The aim of this study is to evaluate the influence of age on net energy and dietary phytase supplementation on the standardized ileal digestibility (SID) of amino acids of palm kernel meal (PKM). To determine the SID, A total of 162 12-day-old and 72 32-day-old male Arbor Acres chickens were divided into three groups (D0, D1 and D2). For the net energy a total of 72 11- and 31-day-old broiler chickens were divided into two groups (R1 and R2). Each group consisted of six repetitions and was fed its respective ration. The group D0 received a diet without nitrogen, then group D1 received an experimental diet with PKM as the sole nitrogen source, and finally group D2 received a diet without mineral phosphorus while supplemented with 1,000 FTU phytase/kg diet. For net energy trial, group R1 received a basal diet, while group R2 received a diet consisting of 70%R1 and 30% PKM. Bird performance, AME, NE, and N balance were measured in a calorimetry system. The results showed that there was no interaction (P > 0.05) between the age of the birds (20 versus 40 days) and the dietary treatments (D1 and D2) for the AID and SID of most Aas, except for the values of aspartate (Asp) regarding AID and SID. The trends of age effect on AA digestibility were used and the effect of diets on AA digestibility was similar to the AID of AA values. Finally, results regarding the effective energy value and energy conversion efficiency of PKM revealed that age significantly affected AME, NE, and AME/GE of PKM (P < 0.05). Additionally, the conversion rates of NE and AME of PKM were 72.22% and 79.98% during the starter and finisher phases, respectively. In conclusion, the results indicate that age affects the NE of PKM and the supplementation of phytase did not improve the digestibility of PKM amino acids.

There is an energy deficiency during the later stage of embryonic development, as the metabolic demands show an “explosive increase”. Vegetable oils are already used for in ovo feeding in poultry to provide energy for the embryos. What would be the effectiveness of animal oils used as alternative energy sources for the chicken embryo? To find out more, BSF larvae oil was used for in ovo feeding of the chicken embryo in this study. A total of 2300 Arbor Acres chicken eggs were used for incubation. On the tenth day of incubation, 2268 eggs were selected after candling and then divided into three groups for in ovo feeding in the yolk sac on the 11th, 14th, and 17th days of incubation. Each group was divided into seven lots, such as CON−, CON+, L0.1, L0.2, L0.3, L0.4, and L0.5. The CON− and CON+ were not injected. L0.1, L0.2, L0.3, L0.4, and L0.5 were pierced and then received the injection of 0.1 mL, 0.2 mL, 0.3 mL, 0.4 mL, and 0.5 mL of BSF maggot oil per egg, respectively. After hatching, 48 chicks from each lot of each group were housed in cages and then fed the same diet for six weeks. A better hatch rate and growth performance were observed for lots L0.1 and L0.2 compared to the other lots on the 14th and 17th days of incubation (p < 0.05). The injected lots showed reduced levels of low-density lipoprotein (LDL) cholesterol (p < 0.05). The injection of 0.1 mL BSF maggot oil on the 17th day of incubation had 0% embryonic mortality and 100% hatching success. In conclusion, BSF larvae oil can be used as an energy source for in ovo injection, with a dose of 0.1 mL on the 17th day of incubation being most effective and recommended.

The aim of this study was to evaluate the interaction between heat stress (HS) and the incorporation of palm kernel meal (PKM) in broiler chicken diets, as well as their effects on growth performance and metabolism. A total of 288 21‐day‐old male Arbor Acres chicks were used in a 21‐day experiment. The birds were randomly assigned to two temperature conditions: thermoneutral (TN; 23°C) and HS (33°C for 9 h per day). Each group received one of two diets (P0: 0% PKM; P1: 10% PKM) in a 2 × 2 factorial design, with environment (TN vs. HS) as the first factor and diet (P0 vs. P1) as the second. Each treatment included six replicates. The results showed that HS increased cloacal temperature ( p < 0.05). Serum CK concentrations were not affected by treatment ( p > 0.05), but an interaction was observed for serum corticosterone ( p = 0.0049). In contrast, analysis of serum oxidative stress revealed no differences in CAT or SOD activity ( p > 0.05), whereas GSH‐Px, T‐AOC, and malondialdehyde levels were influenced by treatment ( p < 0.05). Examination of tight junction proteins in the jejunum indicated no effects of temperature or diet ( p > 0.05), although an interaction was found for claudin‐1 gene expression ( p = 0.026). Finally, analysis of the cecal microbiota showed that temperature increased the relative abundance of several bacterial species ( p < 0.05), whereas dietary treatment affected only the Phocaeicola species ( p < 0.05). In summary, PKM supplementation did not mitigate the adverse effects of HS.