Effects of restricted feeding and re-alimentation on intake, growth, cost and profit analysis, development of non-carcass components, carcass physical and chemical composition, fatty acid composition of whole carcass and longisimus dorsi muscle, concentration of insulin–like growth factor-I (IGF-I), were study by 48, and IGF-I polymorphism were determine by 60 fat-tailed weaned Lori- Bakhtiari sheep. At the beginning of the experiment, six lambs were slaughtered to determine the initial body composition and the remaining animals )42 ) were randomly assigned to two groups of 18 and 24 as control (C) and restricted (R) groups, respectively. The feeding management was divided to feed restriction period (FRP) and re-alimentation periods (RAP). During the FRP, the C animals were fed low-quality roughage ad libitum , (85 g CP and 1.17 Mcal of ME kg -1 DM) and mixed concentrate (180 g CP and 2.9 Mcal of ME kg -1 DM). The R animals were only fed low-quality roughage. At the end of FRP, of each group six lambs were slaughtered. In the RAP, the 18 remaining lambs in restricted treatment divided into two groups of R1 and R2. They received low-quality roughage and two different levels of concentrate supplement as mentioned before, the 12 C animals in this period were fed roughage and mixed concentrate. At the end of RAP, of each group six lambs were slaughtered. During restriction period, the control group had a significantly higher (P 0.05) ADG, weight of liver and kidneys than restricted group. The average weights of meat and bone in restricted group was higher (P 0.01), but percentage of boneless DM and EE was higher (P 0.01) in the C group. Percent of unsaturated fatty acid of linolenic, linoleic and total of polyunsaturated fatty acid and PUFA/SFA ratio in total fat carcass was significantly higher (P 0.01) in R group than C animals. Percent of linolenic and linoeic acids of Longisimous dorsi muscle was higher in R group than C animals. In the RAP and with both concentrate levels, the compensating animals showed the same growth rate as the previous unrestricted ones and have better FC (P 0.05) than control, thus ADG and DMI (gr/kg BW -0.75 ) were similar between groups. At the end of RAP net profit and net income for unit of product was lower in C group than R1 and R2, efficiency of R2 group were higher (P 0.05) than control group. The percentage means of bone in R2 was higher but, subcutaneous fat was higher (P 0.05) in C group than other groups. Percentage of boneless CP and ash was lower (P 0.01) in the C group than RRA groups. In RAP palmetic acid and total of saturated fatty acid in R2 group was significantly lower than C group, but there were no significant differences for any of fatty acid in Longisimous dorsi muscle. PCR-RFLP technique do not show polymorphisms for IGF-I gene in Lori- Bakhtiari sheep, which observed, the .
