Effect of dietary vitamin A level on performance, vitamin A content in the liver and leg weakness of growing finishing pigs

Abstract

A total of 160 piglets, females and castrates, were divided at weight of 25 kg into four groups in order to study the effects of dietary vitamin A supplementation. The groups were balanced according to initial weight,sex and litter origin.The same basic mixture, consisting of barley and commercial protein concentrate with all minerals and vitamins except vitamin A, was used in feeding of all the piglets. The vitamin A activity of the mixture, however, was 646 IU/kg. Special vitamin Apremixes were prepared by using a commercial product providing the four final four diets with 0, 1000, 3000 and 50000 IU/kg.Three piglets were sacrificed at the beginning of the trial to determine the content of liver vitamin A. It was found to vary between 7.3 and 10.2 mg/100 g fresh liver.There were no differences between the groups in daily gain,feed: gain ratio or carcass quality. A histological examination of leg joints did not reveal an increased frequency of osteochondrosis in pigs fed with a high level ofvitamin A.Growing finishing pigs, having adequate liver stores of vitamin A at 25 kg of live weight, grew without showing any visible signs of deficiency up to 100 kg weight with no vitamin A additions. However, the liver vitamin A analysis at slaughter showed that the recommendation for vitamin A in practical pig feeds should be higher than 1000 IU/kg. In the present experiment, 3000 HJ/kg was found to be a sufficient level.

Reducing crude protein content with supplementation of synthetic lysine and threonine in barley - rapeseed meal - pea diets for growing pigs

“…A higher rate of fat deposition in castrated males is usually accompanied by reduced growth (Yen et al 1986). However, results similar to ours have been obtained in earlier studies (Taylor et al 1979, Alaviuhkola et al 1992. It is possible that the amount of lysine in our trial diets was not sufficient for the gilts to show their full performance.…”