ARS | Publication request: EFFECTS OF DIVERSE DEVELOPMENTAL ENVIRONMENTS ON NEURONAL MORPHOLOGY IN DOMESTIC PIGS (SUS SCROFA)

Submitted to: Brain Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 18, 1997
Publication Date: N/A

Interpretive Summary: How does the environment we provide for our farm animals affect the growth of their brains? The goal of the present experiment was to determine whether different developmental environments in use in agricultural production units affect the structure and shape of brain cells (their neuronal morphology) in the pig brain. Littermate female pigs were cross fostered at birth and reared in either an indoor or outdoor production uni for 8 weeks. Additional littermates were sacrificed at 3 days of age to provide a reference point in an undeveloped brain. Brains were stained by the Golgi-Cox method, a silver stain that allows one to observe individual brain cells under the microscope. In the part of the brain that processes sounds (the auditory cortex), outdoor pigs compared to indoor pigs had more branches on their cells (referred to as primary dendrites). Further investigations are needed to determine which environmental factors are critical in producing the observed change in brain morphology and whether other brain effects may be produced by varying developmental environments. By conducting this work we have determined a novel way to quantify how animals process information about their environment and we now have a new tool to assess well-being in food producing animals.

Technical Abstract: Experimental observations have not been made on potential effects of environmental rearing conditions on the brains of farm animals, 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 were cross fostered at birth and reared in either an indoor or outdoor production unit for 8 weeks. Additional littermates 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 sectional at 170 micrometers, and layer IV stellate neurons (N=429) were digitized and 3-dimensionally reconstructed. In auditory cortex neurons, outdoor pigs compared to indoor pigs had more primary dendrites (P<.05). Further investigations are needed to determine which environmental factors are critical in producing the observed change in brain morphology and whether other brain effects may be produced by varying developmental environments.