Hydrogen Sulfide Regulates Glucose Uptake in Skeletal Muscles via S-Sulfhydration of AMPK in Muscle Fiber Type-Dependent Way.

BACKGROUND: The effect of hydrogen sulfide (H2S) on glucose homeostasis remains to be elucidated, especially in the state of insulin resistance. OBJECTIVES: In the present study, we aimed to investigate H2S-regulated glucose uptake in the M. pectoralis major (PM) muscle (which mainly consists of fast-twitch glycolytic fibers) and M. biceps femoris (BF) muscle (which mainly consists of slow-twitch oxidative fibers) of the chicken, a potential model of insulin resistance. METHODS: Chicks were subjected to intraperitoneal injection of sodium hydrosulfide (NaHS, 50 µmol/kg body mass/day) twice a day to explore glucose homeostasis. In vitro, myoblasts from PM and BF muscles were used to detect glucose uptake and utilization. Effects of AMP-activated protein kinase (AMPK) phosphorylation, AMPK S-sulfhydration, and mitogen-activated protein kinase (MAPK) pathway induction by NaHS were detected. RESULTS: NaHS enhanced glucose uptake and utilization in chicks (P < 0.05). In myoblasts from PM muscle, NaHS (100 µM) increased glucose uptake by activating AMPK S-sulfhydration, AMPK phosphorylation, and the AMPK/p38 MAPK pathway (P < 0.05). However, NaHS decreased glucose uptake in myoblasts from BF muscle by suppressing the p38 MAPK pathway (P < 0.05). Moreover, NaHS increased S-sulfhydration and, in turn, the phosphorylation of AMPK (P < 0.05). CONCLUSIONS: This study reveals the role of H2S in enhancing glucose uptake and utilization in chicks. The results suggest that NaHS is involved in glucose uptake in skeletal muscle in a fiber type-dependent way. The AMPK/p38 pathway and protein S-sulfhydration promote glucose uptake in fast-twitch glycolytic muscle fibers, which provides a muscle fiber-specific potential therapeutic target to ameliorate glucose metabolism.

Chicken embryo thermal manipulation alleviates postnatal heat stress-induced jejunal inflammation by inhibiting Transient Receptor Potential V4.

Intestinal inflammation induced by heat stress is an important factor restricting the healthy growth of broilers. The aim of this study was to evaluate the effect of chicken embryo thermal manipulation (39.5 â„ƒ and 65 % RH for 3 h daily during 16-18 th embryonic age) on intestinal inflammation in broilers under postnatal heat stress and to investigate whether transient receptor potential V4 (TRPV4) plays a role in this process. Our results suggest that broilers with embryo thermal manipulation experience could delay the rising of rectal temperature during postnatal heat stress (P < 0.05), and had better production performance (P < 0.05), intestinal morphological parameters (P < 0.05) and higher expression of tight junction related genes (P < 0.05). The increased serum lipopolysaccharide (LPS) content, activation of nuclear factor-kappa B (NF-κB) signaling pathway and the increased expression of pro-inflammatory cytokines interleukin (IL)-1ß, IL-6 and tumor necrosis factor alpha (TNF-α) in jejunum during postnatal heat stress were alleviated by embryo thermal manipulation (P < 0.05). Postnatal heat stress induced an increase in mRNA and protein expression of TRPV4 in jejunum (P < 0.05), but had no effect on broilers which experienced embryo thermal manipulation (P > 0.05). Inhibition of TRPV4 reduced LPS-induced Ca2+ influx and restrained the activation of NF-κB signaling pathway and the expression of downstream pro-inflammatory cytokines (P < 0.05). The expression of DNA methyltransferase (DNMT) in the jejunum of broilers exposed to postnatal heat stress was increased by embryo thermal manipulation (P < 0.05). The DNA methylation level of TRPV4 promoter region was detected, and the results showed that embryo thermal manipulation increased the DNA methylation level of TRPV4 promoter region (P < 0.05). In conclusion, Chicken embryo thermal manipulation can alleviate jejunal inflammation in broilers under postnatal heat stress. This may be due to the decreased circulating LPS or the increased DNA methylation level in the promoter region of TRPV4, which inhibits TRPV4 expression, thereby reducing Ca2+ influx, and finally alleviating inflammation by affecting NF-κB signaling pathway. The work is an attempt to understand the mechanism involved in alleviation of adverse effects of heat stress during postnatal life through prenatal thermal manipulation and to reveal the important role of epigenetics.

The regulating pathway of creatine on muscular protein metabolism depends on the energy state.

Creatine (Cr) is beneficial for increasing muscle mass and preventing muscle atrophy via involving in energy metabolism through the Cr and phosphocreatine (PCr) system. This study aimed to evaluate the supplemental effect of Cr on protein metabolism under normal and starvation conditions. The primary myoblasts were obtained from the breast muscle of chicks. The mammalian target of rapamycin (mTOR)/P70S6 kinase (P70S6K), ubiquitin-proteasome (UP) pathways, and mitochondrial function of myotubes were evaluated at normal or starvation state and with or without glucose supplementation. Under normal condition, Cr supplementation enhanced protein synthesis rate as well as upregulated the total and phosphorylated P70S6K expressions. Cr had little influence on protein catabolism and mitochondrial function. In a starvation state, however, Cr alleviated myotube atrophy and enhanced protein accretion by inhibiting Atrogin1 and myostatin (MSTN) expression. Furthermore, Cr treatment upregulated the transcriptional coactivators peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression and decreased reactive oxygen species (ROS) accumulation under starvation condition. In the presence of glucose, however, the favorable effect of Cr on protein content and myotube diameter did not occur under starvation condition. The present result indicates that at a normal state, Cr stimulated protein synthesis via the mTOR/P70S6K pathway. In a starvation state, Cr mainly takes a favorable effect on protein accumulation via suppression of the UP pathway and mediated mitochondrial function mainly by serving as an energy supplier. The result highlights the potential clinical application for the modulation of muscle mass under different nutritional conditions.

Dietary L-citrulline influences body temperature and inflammatory responses during nitric oxide synthase inhibition and endotoxin challenge in chickens.

Recent studies have revealed the role of L-citrulline (L-CIT) in thermoregulation, but very little is known about the mechanisms involved. In this study, nitric oxide synthase inhibition and endotoxin-induced fever were used to investigate the effects of L-CIT on body temperature and inflammatory responses. In experiment 1, NW-nitro-L-arginine methyl ester (L-NAME, 150 mg/kg BW), was i. p. injected into chicks fed with basal (CON) or L-CIT diets for 14 days. In experiment 2, Lipopolysaccharide (LPS, 2 mg/kg BW) was i. p. injected following 21d feeding with CON or L-CIT diets. In experiment 3, chickens were injected with either L-NAME, LPS, or L-NAME + LPS following 26 days feeding with CON or L-CIT diets. The rectal (RT), ear (ET), and core body temperature (CBT) of chickens were examined. Results showed that L-NAME effectively decreased the RT, ET, CBT, and plasma NO concentration. In contrast, LPS increased NO levels and initiated hyperthermia by increasing RT, ET, CBT, and PGE2 levels. L-CIT diet reduced the mean CBT in experiment 1 and diminished the NO level, PGE2 level, and mean RT in experiment 3. Co-administration of L-CIT + LPS upregulated IL-6 expression, whereas, LPS injection alone induced IL-10, IL-1ß, and TLR4 gene expressions. Therefore, this study reveals that L-CIT-induced hypothermia was related to NO inhibition and a decrease in PGE2 concentration. Conversely, LPS induced hyperthermia was associated with an increase in both NO and PGE2 concentrations.

Effects of dietary L-citrulline supplementation on nitric oxide synthesis, immune responses and mitochondrial energetics of broilers during heat stress.

L-Citrulline is a non-protein amino acid that promotes arginine recycling and muscle protein synthesis. This study investigated whether L-citrulline can exert these functions in heat-stressed chickens. Arbor acre broilers were fed either basal diets (Control) or basal diets supplemented with 1% L-citrulline (L-Cit). At 28 d old, broilers were subjected to two environmental temperatures, 35 °C for 8 h/d (HS) or 24 °C for 24 h/d (TNZ) for 2 weeks. The experiment was designed as a 2 by 2 factorial arrangement. Results showed that HS increased the core body temperature (CBT) and rectal temperature of broilers compared to the TNZ condition. The CBT and mean CBT decreased by ∼0.5oC in TNZ + L-Cit broilers compared to the TNZ + Control group (P < 0.05). L-Cit supplementation at TNZ significantly (P < 0.05) lowered the plasma malondialdehyde content but this was increased during HS. Exposure to HS significantly (P < 0.05) elevated plasma malondialdehyde compared to TNZ condition. Plasma immunoglobulin A, G, and M were increased (P < 0.05) by TNZ + L-Cit compared to the TNZ + Control group. Plasma nitric oxide and endothelial nitric oxide synthase (NOS) activity was increased during HS, whereas the total and inducible NOS enzymes were decreased. In addition, L-Cit supplementation increased both the inducible and endothelial NOS isoforms (P < 0.05). The mRNA expression of peroxisome proliferator-activated receptor γ coactivator 1-α, avian uncoupling protein, cytochrome C oxidase subunit 3, and ATP synthase F1 subunit beta (ATP5ß) in the breast muscle were downregulated (P < 0.05) during HS. However, L-Cit supplementation upregulated the mitochondrial transcription factor A and during HS, L-Cit increased ATP5ß expression similar to TNZ housed broilers. Therefore, this study demonstrates that dietary L-Cit can lower the body temperature, decrease lipid peroxidation and promote the immune status of broilers under thermoneutrality. Also, L-Cit would act to promote muscle ATP generation during heat stress in broilers.

Dusk feeding in laying hens is shifted by light program via involvement of clock genes.

Dusk feeding is practised probably to satisfy the energy requirement during night. However, little is known on the changes with clock gene expressions during this feeding behaviour. In our present study, the linkage of clock gene expressions and feeding behaviour in dusk feeding was investigated in laying hens under two lighting programs: the conventional lighting program (Control) with a light period from 05:00 AM to 21:00 PM and a dark period from 21:00 PM to 05:00 AM; or the shifted lighting program group (SLP) with a light period from 02:00 AM to 18:00 PM and a dark period from 18:00 PM to 02:00 AM. The gene expression-related appetite and circadian rhythm were investigated in hypothalamus and proventriculus at 1, 3 and 5 h before scotophase. The results demonstrated that dusk feeding was synchronously shifted with altered lighting program, dusk feeding was observed from 5 h before scotophase in both groups. The expressions of anorexigenic gene proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) were downregulated (p < 0.05) during dusk feeding and changed in pace with lighting program. The expressions of clock gene period 2 (Per2) and cryptochrome 1 (Cry1) in hypothalamus were downregulated (p < 0.05) during dusk feeding and shifted by lighting program. In the proventriculus, ghrelin expression was decreased (p < 0.05) during dusk feeding by lighting program. In conclusion, the expressions of clock genes Per2 and Cry1 are linked with the downregulated expressions of anorexigenic genes, POMC and CART, and in turn the augmented feed intake at dusk.

Ghrelin serves as a signal of energy utilization and is involved in maintaining energy homeostasis in broilers.

Ghrelin, one of the most important appetite regulating peptides, is involved in the regulation of energy homeostasis. The anorexia effect of ghrelin in chickens is contrary to that of ghrelin in mammals. In the present study, the effects of feeding status and dietary energy level on plasma total ghrelin levels and expression were studied in broilers. The gene expression of ghrelin and its receptor GHS-R1a were measured in the hypothalamus, proventriculus, duodenum, liver, and abdominal fat pad. The results showed that ghrelin mRNA and GHS-R1a mRNA are moderately expressed in liver and abdominal fat. Ghrelin secretion was increased by fasting and refeeding. The gene expression of ghrelin and GHS-R1a in the hypothalamus, proventriculus, liver, and abdominal fat pad were changed by feeding status and dietary energy level. The results suggest that ghrelin is a signal of energy utilization in chickens. The abundant expression of ghrelin and GHS-R1a in liver and abdominal fat pad may be associated with energy balance.

Dexamethasone and insulin stimulate ghrelin secretion of broilers in a different way.

Ghrelin is one of the most important appetite regulating peptides, involved in the regulation of energy homeostasis. The role of ghrelin on the appetite and fat metabolism in chickens is different from that of ghrelin in mammals. Glucocorticoids and insulin are important hormones and work differently in energy regulation of body. In this study, the effects of dexamethasone (DEX, 2.0 mg/kg BW), subcutaneous insulin injection (40 µg/kg BW), and glucose load on ghrelin secretion and expression were determined in broilers. DEX treatment increased circulating ghrelin concentration in broiler fed with either a low-energy diet (11.05 MJ/kg of metabolizable energy) or a high-energy diet (14.44 MJ/kg of metabolizable energy). The expression levels of ghrelin were increased while both ghrelin and its receptor GHS-R1a expression levels were stimulated by DEX. A single subcutaneous insulin injection (40 µg/kg BW) or oral glucose infusion (2 g/kg BW) rise circulating ghrelin level. Ghrelin expression in the proventriculus was increased by insulin treatment but unchanged by glucose load. DEX had no detectable influence on ghrelin and GHS-R1a expression in the hypohtalamus, whereas insulin suppressed their expression. In conclusion, both insulin and glucocorticoid stimulate ghrelin secretion in chickens, in contrast to mammals. Glucocorticoids evoke peripheral ghrelin/GHS-R1a system while insulin increases peripheral ghrelin expression and suppress the activation of central ghrelin/GHS-R1a system. The result suggests that ghrelin involved in the modulating network of energy homeostasis in concert with glucocorticoids and insulin.

Glucocorticoids induced high fat diet preference via activating hypothalamic AMPK signaling in chicks.

Glucocorticoids (GCs) stimulate appetite, contributing to enhanced fat deposition. Our present study was conducted to determine whether GCs could evoke an appetite specifically for fat-rich diets in chicks. Chicks were subjected to a subcutaneous injection of corticosterone (CORT, 2mg/kg body weight/day) or corn oil (control), and food preference was tested. The results showed that CORT-chicks consumed more high-fat diet (HFD) compared with controls. In HFD-fed chicks, hypothalamic phosphorylated AMP-activated protein kinase α (AMPKα) and neuropeptide Y (NPY) mRNA levels were increased by CORT treatment. Activating AMPK with 5-aminoimidazole-4-carboxamide-1-ß-d-ribofuranoside, an AMPK activator, via intracerebroventricular injection further enhanced the CORT-induced HFD consumption and concurrently up-regulated NPY mRNA levels and phosphorylated AMPKα and acetyl-coenzyme A carboxylase levels. The dramatic increase in HFD consumption and upregulation of NPY mRNA levels and phospho-AMPKα levels induced by peripheral CORT injection was not altered by intracerebroventricular infusion of compound C (4-16µg), an AMPK inhibitor. In conclusion, CORT challenge caused a HFD preference by enhancing the AMPK pathway in the hypothalamus.

Peripheral Insulin Doesn't Alter Appetite of Broiler Chicks.

An experiment was conducted to investigate the effect of peripheral insulin treatment on appetite in chicks. Six-d-age chicks with ad libitum feeding or fasting for 3 h before injection received a subcutaneous injection of 0, 1, 3, 5, 10, or 20 IU of insulin or vehicle (saline). The results showed peripheral insulin treatment (1 to 20 IU) did not alter significantly the feed intake in chicks under either ad libitum feeding or fasting conditions within 4 h (p>0.05). Compared with the control, plasma glucose concentration was significantly decreased after insulin treatment of 3, 5, 10, and 20 IU for 4 h in chicks with ad libitum feeding (p<0.05). In fasted chicks, 10 and 20 IU insulin treatments significantly decreased the plasma glucose level for 4 h (p<0.05). Peripheral insulin treatment of 10 IU for 2 or 4 h did not significantly affect the hypothalamic genes expression of neuropeptide Y, proopiomelanocortin, corticotropin-releasing factor and insulin receptors (p>0.05). All results suggest peripheral administration of insulin has no effect on appetite in chicks.

Glucocorticoids retard skeletal muscle development and myoblast protein synthesis through a mechanistic target of rapamycin (mTOR)-signaling pathway in broilers (Gallus gallus domesticus).

Glucocorticoids exert a well-known catabolic protein action on skeletal muscle. The mechanistic target of rapamycin (mTOR) signaling pathway acts as a central regulator of protein metabolism. Whether glucocorticoids regulate protein synthesis through the mTOR pathway in skeletal muscle of chickens remains unknown. This study was performed to characterize the effect of glucocorticoids on the mTOR pathway in skeletal muscle development in chickens, and on protein synthesis in cultured embryonic myoblasts. Male 29-d-old chickens were given a dexamethasone injection (2 mg/kg) twice per day for 4 d (n = 16). Chicken embryonic myoblasts were exposed to dexamethasone for 24 h (100 µmol/L, n = 4 cultures). The interaction between dexamethasone and leucine was also investigated. ANOVA and Duncan's multiple test were used to analyze the effects of the dexamethasone and leucine treatments. The results showed that dexamethasone decreased body weight gain, body weight, and feed efficiency. Protein synthesis was inhibited by in vitro dexamethasone exposure. Phosphorylation of mTOR and ribosomal protein S6 protein kinase (p70S6K) were inhibited by dexamethasone, suggesting the mTOR pathway may be involved in dexamethasone-regulated muscle protein synthesis. Phosphorylation of AMP-activated protein kinase (AMPK) was not altered in vitro but was reduced in vivo by dexamethasone. These results imply that the mTOR and AMPK pathways are both involved in retarding muscle development and protein synthesis by glucocorticoids, but the mTOR pathway is a critical point linking glucocorticoid and protein synthesis. Leucine, at least partially, inhibited the effects of dexamethasone on protein synthesis via the mTOR pathway.

Effects of heat stress on the gene expression of nutrient transporters in the jejunum of broiler chickens (Gallus gallus domesticus).

In broiler chickens, heat stress disrupts nutrient digestion and absorption. However, the underlying molecular mechanism is not clearly understood. Hence, to investigate the effects of high ambient temperatures on the expression levels of nutrient transporters in the jejunum of broiler chickens, seventy-two 35-day-old male broiler chickens with similar body weights were randomly allocated into two groups: control (24 ± 1 °C) and heat-stressed (32 ± 1 °C). The chickens in the heat-stressed group were exposed to 10 h of heat daily from 08:00 to 18:00 and then raised at 24 ± 1 °C. The rectal temperature and feed intake of the chickens were recorded daily. After 7 days, nine chickens per group were sacrificed by exsanguination, and the jejunum was collected. The results show that heat exposure significantly decreased the feed intake and increased the rectal temperature of the broiler chickens. The plasma concentrations of uric acid and triglyceride significantly increased and decreased, respectively, in the heat-stressed group. No significant differences in the levels of plasma glucose, total amino acids, and very low-density lipoprotein were observed between the heat-stressed and control groups. However, the plasma concentration of glucose tended to be higher (P = 0.09) in the heat-stressed group than in the control group. Heat exposure did not significantly affect the mRNA levels of Na(+)-dependent glucose transporter 1 and amino acid transporters y + LAT1, CAT1, r-BAT, and PePT-1. However, the expression levels of GLUT-2, FABP1, and CD36 were significantly decreased by heat exposure. The results of this study provide new insights into the mechanisms by which heat stress affects nutrient absorption in broiler chickens. Our findings suggest that periodic heat exposure might alter the jejunal glucose and lipid transport rather than amino acid transport. However, intestinal epithelial damage and cell loss should be considered when interpreting the effects of heat stress on the expression of intestinal transporters.

Effect of energy level of pullet diet and age on laying performance and expression of hypothalamus-pituitary-gonadal related genes in laying hens.

Dietary energy density influences feed intake (FI) and development of layer-type pullets. A total of 384 nine-wk-old Hy-Line Brown pullets were randomly assigned to one of 3 dietary treatments: fed a diet with 2,600, 2,750, and 2,900 Kcal metabolizable energy/kg (ME/kg) from 10 to 21 wk of age. The results showed that the 2,900 and 2,600 ME groups had lower feed and ME intake (P < 0.01) from 10 to 21 wk of age. The 2,600 ME pullets had heavier body weight (BW) and longer shank length (P < 0.05) at 21 wk of age than the 2,750 ME group. The eggshell percentage was increased by the 2,600 and 2,900 kcal/kg treatments (P = 0.002). Serum concentration of 17-ß-estradiol (E2), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) decreased at 70 wk of age (P < 0.05). Pullet diet and its interaction with age had a significant influence (P < 0.001) on the expression of gonadotropin-releasing hormone 1 (GnRH-1) and gonadotropin-inhibitory hormone (GnIH) in the hypothalamus and of gonadotropin releasing hormone 1 receptor (GnRH-1R) and gonadotropin-inhibitory hormone receptor (GnIHR) in the pituitary. In the hypothalamus, GnRH-1 expression increased from 9 to 40 wk of age and then decreased; however, GnIH expression was highest at 70 wk of age. Follicle-stimulating hormone receptor (FSHR) expression increased (P < 0.001) at wk 40 and decreased at wk 70 compared to wk 21 at various follicular stages. In conclusion, the energy level of pullet diet had no unfavorable influence on feed intake, laying rate, egg mass, and FCR, whereas change egg weight and mortality during the laying period from 21 to 70 wk of age. during the laying period. These results suggest that pullet dietary energy can activate the expression of genes related to reproduction in the hypothalamus, whereas it plays a minor role in the regulation of genes in the pituitary and ovary. Age-induced gene expression in the hypothalamus-pituitary-gonadal (HPG) axis is associated with laying performance in hens.

Allicin Promotes Glucose Uptake by Activating AMPK through CSE/H2S-Induced S-Sulfhydration in a Muscle-Fiber Dependent Way in Broiler Chickens.

SCOPE: Allicin, a product of enzymatic reaction when garlic is injured, plays an important role in maintaining glucose homeostasis in mammals. However, the effect of allicin on glucose homeostasis in the state of insulin resistance remains to be elucidated. This study investigates the effect of allicin on glucose metabolism using different muscle fibers in a chicken model. METHODS AND RESULTS: Day-old male Arbor Acres broilers are randomly divided into three groups and fed a basal diet supplemented with 0, 150, or 300 mg kg-1 allicin for 42 days. Results show that allicin improves the zootechnical performance of broilers at the finishing stage. The glucose loading test (2 g kg-1 body mass) indicates the regulatory role of allicin on glucose homeostasis. In vitro results demonstrate allicin increases glutathione (GSH) level and the expression of cystathionine γ lyase (CSE), leading to endogenous hydrogen sulfide (H2S) production in M. pectoralis major (PM) muscle-derived myotubes. Allicin stimulates adenosine monophosphate-activated protein kinase (AMPK) S-sulfhydration and AMPK phosphorylation to promote glucose uptake, which is suppressed in the presence of d,l-propargylglycine (PAG, a CSE inhibitor). CONCLUSION: This study demonstrates that allicin induces AMPK S-sulfhydration and AMPK phosphorylation to promote glucose uptake via the CSE/H2S system in a muscle fiber-dependent manner.

Prevotella and succinate treatments altered gut microbiota, increased laying performance, and suppressed hepatic lipid accumulation in laying hens.

BACKGROUND: This work aimed to investigate the potential benefits of administering Prevotella and its primary metabolite succinate on performance, hepatic lipid accumulation and gut microbiota in laying hens. RESULTS: One hundred and fifty 58-week-old Hyline Brown laying hens, with laying rate below 80% and plasma triglyceride (TG) exceeding 5 mmol/L, were used in this study. The hens were randomly allocated into 5 groups and subjected to one of the following treatments: fed with a basal diet (negative control, NC), oral gavage of 3 mL/hen saline every other day (positive control, PC), gavage of 3 mL/hen Prevotella melaninogenica (107 CFU/mL, PM) or 3 mL/hen Prevotella copri (107 CFU/mL, P. copri) every other day, and basal diet supplemented with 0.25% sodium succinate (Succinate). The results showed that PM and P. copri treatments significantly improved laying rate compared to the PC (P < 0.05). The amount of lipid droplet was notably decreased by PM, P. copri, and Succinate treatments at week 4 and decreased by P. copri at week 8 (P < 0.05). Correspondingly, the plasma TG level in Succinate group was lower than that of PC (P < 0.05). Hepatic TG content, however, was not significantly influenced at week 4 and 8 (P > 0.05). PM treatment increased (P < 0.05) the mRNA levels of genes PGC-1ß and APB-5B at week 4, and ACC and CPT-1 at week 8. The results indicated enhanced antioxidant activities at week 8, as evidenced by reduced hepatic malondialdehyde (MDA) level and improved antioxidant enzymes activities in PM and Succinate groups (P < 0.05). Supplementing with Prevotella or succinate can alter the cecal microbiota. Specifically, the abundance of Prevotella in the Succinate group was significantly higher than that in the other 4 groups at the family and genus levels (P < 0.05). CONCLUSIONS: Oral intake of Prevotella and dietary supplementation of succinate can ameliorate lipid metabolism of laying hens. The beneficial effect of Prevotella is consistent across different species. The finding highlights that succinate, the primary metabolite of Prevotella, represents a more feasible feed additive for alleviating fatty liver in laying hens.

An enhancement algorithm for head characteristics of caged chickens detection based on cyclic consistent migration neural network.

The enclosed multistory poultry housing is a type of poultry enclosure widely used in industrial caged chicken breeding. Accurate identification and detection of the comb and eyes of caged chickens in poultry farms using this type of enclosure can enhance managers' understanding of the health of caged chickens. However, the accuracy of image detection of caged chickens will be affected by the enclosure's entrance, which will reduce the precision. Therefore, this paper proposes a cage-gate removal algorithm based on big data and deep learning Cyclic Consistent Migration Neural Network (CCMNN). The method achieves automatic elimination and restoration of some key information in the image through the CCMNN network. The Structural Similarity Index Measure (SSIM) between the recovered and original images on the test set is 91.14%. Peak signal-to-noise ratio (PSNR) is 25.34dB. To verify the practicability of the proposed method, the performance of the target detection algorithm is analyzed both before and after applying the CCMNN network in detecting the combs and eyes of caged chickens. Different YOLOv8 detection algorithms, including YOLOv8s, YOLOv8n, YOLOv8m, and YOLOv8x, were used to verify the algorithm proposed in this paper. The experimental results demonstrate that compared to images without CCMNN processing, the precision of comb detection of caged chickens is improved by 11, 11.3, 12.8, and 10.2%. Similarly, the precision of eye detection for caged chickens is improved by 2.4, 10.2, 6.8, and 9%. Therefore, more complete outline images of caged chickens can be obtained using this algorithm and the precision in detecting the comb and eyes of caged chickens can be enhanced. These advancements in the algorithm offer valuable insights for future poultry researchers aiming to deploy enhanced detection equipment, thereby contributing to the accurate assessment of poultry production and farm conditions.

Research Note: Effect of fasting time on the fasting heat production, blood metabolites, and body components of layer-type pullets.

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 4 groups of 4 chickens and placed in 4 respiratory chambers. Pullets had free access to feed and water. After 4-d acclimatization, feed was withdrawn, and chickens were measured for FHP for 3 consecutive days. In trial 2, twenty-four 40-day-old pullets were placed in 4 respiratory calorimetry chambers, with 6 pullets per chamber. After 4-d 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-wk-old layer-type pullets was 562.20 kJ/kg of BW0.75/d under a 10-h light and 14-h dark lighting regime.

Daily feeding frequency affects feed intake and body weight management of growing layers.

The objective of this study was to investigate the effect of feeding behavior on feed intake and body weight in growing layers and the underlying mechanisms, thereby providing a scientific foundation for optimal feeding practices in growing layers' management. A total of 144 Hy-line brown growing layers of 10 wk old and similar body weight, were divided into 3 treatment groups with different feeding frequency and equal cumulative daily feeding amount: the once-a-day feeding group (F1) was fed at 9:00 am every day, with feeding amount of 150 g/layer; the twice-a-day feeding group (F2) were fed at 9:00 am and 13:00 pm every day, with each feeding amount of 75 g/layer; the 4 times-a-day feeding group (F4) were fed at 9:00 am, 11:00 am, 13:00 pm, and 15:00 pm every day, with each feeding amount of 37.5 g/layer. Pre-experiment lasted for 1 wk and formal experiment lasted for 8 wk. The results indicated that the daily feed intake and body weight were decreased (P < 0.05) while feed conversion ratio was not affected (P > 0.05) as daily feeding times increased. The glandular stomach proportion was significantly increased in twice-a-day feeding group, while liver proportion and ileum length were significantly increased in 4 times-feeding group (P < 0.05). Additionally, 4 times-feeding daily resulted in a significant elevation of blood glucose levels, which may have suppressed feed intake (P < 0.05). In 4 times-feeding group, the plasma triglyceride levels increased as feeding times, accompanied by a notable up-regulation in the mRNA level of appetite-suppressing gene, hypothalamic pro-opiomelanocortin (POMC) and glandular stomach ghrelin. This modulation effectively suppressed the subsequent feed intake and body weight. Therefore, 4 times feeding daily is recommended in growing layers' management, because it reduced the feed cost without affecting the feed conversion efficiency.

Corticosterone regulation of ovarian follicular development is dependent on the energy status of laying hens.

Glucocorticoids participate in the arousal of stress responses and trigger physiological adjustments that shift energy away from reproduction toward survival. Ovarian follicular development in avians is accompanied by the supply of yolk precursors, which are mainly synthesized in the liver. Therefore, we hypothesized energy status and hepatic lipogenesis are involved in the induction of reproductive disorders by glucocorticoids in laying hens. The results show that corticosterone decreased the laying performance by suppressing follicular development in energy-deficit state, rather than in energy-sufficient state. In corticosterone-treated hens, the suppressed follicular development was associated with the reduced availability of yolk precursor, indicated by the plasma concentration of VLDL and vitellogenin and the decreased proportion of yolk-targeted VLDL (VLDLy). Corticosterone decreased the expression of apolipoprotein B and apolipoprotein VLDL-II in the liver. A drop in VLDL receptor content and an increase in the expression of tight junction proteins occludin and claudin1 were also observed in hierarchical follicles. The results suggest corticosterone-suppressed follicular development is energy dependent. The decreased apolipoprotein synthesis and VLDLy secretion by liver are responsible for the decreased availability of circulating yolk precursor, and the upregulation of occludin and claudin expression further prevents yolk deposition into oocytes.

Effects of in ovo feeding of chlorogenic acid on antioxidant capacity of postnatal broilers.

In this study, chlorogenic acid (CGA) was injected into the amniotic cavity of chicken embryos to study the effects of in ovo feeding of CGA on the antioxidant capacity of postnatal broilers. On the 17th day of embryonic age, a total of 300 healthy broiler fertile eggs with similar weights were randomly subjected to five groups as follows; in ovo injection with 0.5 ml CGA at 4 mg/egg (4CGA) or 7 mg/egg (7CGA) or 10 mg/egg (10CGA), or sham-injection with saline (positive control, PC) or no injection (negative control, NC). Each group had six replicates of ten embryos. Six healthy chicks with similar body weights hatched from each replicate were selected and reared until heat stress treatment (35°C ± 1°C, 8 h/d) at 28-42 days of age. The results showed that there was no significant difference in the hatching rate between the groups (p > 0.05). After heat stress treatment, 4CGA group showed an improved intestinal morphology which was demonstrated by a higher villus height in the duodenum and a higher villus height/crypt depth ratio in the jejunum, compared with the NC group (p < 0.05). The antioxidant capacity of chickens was improved by in ovo feeding of CGA since 4CGA decreased the plasma content of malondialdehyde (MDA) (p < 0.05), whereas, it increased the superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT) activities compared with NC group (p < 0.05). Also, the MDA content of the different injection groups had a quadratic effect, with the 4CGA group having the lowest MDA content (P quadratic < 0.05). In the duodenum, 4CGA injection significantly increased the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (H O -1), glutathione synthetase (GSS), and SOD1 compared to the NC and PC groups (p < 0.05). The mRNA expressions of glutathione reductase (GSR) and GPX7 were significantly increased in all CGA-treated groups compared with the PC group (p < 0.05), while the mRNA expression of CAT was significantly increased by 4CGA group than the NC group (p < 0.05). The mRNA expressions of epigenetic-related genes, ten eleven translocation 1 and 2 (Tet1 and Tet2), and DNA-methyltransferase 3 alpha (DNMT3A) in the duodenum of 4CGA injected group was significantly increased compared with the NC and PC groups (p < 0.05). The mRNA expressions of Nrf2, SOD1, and Tet2 showed a significant quadratic effects with the 4CGA group having the highest expression (P quadratic < 0.05). In conclusion, in ovo feeding of CGA alleviated heat stress-induced intestinal oxidative damage. Injection with CGA of 4 mg/egg is considered most effective due to its actions in improving intestinal antioxidant capacity, especially in the duodenum. The antioxidant effects of in ovo CGA on postnatal heat-stressed broilers may be related to its regulation of epigenetic mechanisms. Thus, this study provides technical knowledge to support the in ovo feeding of CGA to alleviate oxidative stress in postnatal heat-stressed broilers.