Zeolita em dietas de bovinos de corte / Zeolite in diets for beef cattle

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

19/08/2010

RESUMO

The objective was to evaluate the effect of adding different levels of zeolite on the intake and total and partial apparent digestibility of nutrients, ruminal parameters (pH and ammonia nitrogen), production of microbial nitrogen compounds, microbial efficiency and blood parameters (glucose and urea) in the diet of beef cattle. The treatments consisted of the following levels of zeolite, a commercial nutritional additive based on clinoptilolite, a hydrated aluminosilicate- based diet DM: 0, 0.75, 1.5, 2.25 and 3.0. We used five steers and crossbred GxZ with ruminal and abomasal fistula, fed 65% corn silage and 35% concentrate based on corn, mineral salt and urea / SA (1.5% of total diet DM ). The animals were distributed in a 5x5 Latin square, consisting of five periods of 15 days each, totaling 75 days of experimental period. The adaptation to the diet was nine days. In each experimental period samples were taken of total feces and urine (from 10th to 12th day) and the 10th to 13th day, samples were collected (approximately 200 mL) of abomasal digesta in 15 hours. During the collection period (from 10th to 15th day), samples were of forage and concentrates and remains for further analysis. From 3rd to 12th day of each experimental period was provided, via rumen fistula, 15 g of titanium dioxide (TiO2) wrapped in paper, 4 hours after feeding in the morning (12:00 h) for subsequent estimation of nutrient digestibility. The bacterial isolation was performed in 13 (8h) and 14 days (14:00 h). On the 14th day of each experimental period samples were collected for analysis of blood glucose and urea. Samples were collected in 50 ml of rumen fluid at 0 (before feeding), 1, 2, 3, 4, 6, 8, 9, 10, 11, 12, 20 and 24 hours after the delivery of food, in the 15th day of each period, for evaluation of pH and ammonia concentration in the rumen. In the urine samples were determined the concentrations of allantoin, uric acid, urea and creatinina. There was no effect of levels of zeolite (P>0.05) on daily nutrient intake (kg / day) of DM, OM, EE, CHO, NDF, NFC, and TDN. However, we observed the effect of zeolite (P <0.05) on CP intake. However, we detected a linear positive effect of zeolite (P <0.05) on DM and NDF when expressed in g / kg BW. The total digestibility of DM, OM, EE, NDF and NFC was not affected (P>0.05) by the zeolite, which was not observed for TDN (P <0.05). Ruminal of NFC was affected (P <0.05) quadratically (values above 1.55% of zeolite increases ruminal digestibility of NFC) and intestinal CP and NFC were affected (P <0.05) by the addition of levels of zeolite, respectively, linear quadratic (higher x digestibility with 1.55% of zeolite). The intake and fecal nitrogen excretion (g / day) were affected linearly positive (P <0.05) with increasing levels of zeolite in the diet. No effect (P>0.05) levels of zeolite on the excretion of purine derivatives and purine absorbed as well as on the production of microbial protein and microbial efficiency. The concentrations of plasma glucose and urea were not affected (P>0.05) by the zeolite. There was no interaction (P>0.05) between the level of zeolite and the time of evaluation of pH or ammonia nitrogen, however, the time of assessment affect the pH and ammonia nitrogen (P <0.05), ie different throughout the day. No significant differences (P>0.05) in ruminal bacteria composition depending on the levels of zeolita, demonstrating that the additive was not able to change the DM, OM and N-RNA of the same. It was concluded that the addition of zeolite in the diet does not improve the utilization of urea in diets for beef cattle, since it does not alter the intake and digestibility of nearly all nutrients, and did not affect ruminal evaluated.

ASSUNTO(S)

alimentação bovinos zeolita nutricao e alimentacao animal feeding cattle zeolite

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