Effect of cowpea (Vigna Unguiculata (L.) Walp) Stover dietary inclusion level on total tract apparent digestibility of nutrients in growing rabbits

Although agro-industrial co-products have low economic value as foods for human consumption, they may have potential value as animal feedstuffs. This experiment was carried out to evaluate the effect of cowpea stover inclusion in rabbits’ diet on growth performance and nutrient digestibility. A total of 180 animals were randomly assigned to 3 treatments (CS0, CS2 or CS4, with no inclusion, 20 or 40 g/kg of cowpea stover, respectively). Animal performance was evaluated between the 53rd and 67th d of age in 48 animals per treatment. The coefficients of total tract apparent digestibility (CTTAD) of organic matter, crude protein, neutral detergent fibre and gross energy were measured between 63 to 67 d of age in 12 animals per treatment. Results showed that, in general, CTTAD values were not affected by the inclusion of cowpea stover. Nevertheless, a trend towards a decrease in crude protein digestibility (P=0.0848) was observed when including cowpea stover. This had a negative influence on digestible protein (P=0.0240) and on the ratio between digestible protein and digestible energy (P=0.0231) for diet CS4. Rabbits showed normal figures for growth rate (on av. 46.8 g/d), feed intake (on av. 168.3 g/d) and feed conversion ratio (on av. 3.61). Future studies should assess the possibility of incorporating higher levels of cowpea stover while analysing the economic impact of this inclusion.