The relationship between crude protein and amino acid levels with nitrogen and sulfur excretion in feaces, urine of growing pigs

Experimental studies on the relationship between crude protein and amino acid levels with nitrogen and sulfur excretion in feaces and urine of growing pigs. The hybrid pigs of [¡áF1(Pietrain x Duroc) x ¡âF1 (Landrace x Yorshire)] were used with the initial body weight of 18.15 -18.22 kg/head. The pigs were kept in balanced cages having automatic feeder and drinking water taps. The cages are arranged adjacent to each other, is relatively reasonable assurance about microclimate regimes such as temperature from 20-25 0 C, humidity from 75-80%. The experiment rations were designed into two pilots: The first includes 3 formulas (1a, lb and lc) corresponding to 18, 17 and 16 % of crude protein levels, amino acid level calculated to lysine is 11 g/kg of feed and 3200 kcal ME. The second includes 3 formulas (2a, 2b and 2c) corresponding to amino acid level calculating to lysine is 11,10 and 9 g/kg of feed; crude protein level is 18% and 3200 kcal ME. The indicators are the nitrogen and sulfur intake; the amount of nitrogen and sulfur excretion in feaces and urine (g/head/day); the relationship between crude protein and amino acid levels with nitrogen and sulfur excretion in feaces and urine. Experimental results showed that: (1) The rations having crude protein reduced from 18% to 17 and 16% which keep the same 11 g of amino acid level calculated to lysine per kg of feed, the amount of nitrogen eliminated from feaces and urine was going down (Reduced from 9.12 to 8.21 and 7.47 g/head/day in feaces and from 23.83 to 22.48 and 20.41 g/head/day in urine; P0.05). The amount of sulfur eliminated in feaces and urine was not significant (P¡Ý0.05). (2) The rations having amino acid levels calculated to lysine reduced from 11 g to 10 and 9 g/kg of feed but keep the same crude protein level of 18%, the amount of nitrogen eliminated from fcaces and urine was going down too (reducing from 9.88% to 16,93% in feaces and from 6.91 to 19.93% in urine in compare with highest amino acid levels (P0.05). (3) The amount of sulfur eliminated from feaces and urine in growing pigs depends on amino add levels of the ration (P0.05; r