Effectiveness of calcium oxide and autoclaving for the detoxification of castor seed meal in finishing diets for lambs

• Published in: Animal feed science and technology 2017-09, Vol.231, p.76-88
• Main Authors: Borja, M.S., Oliveira, R.L., Silva, T.M., Bezerra, L.R., Nascimento, N.G., Borja, A.D.P.
• Format: Article
• Language: English
• Subjects: Autoclaving; Castor seed meal; Lambs; Ricin
• ISSN: 0377-8401; 1873-2216
• DOI: 10.1016/j.anifeedsci.2017.07.001

•Efficiency detoxification of castor seed meal using 10g CaO and 30min autoclaving.•300g/kg castor seed detoxified in lambs diet increase feeding time and blood urea.•Detoxified castor seed meal used in lamb diet reduces intake and digestibility.•Castor seed meal detoxified 300g/kg inclusion in lambs diet reduces the performance.•There was no toxic effect of feeding lambs with detoxified castor seed up 300g/kg. This study aimed to evaluate the efficiency of a detoxification process (calcium oxide (CaO) levels×different autoclaving times) on castor seed meal and to test the effects of diets incorporating detoxified castor seed meal on the performance, digestibility, ingestive behavior, blood concentrations, carcass weight, and in vitro gas production in lambs. Changes in detoxification capacity through the interaction of autoclaving time and the amount of CaO were evaluated by an experiment with a non-detoxified castor seed meal and a 4×2 factorial design with four levels of CaO (10, 20, 30 and 40g/kg) and two autoclaving times (15 and 30min at 15psi and 121°C), with five replicates per treatment. The treatment of castor seed meal with 10g of CaO/kg and 30min of autoclaving promoted the disappearance of the bands that represent the ricin subunits of castor seed meal, and this was the most efficient method because it used less CaO. Therefore, this method was used to detoxify the castor seed meal used for the formulation of the experimental diets. Forty crossbred male sheep, with an average weight of 25±3.0kg, were used in a completely randomized design with four treatments and ten replicates. The diets consisted of 0, 100, 200 and 300g/kg castor seed meal inclusion (dry matter (DM) basis). The inclusion of up to 300g/kg castor seed meal in the lamb diets did not affect the daily intake of DM and crude protein (CP), which averaged 1194 and 191g/day, respectively. However, due to the chemical composition of the castor seed meal, the intake of ether extract and neutral detergent fiber (NDFan) was increased by approximately 110g/day, while the intake of non-fibrous carbohydrates (NFC) was reduced by 95g/kg. A linear decrease was observed in the digestibility of the DM and NDFan with the inclusion of detoxified castor seed meal. However, the digestibility coefficients of CP and EE did not change. The castor seed meal increased intake and reduced idling times. The performance data of lambs fed diets containing different levels of castor seed meal showed a decreasi