AA was higher in LPP than in RPP (87.2 vs 79.2%) whereas it was lower in LS than in RS (33.2 vs 56.8%). The lower SID values in silages were explained by the protein degradation during the ensiling process and a high proportion of AA linked to the NDF fraction. The results of the present study show that protein pastes obtained from lucerne and red clover are valuable protein sources for pig. In contrast, legume silages have to be considered as an energy source rather than a protein source.

In the present study, 199 pre-selected Carbohydrate-Active enZymes (CAZymes) and sulfatases were assessed, either alone or in combination, to evaluate their capacity to disrupt Laminaria digitata cell wall, with the consequent release of interesting nutritional compounds. A previously characterized individual alginate lyase, belonging to the family 7 of polysaccharide lyases (PL7) and produced by Saccharophagus degradans, was shown to be the most efficient in the in vitro degradation of L. digitata cell wall. The alginate lyase treatment, compared to the control, released up to 7.11 g/L of reducing sugars (p p p = 0.001). The hydrolysis of gel-forming polymer alginate by the alginate lyase treatment could prevent the trapping of fatty acids and release beneficial monounsaturated fatty acids, particularly 18:1c9 (p p > 0.170) or pigments (p > 0.070) was observed. Overall, these results show the ability of an individual alginate lyase, from PL7 family, to partially degrade L. digitata cell wall under physiological conditions. Therefore, this CAZyme can potentially improve the bioavailability of L. digitata bioactive compounds for monogastric diets, with further application in feed industry.