Tolerance of growing pigs for dietary vitamin A, with special reference to bone integrity
Blair, R.; Aherne, F.X.; Doige, C.E.
International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift für Vitamin- und Ernahrungsforschung. Journal International de Vitaminologie et de Nutrition 62(2): 130-133
1992
ISSN/ISBN: 0300-9831 PMID: 1517034 Document Number: 391395
Weanling cross bred pigs (144) of 8 kg initial weight were fed to 90 kg on diets containing graded levels of vitamin A representing 0, 1, 5, 10, 50 and 100 times the NRC (1988) estimated requirement. No clinical signs of deficiency or toxicity were recorded although plasma and liver retinol levels were affected by treatment. Histopathological examination indicated a high incidence of lesions in the cartilage of the distal femur and ulna, but they were not related to treatment. There was some evidence that excessive vitamin A levels in the diet significantly reduced the uronic acid concentration in joint cartilage, indicating a reduced concentration of proteoglycans. However no relationship was established between dietary vitamin A level and the incidence of clinical osteochondrosis. The results suggest that the allowable range of vitamin A set out in the Canadian feeds regulations is appropriate for practical pig production.