Effect on performance and carcass characteristics of nursery to finisher pigs fed reduced crude protein, amino acid-supplemented diets.
An experiment was conducted to evaluate the effect of feeding reduced CP, amino acid (AA)-supplemented diets to pigs from weaning to slaughter weight on growth performance and carcass characteristics. Pigs were fed a 19%-16%-14% CP starter-grower-finisher high-CP sequence of diets, respectively, or a sequence of diets reduced in CP by 4 percentage units (3 percentage units in the finisher period) with or without lysine (LYS), tryptophan (TRP), and threonine (THR) supplementation. Pigs fed the low-CP diets without AA supplementation grew more slowly, were less efficient in feed conversion, and developed carcasses that contained a smaller longissimus muscle, greater, average backfat depths, and a lower percentage of muscle compared with pigs fed the high-CP sequence of diets (P < .01). The reduction in growth performance, feed efficiency, longissimus muscle area, and percentage of muscle in pigs fed the low-CP diets was alleviated by LYS, TRP, and THR supplementation (P > .10). Although pigs fed the low-CP diets supplemented with AA had reduced average and 10th rib backfat depths compared with pigs fed the unsupplemented, low-CP diets (P < .01), these fat depth measures remained greater (P < .05) than those of pigs fed the high-CP diets. Feeding reduced dietary CP, regardless of AA supplementation, resulted in reduced heart (P < .10) and liver weights (P < .01) compared with feeding the high-CP diets.(ABSTRACT TRUNCATED AT 250 WORDS)
Kerr
B J
BJ
Department of Animal Sciences, University of Illinois, Urbana 61801, USA.
McKeith
F K
FK
Easter
R A
RA
D000375:Aging / Q000502:physiology; D000596:Amino Acids / Q000592:standards*; D000818:Animals; D001823:Body Composition / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D004032:Diet / Q000662:veterinary*; D004044:Dietary Proteins / Q000592:standards*; D005260:Female; D005527:Food, Fortified; D007668:Kidney / Q000033:anatomy & histology; D008239:Lysine / Q000592:standards; D008297:Male; D024510:Muscle Development; D018482:Muscle, Skeletal / Q000254:growth & development / Q000502:physiology; D009929:Organ Size / Q000502:physiology; D013552:Swine / Q000254:growth & development* / Q000502:physiology; D013912:Threonine / Q000592:standards; D014357:Trypsin / Q000592:standards
D000596:Amino Acids; D004044:Dietary Proteins; D013912:Threonine; D014357:Trypsin; D008239:Lysine