Dataset Information

Effect of heat exposure on gene expression of feed intake regulatory peptides in laying hens.

ABSTRACT: The aim of this paper was to investigate the effect of heat stress on the regulation of appetite-associated genes in laying hens. Forty eight laying hens were randomly divided into two circumstances: high (31?±?1.5°C; relative humidity, 82.0?±?2.2%) or normal (20?±?2°C, control; relative humidity, 60.1?±?4.5%) ambient environment. Heat stress decreased body weight gain (P < 0.01), feed intake (P < 0.01), laying rate (P < 0.05), average egg mass (P < 0.01), egg production (P < 0.01), shell thickness (P < 0.01), and feed efficiency (P < 0.05). High ambient temperature decreased plasma uric acid (P < 0.05). Heat stress significantly increased mRNA levels of ghrelin and cocaine- and amphetamine-regulated transcript (P < 0.05) and decreased mRNA levels of cholecystokinin (P < 0.05) in the hypothalamus. Heat stress significantly increased (P < 0.05) mRNA levels of ghrelin in the glandular stomach and jejunum but significantly decreased (P < 0.05) mRNA levels of cholecystokinin in the duodenum and jejunum. In conclusion, heat stress plays a unique role in some special neuropeptides (e.g., ghrelin, cocaine- and amphetamine-regulated transcript, and cholecystokinin), which might participate in the regulation of feed intake in laying hens under high ambient temperature.

SUBMITTER: Song Z

PROVIDER: S-EPMC3352661 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Effect of heat exposure on gene expression of feed intake regulatory peptides in laying hens.

Song Zhigang Z Liu Lei L Sheikhahmadi Ardashir A Jiao Hongchao H Lin Hai H

Journal of biomedicine & biotechnology 20120507

The aim of this paper was to investigate the effect of heat stress on the regulation of appetite-associated genes in laying hens. Forty eight laying hens were randomly divided into two circumstances: high (31 ± 1.5°C; relative humidity, 82.0 ± 2.2%) or normal (20 ± 2°C, control; relative humidity, 60.1 ± 4.5%) ambient environment. Heat stress decreased body weight gain (P < 0.01), feed intake (P < 0.01), laying rate (P < 0.05), average egg mass (P < 0.01), egg production (P < 0.01), shell thickn ...[more]

PMID: 22619495

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Project description:Climate change is increasingly manifesting in temperate regions. Laying hens are highly sensitive to heat stress and mitigation strategies should be implemented to reduce the negative effects. The goal of this experiment was to evaluate the effects of betaine in drinking water (0.55 g/L) and 4 h feed restriction during peak heat stress on laying performance, egg quality, blood gas parameters, body temperature (Tb), and oxidative stress in 2 different breeds of laying hens. Therefore, 448 ISA Brown hens (25 wk) and 448 Lohmann LSL classic laying hens (26 wk) were housed in 128 cages (7 hens/cage). Thermoneutral (TN) data was collected for 21 d before cyclic heat stress (HS) (21d; 32 ± 2°C; 6 h daily). During HS, hens were divided into 4 treatments: 1) feed restriction (FR), 2) betaine supplementation in drinking water (BET), 3) feed restriction and betaine supplementation in drinking water (FR-BET), or 4) control (CON). The effects were evaluated after 1 wk of HS (acute heat stress; AHS) and 3 wk of HS (chronic heat stress; CHS). Laying rate and egg mass (EM) diminished during CHS but decreased more in white than brown hens (2.78% and 1.94%; -1.57% and -0.81%, respectively; P = 0.004) and remained unaltered by BET or FR. During AHS, average daily feed intake (ADFI) increased compared to TN, but the increase was higher in white than brown hens (6.36% and 2.62%, respectively; P = 0.001). Egg shell quality deteriorated during AHS and CHS, but was most affected in white hens, FR or BET did not impact this. Blood pCO2, HCO3- and base excess significantly decreased during AHS and CHS, but pH and iCa were unaltered. Blood glucose increased in white hens during AHS compared to TN (P < 0.001), while plasma malondialdehyde increased in brown hens (P < 0.001). Results indicated that laying hens experienced HS, but breed differences were observed and white hens were generally most affected. FR affected feed conversion ratio negatively during CHS. However, FR and BET could not improve laying performance, egg quality, Tb, or blood parameters during HS.

Project description:BackgroundHeat stress in laying hens negatively affects egg production and shell quality by disrupting the homeostasis of plasma calcium and phosphorus levels. Although the kidney plays an important role in calcium and phosphorus homeostasis, evidence regarding the effect of heat stress on renal injury in laying hens is yet to be elucidated. Therefore, the aim of this study was to evaluate the effects of chronic heat stress on renal damage in hens during laying periods.MethodsA total of 16 white-leghorn laying hens (32 weeks old) were randomly assigned to two groups (n = 8). One group was exposed to chronic heat stress (33 °C for 4 weeks), whereas the other group was maintained at 24 °C.ResultsChronic heat exposure significantly increased plasma creatinine and decreased plasma albumin levels (P < 0.05). Heat exposure also increased renal fibrosis and the transcription levels of fibrosis-related genes (COLA1A1, αSMA, and TGF-β) in the kidney. These results suggest that renal failure and fibrosis were induced by chronic heat exposure in laying hens. In addition, chronic heat exposure decreased ATP levels and mitochondrial DNA copy number (mtDNA-CN) in renal tissue, suggesting that renal mitochondrial dysfunction occurs under conditions of heat stress. Damaged mitochondria leak mtDNAs into the cytosol and mtDNA leakage may activate the cyclic GMP-AMP synthase (cGAS) stimulator of interferon genes (STING) signaling pathway. Our results showed that chronic heat exposure activated the cGAS-STING pathway as indicated by increased expression of MDA5, STING, IRF7, MAVS, and NF-κB levels. Furthermore, the expression of pro-inflammatory cytokines (IL-12) and chemokines (CCL4 and CCL20) was upregulated in heat-stressed hens.ConclusionsThese results suggest that chronic heat exposure induces renal fibrosis and mitochondrial damage in laying hens. Mitochondrial damage by heat stress may activate the mtDNA-cGAS-STING signaling and cause subsequent inflammation, which contributes to the progression of renal fibrosis and dysfunction.

Project description:Rice bran is a high-quality and renewable livestock feed material rich in nutrients and bioactive substances. To investigate the effects of dietary supplementation with fermented heat-treated rice bran on the performance, apparent digestibility of nutrients, cecal microbiota and metabolites in laying hens, a total of 128 18-week-old Hy-Line brown layers were randomly assigned to four treatment groups: 2.5% HRB (basal diet contained 2.5% heat-treated rice bran), 5.0% HRB (5.0% heat-treated rice bran), 2.5% FHRB (2.5% fermented heat-treated rice bran), 5.0% FHRB (5.0% fermented heat-treated rice bran). Results showed that FHRB supplementation significantly increased the average daily feed intake (ADFI) during 25-28 weeks, and improved apparent digestibility of dry matter (DM), crude protein (CP), ether extract (EE) and crude fiber (CF) in laying hens. Moreover, feeding 5.0% of HRB and FHRB resulted higher egg production (EP) and average egg weight (AEW) during the feeding period, and decreased the feed conversion ratio (FCR) during 21 to 28 weeks. The alpha and beta diversity indices indicated that FHRB altered the cecal microbiota. In particular, dietary supplementation with FHRB significantly increased the relative abundances of Lachnospira and Clostridium. Compared with the 2.5% level of supplementation, supplementing 5.0% HRB and 5.0% FHRB increased the relative abundances of Firmicutes, Ruminococcus and Peptococcus, and lowered the relative abundance of Actinobacteria. Furthermore, dietary FHRB supplementation significantly increased the concentration of short-chain fatty acids in cecum and changed the overall metabolome. The results of correlation analysis showed a close interaction between cecal microbiota, metabolites and apparent digestibility of nutrients. Taken together, we revealed that FHRB supplementation can induce characteristic structural and metabolic changes in the cecal microbiome, which could potentially promote nutrient digestion and absorption, and improve the production performance of laying hens.

Project description:To evaluate dietary soybean oil supplementation on production performance, egg quality, and keel bone health in laying hens. Two hundred and four laying hens at 20 weeks of age (WOA) were distributed into 12 cages containing 17 birds each. Birds were either fed a commercial diet (control group, CON) or a diet supplemented with 3% of soybean oil (SO group). Experiments lasted 17 weeks. Body weight, daily feed intake, production performance and egg quality were measured at 25, 29, 33, and 37 WOA. Birds were subsequently assessed for keel bone status by palpation, and keel was excised to measure bone length, microstructure, bone mineral density (BMD), elements contents, and the expression of osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B ligand (RANKL), collagen type II alpha 1 (COL2α1), periostin (POSTN), and sclerostin (SOST). The results showed that dietary SO supplementation did not affect production performance and egg quality (P > 0.05), but improved body weight of hens at 29 and 37 WOA (P < 0.05), and decreased daily feed intake at 33 and 37 WOA (P < 0.05). Incidence of keel bone damage (especially fracture) was higher in hens of SO group. Keel bone length in birds of SO group was significantly decreased compared to CON (P < 0.05). Keel bone of supplemented hens showed increased trabecular separation at 29 WOA and higher levels of V, Mn, Fe, Se, and Ba at 33 WOA (P < 0.05). Moreover, decreased BMD, trabecular number and thickness were observed in keel bone of laying hens receiving supplementation at 29 and 37 WOA (P < 0.05); decreased levels of Li, Ca, Hg, and TI at 33 WOA and trabecular thickness at 37 WOA (P < 0.05) were also identified. mRNA levels of SOST and RANKL and the ratio of RANKL/OPG mRNA levels were increased in birds fed a SO-supplemented diet (P < 0.05); COL2α1, OPG, and POSTN were downregulated at all sampling points (P < 0.05). Taken together, results indicate that feeding laying hens a diet supplemented with soybean oil can decrease daily feed intake and impair keel bone health but not influence production performance and egg quality.

Dataset Information

Effect of heat exposure on gene expression of feed intake regulatory peptides in laying hens.

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Effect of heat exposure on gene expression of feed intake regulatory peptides in laying hens.

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