Sarria et al., 2010. Livest. Res. Rural Dev., 22 (6): 110

Pigs of 22-29 kg body weight (n=24) were used to assess the effect on consumption and digestibility of inclusion of 0, 15 and 30% (dry basis) of leaf meal of cowpea (Vigna unguiculata) (CLM). The main elements in the control diet were maize and soybean meal. The intake trial lasted 10 days after an adaptation period of 10 days, with the offer level of the diet set at 90g DM / kg LW0.75 (40 g DM / kg LW). Digestibility coefficients were measured in three ways: total collection of feces, use of chromium oxide (Cr2O) as internal marker to determine the ileal digestibility and digestibility by "difference" to estimate the coefficients of digestibility of CLM alone. In these tests the CLM contributed 0, 15 or 30% of the crude protein of the diet.  The inclusion of CLM up to 30% of the diet increased DM intake in a curvilinear way.  The coefficients of apparent digestibility (total collection) of the DM, GE (gross energy),  NDF and ADF were similar in the three treatments. In contrast, the apparent digestibility of crude protein showed a downward trend as the level of the CLM increased. At the level of the ileum, the digestibility coefficients of DM, CP and GE were lower in the diet with 30% protein coming from the CLM. The apparent digestibility coefficients of the CLM, determined by the "difference method " were 57 and 53%  for DM and crude protein, respectively.

Pigs fed the diet with 30% of the crude protein from CLM had greater development of the large intestine and less development of the small intestine, compared with pigs fed the control diet.  It is concluded that the CLM was well accepted by the pigs, increasing consumption by 8% without affecting the apparent digestibility of DM and GE. However, the digestibility of crude protein was decreased in a curvilinear way with increasing CLM in the diet up to 30%.