Comparative yield and chemical composition of soilless-grown green fodder crops as dietary supplements for growing rabbits

Abstract:

Can soilless fodder production reliably supply fresh green feed to small-scale rabbit farms operating where arable land is scarce? This research compared the biomass yield, proximate composition, and mineral content of four hydroponic fodder species maize (Zea mays L.), barley (Hordeum vulgare L.), sorghum (Sorghum bicolor L.), and cowpea (Vigna unguiculata L.)  grown on plastic trays under a controlled indoor environment at Cairo Institute of Animal Sciences, Egypt, from March to August 2021. Seeds were surface-sterilised, soaked for 24 h, spread at a density of 3.5kgm⁻² , and irrigated with potable water four times daily. Green mats were harvested on day 8 and analysed for dry mater (DM), crude protein (CP), crude fibre (CF), ether extract (EE), ash, nitrogen-free extract (NFE), calcium, and phosphorus. A parallel feeding trial allocated 48 weaned New Zealand White rabbits (aged 35 d, mean weight 623±18 g) to four dietary groups in a completely randomised design; each group received a pelleted basal diet supplemented with one of the four fresh fodder species at 30 % of daily DM intake over 56 d. Maize recorded the highest fresh-weight yield per tray (6.83 kg) followed by barley (5.47 kg), sorghum (4.92 kg), and cowpea (3.61 kg). Cowpea sprouts contained the greatest CP fraction (23.7 % DM), while barley showed the lowest CF value (14.2 % DM). Rabbits supplemented with barley fodder achieved the best feed conversion ratio (3.41), whereas those receiving cowpea sprouts exhibited the highest daily weight gain (24.8 : g : d⁻¹) . Mineral profiles difered markedly: cowpea supplied 1.87 % Ca and 0.41 % P, exceeding the other species. These results point to a practical role for soilless fodder as a dietary supplement in rabbit production, with crop selection depending on whether protein enrichment or feed eficiency is the primary breeding objective.