Effect of two types of feed restriction, intermittent total starvation or intermittent protein starvation, on growth, lipogenesis, and fatty acid composition of liver and adipose tissues in chicks.

Abstract

Seventy-two 4-week-old Arbor Acres male chicks were divided into four groups: group ITS 1-1 was intermittently starved for 1 day and fed a balanced diet ad libitum for the next day throughout the experiment; group ITS 2-4 was intermittently starved for 2 days and then fed ad libitum for the next 4 consecutive days; group IPS 1-1 was alternately fed a protein-free diet for 1 day and a balanced diet for the next day; a fourth group was used as control and fed ad libitum throughout. The experiment lasted 50 days. Growth rate in all restricted groups was slower than in control birds but within the restricted groups there was no difference (P = 0.05). Hyperphagia was observed in all restricted groups, but was insufficient to completely prevent the growth retardation induced by the feed restriction schedules. Fat deposition, as measured by weight of abdominal tissue, considerably increased in the protein-restricted birds, when compared to all other groups. Lipogenesis, measured in vitro with sodium acetate-1-14C, was stimulated by both types of feed restriction, but to a greater extent by the ITS treatments. In liver and abdominal fat tissues of all restricted birds, oleic acid was increased and linoleic acid decreased. This might be the result of an increased endogenous fatty acid synthesis.