TY - JOUR
T1 - Effects of diverse developmental environments on neuronal morphology in domestic pigs (Sus scrofa)
AU - Jarvinen, Michael Keith
AU - Morrow-Tesch, Julie
AU - McGlone, John J.
AU - Powley, Terry L.
N1 - Funding Information:
We would like to thank Drs. Jerome Busemeyer, Robert Meisel and Richard Schweikert for their suggestions on statistical analyses. In addition, we thank Zixi Cheng, Fred Martinson, Robert Meisel, Robert Phillips, Elwood Walls and Wyatt Wollmann for comments on an earlier draft of this manuscript. We are also grateful to Stanley Harris for care of the experimental pigs, Jeff Dailey and Steve Fullwood for tissue collection and post-hoc sound data collection, and Jeffrey Mitchell for providing the illustration ( Fig. 1 ). This research was supported by USDA–ARS (JM-T), NIH grant DK27627 (TP) and NIMH grant MH01023 (TP) and by the state of Texas line item for efficient pork production (JM) and a USDA–ARS cooperative research agreement (JM).
PY - 1998/4/17
Y1 - 1998/4/17
N2 - Potential effects of environmental rearing conditions on the brains of farm animals have not been examined experimentally, with the exception of one report for pig somatosensory cortex. The goal of the present experiment was to determine whether different developmental environments in use in agricultural production units affect neuronal morphology in the pig cerebral cortex. Littermate female pigs (gilts) were cross-fostered at birth and reared in either an indoor (n = 6) or outdoor (n = 6) production unit for 8 weeks. Additional littermates (n = 6) were sacrificed at 3 days of age to provide a developmental reference point. Brains were fixed by perfusion and stained by the Golgi-Cox method. The primary somatosensory, auditory and visual cortices were sectioned at 170 μm, and layer IV stellate neurons (n = 492) were digitized and 3-dimensionally reconstructed. Measurements of dendritic length, membrane surface area, total number of segments, number of 1st- through 7th-order dendrites, spine density, soma area, and soma form factor were taken. In auditory cortex neurons, outdoor pigs compared to indoor pigs had (a) significantly more primary dendrites, (b) significantly greater spine density, and (c) trends of increases both in number of 2nd- and 3rd-order dendrites and in total dendritic length. In visual cortex neurons, indoor pigs had significantly more 7th-order dendrites, whereas in all three cortical areas, the indoor animals had more 5th-order dendrites. Multiple morphological differences occurred in stellate cell populations between the three sensory areas of the Week 8 pigs. Also, within different cortical areas, dendritic morphology changed substantially from 3 days to 8 weeks of age. Further investigations are needed to determine which environmental factors are critical in producing the observed changes in brain morphology and whether other brain effects may be produced by varying developmental environments.
AB - Potential effects of environmental rearing conditions on the brains of farm animals have not been examined experimentally, with the exception of one report for pig somatosensory cortex. The goal of the present experiment was to determine whether different developmental environments in use in agricultural production units affect neuronal morphology in the pig cerebral cortex. Littermate female pigs (gilts) were cross-fostered at birth and reared in either an indoor (n = 6) or outdoor (n = 6) production unit for 8 weeks. Additional littermates (n = 6) were sacrificed at 3 days of age to provide a developmental reference point. Brains were fixed by perfusion and stained by the Golgi-Cox method. The primary somatosensory, auditory and visual cortices were sectioned at 170 μm, and layer IV stellate neurons (n = 492) were digitized and 3-dimensionally reconstructed. Measurements of dendritic length, membrane surface area, total number of segments, number of 1st- through 7th-order dendrites, spine density, soma area, and soma form factor were taken. In auditory cortex neurons, outdoor pigs compared to indoor pigs had (a) significantly more primary dendrites, (b) significantly greater spine density, and (c) trends of increases both in number of 2nd- and 3rd-order dendrites and in total dendritic length. In visual cortex neurons, indoor pigs had significantly more 7th-order dendrites, whereas in all three cortical areas, the indoor animals had more 5th-order dendrites. Multiple morphological differences occurred in stellate cell populations between the three sensory areas of the Week 8 pigs. Also, within different cortical areas, dendritic morphology changed substantially from 3 days to 8 weeks of age. Further investigations are needed to determine which environmental factors are critical in producing the observed changes in brain morphology and whether other brain effects may be produced by varying developmental environments.
KW - Auditory cortex
KW - Golgi-Cox
KW - Somatosensory cortex
KW - Stellate neuron
KW - Visual cortex
UR - http://www.scopus.com/inward/record.url?scp=0032540363&partnerID=8YFLogxK
U2 - 10.1016/S0165-3806(97)00210-1
DO - 10.1016/S0165-3806(97)00210-1
M3 - Article
C2 - 9602033
AN - SCOPUS:0032540363
SN - 0165-3806
VL - 107
SP - 21
EP - 31
JO - Developmental Brain Research
JF - Developmental Brain Research
IS - 1
ER -