جستجوی مقالات مرتبط با کلیدواژه "مرحله پایانی" در نشریات گروه "علوم دام"

Based on the recommendations of some poultry nutrition references as National Research Council (NRC 1994), growth period of growing Japanese quails have been considered to be six weeks and only one dietary protein concentration was recommended for the entire growth period. However, the amino acid requirements of growing quails are similar to those of broilers as the percentage of the diet decreases with age, and applying one level of protein throughout the rearing period may cause deficiency or loss of amino acids compared with daily requirements. Given the high cost of protein in quail diets and the fact that few researches has been done on the effect of dietary protein levels at different phases of growth period on quail performance, this experiment was conducted to investigate different dietary regimens of protein on production and economic performances and also carcass characteristics of Japanese quails.

The experiment was carried out in a 3×3 factorial arrangement (3 protein levels: low (L)=20%, medium (M)=22% and  high (H)=24 percent in grower phase (8-21 days)× the same dietary protein levels, in finisher phase (22-42days)) with 9 treatments, 5 replicates and 8 pieces of quails per each replication. All chicks were received the same starter diet with 2900 kcal/kg Metabolizable energy and 24% crude protein (CP) from time of hatch up to 7 days of age and after that they were received dietary L×L, L×M, L×H, M×L, M×M, M×H, H×L, H×M and H×H protein programs. Production traits such as feed consumption, body weight gain, feed conversion ratio and production index at the whole growth period, as well as some economic traits such as feed cost per gain monetary returns per quail and also some traits related to carcass characteristics and meat quality such as edible carcass percentage, water holding capacity and oxidative spoilage index of meat were measured or calculated.

During 8-42 days of age, different dietary protein levels in growing phase had no significant effect on feed intake, weight gain and feed conversion ratio (FCR). While, higher protein levels (22 and 24%) in finishing phase significantly resulted in a better weight gain, FCR and production index of quails. Protein levels in grower and finisher phases had no significant effect on monetary returns however, increase in dietary protein level in finishing phase resulted in a significant feed cost to the gain at 8-42 days. Different dietary protein programs had no significant effect on carcass part percentages, water holding capacity and oxidative rancidity of meat.

For proper performance and economic production of quails protein regimen with at least 20% protein in grower and 22% protein in finisher phases could be recommended.