The effects of different levels of dietary protein, energy and using fat on the performance of broiler chicks at the end of the third weeks

Abstract

The purpose of this study was to assess and compare the different levels of energy, protein and using fat in diet on the performance of broiler at the end of the third week. A total of 2000 one-day-old male broilers (Ross 308) were randomly assigned in a 2×2×2 factorial design according to the following factors: the amount of protein (23 and 21 percent GP), the amount of energy (3200 and 3000 kcal kg-1 ME) and using fat (limiting or non-limiting dietary fat). During the first third week, significant independent effects of dietary protein levels on Bodyweight (BW) and energy levels on Feed Conversion Rate (FCR) were observed. There was no significant difference between energy and bodyweight at all weeks. The significant difference observed between protein and bodyweight in 1st and 2nd weeks (p<0.001) and 3rd week (p<0.05). There was no significant difference between using unlimited fat diet and limited one on both BW and FGR. In 0-7 day old, feeding diets didn't show any significant difference in feeding conversion but in 7-21 day old chicks, feeding diets with higher energy level significantly decreased FCR especially at the 2nd and 3rd week (p<0.001) but there was no significant difference in FCR with higher and lower levels of protein. There was no significant interaction effect between any of the parameters except for "energyxfat" (BW: 1st and 2nd weeks: p<0.001), 3rd week: pO.Ol; FCR: 1st, 2nd and 3rd weeks: p<0.05) and proteinxfat (just the FCR in 1st week: p<0.05). So using the soybean oil with the diet containing 3200 kcal kg-1 and 21% CP is suggested in 0-21 day old broiler chickens. © 2011 Academic Journals Inc.