Dietary Inclusion of Crickets (Acheta domesticus) and Yellow Mealworm Meal (Tenebrio molitor) in Comparison with Soybean Meal: Effect on the Growth, Total Tract Apparent Digestibility, and Nitrogen Balance of Fattening Rabbits

Three diets were formulated, i.e., soybean meal (SM diet), adult Acheta domesticus (AD diet), and Tenebrio molitor larvae (TM diet), as the main crude protein (CP) sources. A total of 45 rabbits (Hyplus, weaned at 32 days of age) were divided into three groups (15 per treatment) and fed one of the three diets for 42 days. A higher daily weight gain (p = 0.042), as well as daily feed intake (p = 0.022), was observed in rabbits fed the AD and TM diets than in rabbits fed the SM diet within 21 days after weaning. The coefficients of total tract apparent digestibility (CTTAD) of gross energy were higher (p = 0.001) in rabbits fed the SM diet than in rabbits fed the other diets. The CTTAD of CP (p = 0.040) and starch (p = 0.041) was higher in rabbits fed the SM diet compared to those fed the AD diet. There were non-significantly higher losses of nitrogen in the urine (an average by 0.227 g/day; p = 0.094) in rabbits fed the TM diet than in rabbits fed the other diets. It can be concluded that the growth of rabbits and nitrogen output were not detrimentally affected by the insect meal (AD or TM) used in this study.

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 53^rd and 67^th 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 (<em>P</em>=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 (<em>P</em>=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.