| Energy is the first limiting factor in the broiler feed. To some extent, if lacking of energy, the effect of other nutrients could be restricted, and then the growth of broiler and its immunity performance would also be affected. In most cases, based on NRC, ME values of feed ingredients were calculated from regression equations based on composition and ME values of adult cock trials done 15 to 25 years ago. In practice, fats or oils were classified to animals and plants fats or oils, and the ME of these are 7920 KCal/kg and 8250 KCal/kg, respectively. Obviously, this could not meet today's feed and animal husbandry development. This research was conducted to determine the exact substitution ratio of the tested fats or oils in the substitution assay in broiler AMEn determination of fats or oils, and AMEn of 8 kinds of oil for broiler was estimated, then prediction equations were developed for AMEn of fats or oils, so as to provide some basic data for chinese nutrient and energy databank and utilization of different fats or oils in broiler production.Experiment 1 Study On the Effects of Ration of Fats or Oils on Nutrients Utilization and AMEn of the Broiler Diet. Experiment was conducted to determine the exact substitution ratio of the tallow in the substitution assay by extrapolation in broiler AMEn determination for fats or oils. At the same time, nutrients utilization of the diet was determined. A total of 224 AA broilers were raised to 22 days of age and randomly allotted into 7 different treatments consisted of 8 replicates. Broilers in different treatment were fed the tested diets substituted by different ratio of tallow (0, 2%, 4%, 9%, 12% and 15%) in metabolizable experiment. Meanwhile, the growth performance and nutrients Utilization were calculated. The results showed that the diets AMEn value increased at first, then decreased in the substitution assay with the substitution ratio of the tallow increasing. When the substitution ratio of tallow was in 9-12%, the AMEn of tallow was in a plateau period and there is a little variation within the groups. AMEn value of tallow was calculated by extrapolation. The value was substituted into the regression models established with the AMEn value of tested tallow(Y) and its substitution ratio in basal diets(X), the corresponding percent is 9.8%. But the growth performance and nutrients utilization results showed that, ADG and the ration of feed to chicken of 2%~6% groups were better than that of other groups, and there is a significant different as compare to control(P<0.05); With the increase of oils 0r fats in diet, Metabolic rate of feed nutrients first increased, then decreased. Metabolic rate of feed and energy of 2% group was higher than that of other groups (P<0.05). Therefore, 2%~4%, no more than 6% of the diet fats or oils should be added in order to increase the broiler growth.Experiment 2 Study on the AMEn Values of Different Fats or Oils for Broilers. A metabolizable experiment was carried out using indicator method assay to determine the AMEn of 7 kinds of oil in broiler chicks. Meanwhile, the study was to establish mathematical relationships between fatty acid components or quality characters and broilers AMEn of fats or oils. A total of 256 AA broilers of 22 days old were randomly allotted into 8 different treatments consisted of 8 replicates. One treatment was fed by basal diets, and the other 7 treatments were used to evaluate AMEn values of 7 kinds of fat or oil by substitution assay (ratio of tested fats or oils was 10%). At the same time, fatty acid components and quality characters of 8 kinds of fat or oil were also measured during the experiment including moisture, impurity, unsaponifiable matter, saponifiable matter, acid value, iodine value and phospholipids. The AMEn of the fats or oils obtained by using 26~31 day-old broilers in this experiment varied a little and proved stable. The determined figure could be used for making the formula of the broilers. The optimal AMEn- fatty acid components or quality characters stepwise regression equations were established. Predict equation for broiler AMEn of 8 kinds of fat or oil is:AMEn=10.24460-0.06023lg (UM)+0.0.95000lg (pL)+0.04771lg (AV)(R2=0.97740, P<0.01)AV - Acid Value UM- Unsaponifiable Matter PL- Phospholipid... |
PDF Full Text Request