Effects of Graded Levels of Spirulina on Ingestion and In Vivo Digestibility of Rice Straw Associated with Molasses in Small Ruminants

Abstract

The assessment of the effects of spirulina incorporation on ingestion and in vivo digestibility of rice straw was conducted at the Application and Research Farm and at the Animal Nutrition and Feeding Laboratory of Dschang University. The rations were distributed in a completely randomized design comprising three groups of three West African dwarf goats and three groups of three sheeps aged between 18 and 24 months. These animals were housed individually in digestibility cages. Periods of adaptation and data collection were 8 and 6 days, respectively. Each animal received 700g of rice straw per day with 0% spirulina (RS5 + S0) for group 1; 5% spirulina (RS5 + S5) for group 2 and 10% spirulina for group 3 (RS5 + S10). The leftover of each group was evaluated every morning before serving the new ration. A sample of 100g of each ration, faeces and 10 ml of urine was collected for the purpose of carrying out bromatological analyzes and the evaluation of digestibility. The results of this study showed that the addition of spirulina increased digestibility of organic matter and digestible nitrogenous matter of rice straw. The addition of spirulina did not significantly (P> 0.05) influence ingestion of dry matter (DM), organic matter (OM) and cell walls (NDF) in goats. However, the highest intake of DM, OM and cell walls (NDF) was obtained with RS5 + S10 ration (673.06; 541.40; 481.91g DM / day) and the lowest with RS5 + S0 (561.19; 480.61; 457.65g DM / day). On the other hand, in sheep, the addition of Spirulina significantly (P<0.05) influenced intake of rations. Dry matter (DM) intake of RS5 + S0 diet (566.20g DM/day) was comparable (P>0.05) to that of the RS5 + S5 diet (570.39 g DM/day), but significantly (P<0.05) lower than RS5 + S10 diet (603.76g DM/day). The addition of spirulina to rice straw associated with molasses resulted to the best digestive utilization coefficients of DM, OM, cell walls (NDF) and nitrogen in West African dwarf goats. On the other hand, in sheep, the best digestibility coefficients of DM, OM, cell walls and nitrogen were obtained with RS5 + S10 ration. The addition of spirulina to rice straw improved apparent digestibility of nitrogen (P>0.05) in Djallonke ewes. On the other hand, it improved significantly (P<0.05) the apparent digestibility of nitrogen in dwarf goats