The effects of starter period length and crude protein level of diets on performance, carcass traits and intestinal morphology of broilers

This study was conducted to investigate the effects using different levels of dietary crude protein starter period length on performance, carcass characteristics and intestinal morphology of broilers. 288 Rass 308 broilers were used as factorial arrangement (2*3) included 2 levels of dietary cured protein (Rass company recommended and 5% more than it) and 3 starter period length included (7, 10 and 16 days) in a completely randomized design. Reduce the starter period length to 7 days reduced the amount of feed intake and weight gain, whereas increase the starter period length to 16 increased the amount of feed intake, weight gain and final live weight (P<0.05Reduce or increase of the amount of feed intake and weight gain were observed in interaction between starter period length and crude protein levels (P<0.05). Starter period length and crude protein levels had not significant effect on feed conversion ratio and carcass traits (P>0.05). Starter period length and crude protein level had significant effects on intestinal morphology (P<0.05). Reduce the starter period length to 7 days increased the intestinal villi width and length, whereas using crude protein 5% more than Ross recommendation reduce them. In broilers reduce the length of using stater period diet via reduce of the amounts of daily feed consumption and weight gain, reduce the final weight, whereas increase of the use of starter period via increase the amounts of daily feed intake and weight gain, incearse the final weight.