Broiler chickens grow rapidly within a short period; in this regard, our group had previously reported a decrease in the active transport of glucose in the intestines of broiler chickens with their growth. Therefore, in this study, we compared the active transport process of amino acids in the intestines between 1- and 5-week-old broilers using everted sac, Ussing chamber techniques, and real-time quantitative polymerase chain reaction (RT-PCR). The everted sac experiment showed that amino acids were absorbed from all segments of the small intestine in both age groups. There were no significant differences in the serosal to mucosal ratio between 1- and 5-week-old broilers. The Ussing chamber experiment showed that amino acid-induced short-circuit current (ΔIsc) in the ileal epithelium was significantly greater in the 5-week-old chickens than in the 1-week-old chicks (P=0.035). Membrane conductance, an indicator of ion permeability, showed no significant difference between the two groups. Moreover, the mRNA expression levels of amino acid transporters (ASCT1, EAAT3, B0AT1, and y+LAT1) were significantly elevated in the distal ileum of the 5-week-old broilers compared to those in the 1-week-old broilers (P less then 0.05), while no significant differences were observed in the mRNA levels of ATB0'+, B0/+AT, rBAT, CAT1, and CAT2 in both groups. Our study provides clear evidence that age-dependent increase in the active transport of amino acid across the ileal epithelium is caused by the high expression of Na+-dependent amino acid transporters in broiler chickens.1α-Hydroxycholecalciferol (1α-OH-D3) is an active vitamin D derivative. In this study, three experiments were conducted to evaluate the optimal dietary levels of 1α-OH-D3 in broiler chickens from 1 to 42 days of age. 1α-OH-D3 levels used were 0, 1.25, 2.5, 5, and 10 µg/kg in experiment 1, 0.625, 1.25, 2.5, 5, 7.5, and 10 µg/kg in experiment 2, and 2, 2.5, 3, 3.5, 4, 4.5, and 5 µg/kg in experiment 3. In experiment 1, the addition of 0 to 10 µg/kg of 1α-OH-D3 quadratically improved growth performance, tibia development, and mRNA expression levels of nuclear vitamin D receptor (nVDR), membrane vitamin D receptor (mVDR), and type IIb sodium-phosphate cotransporter (NaPi-IIb) in the duodenum of broiler chickens from 1 to 12 days of age. Body weight gain (BWG), the weight and ash weight of the tibia, and mRNA expression levels of mVDR and NaPi-IIb of broilers fed with 0 and 10 µg/kg of 1α-OH-D3 were lower than those of birds fed with 2.5 µg/kg of 1α-OH-D3. In experiment 2, 1α-OH-D3 levels were quadratically related to BWG and to weight and ash weight of the femur and the tibia of broiler chickens at 42 days of age. The highest values of growth performance and bone mineralization were recorded in broilers fed with 2.5 to 5 µg/kg of 1α-OH-D3. In experiment 3, there was no difference observed in BWG and the weight and ash weight of the femur and the tibia of the 42-day-old broilers fed with 2 to 5 µg/kg of 1α-OH-D3. These data suggest that the optimal dietary levels of 1α-OH-D3 were 2 to 5 µg/kg for broiler chickens from 1 to 42 days of age.The objective of this study was to examine the effect of Gynura divaricata (Jakr-Na-Rai, JNR) on the growth performance, hematology, and carcass fat deposition of broilers. A total of 240 male Cobb-500 birds, 22 d old, were randomly allocated into five treatment groups of six replicates. Each group was raised at a high stocking density of 28 kg of bodyweight/m2 until day 43. The treatments consisted of (i) a basal diet, or the basal diet supplemented with (ii) 2.5 mg/kg avilamycin (T2), (iii) JNR crude ethanol extract at a flavonoid level of 1.3 g/kg (T3), and (iv and v) JNR powder at a flavonoid level of 1.3 (T4) or 2.6 g/kg (T5). Dietary supplementation with JNR powder at both flavonoid levels decreased the heterophil/lymphocyte ratio compared to the other groups (P less then 0.001). Birds in the T5 group presented decreased blood glucose (P less then 0.005) and cholesterol (P less then 0.002) levels and a numerically (P=0.056) decreased triglyceride level. The total bile acid concentration increased (P less then 0.001) in all the JNR-fed groups, but there was no significant effect on the digestibility of ileal protein or fat. At 1.3 g/kg of diet, JNR increased the final bodyweight and feed intake (P less then 0.05), but the average daily gain and feed conversion ratio were not different among groups. The carcass and abdominal fat percentages were lowest in chicks fed on the diets supplemented with 2.6 g/kg JNR powder (P less then 0.007 and P less then 0.025, respectively). Drip loss and malondialdehyde concentrations in the breast meat did not change. In conclusion, JNR powder improved several hematological parameters, increased total bile acid concentrations, and decreased the percentage of abdominal fat. The powder form of JNR elicited better results than the ethanol extract form at the same flavonoid inclusion level.A significant association was reported between a single nucleotide polymorphism (SNP; AB604331, g.420 C>A) in the cholecystokinin type A receptor gene and growth traits in some Japanese slow-growing chickens. Demonstration tests of the genetic improvement effect by comparing the superior allele-A fixed chickens with conventional ones were carried out considering the effect of different seasons on growth traits in other slow-growing chickens. Meat-type Okumino-kojidori chickens from Gifu Prefecture are a three-way cross of Gifu-jidori improved, White Plymouth Rock, and Rhode Island Red breeds. We used a total of 468 meat-type Okumino-kojidori 264 individuals from a private hatchery as conventional chickens and 204 A-allele fixed individuals from the Gifu Prefectural Livestock Research Institute as improved chickens. We performed fattening experiments over two seasons summer and winter.  https://www.selleckchem.com/products/ipi-549.html  In each season, experimental birds of both sexes were hatched on the same day, raised in the same chicken house, and fed the same diet ad libitum for 12 weeks. Body weight was recorded at 3, 6, 9, and 12 weeks of age. SNP genotypes were determined using the mismatch amplification mutation assay. Association between the SNP and growth traits was analyzed using generalized linear models built on sex-based, seasonal, additive, and dominance genetic effects. The observed AA, AC, and CC genotype frequencies in the conventional chickens were 0.158, 0.479, and 0.363, respectively; body weight at 12 weeks and average daily gain from 3 to 12 weeks was superior for the A allele compared to the C allele. The improved chickens were heavier than the conventional ones at 12 weeks. Body weight at 12 weeks in allele-A fixed chickens increased by 3.2% compared to the conventional chickens. We concluded that g.420 C>A is a good selective marker that increases slaughter weight in the meat-type Okumino-kojidori chickens.