mRNA levels of the calpain system in longissimus muscle of young pigs during prolonged feeding of a protein-free diet.
This experiment was conducted to investigate the effects of feeding a protein-free diet on mRNA levels of the calpain system in skeletal muscle of growing pigs during a 15-d feeding trial. Twenty crossbred barrows were divided into two dietary treatments: control or protein-free diet (mean initial weight for both groups: 38.3 kg). Daily diets were provided at 2.5 times energy for maintenance (twice a day). On d 0, 3, and 14, biopsies were taken from longissimus muscle between the third and fourth ribs (d 0 and 3) and between the fourth and fifth rib (d 14). On d 15, animals were slaughtered and longissimus muscles were dissected and analyzed for calpastatin, and mu- and m-calpain activity. From biopsies, mRNA level of skeletal muscle calpain, mu- and m-calpain, and calpastatin were measured using reversed transcription PCR. Subsequently, PCR products were quantified using ELISA. Feeding the protein-free diet lowered growth rate to almost zero. Only total level of mRNA of mu-calpain on d 14 was influenced by dietary treatments, being lower for the protein-free group than for the control group (P < .05). However, proteolytic activities were not different between treatments. Total RNA concentration in longissimus muscle decreased during the experiment for both treatments, but on d 14 this was more pronounced for the protein-free than for the control group (P < .05). If mRNA levels were corrected for this change, specific mRNA level on d 14 of skeletal muscle calpain and mu-calpain were lower (P < .05) for the protein-free than for the control group. These data suggest that activity of the components of the calpain system are differentially regulated.
van den Hemel-Grooten
H N
HN
DLO-Institute for Animal Science and Health (ID-DLO), Department of Food Science, Lelystad, The Netherlands.
te Pas
M F
MF
van den Bosch
T J
TJ
Garssen
G J
GJ
Schreurs
V V
VV
Verstegen
M W
MW
D000375:Aging / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D001483:Base Sequence; D001706:Biopsy / Q000379:methods / Q000662:veterinary; D001835:Body Weight / Q000502:physiology; D002135:Calcium-Binding Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D002154:Calpain / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D015342:DNA Probes / Q000032:analysis / Q000737:chemistry / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004032:Diet / Q000662:veterinary*; D018753:Diet, Protein-Restricted / Q000592:standards*; D004435:Eating / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D013552:Swine / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D015430:Weight Gain / Q000502:physiology
D002135:Calcium-Binding Proteins; D017931:DNA Primers; D015342:DNA Probes; D018076:DNA, Complementary; D012333:RNA, Messenger; C033668:calpastatin; D002154:Calpain