Effect of heat stress on the hypothalamic expression of water channel- and noncoding RNA biogenesis-related genes in modern broilers and their ancestor red jungle fowl.

Genetic selection for high growth rate has resulted in spectacular progress in feed efficiency in chickens. As feed intake and water consumption (WC) are associated and both are affected by environmental conditions, we evaluated WC and its hypothalamic regulation in three broiler-based research lines and their ancestor jungle fowl (JF) under heat stress (HS) conditions. Slow growing ACRB, moderate growing 95RB, fast growing MRB, and JF were exposed to daily chronic cyclic HS (36 °C, 9 h/d) or thermoneutral temperature (24 °C). HS increased WC in the MRB only. Arginine vasopressin (AVP) mRNA levels were decreased by HS in the MRB. Within the renin-angiotensin-aldosterone system (RAAS) system, renin expression was increased by HS in the JF, ACRB, and 95RB, while angiotensin I-converting enzyme (ACE), angiotensin II receptors (type 1, AT1, and type 2, AT2) were affected by line. The expression of aquaporin (AQP2, 7, 9, 10, 11, and 12) genes was upregulated by HS, whereas AQP4 and AQP5 expressions were influenced by line. miRNA processing components (Dicer1, Ago2, Drosha) were significantly different among the lines, but were unaffected by HS. In summary, this is the first report showing the effect of HS on hypothalamic water channel- and noncoding RNA biogenesis-related genes in modern chicken populations and their ancestor JF. These results provide a novel framework for future research to identify new molecular mechanisms and signatures involved in water homeostasis and adaptation to HS.

A review of heat stress in chickens. Part II: Insights into protein and energy utilization and feeding.

With the growing global demand for animal protein and rising temperatures caused by climate change, heat stress (HS) is one of the main emerging environmental challenges for the poultry industry. Commercially-reared birds are particularly sensitive to hot temperatures, so adopting production systems that mitigate the adverse effects of HS on bird performance is essential and requires a holistic approach. Feeding and nutrition can play important roles in limiting the heat load on birds; therefore, this review aims to describe the effects of HS on feed intake (FI) and nutrient digestibility and to highlight feeding strategies and nutritional solutions to potentially mitigate some of the deleterious effects of HS on broiler chickens. The reduction of FI is one of the main behavioral changes induced by hot temperatures as birds attempt to limit heat production associated with the digestion, absorption, and metabolism of nutrients. Although the intensity and length of the heat period influences the type and magnitude of responses, reduced FI explains most of the performance degradation observed in HS broilers, while reduced nutrient digestibility appears to only explain a small proportion of impaired feed efficiency following HS. Targeted feeding strategies, including feed restriction and withdrawal, dual feeding, and wet feeding, have showed some promising results under hot temperatures, but these can be difficult to implement in intensive rearing systems. Concerning diet composition, feeding increased nutrient and energy diets can potentially compensate for decreased FI during HS. Indeed, high energy and high crude protein diets have both been shown to improve bird performance under HS conditions. Specifically, positive results may be obtained with increased added fat concentrations since lipids have a lower thermogenic effect compared to proteins and carbohydrates. Moreover, increased supplementation of some essential amino acids can help support increased amino acid requirements for maintenance functions caused by HS. Further research to better characterize and advance these nutritional strategies will help establish economically viable solutions to enhance productivity, health, welfare, and meat quality of broilers facing HS.

Effects of heat stress on cyto(chemo)kine and inflammasome gene expression and mechanical properties in isolated red and white blood cells from 4 commercial broiler lines and their ancestor jungle fowl.

Commercial broilers have been selected for high growth rate and productivity; however, this has negatively impacted their susceptibility to heat stress (HS). Insight into the molecular mechanisms underlying this vulnerability can help design targeted strategies for improvement of HS tolerance. Red blood cells (RBC) and white blood cells (WBC) were isolated from red jungle fowl and 4 lines of commercial modern broilers. Lines A and B are considered standard-yielding lines, whereas Lines C and D are high-yielding. Cells were cultured at either 37°C or 45°C for 2 h to induce heat stress (HS). Gene expression of cytokines, chemokines, and inflammasome components were measured. Heat shock proteins 27 and 70 (HSPs) in RBC were significantly affected by line (P < 0.05), whereas HSP27 and 60 were affected by temperature (P < 0.05). In WBC, there was a significant line effect on HSP gene expression (P < 0.05), and a significant increase (P < 0.05) in HSP90 in Line D in HS compared to TN conditions. In RBC, there was a main effect of HS on TNFα, CCL4, and CCLL4 (P < 0.05). HS significantly increased IL-8L1 (>30-fold, P < 0.0001) in Line C. Inflammasome genes (NLRP3, NLRC5 and NLRC3) were significantly affected by the line studied (P < 0.05). In WBC, the effect of line was significant for all cytokines, chemokines, and inflammasome components studied (P < 0.05). To examine the mechanical properties of isolated RBC from the 4 commercial lines and jungle fowl, RBC were placed into nematic liquid crystals, where Lines B and D were the most strained, and Line A and the jungle fowl were the least strained. Together, these findings indicate not only the dynamic nature of circulating cells, but the differences in the stress and inflammatory response among commercially available lines and their common ancestor. These profiles have the potential to serve as a future marker for stress responses in broilers, though further study is warranted.

Effects of Herbal Adaptogen Feed-Additive on Growth Performance, Carcass Parameters, and Muscle Amino Acid Profile in Heat-Stressed Modern Broilers.

Heat stress has strong adverse effects on poultry production and, thereby, threats its sustainability, which energized scientists to search for innovative and effective solutions. Here, we undertook this study to evaluate the effects of in-feed herbal adaptogen (stress response modifier) supplementation on growth performances, meat quality, and breast amino acid profile in chronic cyclic heat-stressed broilers. Day-old male Cobb 500 chicks (n = 720) were randomly assigned, in environmental chambers (n = 12, 24 pens), to three diet-treatments: a three-phase corn-soybean based diet fed as such (Control, C), or supplemented with the herbal adaptogen at 500 g/1000 kg control diet (NR-PHY-500) or at 1 kg/1000 kg control diet (NR-PHY-1000). From d29 to d42, birds from 9 chambers were exposed to cyclic heat stress (HS, 35°C from 9:30 am-5:30 pm), however, the rest of the chamber were maintained at thermoneutral conditions (24°C, TN), which creates 4 experimental groups: C-TN, C-HS, NR-PHY-500HS, and NR-PHY-1000HS (6 pens/group, 168 birds/group). HS altered growth performance via depression of feed intake and body weight. Adaptogen supplementation stimulated feed intake and averaged 65.95 and 83.25 g better body weight and 5 and 10 points better FCR at low and high dose, respectively, compared to heat-stressed birds. This increase in body weight was mirrored in enhanced weights of body parts (breast, tender, wings, and legs). Adaptogen supplementation modulated also breast amino acid profile, pH, color, and quality. Together, these data suggested that adaptogen supplementation could be a promising solution to alleviate heat stress, however further in-depth investigation for its mode of action and its underlying mechanisms are warranted.

Neuropeptide Y and its receptors are expressed in chicken skeletal muscle and regulate mitochondrial function.

Neuropeptide Y (NPY) is a highly conserved 36-amino acid neurotransmitter, which is primarily expressed in the mammalian arcuate nucleus of the hypothalamus. It is a potent orexigenic neuropeptide, stimulating appetite and inducing feed intake in a variety of species. Recent research has shown that NPY and its receptors can be expressed by peripheral tissues, but their role is not yet well defined. Specifically, this information is particularly sparse in avian species. Therefore, the aim of this study was to determine the expression of NPY and its receptors, and determine their regulation by environmental and nutritional stressors, in the skeletal muscle of avian species using in vivo and in vitro approaches. Here, we show that NPY and its receptors are expressed in chicken breast and leg muscle as well as in quail myoblast (QM7) cell line. Intraperitoneal injection of recombinant NPY increased feed intake in 9-d old chicks and upregulated the expression of NPY and NPY receptors in breast and leg muscle, suggesting autocrine and/or paracrine roles for NPY. Additionally, NPY is able to modulate the mitochondrial network. In breast muscle, a low dose of NPY upregulated (P < 0.05) the expression of genes involved in ATP production (uncoupling protein, UCP; nuclear factor erythroid 2 like 2, NFE2L2) and dynamics (mitofusin 1, MFN1), while a high dose decreased (P < 0.05) markers of mitochondrial dynamics (mitofusin 2, MFN2; OPA1 mitochondrial dynamin like GTPase, OPA1) and increased (P < 0.05) genes involved in mitochondrial biogenesis (D-loop, peroxisome proliferator activated receptor gamma, PPARG). In leg muscle, NPY decreased (P < 0.05) markers of mitochondrial biogenesis and ATP synthesis (D-loop; peroxisome proliferator activated receptor alpha, PCG1A; peroxisome proliferator-activated receptor gamma, coactivator 1 beta, PPARGC1B; PPARG; NFE2L2). In QM7 cells, genes associated with mitochondrial biogenesis, dynamics, and ATP synthesis were all upregulated (P < 0.05), even though basal respiration and ATP production were decreased (P < 0.05) with NPY treatment as measured by XF Flux analysis. Together, these data show that the NPY system is expressed in avian skeletal muscle and plays a role in mitochondrial function.

Evaluation of Three Formulations of Essential Oils in Broiler Chickens under Cyclic Heat Stress.

The objective of the present research was to assess the dietary supplementation of three formulations of essential oils (EO) in chickens under heat stress (HS). Day-of-hatch Cobb 500 chicks (n = 500) were randomly distributed into four groups: 1. HS control + control diets; 2. HS + control diets supplemented with 37 ppm EO of Lippia origanoides (LO); 3. HS + control diets supplemented with 45 ppm LO + 45 ppm EO of Rosmarinus officinalis (RO) + 300 ppm red beetroot; 4. HS + 45 ppm LO + 45 ppm RO + 300 ppm natural betaine. Chickens that received the EO showed significant (p < 0.05) improvement on BW, BWG, FI, and FCR compared to control HS chickens. Average body core temperature in group 3 and group 4 was significantly (p < 0.05) reduced compared with the HS control group and group 2. Experimental groups showed a significant reduction in FITC-d at 42 days, a significant increase in SOD at both days but a significant reduction of IFN-γ and IgA compared with HS control (p < 0.05). Bone mineralization was significantly improved by EO treatments (p < 0.05). Together these data suggest that supplemental dietary EO may reduce the harmful effects of HS.

Phytogenic feed additives improve broiler feed efficiency via modulation of intermediary lipid and protein metabolism-related signaling pathways.

Diets enriched with phytogenic feed additives (PFA) such as AV/HGP/16 premix (AVHGP), Superliv concentrate premix (SCP), and bacteriostatic herbal growth promotor (BHGP) with essential oils have been shown to improve feed efficiency (FE) in broilers. This FE improvement was achieved via modulation of hypothalamic neuropeptides, which results despite feed intake reduction, in increased breast yield without changes in body weight compared to the control group. To gain further insights into the mode of action of these PFA, the present study aimed to determine the potential involvement of signaling pathways associated with lipid and protein metabolism. One day-old male Cobb 500 chicks were randomly assigned into 1 of 4 treatments, comprising 8 replicates per treatment in a completely randomized design. The dietary treatments included a basal diet (control) or 0.55 g/kg diet of AVHGP, SCP, or BHGP. The birds had ad libitum access to water and feed. On day 35, after blood sampling, the liver, abdominal adipose tissue (AT), and breast muscle samples were collected. The levels of phosphorylated mechanistic target of rapamycin (mTOR)Ser2481 as well as its levels of mRNA and those of its downstream mediator RPS6B1 were significantly upregulated in the muscle of the PFA-fed groups compared with the control group. In the liver, the phosphorylated levels of acetyl-CoA carboxylase alpha at Ser79, the rate-limiting enzyme in fat synthesis, was significantly induced in the PFA-fed groups compared with the control group, indicating a lower hepatic lipogenesis. The hepatic expression of hepatic triglyceride lipase (LIPC) and adipose triglyceride lipase (ATGL) was significantly upregulated in the AVHGP-fed group compared with the control group. These hepatic changes were accompanied by a significant downregulation of hepatic sterol regulatory element-binding protein cleavage-activating protein in all the PFA groups and an upregulation of peroxisome proliferator-activated receptor alpha and gamma in the SCP-fed compared with the control group. In the AT, the mRNA abundances of ATGL and LIPC were significantly increased in both SCP- and BHGP-fed birds compared with the control group. Together these data indicate that PFA improve FE via modulation of muscle mTOR pathway and hepatic lipolytic/lipogenic programs, thus, favoring muscle protein synthesis and lowering hepatic lipogenesis.

Research Note: Phytobiotics modulate the expression profile of circulating inflammasome and cyto(chemo)kine in whole blood of broilers exposed to cyclic heat stress.

Heat stress (HS) is a critical concern to the poultry industry as it affects both productivity and well-being. Various managerial and nutritional strategies have been proposed to mitigate the negative effects of HS in chickens, with plant-based additives showing promise. Recently, we reported the positive effect of a phytogenic feed additive (PFA) on growth performance in HS birds. Owing to the antioxidant nature of these compounds, we sought to further explore the effect of PFA on whole blood circulating chemokines, cytokines, and inflammasomes in HS broilers. Broilers (600 males, 1 d) were randomly assigned to 12 environmental chambers, subjected to 2 environmental conditions (12 h cyclic heat stress, HS, 35°C vs. thermoneutral condition [TN], 24°C) and fed 3 diets (control, PFA-C 250 ppm, PFA-C 400 ppm) in a 2 × 3 factorial design. After 21 d of cyclic HS, blood samples were collected for target gene expression analysis. HS upregulated the expression of superoxide dismutase 1 (SOD1) and downregulated glutathione peroxidase-3 (GPX-3), and there was diet × temperature interaction for SOD2, GPX-1, and GPX-3, where gene expression was increased by PFA-C250 during HS but was unchanged for PFA-C400. Plasma total antioxidant capacity (TAC) and malondialdehyde (MDA) content were increased by HS. Gene expression of interleukin-18 (IL-18) was decreased by HS, without further effect of PFA. HS increased tumor necrosis factor α (TNFα), but this effect was mitigated by PFA-C400. C-C motif chemokine ligands 4 and 20 (CCL4 and CCL20) showed a similar pattern to TNFα, with PFA-C400 ameliorating the negative effect of HS. The nucleotide-binding, leucine-rich repeat and pyrin domain containing 3 (NLRP3) inflammasome was decreased by HS and further lowered by PFA-C400, but the nucleotide-binding oligomerization domain, leucine-rich repeat, and CARD domain containing 3 (NLRC3) and nucleotide-binding, leucine-rich repeat containing X1 (NLRX1) inflammasomes were increased by PFA under TN conditions, with no effects of HS. Heat shock proteins (HSP) and heat shock factors (HSF) were unaffected by PFA or HS. Together these data indicate that gene expression of circulating inflammatory factors are dysregulated during HS, and supplemental dietary PFA may be protective.

Research Note: Dietary phytase reduces broiler woody breast severity via potential modulation of breast muscle fatty acid profiles.

Woody breast (WB) myopathy is a major concern and economic burden to the poultry industry, and for which, there is no effective solution because of its unknown etiology. In a previous study, we have shown that phytase (Quantum Blue, QB) reduces the WB severity by 5% via modulation of oxygen homeostasis-related pathways. As WB has been suggested to be associated with lipid dysmetabolism, we aimed to determine the effect of QB on WB and breast muscle fatty acid profile. Male broilers were subjected to 6 treatments (96 birds/treatment): a nutrient adequate control group (PC), the PC supplemented with 0.3% myo-inositol (PC + MI), a negative control (NC) deficient in available P and Ca by 0.15 and 0.16%, respectively, the NC fed with QB at 500 (NC+500 FTU), and 1,000 (NC+ 1,000 FTU) or 2,000 FTU/kg of feed (NC+2,000 FTU). Woody breast and white striping scores were recorded, and fatty acid profiles were determined using gas liquid chromatography. Woody breast-affected muscles exhibited a significant higher incidence of white striping as liquid chromatography analysis reveals an imbalance of fatty acid profile in the breast of WB-affected birds with a significant higher percent of saturated fatty acids (SFA, myristic [14:0], pentadecanoic [15:0], and margaric [17:0]) and monounsaturated fatty acids (myristoleic [14:1], palmitoleic [16:1c], 10-trans-heptadecenoic [17:1t], oleic [18:1c9], and vaccenic [18:1c11]), and lower content of polyunsaturated fatty acids (PUFA) and omega-3 (P < 0.05). Quantum Blue at high doses (1,000 and 2,000 FTU) significantly reduces the percent of SFA and increases that of PUFA compared with the control group. In conclusion, WB myopathy seemed to be associated with an imbalance of fatty acid profile, and QB ameliorates the severity of WB potentially via modulation of SFA and PUFA contents.

Monitoring Phytate Hydrolysis Using Serial Blood Sampling and Feather Myo-Inositol Levels in Broilers.

Phytate forms insoluble precipitates with various cations that are recalcitrant to digestion in poultry. Dietary supplementation with exogenous phytase has been shown to improve phytate solubility and digestibility and, in turn, improve animal growth performance. Although the kinetics of phytate hydrolysis by exogenous phytase are well described in vitro, the progression of the reaction in vivo is still not well defined. The aim of the present study was, therefore, to monitor the kinetic variation of myo-inositol (myo-Ins) levels in both circulation and feather following exogenous phytase supplementation. In experiment 1, 4 week-old male broilers were individually housed with ad libitum access to water and a standard commercial diet. Birds were maintained under environmental temperature of 24°C and 30% RH. Birds were cannulated in the cutaneous ulnar vein on the right wing and remained untouched for 3 days. On the day of the experiment, birds were randomly divided into three body weight-matched groups and fed either the control diet, the control diet-supplemented with myo-Ins or Ronozyme HiPhos (0.06%, DSM Nutritional Products, Switzerland) for 10 h. In the experiment 2, birds were fed only HiPhos for 30 h. Growing feathers and blood were collected at baseline and then every 2 h for 10 h (experiment 1) and 30 h (experiment 2) post-prandially. Plasma and feather myo-Ins levels were determined by UHPLC-MS/MS. The relative expression of inositol polyphosphate-1-phosphatase (INPP1), inositol hexakisphosphate kinase 1-3 (IP6K1-3), inositol-3-phosphate synthase (ISYNA), and multiple inositol-polyphosphate phosphatase 1 (MNPP1) genes in blood and feathers was determined by real-time qPCR using 2-ΔΔCt method. Plasma and feather myo-Ins levels were significantly increased by HiPhos at 6 h to 8 h post-prandial. The mRNA abundances of INPP1, IP6K1, and ISYNA in the circulation were significantly down regulated at all periods compared to the baseline levels. IP6K2, IP6K3, and MINPP1 gene expression, however, was up regulated at 8 h post-prandial and then returned to the baseline levels. In feathers, the expression of INPP1 was induced at 8 h post-prandial and remained higher compared to the baseline. The expression of IP6K2, IP6K3, and MINPP1 was down regulated during the first 10 h and then returned to baseline levels for the rest of the post-prandial period. Taken together, our data show that phytase modulates the expression of genes associated with myo-Ins metabolism and generates release of myo-Ins in both circulation and feather at 6-10 h post-feeding. Feather myo-Ins concentration could be used as a non-invasive method to monitor phytate hydrolysis in practice.

Water amino acid-chelated trace mineral supplementation decreases circulating and intestinal HSP70 and proinflammatory cytokine gene expression in heat-stressed broiler chickens.

Heat stress (HS) is a financial and physiological burden on the poultry industry and the mitigation of the adverse effects of HS is vital to poultry production sustainability. The purpose of this study was, therefore, to determine the effects of an amino acid-chelated trace mineral supplement on growth performance, stress and inflammatory markers, and meat quality in heat-stressed broilers. One day-old Cobb 500 male broilers (n = 480) were allocated into 12 environmental chambers (24 floor pens) and divided into two groups: one group supplemented with amino acid-chelated trace mineral in drinking water and one control group. On day 28, birds were subjected to chronic heat stress (HS, 2 wk, 35 °C and 20% to 30% RH) or maintained at thermoneutral condition (TN, 24 °C) in a 2 × 2 factorial design. Feed intake (FI), water consumption, and body weight were recorded. At day 42, serum fluorescein isothiocyanate dextran (FITC-D) levels, blood gas, electrolyte, and stress markers were measured. Jejunum samples were collected to measure gene expression of stress, inflammation, and tight junction proteins. The rest of the birds were processed to evaluate carcass traits. HS resulted in an increase in core body temperature, which increased water intake and decreased FI, body weight, and feed efficiency (P < 0.05). HS reduced carcass yield and the weight of all parts (P < 0.05). HS significantly increased levels of circulating corticosterone (CORT), heat shock protein 70 (HSP70), interleukin 18 (IL-18), tumor necrosis factor alpha, C-reactive protein, and nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing 3 expression. HS significantly increased serum FITC-D levels and the expression of HSP70 and IL-18 in the jejunum. Although it did not affect the growth performance, amino acid-chelated trace mineral supplementation reversed the effect of HS by reducing CORT and FITC-D levels and the expression of stress and proinflammatory cytokines in the circulation and the jejunum. However, it upregulated these parameters in birds maintained under TN conditions. Together, these data indicate that the amino acid-chelated trace mineral might alleviate stress and inflammation and improve gut integrity in heat-stressed but not thermoneutral broilers.

Phytogenic feed- and water-additives improve feed efficiency in broilers via modulation of (an)orexigenic hypothalamic neuropeptide expression.

Fueled by consumer preference for natural and antibiotic-free products, phytogenics have become the fastest growing segment of the animal feed additives. Yet, their modes of action are not fully understood. This study was undertaken to determine the effect of 5 phytogenics (3 feed- and 2 water-supplements) on the growth performance of commercial broilers, and their potential underlying molecular mechanisms. Day-old male Cobb 500 chicks (n = 576) were randomly assigned into 48 pens consisting of 6 treatments (Control; AVHGP; SCP; BHGP; AVSSL; SG) in a complete randomized design (12 birds/pen, 8 pens/treatment, 96 birds/treatment). Chicks had ad libitum access to feed and water. Individual body weight (BW) was recorded weekly and feed intake was measured daily. Core body temperatures were continuously recorded using thermo-loggers. At d 35, hypothalamic tissues were excised from the thermo-logger-equipped chickens (n = 8 birds/treatment) to determine the expression of feeding-related neuropeptides. Both feed (AVHGP, SCP, BHGP) and water-supplemented (AVSSL, SG) phytogenics significantly improved feed efficiency (FE) compared to the control birds. This higher FE was achieved via a reduction in core body temperature and improvement of market BW, without changes in feed intake in broilers supplemented with phytogenic water additives as compared to the control group. Broilers fed dietary phytogenics, however, attained higher feed efficiency via a reduction in feed intake while maintaining similar BW as the control group. At the molecular levels, the effects of the phytogenic water additives seemed to be mediated by the activation of the hypothalamic AgRP-ORX-mTOR-S6k1 and inhibition of CRH pathways. The effect of the phytogenic feed additives appeared to be exerted through the activation of AdipoQ, STAT3, AMPK, and MC1R pathways. This is the first report describing the likely central mechanisms through which phytogenic additives improve the growth performance and feed efficiency in broilers.

Quantum Blue Reduces the Severity of Woody Breast Myopathy via Modulation of Oxygen Homeostasis-Related Genes in Broiler Chickens.

The incidence of woody breast (WB) is increasing on a global scale representing a significant welfare problem and economic burden to the poultry industry and for which there is no effective treatment due to its unknown etiology. In this study, using diffuse reflectance spectroscopy (DRS) coupled with iSTAT portable clinical analyzer, we provide evidence that the circulatory- and breast muscle-oxygen homeostasis is dysregulated [low oxygen and hemoglobin (HB) levels] in chickens with WB myopathy compared to healthy counterparts. Molecular analysis showed that blood HB subunit Mu (HBM), Zeta (HBZ), and hephaestin (HEPH) expression were significantly down regulated; however, the expression of the subunit rho of HB beta (HBBR) was upregulated in chicken with WB compared to healthy counterparts. The breast muscle HBBR, HBE, HBZ, and hypoxia-inducible factor prolyl hydroxylase 2 (PHD2) mRNA abundances were significantly down regulated in WB-affected compared to normal birds. The expression of HIF-1α at mRNA and protein levels was significantly induced in breasts of WB-affected compared to unaffected birds confirming a local hypoxic status. The phosphorylated levels of the upstream mediators AKT at Ser473 site, mTOR at Ser2481 site, and PI3K P85 at Tyr458 site, as well as their mRNA levels were significantly increased in breasts of WB-affected birds. In attempt to identify a nutritional strategy to reduce WB incidence, male broiler chicks (Cobb 500, n = 576) were randomly distributed into 48 floor pens and subjected to six treatments (12 birds/pen; 8 pens/treatment): a nutrient adequate control group (PC), the PC supplemented with 0.3% myo-inositol (PC + MI), a negative control (NC) deficient in available P and Ca by 0.15 and 0.16%, respectively, the NC fed with quantum blue (QB) at 500 (NC + 500 FTU), 1,000 (NC + 1,000 FTU), or 2,000 FTU/kg of feed (NC + 2,000 FTU). Although QB-enriched diets did not affect growth performances (FCR and FE), it did reduce the severity of WB by 5% compared to the PC diet. This effect is mediated by reversing the expression profile of oxygen homeostasis-related genes; i.e., significant down regulation of HBBR and upregulation of HBM, HBZ, and HEPH in blood, as well as a significant upregulation of HBA1, HBBR, HBE, HBZ, and PHD2 in breast muscle compared to the positive control.

Effect of dietary arginine to lysine ratios on productive performance, meat quality, plasma and muscle metabolomics profile in fast-growing broiler chickens.

BACKGROUND: Due to the important functions of arginine in poultry, it should be questioned whether the currently adopted dietary Arg:Lys ratios are sufficient to meet the modern broiler requirement in arginine. The present study aimed, therefore, to evaluate the effects of the dietary supplementation of L-arginine in a commercial broiler diet on productive performance, breast meat quality attributes, incidence and severity of breast muscle myopathies and foot pad dermatitis (FPD), and plasma and muscle metabolomics profile in fast-growing broilers. RESULTS: A total of 1,170 1-day-old Ross 308 male chicks was divided into two experimental groups of 9 replicates each fed either a commercial basal diet (CON, digestible Arg:Lys ratio of 1.05, 1.05, 1.06 and 1.07 in each feeding phase, respectively) or the same basal diet supplemented on-top with crystalline L-arginine (ARG, digestible Arg:Lys ratio of 1.15, 1.15, 1.16 and 1.17, respectively). Productive parameters were determined at the end of each feeding phase (12, 22, 33, 43 d). At slaughter (43 d), incidence and severity of FPD and breast myopathies were assessed, while plasma and breast muscle samples were collected and analyzed by proton nuclear magnetic resonance-spectroscopy. The dietary supplementation of arginine significantly reduced cumulative feed conversion ratio compared to the control diet at 12 d (1.352 vs. 1.401, P < 0.05), 22 d (1.398 vs. 1.420; P < 0.01) and 33 d (1.494 vs. 1.524; P < 0.05), and also tended to improve it in the overall period of trial (1.646 vs. 1.675; P = 0.09). Body weight was significantly increased in ARG compared to CON group at 33 d (1,884 vs. 1,829 g; P < 0.05). No significant effect was observed on meat quality attributes, breast myopathies and FPD occurrence. ARG birds showed significantly higher plasma concentration of arginine and leucine, and lower of acetoacetate, glutamate, adenosine and proline. Arginine and acetate concentrations were higher, whereas acetone and inosine levels were lower in the breast of ARG birds (P < 0.05). CONCLUSIONS: Taken together, these data showed that increased digestible Arg:Lys ratio had positive effects on feed efficiency in broiler chickens probably via modulation of metabolites that play key roles in energy and protein metabolism.

Effects of phytogenic additives on meat quality traits in broiler chickens1.

Phytogenics have been reported to improve growth performances in farm animals and are thereby considered as potential key solutions for antibiotic-free livestock nutrition. Yet, their effects on meat quality are still not well defined; therefore, the aim of this study was to determine the effects of 5 experimental phytogenic additives (3 dietary and 2 water supplements) on growth and meat quality in broilers. One-day-old broiler chicks (n = 576) were assigned to 48 floor pens and divided into 6 treatments (Control, AV/HGP/16 premix [AVHGP], Superliv concentrate premix [SCP], bacteriostatic herbal growth promotor [BHGP], AV/SSL/12 [AVSSL], and Superliv Gold [SG]) in a complete randomized design (8 pens/treatment with 12 birds/pen, and 96 birds/group). Feed intake and BW were recorded, and birds were processed at 42 d to evaluate carcass traits. Breast muscle tissues were excised to determine stress- and antioxidant-related genes expression. Both AVSSL- and SG-treated broilers produced heavier (P < 0.05) slaughter weights compared with the control-fed broilers, whereas AVSSL supplementation decreased (P < 0.05) fat pad size and increased (P < 0.05) breast weights compared with the control-fed broilers. Although pH and a* values remained unchanged, L* was decreased (P < 0.05) in all treatment and b* was reduced (P < 0.05) in SG when compared with controls. The trained sensory panelists detected more (P < 0.05) green herb flavor in the breast meat from AVHGP than SCP, SG, and control birds. The expression of superoxide dismutase 2, extracellular signal-regulated kinase 1/2, and JNK gene was upregulated in AVHGP and BHGP compared with the control (P < 0.05). Together, these results indicated that phytogenic additives might improve meat quality of broilers through modulation of stress- and antioxidant-related pathways.

Effect of Morinda citrifolia (Noni)-Enriched Diet on Hepatic Heat Shock Protein and Lipid Metabolism-Related Genes in Heat Stressed Broiler Chickens.

Heat stress (HS) has been reported to alter fat deposition in broilers, however the underlying molecular mechanisms are not well-defined. The objectives of the current study were, therefore: (1) to determine the effects of acute (2 h) and chronic (3 weeks) HS on the expression of key molecular signatures involved in hepatic lipogenic and lipolytic programs, and (2) to assess if diet supplementation with dried Noni medicinal plant (0.2% of the diet) modulates these effects. Broilers (480 males, 1 d) were randomly assigned to 12 environmental chambers, subjected to two environmental conditions (heat stress, HS, 35°C vs. thermoneutral condition, TN, 24°C) and fed two diets (control vs. Noni) in a 2 × 2 factorial design. Feed intake and body weights were recorded, and blood and liver samples were collected at 2 h and 3 weeks post-heat exposure. HS depressed feed intake, reduced body weight, and up regulated the hepatic expression of heat shock protein HSP60, HSP70, HSP90 as well as key lipogenic proteins (fatty acid synthase, FASN; acetyl co-A carboxylase alpha, ACCα and ATP citrate lyase, ACLY). HS down regulated the hepatic expression of lipoprotein lipase (LPL) and hepatic triacylglycerol lipase (LIPC), but up-regulated ATGL. Although it did not affect growth performance, Noni supplementation regulated the hepatic expression of lipogenic proteins in a time- and gene-specific manner. Prior to HS, Noni increased ACLY and FASN in the acute and chronic experimental conditions, respectively. During acute HS, Noni increased ACCα, but reduced FASN and ACLY expression. Under chronic HS, Noni up regulated ACCα and FASN but it down regulated ACLY. In vitro studies, using chicken hepatocyte cell lines, showed that HS down-regulated the expression of ACCα, FASN, and ACLY. Treatment with quercetin, one bioactive ingredient in Noni, up-regulated the expression of ACCα, FASN, and ACLY under TN conditions, but it appeared to down-regulate ACCα and increase ACLY levels under HS exposure. In conclusion, our findings indicate that HS induces hepatic lipogenesis in chickens and this effect is probably mediated via HSPs. The modulation of hepatic HSP expression suggest also that Noni might be involved in modulating the stress response in chicken liver.

Noni (Morinda citrifolia) Modulates the Hypothalamic Expression of Stress- and Metabolic-Related Genes in Broilers Exposed to Acute Heat Stress.

Heat stress (HS) adversely affects growth performance and inflicts heavy economic losses to the poultry industry. There is, therefore, a critical need to identify new alternative strategies to alleviate the negative effects induced by HS. The tropic medicinal plant, Morinda citrifolia (Noni), is being used in livestock nutrition, however the literature is limited and conflicting for its impact on growth performance. The present study aimed to determine the effect of Noni on feeding and drinking behavior as well as on the hypothalamic expression of stress- and metabolic-related genes in broiler chickens exposed to acute HS. A total of 480 1 day-old male broiler chicks were randomly assigned to 12 controlled environmental chambers. Birds were subjected to two environmental conditions (TN, 25°C vs. HS, 35°C for 2 h) and fed two diets (control vs. 0.2% Noni) in a 2 × 2 factorial design. Feed intake and core body temperature (BT) were recorded during HS period. Blood was collected and hypothalamic tissues were harvested for target gene and protein analyses. Acute HS-broilers exhibited higher BT (~1°C), spent less time eating with a significant decrease in feed intake, and spent more time drinking along with higher drinking frequency compared to those maintained under TN conditions. Although Noni supplementation did not improve feed intake, it significantly delayed (~30 min) and reduced the BT-induced by HS. At molecular levels and under HS conditions, Noni supplementation down regulated the hypothalamic expression of HSP90 and its related transcription factors HSF1, 2, and 4, increased orexin mRNA levels, and decreased the phosphorylation levels of AMPKα1/2Thr172 and mTORSer2481. Together, these data indicated that Noni supplementation might modulate HS response in broilers through central orexin-AMPK-mTOR pathways.

Leucine supplementation at the onset of high-fat feeding does not prevent weight gain or improve glycemic regulation in male Sprague-Dawley rats

Obesity is a major public health concern and it is essential to identify effective treatments and preventative strategies to stop continued increases in obesity rates. The potential functional roles of the branched chain amino acid leucine make this amino acid an attractive candidate for the treatment and/or prevention of obesity. The objective of this study was to determine if long-term leucine supplementation could prevent the development of obesity and reduce the risk factors for chronic disease in rats fed a high-fat (60 % fat) diet. Male Sprague-Dawley rats (n = 30 per dietary treatment) were meal-fed (3 meals/day) either a control, low-fat diet (LF), control + leucine (LFL), high-fat (HF), or high-fat + leucine (HFL) for 42 days. On day 42, rats were sacrificed at 0, 30, or 90 min postprandial. Animals fed the HF and HFL diets had higher (P < 0.05) final body weights and weight gain compared to animals fed the LF and LFL diets. Leucine supplementation increased epididymal fat mass (P < 0.05) and decreased muscle mass (P < 0.05). There was no effect of leucine supplementation on postprandial glucose or insulin response. However, there was a significant effect (P < 0.05) of diet and time on free fatty acid concentrations. There was no effect of leucine on muscle markers of protein synthesis (4E-BP1, p70S6K) or energy metabolism (Akt, AMPK). Leucine supplementation decreased (P < 0.05) PGC1α expression and increased (P < 0.05) PPARγ expression in skeletal muscle. In conclusion, long-term leucine supplementation does not prevent weight gain, improve body composition, or improve glycemic control in rats fed a high-fat diet (AU)

No disponible

Leucine supplementation at the onset of high-fat feeding does not prevent weight gain or improve glycemic regulation in male Sprague-Dawley rats.

Obesity is a major public health concern and it is essential to identify effective treatments and preventative strategies to stop continued increases in obesity rates. The potential functional roles of the branched chain amino acid leucine make this amino acid an attractive candidate for the treatment and/or prevention of obesity. The objective of this study was to determine if long-term leucine supplementation could prevent the development of obesity and reduce the risk factors for chronic disease in rats fed a high-fat (60 % fat) diet. Male Sprague-Dawley rats (n = 30 per dietary treatment) were meal-fed (3 meals/day) either a control, low-fat diet (LF), control + leucine (LFL), high-fat (HF), or high-fat + leucine (HFL) for 42 days. On day 42, rats were sacrificed at 0, 30, or 90 min postprandial. Animals fed the HF and HFL diets had higher (P < 0.05) final body weights and weight gain compared to animals fed the LF and LFL diets. Leucine supplementation increased epididymal fat mass (P < 0.05) and decreased muscle mass (P < 0.05). There was no effect of leucine supplementation on postprandial glucose or insulin response. However, there was a significant effect (P < 0.05) of diet and time on free fatty acid concentrations. There was no effect of leucine on muscle markers of protein synthesis (4E-BP1, p70S6K) or energy metabolism (Akt, AMPK). Leucine supplementation decreased (P < 0.05) PGC1α expression and increased (P < 0.05) PPARγ expression in skeletal muscle. In conclusion, long-term leucine supplementation does not prevent weight gain, improve body composition, or improve glycemic control in rats fed a high-fat diet.

Chenodeoxycholic acid reduces feed intake and modulates the expression of hypothalamic neuropeptides and hepatic lipogenic genes in broiler chickens.

Bile acids have recently become an emerging research hot spot in mammals due to their roles as metabolic regulators and molecular signatures controlling whole-body metabolic homeostasis. Such effects are still unknown in avian (non-mammalian) species. We, therefore, undertook this study to determine the effect of chenodeoxycholic acid (CDCA) on growth performance and on the expression of hypothalamic neuropeptides and hepatic lipogenic genes in broiler chickens. Chickens fed with diet-containing 0.1% or 0.5% CDCA for two weeks exhibited a significant and a dose dependent reduction of feed intake and body weight compared to the control (standard diet). These changes were accompanied with a significant decrease in plasma glucose levels at d10 and d15 post-treatment. At molecular levels, CDCA treatment significantly up-regulated the expression of feeding-related hypothalamic neuropeptides (NPY, AgRP, ORX, CRH, Ghrl, and MC1R) and down-regulated the hypothalamic expression of SOCS3. CDCA treatment also decreased the mRNA levels of key hepatic lipogenic genes (FAS, ACCα, ME, ATPcl, and SCD-1) and their related transcription factors SREBP-1/2 and PPARα. In addition, CDCA reduced the hepatic expression of FXR and the adipokine, visfatin, and adiponectin genes compared to the control. Together, our data provide evidence that CDCA alters growth performances in broilers and modulates the expression of hypothalamic neuropeptides and hepatic lipogenic and adipocytokine genes.