Growth performance of heavy pigs fed restrictively diets with decreasing crude protein and indispensable amino acids content

摘要: This study aimed to investigate the effect of decreasing dietary crude protein (CP) and indispensable amino acid (AA) content, relative conventional diets, on growth performance heavy pigs for dry cured ham production. Four treatments (conventional: CONV, medium-high protein, medium-low low protein: LP) were formulated by replacing soybean meal with wheat grain contain 146 117 133 108 g CP/kg in early (90 130 kg BW) late finishing (130 165 periods, respectively. Within period, diets contained same amounts AA per unit CP, standardized ileal digestible (SID) Lys content was 42.2 35.5 g/kg CP A total 240 crossbred pigs, grouped 3 batches 80 each, assigned one 4 according BW sex (10 pen, gilts barrows, 2 pens treatment each batch). Pigs fed restrictively using a single-space electronic feeder, feed allowance increased from 2.4 at start (92710 3.2 kg/d end trial (167710 BW), irrespective sex. Initial final backfat depth (P2) measures used estimate body composition, lipid retention (Lr Pr, respectively). These estimates, along intake data, partitioning ME SID among functions. Nitrogen excretion (NEx) estimated as actual N – retention, computed Pr/6.25. Final BW, average daily gain P2 averaged 167 kg, 0.665 kg/d, 18 mm, Diet had no these traits, well ratio (0.253), Lr (265 g/d), Pr (95 available maintenance (0.845 MJ/kg 0.60 ). From CONV LP decreased 137 122 NEx 22%. In this production system, reduction is advisable, negative impact observed compared CONV. reduced inclusion minimal supplementation reduces costs NEx. would increase number raised land where maximum load/ha constrained law.