Growth Performance Carcass Characteristics and Plasma Mineral Chemistry as Affected by Dietary Chloride and Chloride Salts Fed to Broiler Chickens Reared under Phase Feeding System

摘要

Requirements of dietary chloride (dCl) and chloride salts were determined by using 4×2 factorial arrangement under four phase feeding program. Four levels (0.31, 0.45, 0.59 and 0.73%) and two sources (NH4Cl and CaCl2) of the dCl were allocated to 1,472 chicks in eight dietary treatments in which each treatment was replicated four times with 46 birds per replicate. The four phase feeding program was comprised of four dietary phases: Prestarter (d 1 to 10), Starter (d 11 to 20), Grower (d 21 to 33) and Finisher (d 34 to 42); and diets were separately prepared for each phase. The cations, anions, pH, dissolved oxygen (DO), temperature, electrical conductivity (EC), total dissolved solids (TDS) and salinity were analyzed in drinking water and were not affected by dietary treatments. BW gain (BWG; p≤0.009) and feed:gain (FG; p≤0.03) were improved in CaCl2 supplemented diets during d 1 to 10. The maximum response of BWG and FG was observed at 0.38% and 0.42% dCl, respectively, for d 34 to 42. However, the level of dCl for BWG during d 21 to 33 (p≤0.04) and d 34 to 42 (p≤0.009) was optimized at 0.60% and 0.42%, respectively. The level of dCl for optimized feed intake (FI; p≤0.006), FG (p≤0.007) and litter moisture (LM; p≤0.001) was observed at 0.60%, 0.38% and 0.73%, respectively, for d 1 to 42. Water intake (DWI) was not affected by increasing dCl supplementation (p>0.05); however, the ratio between DWI and FI (DWI:FI) was found highest at 0.73% dCl during d 1 to 10 (p≤0.05) and d 21 to 33 (p≤0.009). Except for d 34 to 42 (p≤0.006), the increasing level of dCl did not result in a significant difference in mortality during any phase. Blood pH and glucose, and breast and thigh weights (percentage of dressed weight) were improved while dressing percentage (DP) and gastrointestinal health were exacerbated with NH4Cl as compared to CaCl2 supplemented diets (p≤0.001). Higher plasma Na⁺ and HCO3⁻ and lower Cl⁻ and Ca⁺⁺ were observed in NH4Cl supplemented diets (p≤0.001). Increasing supplementation of dCl increased plasma Cl⁻ (p≤0.04; quadratically) and linearly reduced plasma K⁺ (p≤0.001), Ca⁺⁺ (p≤0.003), HCO3⁻ (p≤0.001), and Na⁺ (p≤0.001; quadratically). Consequently, higher requirements of dietary chloride are suggested for feed intake; nevertheless, lower levels of dietary chloride are sufficient to support optimal BWG and FG with increasing age. The NH4Cl supplemented diets ameliorate breast and thigh meat yield along with overall energy balance (glucose).