Evaluation of Growth Parameters of Ross Broiler Chickens Fed with Different Levels of Raw or Heated Grass Pea Uusing Gompertz Model

The growth parameters of Ross broiler chickens was estimated using Gomperz non-linear model in an experiment with different levels of grass pea seed. In this experiment 210 fourteen days old broilers were randomly assigned to 7 diets including 0، 10، 20 and 30% of raw or oven-heated grass pea seed with 3 replicates including 10 birds per each replicate by using completely randomized design. The results showed that according to the fitted model، the initial weight parameter (w0) was highest for treatments containing 20 and 30 % raw grass pea seed. The birds that received 20 % oven-heated and 30% raw grass pea seed، had significant differences about initial weight (w0)، final weight (wf) and the time of inflection point (t*) parameters. t* was predicted later (47 d) for diet containing 30 % raw grass pea seed than diet containing 10 % oven heated grass pea seed (39 d). There were significant differences (P<0. 05) between diet containing 30 % raw (2279. 4 g) and 10 % oven-heated grass pea seed (1701. 2 g) about body weight، at the t*. A lower initial weight and earlier growth change was revealed for chickens fed with diet containing 20 % oven-heated grass pea seed. Chickens fed with diet containing 30 % raw grass pea seed، showed not only later time but also greater weight at t* as compared to diet containing 20 % oven-heated grass pea seed.