The objective of this study was to evaluate four diets for rabbits whose main component was mulberry. A nutritional assessment was conducted in Cartago Province, Costa Rica, under a supply management system consistent with organic production standards. A pasture housing management system was developed for this specific organic experimentation. Four levels of mulberry meal inclusion were evaluated in the full ration: D1: 45%, D2: 55%, D3 and D4 65%: 75%. Daily weight gains in the order of 17.65 g/d were observed. Diets D1 and D2 showed the highest growth parameters compared to diets containing 65% (D3) and 75% (D4) of mulberry inclusion. The daily gain average obtained were: D1, 17.26 g/d, D2, 21.57 g/d, D3, 14.77 g/d and D4, 17.00 g/d. In relation to feed conver- sion, rabbits under diets D1 and D2 were in the use of feed for growth than D3 and D4 diets (P <0.05). The total feed cost to bring animals to market weight was in the order of D1: 2.26 US$/kg, D2: 2.17 US$/kg, D3: 2,49 US$/kg and D4: 2.44 US$/kg. The fattening and market time resulted up to 2-3.5 under a feeding system exclusively with concentrates. A balance was detected regarding the reduction in the costs between 45 and 50%.
Keywords: forage shrubs, rabbits, organic animal production, rabbit meat, organic farming.