Effect of Low-Protein Diets Having Constant Energy-to-Protein Ratio on Performance and Carcass Characteristics of Broiler Chickens from One to Thirty-Five Days of Age

Abstract

A trial was conducted to determine the effect of low-protein diets with constant ME:CP ratio on performance and carcass characteristics of broilers from 1 to 35 d of age. Four experimental diets were formulated to have 4 levels of CP and ME, respectively, in each phase: 23, 22, 21, and 20% CP with 3,036, 2,904, 2,772, and 2,640 kcal/kg in the starter phase (1 to 10 d); 22, 21, 20, and 19% CP with 3,146, 3,003, 2,860, and 2,717 kcal/kg in the grower phase (11 to 26 d); and 20, 19, 18, and 17% CP with 3,100, 2,945, 2,790, and 2,635 kcal/kg in the finisher phase (27 to 35 d). Digestible Lys was maintained at 1.10, 1.02, and 0.90% of the diet in the starter, grower, and finisher periods, respectively. A total of 1,760 one-day-old Hubbard broiler chickens were randomly divided into 16 experimental pens, 110 chickens in each pen, and each diet was offered to 4 replicates at random. Weight gain was linearly decreased (P < 0.001), whereas feed intake and feed conversion ratio were increased (P < 0.001) linearly as dietary protein and energy decreased during grower, finisher, and overall experimental periods. Protein efficiency ratio and energy efficiency ratio were decreased (P < 0.05) with low-CP and low-ME diets during the grower, finisher, and overall experimental period. However, carcass yield, breast meat yield, thigh yield, abdominal fat, and relative liver and heart weights were not affected by the treatments. Feeding broiler chickens low-CP diets with constant ME:CP ratio has adversely affected the growth performance, but carcass parameters were unaffected without any increase in abdominal fat content.

Effect of starter and finisher feed replacement time on the performance of broiler chickens

“…The chicks in all treatment groups other than T 4 have received the high protein starter diet for a shorter period which could have increased the feed intake of those birds than that of T 4 . These results agree with Kamran et al (2008) that feed intake is linearly increased with reduced crude protein during grower, finisher and overall periods. The increased feed intake is probably due to greater energy requirements of the broiler birds to cope with the high growth rate which is achieved by high intake in low energy diets.…”

The effect of serine protease on broiler growth and carcass quality

“…In similar study low CP diets with standard ME level caused increased body fat deposition (Aletor et al, 2000). In other study, feeding Low CP diets with constant ME:CP ratio had adverse effect on the growth performance, but carcass parameters were unaffected without any increase in abdominal fat content (Kamran et al, 2008). It can explain no difference in abdominal fat and share of abdominal fat between Standard CP and Lower CP diets supplemented with protease, because it should improve digestibility of nutrients and compensate ME : CP ratio.…”

A Mixture of Thyme, Quillaja, and Anise at Different Nutrient Density on Growth Performance, Nutrient Digestibility, Meat Quality, Organ Weight, Cecal Bacteria, Excreta Moisture, and Bone Contents in Broiler Chicks

“…On an overall, there was an improvement in BWG and FCR of birds fed with T3 as compared to T2. In an earlier study, Kamran et al (2008) also noted that reducing CP levels worsened FCR during all growth periods except the starter periods in broilers. Paraskeuas et al (2016) also indicated that reduced protein diet in broiler led to poorer FCR at growing period and overall period compared with basal diet.…”