Dietary creatine nitrate enhances muscle creatine loading and delays postmortem glycolysis of broilers that experienced preslaughter transport

This study investigated the attenuating effects of dietary creatine nitrate (CrN), a novel form of creatine, on energy expenditure and rapid glycolysis in pectoralis major (PM) muscle of broiler induced by preslaughter transport. A total of 288 Arbor Acres broilers (28 day old) were randomly assigned into five dietary treatments, including a basal diet or the basal diet supplemented with 600 mg/kg guanidinoacetic acid (GAA), 300, 600, or 900 mg/kg CrN for 14 d, respectively. On the day of transportation, the broilers from basal diet group were divided into two equal groups: one group was transported for 0.5 h (Control group) and the other group was transported for 3 h (T3h group). Meanwhile, the birds from GAA and CrN supplementation groups were transported for 3 h (identified as GAA600, CrN300, CrN600, and CrN900 group, respectively). The results demonstrated that dietary supplementation of GAA or CrN from 28 to 42 d of age did not significantly affect the growth performance, carcass traits, and textural characteristics (P > 0.05) in PM muscle of transported broilers. Compared with T3h group, GAA600, CrN600, and CrN900 groups increased the pH45min (P < 0.01), and CrN600, CrN900 groups decreased the cooking loss (P < 0.05) of PM muscle. Meanwhile, the muscle of GAA600, CrN600, and CrN900 groups showed a higher glycogen content (P < 0.01) and a lower lactic acid content (P < 0.01). GAA600 and all CrN treatments enhanced muscle Cr content and reduced AMP/ATP ratio (P < 0.01). In addition, GAA600 and all CrN treatments downregulated the relative mRNA expression levels of LKB1 and AMPKα2 (P < 0.001) and the protein expression of p-AMPKαThr172 compared with the T3h group (P < 0.01). All CrN treatments showed lower protein expression levels of LKB1 and p-LKB1Thr189 than those of the T3h group (P < 0.05). In summary, dietary supplementation with GAA and CrN enhanced the content of muscle creatine, and inhibited transport-induced activation of LKB1/AMPK pathway, which is beneficial for delaying rapid muscle glycolysis and improving meat quality.

Transport stress affects the fecal microbiota in healthy donkeys

Background

With the development of large‐scale donkey farming in China, long‐distance transportation has become common practice, and the incidence of intestinal diseases after transportation has increased. The intestinal microbiota is important in health and disease, and whether or not transportation disturbs the intestinal microbiota in donkeys has not been investigated.

Objectives

To determine the effects of transportation on the fecal microbiota of healthy donkeys using 16S rRNA sequencing.

Animals

Fecal and blood samples were collected from 12 Dezhou donkeys before and after transportation.

Methods

Prospective controlled study. Cortisol, ACTH, and heat‐shock protein 90 (HSP90) concentrations were measured. Sequencing of 16S rRNA was used to assess the microbial composition. Alpha diversity and beta diversity were assessed.

Results

Results showed significant (P < .05) increases in cortisol (58.1 ± 14.6 to 71.1 ± 9.60 ng/mL), ACTH (163.8 ± 31.9 to 315.8 ± 27.9 pg/mL), and HSP90 (10.8 ± 1.67 to 14.6 ± 1.75 ng/mL) on the day of arrival. A significantly lower (P = .04) level of bacterial richness was found in fecal samples after transportation, compared with that before transportation without distinct changes in diversity. Most notably, donkeys had significant decreases in Atopostipes, Eubacterium, Streptococcus, and Coriobacteriaceae.

Conclusions and Clinical Importance

Transportation can induce stress in healthy donkeys and have some effect on the composition of the in fecal microbiota. Additional studies are required to understand the potential effect of these microbiota changes, especially significantly decreased bacteria, on the development intestinal diseases in donkeys during recovery from transportation.

Age and Staphylococcus aureus Inoculation Route Differentially Alter Metabolic Potential and Immune Cell Populations in Laying Hens

In 2018 and 2019, Staphylococcus aureus was isolated from multiple post-molt commercial laying hens with unusually high mortality. A challenge study was conducted to elucidate the role of S. aureus in this disease outbreak and the work herein represents the assessment of immunological responses in laying hens experimentally infected with S. aureus isolates from these cases. A total of 200 laying hens at 22 or 96 weeks of age (100/ age group) were assigned to 1 of 4 experimental inoculation groups (negative control, oral gavage, subcutaneous injection, or intravenous injection) after a 72 h acclimation period. Blood samples were taken prior to inoculation (baseline), 6 h post-inoculation (pi), 24 hpi, 3 dpi, and 7 dpi. Additional spleen samples to further assess systemic immunity were taken at baseline, 3 and 8 dpi. Metabolic phenotypes of peripheral blood mononuclear cells (PBMC) were isolated and assessed by Seahorse metabolic assay. Immune cell profiles in the spleen and PBMC were assessed by multicolor flow cytometry. At baseline, 96-week-old laying hens had 26.7% fewer PBMC-derived T cells compared to 22-week-old birds. Older hens had 28.9% increased helper T cell (TH) populations and 60.5% reduced γδ T cells (P = 0.03 and < 0.0001) which may contribute to variable clinical responses between age groups; however, no age-related differences in metabolic potential were observed. Metabolic outcomes showed that birds remained stressed from transport and re-housing past a 72 h acclimation period and through 24 h- 3 days post-inoculation. Inoculation with S. aureus generally reduced oxidative and glycolytic potentials compared to the control, with the greatest reductions observed in birds inoculated by intravenous injection (P < 0.05). Overall CD3+ T cell populations showed significant reductions in the intravenous group compared to other inoculation routes from 24 hpi to 7 dpi (23.6-39.0%; P ≤ 0.0001). These results suggest that age-related baseline differences in T cell populations and changes to T cell subpopulations and other immune cells due to inoculation route may have an additive effect on S. aureus- induced reductions in metabolic potential; however, further research linking metabolic potential and immune cell profiles is needed.

Guanidino-Acetic Acid: A Scarce Substance in Biomass That Can Regulate Postmortem Meat Glycolysis of Broilers Subjected to Pre-slaughter Transportation

The different substances in biomass can regulate the metabolism and reproduction of broilers. Guanidino-acetic acid (GAA) is a natural feed additive that showed a potential application in dietary for broilers, while its amount is scarce in biomass. The objective of the present study was to investigate the effects of dietary supplemented with GAA on muscle glycolysis of broilers subjected to pre-slaughter transportation. A total of 160 Qiandongnan Xiaoxiang chickens were randomly assigned into three treatments, including a basal control diet without GAA supplementation (80 birds) or supplemented with 600 mg/kg (40 birds) or 1,200 mg/kg (40 birds) GAA for 14 days. At the end of the experiment, the control group was equally divided into two groups, thus resulting in four groups. All birds in the four groups aforementioned were separately treated according to the following protocols: (1) no transport of birds of the control group fed with the basal diet; (2) a 3-h transport of birds of the control group fed with the basal diet; (3) a 3-h transport of birds fed with diets supplemented with 600 mg/kg GAA; and (4) a 3-h transport of birds fed with diets supplemented with 1,200 mg/kg GAA. The results demonstrated that 3-h pre-slaughter transport stress increased corticosterone contents and lowered glucose contents in plasma (P < 0.05), decreased pH_{24 h} (P < 0.05), and resulted in inferior meat quality evidenced by elevating the drip loss, cooking loss, and L^∗ value (P < 0.05). Meanwhile, 3-h pre-slaughter transport stress decreased the contents of Cr and ATP in muscle (P < 0.05) and elevated the ratio of AMP:ATP and the glycolytic potential of muscle (P < 0.05). Moreover, 3-h pre-slaughter transport resulted in a significant elevation of mRNA expressions of LKB1 and AMPKα2 (P < 0.05), as well as the increase in protein abundances of LKB1 phosphorylation and AMPKα phosphorylation (P < 0.05). However, 1,200 mg/kg GAA supplementation alleviated negative parameters in plasma, improved meat quality, and ameliorated postmortem glycolysis and energy metabolism through regulating the creatine-phosphocreatine cycle and key factors of AMPK signaling. In conclusion, dietary supplementation with 1,200 mg/kg GAA contributed to improving meat quality via ameliorating muscle energy expenditure and delaying anaerobic glycolysis of broilers subjected to the 3-h pre-slaughter transport.

Effects of chitosan oligosaccharides on meat quality, muscle energy metabolism and anti-oxidant status in broilers that have experienced transport stress

Context Pre-slaughter transport, exposed broilers to various stressors, which resulted in detrimental effects on animal welfare, live bodyweight loss, mortality and meat quality. There was growing interest to explore effective ways to reduce the stress response and improve meat quality of transported broilers by using dietary feed additives. Aims The purpose of the present study was to investigate the effect of chitosan oligosaccharides (COS) on meat quality, muscle energy metabolism and anti-oxidant status of broilers having 3-h transport stress. Methods In total, of 144 35-day-old broilers were randomly allocated to two dietary treatments, including a basal diet (96 broilers), or basal diet supplemented with COS at 200 mg/kg (48 broilers). There were eight broilers per cage, and 12 replication cages in the basal diet group and six replication cages in the basal diet with 200 mg/kg COS group. At the end of the experiment, after a 12-h fast, broilers in the basal diet group were randomly divided into two groups, with six replication cages in each group; then, the broilers were transported as per the following protocols: broilers in the basal diet group (CON group) were without transport stress; broilers in the basal diet group with 3 h of transport stress (TS group), and broilers in the basal diet with 200 mg/kg COS supplementation and 3 h of transport stress (TSC group). The serum corticosterone concentration, serum, liver and muscle anti-oxidant status, as well as meat quality and muscle energy metabolism were analysed. Key results Compared with the CON group, TS group showed increased bodyweight loss, serum corticosterone concentration, breakdown of muscle glycogen, increased muscle lactate dehydrogenase activity, as well as some changes of body anti-oxidant status (higher serum, liver and muscle MDA concentrations, lower serum SOD and GSH-Px, liver SOD and CAT, and lower muscle SOD, GSH-Px, and CAT activity), accompanied with lower pH45min and pH24h. Nevertheless, compared with the TS group, dietary COS supplementation reduced bodyweight loss, decreased muscle MDA concentration, increased muscle SOD and CAT activity, and was accompanied with improving pH24h. Conclusions The results suggested that the positive effects of dietary COS supplementation in maintaining meat quality were mainly due to the improved muscle anti-oxidant status. Implications Dietary supplementation with 200 mg/kg COS could serve as a beneficial and effective way to alleviate transport-impaired meat quality of broilers.

Effects of long-distance transportation on blood constituents and composition of the nasal microbiota in healthy donkeys

BACKGROUND

This study aims to determine the effects of transportation on the nasal microbiota of healthy donkeys using 16S rRNA sequencing.

RESULTS

Deep nasal swabs and blood were sampled from 14 donkeys before and after 21 hours' long-distance transportation. The values of the plasma hormone (cortisol (Cor), adrenocorticotrophic hormone (ACTH)), biochemical indicators (total protein (TP), albumin (ALB), creatinine (CREA), lactic dehydrogenase (LDH), aspartate transaminase (AST), creatine kinase (CK), blood urea (UREA), plasma glucose (GLU)) and blood routine indices (white blood cell (WBC), lymphocyte (LYM), neutrophil (NEU), red blood cell (RBC), hemoglobin (HGB)) were measured. 16S rRNA sequencing was used to assess the nasal microbiota, including alpha diversity, beta diversity, and phylogenetic structures. Results showed that levels of Cor, ACTH, and heat-shock protein 90 (HSP90) were significantly increased (p < 0.05) after long-distance transportation. Several biochemical indicators (AST, CK) and blood routine indices (Neu, RBC, and HGB) increased markedly (p < 0.05), but the LYM decreased significantly (p < 0.05). Nine families and eight genera had a mean relative abundance over 1%. The predominant phyla in nasal microbiota after and before transportation were Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Transportation stress induced significant changes in terms of nasal microbiota structure compared with those before transportation based on principal coordinate analysis (PCoA) coupled with analysis of similarities (ANOSIM) (p < 0.05). Among these changes, a notably gain in Proteobacteria and loss in Firmicutes at the phylum level was observed.

CONCLUSIONS

These results suggest transportation can cause stress to donkeys and change the richness and diversity of nasal microbiota. Further studies are required to understand the potential effect of these microbiota changes on the development of donkey respiratory diseases.

Stress Associated with Simulated Transport, Changes Serum Biochemistry, Postmortem Muscle Metabolism, and Meat Quality of Broilers

Simple Summary

The objective of this study was to investigate the effects of the transportation on broilers through the use of a vibration and motion simulation machine. Short-term transport stress induced significant physiological changes in broiler chickens. Simulation of the vibration and motion associated transport for 2 h altered hormonal secretion and blood biochemical characteristics. However, after 4 h, the birds appear to regain homeostatic equilibrium. Despite this, the stress activated antioxidant defenses, acidified muscles and increased peroxidation, as well as decreasing the meat quality of broilers. This study supports and extends previous work that identified transportation as a major risk in relation to bird welfare and meat quality.

Abstract

Many factors contribute to the stress of transporting broilers from the farm to the processing plant. Using a motion simulation machine, a total of 144 male broilers were employed to determine the effect of motion, vibration, and feed withdrawal during transportation on serum biochemical parameters, postmortem muscle metabolism, and meat quality of broilers. The results indicated that transportation did not affect the activity of lactate dehydrogenase, γ-glutamyl transferase, aspartate aminotransferase, creatine kinase, and glucose in the serum, glutathione peroxidase in the breast and thigh muscle, nitric oxide synthase (NOS) in the breast, and heat stress protein 70 mRNA expression level in the liver (p > 0.05). Serum triiodothyronine, thyroxine, and insulin concentration declined with 2 h transportation (p < 0.05) and recovered with 4 h transportation (p < 0.05). NOS concentration in the thigh increased with 2 h transportation (p < 0.05) and recovered with 4 h transportation (p < 0.05). Two-hour and 4 h transportation increased the activity of superoxide dismutase in both muscles. Malondialdehyde, lactic acid, and drip loss_{24 h} in both thigh and breast muscles increased, and glycogen in both muscles decreased with increasing transportation times (p < 0.05). Two-hour transportation did not influence pH_{45 min} and pH_{24 h} in the breast and thigh muscle, but these indexes decreased with 4 h transportation. This experiment supports and extends previous work that identified transportation as a major risk in relation to bird welfare and meat quality.

Effect of transportation and shackling on plasma concentrations of corticosterone and heterophil to lymphocyte ratios in market weight male turkeys in a commercial operation

There is limited information on the effects of stress and/or physiological manipulation on either plasma concentrations of corticosterone (CORT) and/or heterophil: lymphocyte (H : L) ratios in turkeys. The present studies examine the effects of catching/transportation/lairage in a holding shed and shackling on plasma concentrations of CORT and H : L ratios in male market weight turkeys. Plasma concentrations of CORT were increased after transportation and lairage but not further elevated by shackling, irrespective of its duration up to 240 s. In one study, there were increased H : L ratios following catching/placing birds into transportation cages/transportation/lairage. In one study, H : L ratios declined following shackling. It is concluded that while moving turkeys from the farm to immediately before the shackling line is stressful, shackling for up to 4 min was not perceived as more stressful in turkeys. There were also differences between farms/houses for both plasma concentrations of CORT and H : L ratios.

Transport stress induces heart damage in newly hatched chicks via blocking the cytoprotective heat shock response and augmenting nitric oxide production

Transport stress affects the animal's metabolism and psychological state. As a pro-survival pathway, the heat shock response (HSR) protects healthy cells from stressors. However, it is unclear whether the HSR plays a role in transport stress-induced heart damage. To evaluate the effects of transport stress on heart damage and HSR protection, newly hatched chicks were treated with transport stress for 2 h, 4 h and 8 h. Transport stress caused decreases in body weight and increases in serum creatine kinase (CK) activity, nitric oxide (NO) content in heart tissue, cardiac nitric oxide syntheses (NOS) activity and NOS isoforms transcription. The mRNA expression of heat shock factors (HSFs, including HSF1-3) and heat shock proteins (HSPs, including HSP25, HSP40, HSP47, HSP60, HSP70, HSP90 and HSP110) in the heart of 2 h transport-treated chicks was upregulated. After 8 h of transport stress in chicks, the transcription levels of the same HSPs and HSF2 were reduced in the heart. It was also found that the changes in the HSP60, HSP70 and HSP90 protein levels had similar tendencies. These results suggested that transport stress augmented NO generation through enhancing the activity of NOS and the transcription of NOS isoforms. Therefore, this study provides new evidence that transport stress induces heart damage in the newly hatched chicks by blocking the cytoprotective HSR and augmenting NO production.

Dietary resveratrol supplementation prevents transport-stress-impaired meat quality of broilers through maintaining muscle energy metabolism and antioxidant status

This experiment was to evaluate the effect of dietary resveratrol (Res) supplementation (0, 400 mg/kg) on growth performance, meat quality, and muscle anaerobic glycolysis and antioxidant capacity of transported broilers. A total of 360 21-day-old male Cobb broilers was randomly allotted to 2 dietary treatments (Res-free group and Res group) with 12 replicates of 15 birds each. On the morning of d 42, after a 9-hour fast, 24 birds (2 birds of each replicate) were selected from the Res-free group and then equally placed into 2 crates, and the other 12 birds (one bird of each replicate) were selected from the Res group and then placed into the other crate. All birds in the 3 crates were transported according to the following protocols: 0-hour transport of birds in the Res-free group (control group), 3-hour transport of birds in the Res-free group (T group), and 3-hour transport of birds in the Res group (T + Res group). The results showed that Res not only improved feed conversion ratio (P < 0.05) but also tended to improve birds’ final body weight (P < 0.10). In the Res-free group, a 3-hour transport increased serum corticosterone concentration, muscle malondialdehyde (MDA) and lactate contents, and muscle lactate dehydrogenase (LDH) activity, while it decreased muscle glycogen content, total superoxide dismutase (T-SOD), and glutathione peroxidase (GSH-PX) activities (P < 0.05), which induced decreased breast meat quality (lower pH_24h and higher drip loss and L*_24 h, P < 0.05). Nevertheless, compared with the T group, Res increased muscle glycogen content and T-SOD and GSH-PX activities (P < 0.05 or P < 0.10), while it decreased muscle MDA content and LDH activity (P < 0.05), which is beneficial to the meat quality maintenance of transported broilers (lower drip loss, L*_24 h, and higher pH_24h, P < 0.05 or P < 0.10). This study provides the first evidence that dietary resveratrol supplementation prevents transport-stress-impaired meat quality of broilers, possibly through decreasing the muscle anaerobic glycolysis metabolism and improving the muscle antioxidant capacity.

Gas stunning with CO2 affected meat color, lipid peroxidation, oxidative stress, and gene expression of mitogen-activated protein kinases, glutathione S-transferases, and Cu/Zn-superoxide dismutase in the skeletal muscles of broilers

BACKGROUND

Meat color and lipid peroxidation are important traits related to meat quality. CO2 concentration is a critical factor that can affect meat quality in the commercial use of gas stunning (GS). However, the effect and mechanism of CO2 stunning on meat color and lipid peroxidation during long-term storage remain poorly studied. We aimed to study the effects of GS methods, especially CO2 concentration, on meat color and meat lipid peroxidation in broilers during long-term storage at 4 °C and to explore the potential mechanism of meat color change via lipid peroxidation and the inner lipid peroxide scavenging system.

METHODS

Eighteen broilers were sacrificed after exposure to one of the following gas mixtures for 90 s: 40% CO2 + 21% O2 + 39% N2 (G40%), 79% CO2 + 21% O2 (G79%), or no stunning (0% CO2, control). Meat color, serum variables, enzyme activities, and the gene expression of mitogen-activated protein kinase (MAPK), nuclear factor-erythroid 2-related factor 2 (Nrf2), glutathione S-transferase (GST) and superoxide dismutase (SOD) were determined.

RESULTS

The concentrations of serum triiodothyronine (T3, P = 0.03) and the ratio of serum free triiodothyronine/free thyroxine (FT3/FT4, P <  0.01) were decreased, whereas levels of serum cortisol (P <  0.01) were increased in the 40% CO2 group compared with the control group. Additionally, the thiobarbituric acid-reactive substances (TBARS) 3 d (P <  0.01) and TBARS 6 d (P = 0.01) in breast meat and the TBARS 3 d in thigh meat (P <  0.01) were increased in the 40% CO2 group compared with the control group. Serum T3 was negatively correlated with TBARS6 d both in the breast and thigh meat (r = - 0.63, P <  0.01 and r = - 0.47, P = 0.05 respectively). T3/T4 was negatively correlated with TBARS6 d in the breast meat and in the thigh meat (r = - 0.57, P = 0.01; and r = - 0.53, P = 0.03 respectively). Compared with the control group, Lightness (L*) 1 d (P = 0.03) and L*9 d (P < 0.01) were increased, whereas total chromatic aberration (E*) 1 d (P = 0.05) and E*3 d (P < 0.01) were decreased in the breast meat of both the G40% and G79% groups. The values of yellowness (b*) 3 d (P = 0.01), b*6 d (P < 0.01) and E*6 d (P < 0.01) in the thigh meat were lower in both the G40% and G79% groups than in the control group. In the breast muscle, the mRNA levels of c-Jun N-terminal kinase 2 (JNK2, P = 0.03), GSTT1 (P = 0.04), and SOD1 (P = 0.05) were decreased, and the mRNA levels of JNK1 (P = 0.07), Nrf2 (P = 0.09), and GSTA3 (P = 0.06) were slightly lower in both the G40% and G79% groups compared with the control group. However, among these genes, only the mRNA level of JNK1 was decreased in the G40% group compared with the control group and the G79% group (P = 0.03) in the thigh muscle.

CONCLUSIONS

Compared with the control group, meat color quality in the breast meat was decreased, and the expression of genes in the MAPK/Nrf2/ARE (antioxidant responsive element) antioxidant pathway in breast muscle was partly suppressed by GS of both 40% and 79% CO2. However, oxidative stress and meat lipid peroxidation during storage were aggravated by GS with 40% CO2 compared to GS with 79% CO2 and no GS.

Transport stress induces weight loss and heart injury in chicks: disruption of ionic homeostasis via modulating ion transporting ATPases

Transportation is inevitable in the poultry industry, and it can induce stress to chicks in varying degrees, such as mild discomfort, sometimes even death. However, the research about the effects of transport stress on the weight loss and heart injury of chicks is lacking. To elucidate the underlying mechanism of transport stress-induced effects, chicks were transported for 2h, 4h and 8h. The creatinine kinase (CK) activities, the ionic contents, the ATPases activities and the transcription of the ATPase associated subunits in chick heart were detected. The results showed that transport stress increased the weight loss and the CK activity, disturbed the ionic (K⁺, Ca²⁺, Mg²⁺) homeostasis and inhibited the ATPase (Na⁺-K⁺-ATPase, Ca²⁺-ATPase, Mg²⁺-ATPase and Ca²⁺-Mg²⁺-ATPase) activities, increased the ATP content and downregulated the gene expression levels of the ATPase associated subunits in heart. In conclusion, transport stress disturbed the ionic homeostasis via modulating ion transporting ATPases and the transcriptions of the associated subunits, and ultimately induced weight loss and heart injury in chicks.

Transport stress-induced cerebrum oxidative stress is not mitigated by activating the Nrf2 antioxidant defense response in newly hatched chicks

Transportation of newly hatched chicks from the hatchery to the farm is inevitable, especially for parent stock and grandsire parent stock chicks. However, the possible effects of transport stress in the newly hatched chicks are poorly understood. The aim of this study was to determine the adaptive responses to transport stress by activing the nuclear factor-erythroid 2-related factor 2 (Nrf2)-induced antioxidant defense. One hundred twenty newly hatched chicks were divided into 3 groups (control group, transport group, and simulation transport group) for 2, 4, and 8 h of real or simulated transportation. Transport stress could cause oxidative stress in the cerebrum of newly hatched chicks by increasing lipid peroxidation and production of free radicals and decreasing the activities of antioxidant enzymes and the glutathione:oxidized glutathione ratio. Transport stress activated the Nrf2 signaling pathway and triggered the transcription of antioxidant parameters. However, transport stress-induced cerebrum oxidative stress was not mitigated by activating the Nrf2 antioxidant defense response in newly hatched chicks.

Preslaughter Transport Effect on Broiler Meat Quality and Post-mortem Glycolysis Metabolism of Muscles with Different Fiber Types

Preslaughter transport has been reported to decrease the quality of breast meat but not thigh meat of broilers. However, tissue-specific difference in glycogen metabolism between breast and thigh muscles of transported broilers has not been well studied. We thus investigated the differences in meat quality, adenosine phosphates, glycolysis, and bound key enzymes associated with glycolysis metabolism in skeletal muscles with different fiber types of preslaughter transported broilers during summer. Compared to a 0.5 h transport, a 3 h transport during summer decreased ATP content, increased AMP content and AMP/ATP ratio, and accelerated glycolysis metabolism via the upregulation of glycogen phosphorylase expression accompanied by increased activities of bound glycolytic enzymes (hexokinase, pyruvate kinase, and lactate dehydrogenase) in pectoralis major muscle, which subsequently increased the likelihood of pale, soft, and exudative-like breast meat. On the other hand, a 3 h transport induced only a moderate glycolysis metabolism in tibialis anterior muscle, which did not cause any noticeable changes in the quality traits of the thigh meat.

Evaluation of a stress model induced by dietary corticosterone supplementation in broiler breeders: effects on egg yolk corticosterone concentration and biochemical blood parameters

1. This study aimed to evaluate a stress model induced by corticosterone (CORT) supplementation in the diet of broiler breeder hens. 2. A total of 60 Ross broiler breeder hens at 29 weeks of age were randomly divided into 4 groups with 15 hens each. The first group served as the control. The rest of the hens were given 1, 1.5 or 2 mg of CORT/hen/d (CORT1, CORT1.5 and CORT2, respectively) for 7 d. Concentrations of yolk CORT, plasma uric acid, glucose, cholesterol, creatine kinase, heterophil (H):lymphocyte (L) ratio and duration of tonic immobility (TI) were measured at d 3, 5 and 7 of CORT supplementation. The same measurements were repeated at 3, 5 and 7 d after CORT was withdrawn from the diet. 3. There were no significant CORT dose effect on yolk CORT and plasma glucose concentrations. Higher plasma uric acid and H:L ratio was obtained for CORT1.5 and CORT2 than for CORT1. From 3 to 7 d of dietary CORT supplementation, yolk CORT and plasma uric acid concentrations and H:L ratio increased whereas plasma glucose concentration decreased. After CORT was withdrawn from the diet, the H:L ratio remained elevated. The duration of TI and plasma creatine kinase concentration did not change during and after CORT supplementation. 4. Yolk CORT concentration was correlated with plasma uric acid concentration during CORT supplementation. 5. The results suggest that dietary CORT supplementation could be used as a stress model and to evaluate hormone-mediated maternal effects in broiler breeder hens.

Japanese quail meat quality: characteristics, heritabilities, and genetic correlations with some slaughter traits

The aim of this study was to evaluate the genetic parameters of several breast meat quality traits and their genetic relationships with some slaughter traits [BW, breast yield (BRY), and abdominal fat yield (AFY)]. In total, 1,093 pedigreed quail were slaughtered at 35 d of age to measure BRY, AFY, and breast meat quality traits [ultimate pH (pHU), Commission Internationale d'Eclairage color parameters (L*, lightness; a*, redness; and b*, yellowness), thawing and cooking loss (TL and CL, respectively), and Warner-Bratzler shear value (WB)]. The average pHU, L*, a*, and b* were determined to be 5.94, 43.09, 19.24, and 7.74, respectively. In addition, a very high WB average (7.75 kg) indicated the firmness of breast meat. High heritabilities were estimated for BW, BRY, and AFY (0.51, 0.49, and 0.35). Genetic correlations of BW between BRY and AFY were found to be high (0.32 and 0.58). On the other hand, the moderate negative relationship between BRY and AFY (-0.24) implies that selection for breast yield should not increase abdominal fat. The pHU was found to be the most heritable trait (0.64), whereas the other meat quality traits showed heritabilities in the range of 0.39 to 0.48. Contrary to chickens, the genetic correlation between pHU and L* was low. The pHU exhibited a negative and high correlation with BW and AFY, whereas L* showed a positive but smaller relationship with these traits. Moreover, pHU exhibited high negative correlations (-0.43 and -0.62) with TL and WB, whereas L* showed a moderate relationship (0.24) with CL. This genetic study confirmed that the multi-trait selection could be used to improve meat quality traits. Further, the ultimate pH of breast meat is a relevant selection criterion due to its strong relationships with either water-holding capacity and texture or low abdominal fatness.

Corticosterone stress response of Greater Rhea (Rhea americana) during short-term road transport

The effect of transport stress on blood corticosterone levels in captive Greater Rheas was investigated. Twelve adult individuals (7 males; 5 females) were loaded in pairs inside wooden crates and transported along a paved road for 30 min. Blood samples were taken before the individuals were introduced into the crate (baseline value) and immediately after they were unloaded (30 min after capture). To assess whether corticosterone levels were affected by the blood sampling procedure per se, another 6 (nontransport) control birds (3 males; 3 females) were also captured and sampled at the same times as their transported counterparts. Plasma corticosterone concentrations were measured using a commercially available corticosterone (125)I radio-immunoassay kit. Baseline corticosterone levels were similar in the control and transported birds (9.0 ± 1.6 and 10.4 ± 0.8 ng/mL, respectively). Transportation induced a highly significant (P < 0.001), more than 40-fold increase in the corticosterone levels (433.6 ± 35.4 ng/mL) that was about 5 times higher (P < 0.001) than in their nontransported counterparts (88.4 ± 14.8 ng/mL). The present findings suggest that Greater Rhea is a species highly sensitive to stressful manipulations. Both blood sampling and transportation induced highly significant adrenocortical responses. Considering that transportation is one of the unavoidable common practices in the management of Greater Rheas and, as shown in the present study, that it induces a significant 40-fold corticosterone stress response, efforts should focus on helping to generate management transport standards for optimization of the welfare of this ratite.

Behavioral responses to short-term transport in male and female Greater Rheas (Rhea americana) reared in captivity

Animal transport is an indispensable practice in species that need to be moved for management or commercial purposes. However, transport may have negative effects on individuals' welfare. The aims of the present work were to determine if the behavioral responses of adult Greater Rheas (Rhea americana) bred in captivity are sensitive to short-term transport and if males and females differ in their posttransport behavioral activity and recovery. Eight males and 8 females were placed in individual pens and allowed 6 d to habituate (d 1 to 6) before transport procedure. On the transport day (d 7), half of the birds (4 males and 4 females) were randomly assigned to a transport group that was captured and handled to be placed into the crates, exposed to a 30-min transport stressor, and immediately returned to their pens. Four transports with 1 different male and female each time were performed. The other half remained undisturbed and were used as controls. Behavior of all individuals was video-recorded during habituation days, after transport on d 7, and on the 2 following days (d 8 and 9) to evaluate pre- and posttransport behavioral activity for 2 h per day. No significant behavioral changes were observed during the last 2 d of the habituation period (d 5 and 6), suggesting that Greater Rheas were adapted to the housing conditions before transport. After transportation, several behaviors were affected: transported males and females showed null resting, transported females also showed reduced preening and increased vigilance (P < 0.05), whereas transported males showed increased drinking (P < 0.05) compared with their respective control groups. The results suggest that behavioral responses of captive-bred Greater Rheas are sensitive to short-term transport (which includes handling) and that males and females differ in their posttransport behavioral activity, recovering their overall basal levels on the third day posttransportation.

Effect of stress on carnosine levels in brain, breast, and thigh of broilers

The objective of the present study was to compare carnosine levels in tissues of broilers under stress conditions with those of broilers under nonstress conditions. Blood heterophil:lymphocyte ratio and corticosterone levels were measured as indicators of the level of stress. Corticosterone levels of stressed broilers (24,358.67 pg/mL) were 10-fold higher (P = 0.002) than those of nonstressed broilers (2,275.46 pg/mL). However, no difference (P = 0.29) was found in heterophil:lymphocyte ratio of nonstressed (0.29) and stressed (0.31) birds. Carnosine content in breast of stressed birds (17.39 mg/g) was 10 times higher (P = 0.005) than that of nonstressed birds (1.85 mg/g). Carnosine content in thigh of stressed birds (21.25 mg/g) was approximately 2-fold higher (P = 0.001) than that of nonstressed birds (11.10 mg/g). Carnosine content in brain of stressed birds did not differ (P = 0.82) from that of nonstressed birds. Based on the present study, muscle carnosine recovery levels increase during short-term stress, whereas levels in the brain are not affected.