Dietas com grãos de oleaginosas e quitosana na terminação intensiva de novilhos a pasto

Abstract

The objective of this work was to evaluate the effect of using oleaginous grains associated with chitosan in the supplement of steers on pasture, on consumption, digestibility, fermentation and ruminal biohydrogenation. Chapter II: Five crossbred steers with an average weight of 300 kg, provided with ruminal cannulas, were randomly distributed in a 5x5 Latin square. The animals were kept in individual paddocks in Urochloa brizantha, cv. Marandu (Syn Brachiaria), and supplemented daily in the proportion of 2% of body weight (BW). The experimental treatments were protein/energy supplement based on soybean meal as control (CON); Supplement based on safflower grain (CT); CT with addition of chitosan (CTQ); Supplement based on soybean grain (SJ) and SJ with the addition of chitosan (SJQ). Chitosan was added directly to the animals' rumen at a dosage of 900 mg/kg DM. The presence of oilseeds in the supplementation resulted in an increase in EE consumption (P < 0.001). Animals supplemented with oilseeds (CONxOLE) showed a 4.4% increase in EE digestibility compared to the control diet (P < 0.001). In the comparison between safflower grain and soy (CTxSJ), the addition of soy showed higher values for the DM intake of the supplement, with an average of 7.43 kg/day, and increased the CP intake of the animals by 8.06%, (P < 0.001). The inclusion of safflower showed a 20% increase in EE consumption and a 14% increase in NDF consumption (CTxSJ). Higher EE digestibility (0.964 g/kg) was observed with the supply of CT (CTxSJ). Chitosan in the soy-based diet tends to increase the consumption of MA, MO and CP. CT and SJ supplementation with or without the inclusion of chitosan did not influence (P > 0.05) the patterns of ruminal fermentation, excretion of purine derivatives and microbial N synthesis. The inclusion of oilseeds in the diet of steers promotes changes in intake and digestibility. The supply of safflower grain increases EE consumption; NDF and EE digestibility. The addition of chitosan to the safflower diet improved nutrient digestibility. Chapter III: The same experimental protocol as in Chapter II was used. The values of t9c11-18:2 (P = 0.048) and CLA dimethylester (P = 0.001) characterized lower concentrations for inclusion of oilseeds (CONxOLE). The c13-18:1 cis monounsaturated fatty acid resulted in a higher value (P = 0.029) with soybean (CTxSJ). The safflower grain (CTxSJ) showed the highest responses for the concentration of all trans monounsaturated (MUFA), with an average of 2.294%. The fatty acid t11,c15-18:2 showed a higher average of 0.022% for the addition of soybean grain (CTxSJ). The inclusion of chitosan (CTxCTQ) led to a lower concentration of t11- 18:1 (P = 0.070). The t9c11-18:2 fatty acid showed a lower concentration (P = 0.001) with the inclusion of chitosan (SJxSJQ). The supply of oilseeds (CONTxOLE) showed lower values (P < 0.001) for saturated fatty acids and higher values for C18:2w6 in feces. The safflower grain (CTxSJ) obtained the highest concentration (P < 0.001) of C12:0; C14:0 and C18:2w6 in stool. The inclusion of different oleaginous sources promotes greater changes in ruminal biohydrogenation and the inclusion of chitosan was not very expressive in the fecal excretion of fatty acids.