تاثير شدت محدوديت غذايي در سنين اوليه و افزايش تراكم مواد مغذي جيره پس از اعمال محدوديت بر عملكرد جوجه هاي گوشتي

This experiment was conducted to investigate the effects of intensity of restricted early feed and increased nutrient density after restriction period on performance and compensatory growth in broilers. Two hundred and eighty-eight broiler (Lohman) chicks in a completely randomized design in a 2x3 factorial arrangement of treatments were employed. Birds were fully fed from 7 to 13d or 100% of adlibitum intake on a daily basis. The diets were diluted at 25% and 50% levels with rice hulls. After the restriction period, birds were fed with a diet, formulated to meet all their nutrient needs, according to the NRC (1994) or 10% of protein, methionine and lysine above NRC in the realimentation diet from 13 to 21d. Body weight, feed intake, daily gain and feed conversion were determined weekly and selected carcass characteristics (liver, intestine and abdominal fat pad) were measured at 49 days of age. Feed restriction significantly (P<0.01) decreased body weight gain and feed conversion during the restriction period. Birds were able to fully recover body weight depression up to 49d. The intensity of restriction had no effect on body weight, feed intake, daily gain and feed efficiency at 49d (p>0.05). Increased nutrient density had no effect on growth rate, feed intake and feed efficiency for fully-fed birds and restricted birds at 49d. The results from this experiment showed that broiler chicks may be expected to gain weight similar to chicks with fully feeds even after restricted early feed if fed with NRC diets. The effect may be due to compensatory growth.