Dietas de milho grão inteiro para bovinos com adição de doses de blend enzimático

Abstract

The objective of this research proposal is to evaluate the effect of increasing doses of an enzyme blend on the digestibility, fermentation parameters, and metabolite network of confined beef cattle receiving whole corn grain and different doses of enzymes. In Chapter 2, the following results were found: the in vitro dry matter degradability revealed no significant difference between flaked corn with and without the addition of the enzyme blend. However, for cracked corn, there was a significant difference between treatments. Cracked corn with the addition of the enzyme showed higher degradability, reaching 70.06%. This is also evidenced in Figure 1, where a greater range in data variation is observed compared to the average of cracked corn with the addition of the enzyme blend. Although flaked corn showed higher degradability in both treatments, with an average exceeding 90.52%, the in vitro dry matter digestibility (IVDMD) with the addition of the enzyme blend stood out regardless of the processing type used, with a digestibility of 93.78% on a dry matter basis. In Chapter 3, intake was not affected regardless of the enzyme levels provided (P>0.05). However, when evaluating digestibility in relation to enzyme levels, a significant effect (P<0.05) was observed on Dry Matter Digestibility (DMD) and Neutral Detergent Fiber Digestibility (NDFD) with a dosage of 7.5 g of enzyme. DMD reached 0.8550 g/kg, while NDFD was 0.0836 g/kg. There was no effect on pH with increasing doses of the enzyme blend. The N-NH3 content was higher at a dose of 7.5g of enzyme, with values of 30.88 mg/dL. Regarding the collection time of ruminal fluid, pH was higher than 6.9 at the 6-hour mark with the use of a 5g enzyme dose. In Chapter 4, the metabolic profile of the blood plasma of confined cattle subjected to different dosages of the enzyme blend was analyzed. The metabolites identified in higher concentration were acetate, lactate, alanine, 3-hydroxybutyrate, threonine, ribose, creatine, glucose, glycine, and pantothenate. Most of these metabolites showed a higher incidence in treatment 1 (control), indicating that enzyme supplementation did not result in significant increases in the concentration of these compounds in the blood plasma. For the evaluation of ruminal fluid, only succinate and inosine had higher incidence in treatment 3 (5 g/day), while the other metabolites were more present in the control treatment.