Substituição do farelo de soja pela torta de mamona destoxificada em dietas para ovinos: valor nutritivo e desempenho bioeconômico

Abstract

To evaluate the nutritive value and bioeconomic performance of sheep fed with four substitution levels (0; 33; 67 e 100%) of soybean meal (SM) by detoxified castor cake (DCC), from 2008 August to 2009 March, this research was undertaken. The research was conducted at Forage Science Education and Study Center (NEEF), belonging to the Animal Science Department at Federal University of Ceara, and located at the city of Fortaleza– CE. The animals were acquired by NEEF own herd and constituted of 40 lambs, crossbred, male, whole, live weight of 18.7 ± 1.62 kg and average age of 6.5 months, being 20 lambs to the digestibility assay and 20 lambs to the nutrients intake, behavior and productive performance. A completely randomized design with four treatments and five replicates (lambs) was used to the intake, nutrient digestibility, energy and nitrogen balance, performance, and carcass characteristics. To the animal behavior it was used a split plot design, with substitution level of SM by DDC being parcels and periods sub-parcels, with five replicates (sheep) by treatment. The roughage used consisted of Tifton-85 grass, cut at 50 days-old. It was observed decreasing linear effect of substitution levels of SM by DCC to the DMI and OMI. The regression equation presented decrescent linear effect to the CPI. It was observed square effect of substitution levels to the NDFI, with maxim point of 1.77% LW with 70% substitution level. There was observed increasing linear effect of substitution levels of SM by DCC to the ADFI. The EEI (g/day) was not affected by addition of DCC to the diets, with average of 46.55 g/day. To the NFC, threre is a linear reduction with 0.12 g/kg0,75 to each 1% of addition of DCC to the diets. It was observed decreasing linear effect (P<.05) of substitution levels of SM by DCC to the DMD and OMD. The CPD, NDFD and ADFD were not affected (P>.05) by addition of DCC to the diets, with average of 76.63, 55.36 and 50.86%, respectively. The elevation of EED by addition of DCC to the diets was due to the high level of EE on DCC (6.10%), against 1.8% of SM. It was observed decreasing linear effect (P<.05) of substitution levels of SM by DCC on TCD. The NFCD was not affected (P>.05) by addition of DCC to the diets, with average of 84.68%. It was observed decreasing linear effect (P<.05) of substitution levels of SM by DCC on TDN. The gross energy, digestible energy, metabolizable energy and maintenance energy presented linear effect (P<.05)with increase of substitution levels of SM by DCC. It was observed decreased linear effect (P<.05) of substitution levels of SM by DCC on intake N, fecal N, urinary N, estimated .06 g/day, .02 g/day and .04 g/day, respectively to the each percent of DCC additional to the diets. There is not observed interaction (P>.05) between SM and DCC substitution levels to the IR. However, to the periods, it was observed the biggest IR (P<.05) between 8-11h. The TR wasn’t affected (P>.05) by substitution levels. The 67% DCC level was highest in relation to the 100% DCC to the TA variable. The OA and OD variables weren’t affected (P>.05) by substitution levels. The water ingestion was affected (P<.05) only by day periods, and prevailed among 8 and 11 h and from14 to 17 h. The urination and defecation frequencies were highest at 67% substitution level of soybean meal by detoxified castor cake. The parameters TMT, MMnd,MMnb, MMtb and NRD were not affected (P>.05) by different substitution levels of SM by DCC. It was observed crescent linear effect (P<.05) of substitution levels of SM by DCC over DMR. There were no effect (P>.05) of the substitution levels of SM by DCC on final live weight and total weight gain during the feedlot, however it was observed decreasing linear effect (P<.05) of the substitution levels of SM by DCC on average daily gain and ration: gain ratio. The days to reach 12 kg increased linearly when the DCC was increased in diet. The substitution levels of SM by DCC did not affect (P>.05) the in vivo traits. There were no effect of the substitution levels of SM by DCC on BWf, LWF, EBW, HCW and CCW. The HCY was affected (P<.05) by substitution levels, showing decreasing linear (P<.05) response. The same behavior was observed to the CCY. It was observed a quadratic effect of the substitution levels of SM by DCC on CL, with a minimum point of the 1.43% with 75% substitution level. The substitution levels of SM by DCC did not affect (P>.05) the morphological traits. The loin eye area presented negative linear effect (P<.05) of substitution levels of SM by DCC. The rib weight and yield and shoulders yield had linear decreases of substitution levels of SM by DCC, while the weight and yield of the others regions did not present effect (P>.05) of the substitution levels. The financial-economic analysis showed that when is incorporated DCC in sheep diet, the economic indicators decrease,proportionating profitability reduction.