Effects of replacing soybean meal with alternative sources of protein on nutrient digestibility and energy value of sheep diets

The study determined the potential of eight locally produced protein sources to replace soybean meal (SBM) in the diet of sheep. Three in vivo digestibility trials were conducted using a Latin square (3x3, 4x4 and 4x4) experimental design with castrated Chios rams. The authors estimated nutrient digestibility coefficients and energy value of diets with soybean meal (control), lupin seeds (LS), rapeseed meal (RSM), sunflower meal (SFM), fababean seeds (FBS), vetch seeds (VS), pea seeds (PS), flaxseeds (FS), and chickpea seeds (CS). The results showed that the SBM, RSM, and PS diets had similar nutrient digestibility and energy value. The SFM diet had lower organic matter (OM) digestibility than the SBM diet. The FS and SFM diets had similar crude protein (CP) digestibility to the SBM diet. Additionally, FS, VS, and SBM diets had similar energy value. Furthermore, SBM, SFM, VS and FS diets had similar dry matter (DM), neutral detergent fibre (NDF), hemicelluloses, and cellulose digestibility coefficients. The SBM, LS, FBS, and CS diets had similar DM, OM, NDF, hemicelluloses, and cellulose digestibility coefficients. Additionally, SBM, LS, and CS diets had similar energy value. This study reveals that diets with RSM, PS, FS, and LS, compared with diets with SBM, did not have adverse effects on nutrient digestibility and energy value. These results tend to support the idea that some locally available protein sources seem to have the potential to replace SBM in sheep diets.