Resumen

NORO, Mirela; SCANDOLO LUCINI, Daniel  y  WITTWER MENGE, Fernando. Metabolic response in sheep supplemented in the diet with high content of non protein nitrogen. Zootecnia Trop. [online]. 2012, vol.30, n.3, pp.225-235. ISSN 0798-7269.

Supplementation with non-protein nitrogen (NPN) affects ruminal fermentation and animal metabolism. Eighteen ruminal fistulized (1.5 cm Ø), sheep one year old, kept in individual cages were used to determine the variations on the ruminal pH, urinary excretion of purines, and fluctuations in the blood concentrations of urea, creatinine, glucose, lactate, βOH-butyrate, cholesterol and triacyglicerol. Sheep were allotted in three groups of six animals each according to body weight; control (C, base diet), moderate NPN (MN, 182 mg N/kg^0.75 3 times a day) and high NPN (HN, 425 mg N/kg^0.75 3 times a day). The daily diet was based on lucerne hay pellets (ME: 7.80MJ/kg DM; CP: 16.8% DM), considering 460 kJ/kg^0.75, distributed every 8 hours. The NPN was incorporated to the base diet as urea solution during 17 days. Ruminal fluid and blood samples were obtained the days 1, 8 and 15 at 0, 1.5, 3.0 and 4.5 hours after morning feeding. The treatment with NPN increased ruminal pH (P<0.05) however did not modifyed the urinary excretion of purines (P>0.05). The treatment also increased the plasma concentrations of urea, being higher in HN, medium in MN and lower in the control group (P<0.05). On the other side the treatment increased (P<0.05) plasma concentrations of glucose and cholesterol, and reduced plasma concentration of βOH- butyrate (P<0.05). Results suggest that supplementation with NPN in doses of 182 or 425 mg N/ kg0,75, three times a day did not modifyed bacterial protein synthesis but increases the ureagenesis and energy metabolism according to the amount of NPN in the diet

Palabras clave : Sheep; urea; energy and protein metabolism.

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