Avaliação de um novo método de biodestoxificação do farelo de mamona na alimentação de ruminantes

Abstract

A biologic method to inactive ricin in castorbean meal (CBM) was previously developed and patented in Dairy Cattle Research Lab at the Federal University of Mato Grosso, Sinop. This method completely degraded ricin and did not affect nutritive value of the CBM. However, in-vivo validations need to be conducted before to recommend its use in ruminant feeding. Therefore, we

investigated the effects of the biodetoxified castorbean meal (CBMBio) in diet on intake, total tract- digestibility, ruminal microbial protein synthesis, nitrogen (N) metabolism, hepatic and

hematologic function, and performance of growing sheep. After a 14-days covariate period with animals receiving only control diet (without CBM untreated or treated), 20 Santa Inês males sheep (21.3 ± 2.7 kg body weight (BW)) were blocked by BW and randomly assigned to one of four isonitrogenous diets (150 g crude protein (CP)/kg dry matter): control (soybean meal as protein source), untreated CBM (CBM), CBM treated with 60 g CaO/kg as feed (CBMCaO) and CBMBio; during three periods of 14 days each, analyzed as repeated measure. Alkaline treatment or biodetoxification totally degraded the ricin on CBM. Experimental diets did not affect diet intake (P > 0.05) and total-tract digestibility (P > 0.05), BW gain (P = 0.591), carcass yield (P = 0.108), feed efficiency (P = 0.313) and allantoin urinary excretion (P = 0.509; indicating no effect on ruminal microbial protein synthesis). However, CBM detoxification (CBMCaO and CBMBio versus CBM) reduced N urinary excretion (g/g N intake; P = 0.016) and thus, increased N retention efficiency (g/g N intake; P = 0.031). Experimental diets did not affect plasma glucose (P = 0.115), gamma glutamyl transpeptidase (P = 0.152), alanine aminotransferase (P = 0.086) and aspartate aminotransferase (P = 0.174), indicating no effect on hepatic function. No visual sign of ricin intoxication was observed on animals fed with CBM, CBMCaO or CBMBio. However, CBM detoxification (CBMCaO and CBMBio versus CBM) increased red blood cells account (P = 0.043) and hemoglobin (P = 0.013), and reduced leukocyte (P = 0.009) and eosinophil (P = 0.027) blood accounts, indicating that CBM detoxification (CaO or biodetoxification) reduced negative subclinical effect of the untreated CBM. Detoxification method (CBMCaO versus CBMBio) did not affect (P > 0.05) diet intake and total-tract digestibility, animal performance, allantoin urinary excretion, N retention, hepatic function and blood cells account. The new biologic method tested can be an alternative to the alkaline treatment to detoxify castorbean meal and allow its safety use in ruminant feeding.