Tolerance of young pigs for dietary vitamin A and μ-carotene, with special reference to the immune response
| Autor: | M. Facon, R. J. Bildfell, R. Blair, J. P. Jacob, B. D. Owen |
|---|---|
| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | Canadian Journal of Animal Science. 76:121-126 |
| ISSN: | 1918-1825 0008-3984 |
| DOI: | 10.4141/cjas96-016 |
| Popis: | Guidelines need to be drawn up for the fortification of diets with vitamin A, because of its known toxicity. In exp. 1, 35 pigs aged 5 wk and weighing about 10 kg were placed in individual cages and allocated to seven dietary treatments for 28 d. In treatments 1–6 the levels of vitamin A or β-carotene represented 1, 10 or 100 times the National Research Council (1988) requirement for vitamin A, and in treatment 7 vitamin A and β-carotene were combined 50:50 to provide a total representing 100 times the vitamin A requirement. The vitamin A biopotency of β-carotene was assumed to be 200 IU mg−1. There was no significant effect of vitamin A or β-carotene on growth performance, plasma Escherichia coli antibody, or on lymphocyte proliferation. Serum retinol at 14 and 28 d increased as the level of dietary vitamin A increased but the effect was not significant (P = 0.241 and 0.073, respectively), β-carotene gave higher serum retinol at 14 and 28 d than vitamin A, but the effect was not significant (P = 0.232 and 0.059, respectively). Liver retinol increased with increasing level of dietary vitamin A or β-carotene (P |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|