The aim of the research was to determine the influence of a mixture enriched by linseed oil, after a restricted feeding period, on production results and the concentration of selected hormones (GH, TSH, T₃, T₄, insulin) as well as protein-lipid transformation indicators (TP, ALB, GLU, BUN, TG, CH) in fatteners. The experimental fattening was carried out on 56 fatteners (Polish Large White x Polish Landrace x Duroc) (gilts : barrows, 1 : 1). In the first stage of fattening (23-60 kg of body weight) the animals were fed semi ad libitum or restrictively (less by 25%) on feeds without the linseed oil supplement. In the second fattening stage (60-102 kg of body weight) all the animals were fed semi ad libitum on mixtures with 0 or 4% share of linseed oil. Restricted feeding in the first fattening stage caused a reduction of growth rate (p ≤ 0.001) as well as changes in hormonal management, i.e. the increase of GH and decrease of T4 and insulin. The level of protein-lipid transformation indicators decreased, including total cholesterol and its LDL fraction, which decreased high-significantly (p ≤ 0.01). The increase in the feeding level during the second fattening stage led to hormonal "normalisation", and a small compensatory growth was found only in animals receiving the feed with oil. The linseed oil supplement to the feed sped up the growth rate of the swines (p ≤ 0.05), which was connected with changes of some hormone levels (T₃, T₄, insulin) as well as protein-lipid transformation indicators (TP, ALB, TG).