The efficacy of bile salt, lipase, or fiber-degrading enzyme supplementation in the nonstarch polysaccharides (NSP) of defatted rice bran (DRB) diet on nutrient digestibilities and energy value was examined in 1- to 14-d-old chicks. Two types of NSP, Extracted-NSP (isolated from DRB, 15%/kg of diet) and Natural-NSP (given as intact DRB, 30%/kg of diet), were tested in this experiment. The 15%-Extracted- and the 30%-Natural-NSP provided a comparable amount of total-NSP concentration. The birds fed the Extracted-NSP diet had better weight gain and lower feed : gain ratio compared with those given the Natural-NSP diet, although fat digestibility did not differ between the two NSP diets. Addition of bile salt improved fat digestibility more than that of lipase or fiber-degrading enzyme in both NSP diets on d 7 (P<0.001). There was a significant NSP type x supplements on fat digestibility showing that the effect of the fiber-degrading enzyme during the first week of age was more profound (P<0.01) in diets containing the Extracted-NSP than those with the Natural-NSP. But, pancreatic lipase activity did not correlate well with fat digestibility. During the second week of age, the effect of bile salt on protein digestibility was inferior whereas the effect of lipase was superior in the two NSP diets (P<0.05). The dietary ME_n values of the diets containing the Extracted-NSP were greater than those with the Natural-NSP (P<0.001). Bile salt had the greatest effect among the three supplements on the ME_n (P<0.001) of the NSP diets. Tibia ash content of the birds was adversely affected only by feeding diets containing the Natural-NSP. The current study suggested that bile salt appeared the most effective supplement in increasing fat digestibility and energy value of the diet containing considerable amounts of defatted rice bran-nonstarch polysaccharides.

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An aromatase inhibitor, Fadrozole (CGS16949A), was administered into chick embryo on the 5th day of incubation to clarify the roles of endogenous estrogen in the regulation of circulating lipoprotein levels during the development. The plasma of 10-, 16- and 20-day embryos and neonatal chicks were separated by polyacrylamide gel electrophoresis. Amounts of plasma lipoproteins, high density lipoprotein (HDL), low density lipoprotein (LDL) and very low density lipoprotein (VLDL) were then measured using a densitometer and expressed as a percentage in total lipoproteins. Changes in HDL percentages of the groups treated with the aromatase inhibitor (AI group) and propylene glycol (Vehicle group) showed similar patterns during the experimental period. This was also the case in the changes in LDL percentages. The 16-day embryos of the AI group, in which endogenous estrogen synthesis was inhibited, showed a distinctly high VLDL percentage, whereas plasma VLDL in the Vehicle group showed only a little developmental changes. The plasma concentration of triglyceride (a major component of VLDL), phospholipid and total cholesterol in the AI group showed a profile similar to that of VLDL, with the maximum level in the 16-day embryo. These results suggest that endogenous estrogen of the embryo plays an important role in the utilization and resulting clearance of plasma lipids from the circulation, in addition to its well-documented role in sex differentiation.

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Two experiments were conducted to determine effect of dietary sorbitol on growth performance, plasma α1 acid glycoprotein (AGP) and ceruloplasmin concentrations in male broiler chicks during immunological stimulation due to injections with Escherichia coli lipopolysaccharide (LPS) and Sephadex-G50 superfine. In experiment 1, 10 days old chicks were fed a 6% glucose, xylitol, sorbitol or fructose for 8 days. In experiment 2, 7 days old chicks were fed either diet containing 10% glucose or sorbitol supplemented diet for 12 days. During final 6 days of the experimental periods, all chicks in experiment 1 and a half of birds fed each diet in experiment 2 were injected intraperitoneally with Escherichia coli LPS (0.5 mg/kg BW) on days 1, 3 and 5 and Sephadex (250 mg/kg BW) on days 2 and 4. Chicks fed the sorbitol diets tended to be better in growth performance than birds fed the glucose or fructose diet in experiment 1. In experiment 2, feeding the sorbitol diet prevented the reductions in body weight gain due to LPS and Sephadex injections. Plasma AGP concentration on day 2 after the immune stimulation in chicks fed the sorbitol diet was lower than that in chicks fed the glucose diet, but that on day 6 did not differ. Plasma ceruloplasmin concentration on days 2 and 6 after the immune stimulation in chicks fed the sorbitol diet was significantly lower than that in chicks fed the glucose diet. These results indicate that dietary sorbitol reduces early inflammatory responses and tended to prevent the reduction of growth due to repeated injections of LPS and Sephadex. In addition, mode of action of sorbitol in preventing growth retardation during immunological stimulation appeared to be different from that of xylitol, which was previously reported in chicks.

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Effects of estradiol-17β (E2) and p-nonylphenol (NP) on the mRNA expression of sex determination-related genes were examined in the embryonic gonad of chickens. Fertilized eggs were treated with either E2 (0.1 and 1.0 mg/egg) or NP (0.001, 0.01, 0.1 and 0.2 mg/egg) twice on days 13 and 16 of incubation. The mRNA expressions of anti-Müllerian hormone (AMH), SRY-related HMG box 9 (SOX9), cytochrome P450 aromatase (P450arom) and steroidogenic factor 1 (SF-1) in the embryonic gonads were determined by the reverse transcription-polymerase chain reaction (RT-PCR) on day 18 of incubation. AMH, SOX9 and P450arom, but not SF-1, showed sexually dimorphic expression in the control ; AMH and SOX9 were male-specific while P450arom was female-specific. E2 had no significant effects on these expressions in either sex. In contrast, NP reduced the expressions of AMH and SOX9 only in the males but had no effects on the expressions of P450arom and SF-1. These results suggest that NP has endocrine disrupting effects on the mRNA expression of sex determination-related genes in the gonads of chicken embryos.

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We examined whether very low-density lipoprotein receptors (VLDLR) on the oocyte membrane contributed to changes in VLDL uptake into the yolk by the ovarian follicle during the ovulation cycle of the laying hen. White and yellow (F₅-F₁) follicles were collected from laying hens at 14-16 h (when the yellow follicles actively uptake yolk) and 0-2 h (when the yolk uptake is less active) before ovulation and subjected to binding experiments with ¹²⁵I-VLDL and assays for aromatase activity. The preparations from white follicles did not bind to ¹²⁵I-VLDL, while yellow follicle preparations bound to the radioligand. The ¹²⁵I-VLDL bindings of F₃-F₁ yellow follicles were higher at 14-16 h than 0-2 h before ovulation. Values of the dissociation constant (Kd) and the maximum binding capacity (Bmax) of VLDLR calculated from the ¹²⁵I-VLDL bindings to the oocyte membranes showed profiles related to the changes in ¹²⁵I-VLDL bindings; in F₃ and F₂ follicles Bmax values were higher at 14-16 h than 0-2 h before ovulation and Kd values were higher at 0-2 h than 14-16 h before ovulation. High aromatase activities of the F₃-F₁ yellow follicles of 14-16 h before ovulation decreased 0-2 h before ovulation, which was a change consistent with the change in ¹²⁵I-VLDL bindings of the same follicles. These results suggest that the yolk VLDL uptake during the ovulation cycle is regulated by changes in VLDL binding underlined by changes in Bmax and Kd of VLDLR. Estrogen produced by the aromatase of the theca layer of the yellow follicles might facilitate VLDL binding by affecting VLDLR on the oocyte membrane of the same follicles in a paracrine manner.

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This experiment was conducted to study the effect of varying levels (0, 4, and 7%) of total nonstarch polysaccharides (NSP) prepared from defatted rice bran on performance, nutrient digestibility, and energy value of the diet in the 1- to 14-d-old broiler chicks. Two of the 7%-NSP diets were supplemented with LAMINEX XL^® (3,080 units xylanase/kg of diet), or LAMINEX XL^® plus LAMINEX BG^® (366 units β-glucanase/kg of diet). All diets contained 3.00 Mcal of metabolizable energy (ME_n)/kg of diet and 22% of crude protein. The results showed that feeding chicks a diet containing up to 7% of NSP had no effects on feed intake, body weight gain, feed : gain ratio, and fat digestibility. However, chicks receiving the 7%-NSP diet showed a greater protein digestibility compared with those receiving the 0%- or the 4%-NSP diet at d 7 (P<0.01) or with those receiving the 0%-NSP at d 14 (P<0.05). Dietary 7%-NSP depressed pancreatic lipase activities at d 14. Although this depressing effect was ameliorated with xylanase or xylanase plus β-glucanase supplementations, the supplemental enzymes did not improve fat digestibility that was adversely affected (P<0.01) by 7% of NSP in the diet on d 14. Xylanase improved protein digestibility of the 7%-NSP diet on d 7 (P<0.05), and xylanase plus β-glucanase also showed an improving effect on d 14 (P<0.05). The supplementation of enzyme did not influence the ME_n values of the diet. The results of the present study suggest that at up to 7%, NSP of defatted rice bran possesses no antinutritive effects on nutrient digestibility, but positively influences the ME_n value of the diet. The favoring effect of enzymes on protein digestibility did not contribute to the performance of the chicks at early age.

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Eight Single Comb White Leghorn laying hens were used to investigate the effects of feeding levels (FL), ad libitum and 40% feeding, and physical activities on heat production (HP) under different ambient temperatures (Ta) of 25, 29 and 33°C. HP were measured by the indirect calorimetry where each hen was observed for 48 h in each condition. Activity count (ACT), standing time (STN) and eating time (ETN) were also measured for the same 48 h. ACT was measured by the Actigraph and the STN and ETN were detected by the infra-red beam switches. HP decreased with the increase of Ta and with the decrease of food intake (FI). The daily ACT decreased significantly (P<0.05) at 33°C in the ad libitum fed hens in comparison with that of 29°C, and in the 40% fed hens ACT had a decreasing tendency with the increase of Ta. On the other hand, the daily STN increased significantly (P<0.05) at 33°C comparing with that of 25 and 29°C in both the ad libitum and 40% fed hens. HP in the 40% fed hens decreased by 24%, 17% and 17% at 25, 29 and 33°C, respectively in comparison with that of ad libitum fed hens. From the multiple regression equations, excluding the activity-related HP, an estimation of the increase of HP for 1 g of FI was done and it was approximately 3.9kJ at each Ta in the ad libitum fed hens. Almost 28% of the daily HP was related to the activity at each Ta. The hens changed their physical activities with the increase of Ta in both the ad libitum and 40% feeding and the maintenance energy expenditure may decrease with the increase of Ta.

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