Intake, digestibility and performance of hair sheep lambs fed with ammoniated cotton gin trash treated with exogenous fibrolytic enzymes

Abstract Text: This study was carried out to evaluate intake, digestibility and performance of Santa Ines lambs fed with diets containing ammoniated cotton gin trash (CGT) treated with exogenous fibrolytic enzymes (EFE). CGT was pre-treated with 6% urea (25% of moisture for 80 days) according previous studies. Treatments were 0, 2, 4 and 6% of EFE (75% cellulase and 25% hemicellulase), applied 24h before feeding. In addition, there was a control group fed with non-ammoniated and untreated CGT. The experiment was a completely randomized block design with five treatments and six replications (animals), with three males and three females per treatment, from February to May 2014 in Animal Science Center at UESB, in Vitoria da Conquista, Bahia, Brazil. Isonitrogenous and isocaloric diets were balanced according NRC for 20kg animals, liveweight gain of 200g with estimated intake of 4.5% of bodyweight (61% TDN and 15% CP). Concentrate contained corn, soybean meal and minerals, fed in a concentrate:roughage ratio of 50:50. The lambs were feedlotted for 84 days, being the first 21 days of adaptation and three periods of data collection of five consecutive days in each 16 days. For evaluating intake and digestibility, feed, orts and feces were collected, using NDFi as internal marker. There was no effect of EFE on intake, with the average values of 1311.4; 1189.9; 254.1; 748.9 and 810.0 g per day for DM, OM, CP, NDF and TDN, respectively. EFE increased NFC intake (P<0.05), by 17.0 percentage units for each 1% of EFE. There were no differences on apparent digestibility of CP and EE (P>0.05) with EFE application; however, digestibility of DM, OM, NDF, ADF, FC, NFC and TDN were increased linearly (P<0.05). Males (240 g) gained daily more weight than females (158.4 g) (P<0.05), although there was no effect of EFE (P>0.05). Despite the benefits of ammonization and EFE on digestibility and intake of CGT, there was no significative effect on performance.

Keywords: cellulase, feedlot, hemicellulase, ruminants.