A total of 440 one-day-old healthy male Arbor Acres broilers were equally assigned to a control group (CTL) and an early-age high-temperature exposure (EHT) group (4 replicates per group, 55 chickens per replicate). At d 3, the broilers in CTL group were reared in the normal temperature 33 ± 1°C, while the broilers in EHT group were exposed to 36 ± 1°C for 24 h. At d 43, all broilers were treated with an acute high temperature 35 ± 1°C for 5 h. The results showed that average daily gain in EHT group was decreased at d 3, but average daily gain in EHT group was increased at d 36 to 42 (P < 0.05). Plasma GLU level in EHT group was lower in broilers at d 7 or facing subsequently high temperature for 5 h (P < 0.05). The relative expression of myogenic differentiation (MyoD) gene in pectoralis major and myogenic factor 5 (Myf5) gene in biceps femoris were significantly improved at d 42 after early-age heat exposure (P < 0.05). Broilers in EHT group have a higher temperature tolerance with a lower mortality than control broilers (P < 0.05). Broilers in EHT group have a lower rectal temperature and a higher comb and ear temperature when facing subsequently acute high temperature than control broilers (P < 0.05). In addition, our study demonstrated that early-age heat exposure significantly decreased the mortality and increased the heat tolerance of broilers when facing an acute short-term heat exposures. Early-age heat exposure increased the process of myogenesis via up-regulating the MyoD and Myf5 gene expression in skeletal muscle, which accelerated average daily gain.
Conventional methods of house dust mite control often involve chemical pesticides, raising concerns about their potential hazards. Mint essential oil presents a natural and eco-friendly alternative for managing house dust mite infestations. In this study, ten varieties of mint plants were cultivated, and their essential oils were extracted through steam distillation. The toxicity of these mint essential oils and their main compounds on adult house dust mites was assessed using contact+fumigant mortality bioassays and vapour-phase mortality bioassays. A repellent bioassay was also conducted to evaluate the repellent effects of mint oils and main compound on house dust mites. The toxicity of mint essential oils varied among the different varieties, with some demonstrating higher potency in eradicating house dust mites. Mint oils showed both acaricidal action and repellent effects on house dust mites, with certain varieties exhibiting stronger efficacy. Linalool as active compounds was identified as key contributors to the acaricidal properties of mint essential oil. Mint essential oil, particularly certain varieties rich in active compounds, shows promise as a natural and effective agent for controlling house dust mites. Its dual functionality in killing and repelling house dust mites, along with its environmentally friendly nature, make it a viable alternative to chemical pesticides for house dust mite management. Further research on the specific mechanisms of action and long-term effectiveness of mint essential oil in house dust mite control is warranted to explore its full potential as a sustainable pest management solution.
Fasting heat production (FHP) is used to assess the maintenance net energy requirement of animals. Herein, the FHP of layer-type pullets was estimated. In trial 1, 16 40-day-old Jingfen layer-type pullets were divided into four groups of four chickens and placed in four respiratory chambers. Pullets had free access to feed and water. After 4-days acclimatization, feed was withdrawn, and chickens were measured for FHP for three consecutive days. In trial 2, 24 40-day-old pullets were placed in four respiratory calorimetry chambers, with six pullets per chamber. After 4-days acclimatization, one chamber was randomly selected and all pullets in the chamber was sampled at 5, 25, 50, or 65 h after feed withdrawal. The result showed that FHP declined with fasting time and reached the lowest level between 48 and 72 h. Respiratory quotient was decreased (P < 0.05) between 24 and 48 h compared with that in the first 24 h after fasting. The FHP in the light period showed a significant to decline with fasting time (P < 0.01), whereas the FHP in the dark period was decreased (P < 0.01) 24 h after fasting. Body weight, thigh mass, and abdominal fat decreased (P < 0.05) at 25 h after fasting. Serum glucose were increased (P < 0.01) and while triglycerides were significantly decreased (P < 0.01) at 50 h compared with that at 5 and 25 h time point. The result suggests that the adequate measuring period for FHP for layer-type pullets is from 24 to 48 h after fasting. The FHP of 7-week-old layer-type pullets was 562.20 kJ/kg of BW0.75/d under a 10-h light and 14-h dark lighting regime.
Abstract Glucocorticoids (GCs) induce the activation of the central adenosine 5′-monophosphate-activated protein kinase (AMPK) signaling pathway in birds. In this study, we aimed to investigate the effects of corticosterone (CORT) supplemented in diet on the central AMPK signaling pathway in broilers. The average daily gain was reduced by CORT treatment, and the average daily feed intake remained unchanged. Plasma glucose, triglyceride, total cholesterol, and CORT contents were increased by CORT administration. In addition, CORT treatment decreased the relative weights of heart, spleen, and bursa and increased the relative weights of liver and abdominal fat. The glycogen contents in the liver and breast muscle were higher in the chicks treated with CORT. CORT treatment upregulated the gene expression of mammalian target of rapamycin, glucocorticoid receptor, AMPKα2, neuropeptide Y(NPY), liver kinase B1 (LKB1), AMPKα1, and fatty acid synthase in the hypothalamus. Moreover, CORT treatment increased the protein levels of acetyl-coenzyme A carboxylase (ACC) phosphorylation and total AMPK and phosphorylated AMPK in the hypothalamus. Hence, CORT administration in the diet activated the LKB1-AMPK-NPY/ACC signaling pathway in the hypothalamus of broiler.
In mammals, fibroblast growth factor 23 (FGF23) regulates phosphate homeostasis in kidney by binding α-Klotho, a coreceptor of FGF23. FGF23 mRNA is highly expressed in bone and slightly expressed in liver, and is regulated by dietary phosphorus. Little is known about distribution and regulation of FGF23 mRNA in avian lineage. The expression of FGF23 and its coreceptor α-Klotho in chicken and embryo were investigated by real-time quantitative PCR. The effect of dietary phosphorus on FGF23 expression was measured. 36 laying hens at 25 wk were randomly assigned to three dietary available phosphorus (AP) treatments for 11 days: 0.15% AP (LP), 0.40% AP (MP), and 0.80% AP (HP). We first cloned the full coding sequence of FGF23 by the reverse transcription PCR from chicken liver and calvaria. Bioinformatics analysis indicated that the deduced amino acid sequence was 57–87% identical to FGF23 of other species. In adult chicken FGF23 mRNA was expressed at unexpected higher level in liver than other tissues evaluated, including calvaria, femur, tibia, medullary bone, brain, spleen, duodenum, jejunum, ileum, heart and kidney (P < 0.0001), and α-Klotho was expressed at highest level in kidney. However, in 18-d chicken embryos, FGF23 mRNA level was much higher in tibia than in liver, heart and jejunum (P < 0.0001). Chickens at 2, 25, 50 and 80 wk had higher FGF23 expression in liver than 18-d chicken embryos, whereas chickens at 25 wk had lower FGF23 expression in tibia than 18-d chicken embryos and 2-wk-old chickens. HP diets significantly increased serum inorganic phosphorus level (P < 0.001) and FGF23 expression (P < 0.05) in bone tissue compared with LP diets, however, FGF23 mRNA abundance in liver was not changed significantly (P > 0.05) by dietary phosphorus treatments. In conclusion, FGF23 mRNA expression pattern in chicken was clearly different from that in mammals and dietary phosphorus regulated the expression of FGF23 in a tissue-specific way.
The total contents and chemical phase partitioning of Cd, Ni, Cu, Zn and Pb from long-time sewage- irrigated soil were analyzed in this paper. The results showed that the contents of Ni, Cu, Zn, and Pb did not exceed the the second-level limit of Standard of Soil Environment (GB15618-1995), but the average content of Cd was 1.81 mg•kg -1 , which was about three times more than the national standard. The chemical partitioning of metals analysis showed that Cd was present dominantly in the acetic acid extractable fraction with the average percentage of 37.44%, while the other four elements mostly in residual fraction, which indicated that Cd had the highest bioavailability, mobility and phyto-toxicity. Compared to the well-irrigated soils, the percentages of acetic acid extractable fractions of Cd, Ni, Zn and Cu were obviously higher in the contaminated soils, which increased the potential danger of heavy metals pollution.
Abstract Background : L-citrulline (L-Cit), a non-protein amino acid, has been implicated in several physiological functions including anti-inflammatory, anti-oxidative, and hypothermic roles, however, there is a paucity of information with regards to its potential in poultry production. This study was designed to investigate the effects of dietary L-Cit supplementation on the production performance, nitric oxide production, and antioxidant status of laying hens during summer period. Hy-Line Brown laying hens (n=288, 34 weeks old) were allotted to four treatment, 6 replicates of 12 chickens each. Dietary treatments of control (basal diets), 0.25%, 0.50 % and 1.00 % L-Cit supplementation were fed to chickens for eight (8) weeks. Production performance, free amino acid profiles, nitric oxide production, and antioxidant properties were measured. Blood samples were collected at the 4 th and 8 th weeks of the experiment. Results : Air temperature monitoring indicated an average daily minimum and maximum temperatures of 25.02 o C and 31.01 o C respectively. Dietary supplementation with L-Cit did not influence ( P > 0.05) the production performance, and rectal temperature of laying hens. Egg shape index was increased ( P < 0.05) with increasing levels of L-Cit. Serum-free content of arginine, citrulline, ornithine, tryptophan, histidine, GABA, and cystathionine were elevated, but taurine declined with L-Cit diets. Plasma nitric oxide (NO x ) concentration was highest at 1% L-Cit. Likewise, nitric oxide synthase (NOS) activity for total NOS (tNOS) and inducible NOS (iNOS) were upregulated with increasing L-Cit levels, although, tNOS was not affected at the 4 th week. Anti-oxidant enzymes including catalase and superoxide dismutase (SOD) were increased with L-Cit supplementation, however, SOD activity was unchanged at 4 th week, while total anti-oxidant capacity increased at the 8 th week. L-Cit supplementation attenuated the extent of lipid peroxidation, and also inhibited glutathione peroxidase activity. Conclusion : Dietary L-Cit supplementation modulated systemic arginine metabolism, nitric oxide synthesis, antioxidant defense system, and increased the egg shape index of laying hens during the summer season. 1% L-Cit supplementation proved most effective in potentiating these effects and may be adopted for feed formulation strategies.
Two experiments were conducted to investigate the effect of RH (35, 60, and 85%) on thermoregulation of broiler chickens at high (35 ° C) and mild (30 ° C) temperatures at the age of 4 wk. The effects of humidity on rectal temperature (RT) and plumage temperature at back (PBAT) and skin temperature at breast (SBRT) were determined at 1, 4, 8, 16, and 24 h after exposure. The RT, PBAT, and SBRT were all significantly increased by high temperature (35 ° C). Humidity had a significant influence on RT at 35 ° C but not at 30 ° C. The peripheral temperatures (PBAT and SBRT) were significantly affected by humidity but responded differently at high (35 ° C) compared with mild temperature (30 ° C). In conclusion, high humidity above 60% impaired the heat transmission from body core to the periphery at 35 ° C but facilitated it at 30 ° C in 4-wk-old broiler chickens. The effect of humidity on nonevaporative heat loss was depended on air temperature, as nonevaporative heat loss was suppressed by high humidity (>60% RH) at high temperature but enhanced at the mild temperature. The effect of humidity on the relationship between peripheral and core temperature depends on ambient temperature as well as on the age of the broiler chicken. The disturbance of thermal balance could not be determined only by changes in RT or peripheral temperature at a single time point but could be determined by mean body temperature within a certain time frame.
The experiment was conducted to investigate the possible effect of corticosterone treatment at different hatching time on the development of chicken embryos.Seven hundreds of AA broiler eggs were divided into 7 groups and randomly subjected to one of the seven treatments:corticosterone treatment(200 ng) at E0,E7 and E14,three positive control groups that injected with corn oil at E0,E7 and E14,and one negative control group.The incubation time,hatching ability and posthatching body weight were recorded.The blood samples were collected and the organs weight were measured after hatching.The results indicated that corticosterone treatment at E0 significantly reduced hatching ability(P0.05) and increased mortality of embryo.Corticosterone treatment at E7 shortened the incubation time(P0.05) and tended to reduce the hatching ability.The development of heart and liver were restrained by corticosterone treatment(P0.05).The result showed that the effect of corticosterone on the development of chicken embryo was age dependent.Moreover,the effect of injection had an adverse effect on embryos as well.
In order to investigate the heavy metal polluted states and the safe levels of vegetables in Xinxiang suburb,the contents of cadmium (Cd),chromium(Cr),lead(Pb),copper(Cu) and zinc(Zn) in 11 kinds of common vegetables in Xinxiang suburb have been determined in this study.According to national hierarchical standard of heavy metal to appraise vegetables,sanitary standard of food and quality of vegetables,polluted degree of heavy metals has been evaluated.The results indicate: the qualification rates of Cd,Cr,Pb,Cu and Zn in the vegetables are 54.54%,90.91%,45.45%,100% and 81.82% respectively. Their maximum is 2.42 times,1.46 times,3.88 times,0.28 times and 1.31 times as big as the national sanitary standard allowed quantity separately.The results of evaluation show: tomato is safe;spinach,black-and-white dish and cauliflower are in warning;Chinese vegetable,celery,crown daisy chrysanthemum,naked oats dish and cucumber begin to be polluted;middle degree of pollution in French gourd and garlic shoot are received.The heavy metals that polluted vegetables are mainly Cd and Pb,and Pb is more serious.
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