Muscle Of Broilers Research Articles

Effect of temperature manipulation during incubation on body weight, plasma parameters, muscle histology, and expression of myogenic genes in breast muscle of embryos and broiler chickens from two commercial strains

ABSTRACT 1. This study evaluated the effect of a higher incubation temperature on body weight, plasma profile, histology and expression of myogenin (MYOG), insulin-like growth factor-I (IGF-I) and vascular endothelial growth factor A (VEGFA) genes in breast muscle of embryos and broilers from two commercial strains. 2. A total of 784 eggs from Ross 308 and Cobb 500 broiler breeder flocks were used. Half of the eggs per strain were incubated at control temperature (37.8°C), whereas the other half were exposed to heat treatment (HT) of 38.8°C between embryonic day (ED) 10 and 14, for 6 h/day. Embryos and chicks were sampled on ED 19 and at hatch. A total of 480, one-day-old chicks per strain and incubation temperature were reared up to 42 d post-hatch. 3. The HT increased hatch weight of Ross chicks and 42-d body weight of broilers from both strains. Lower plasma triacylglycerol levels were measured for HT embryos and broilers on ED 19 and 42 d post-hatch, respectively. HT reduced plasma T3 levels in Ross embryos and broilers for the same periods. Hepatic TBARS concentrations were elevated by HT compared to the control incubation. 4. The HT reduced breast muscle VEGFA gene expression of Cobb embryos on ED 19, whereas expression was stimulated in day-old chicks. At 42 d post-hatch, fibre area was increased by HT regardless of strain. Compared to the control incubation, HT increased the breast yield of Ross broilers and leg yield of Cobb. Ross-HT broilers had a higher pH at 24 h after slaughter and better water holding capacity than Cobb-HT broilers. 5. These results suggested that HT increased body weight, fibre area, IGF-I gene expression and lowered plasma triacylglycerol levels of broiler chickens from both strains at 42 d. However, HT influenced the expression of VEGF-A and MYOG genes and meat quality differently between the broiler strains.

The dopamine receptor D4 regulates the proliferation of pulmonary arteries smooth muscle in broilers by downregulating AT1R

The major cause of pulmonary vascular remodeling in broilers is abnormal proliferation of vascular smooth muscle cells (VSMCs), and one of the main causes of pulmonary hypertension syndrome (PHS) in broilers is pulmonary artery vascular remodeling. Forty Arbor Acres (AA) broilers were randomly divided into four groups (n = 10): a control group (deionized water, 0 g/L NaCl), a freshwater group (FW, deionized water + 1 g/L NaCl), highly salinized freshwater group 1 (H-SFW-1, deionized water + 2.5 g/L NaCl) and highly salinized freshwater group 2 (H-SFW-2, deionized water + 5 g/L NaCl). The results of in vivo experiments showed that vascular smooth muscle of the broilers could be significantly proliferated by intake of high-salinity fresh water (H-SFW-1 & H-SFW-2), which significantly increased the content of angiotensin II (Ang II) and the expression of angiotensin II type 1 (AT1) receptor protein. Meanwhile, it significantly decreased the expression of dopamine receptor D4 (DRD4) protein. The results of in vitro experiments showed that exogenous Ang II induced the proliferation of primary VSMCs in broilers, which could be significantly inhibited by DRD4 agonists (D4A, HY-101384A) and enhanced by DRD4 inhibitors (D4I, HY-B0965). In addition, the results of immunoblotting and fluorescence quantitative PCR showed that AT1 receptors could be negatively regulated by DRD4 in VSMCs of broilers, either at the transcriptional or translational level. At the same time, the expression of AT1 receptor could be increased by DRD4 inhibition by D4I and decreased by DRD4 activation by D4A. The negative regulatory effect of DRD4 on AT1 receptor occurred in a dose-dependent manner. These results indicate that long-term intake of highly salinized fresh water can cause PHS in broilers, accompanied by varying degrees of proliferation of pulmonary artery smooth muscle. This mechanism may involve response of its receptor being induced by increased Ang II, while DRD4 can negatively regulate it.

Antioxidant Status of Broiler Chickens Fed Diets Supplemented with Vinification By-Products: A Valorization Approach.

Vinification by-products display great potential for utilization as feed additives rich in antioxidant compounds. Thus, the effect of dietary ground grape pomace (GGP), wine lees extract rich in yeast cell walls (WYC), and grape stem extracts (PE) on the relative expression of several genes involved in liver oxidative mechanisms and the oxidative status of the blood and breast muscle of broiler chickens was investigated. In total, 240 one-day-old as hatched chicks (Ross 308) were assigned to four treatments, with four replicate pens and 15 birds in each pen. Birds were fed either a basal diet (CON) or a basal diet supplemented with 25 g/kg GGP, or 2 g/kg WYC, or 1 g starch including 100 mg pure stem extract/kg (PE) for 42 days. The polyphenolic content of vinification by-products was determined using an LC-MS/MS library indicating as prevailing compounds procyanidin B1 and B2, gallic acid, caftaric acid, (+)-catechin, quercetin, and trans-resveratrol. Body weight and feed consumption were not significantly affected. The relative transcript level of GPX1 and SOD1 tended to increase in the liver of WYC-fed broilers, while NOX2 tended to decrease in the PE group. SOD activity in blood plasma was significantly increased in WYC and PE compared to the CON group. The total antioxidant capacity measured with FRAP assay showed significantly higher values in the breast muscle of PE-fed broilers, while the malondialdehyde concentration was significantly decreased in both WYC- and PE-fed broilers compared to the CON group. The exploitation of vinification by-products as feed additives appears to be a promising strategy to improve waste valorization and supply animals with bioactive molecules capable of improving animals’ oxidative status and products’ oxidative stability.

Heavy metal residues in offals, muscle and eggs of intensively reared poultry birds in Umuahia, Abia State

Poultry meat and poultry products have gradually become delicacy in Nigeria and are used in most celebrations for entertainment. Therefore there is the need for constant monitoring to ensure they are wholesome and suitable for human consumption. The aim of this study was to determine the presence and concentrations of Manganese (Mn), Zinc (Zn) and Iron (Fe) in the thigh muscle and offals (kidney, liver and gizzard) of both broilers and layers reared under intensive system of management using an Atomic Absorption Spectrophotometer (AAS). In both broilers and layers, all meat and offal samples had concentrations of Mn and Fe that were above the maximum permissible levels (MPL) stipulated by FAO/WHO. In layers, the concentrations of Mn (5.276 ± 0.023mg/kg) and Fe (7.067 ± 0.569mg/kg) were highest in the liver. The concentration of Zn (5.039 ± 0.009mg/kg) was found to be highest in the kidney. In broilers, Mn (5.105 ± 0.053mg/kg) accumulated more in the thigh muscle than any other organ whereas the highest concentration of Fe (6.256 ± 0.246 mg/kg) was found in the liver. The mean concentration of Mn, Zn and Fe in eggs was 5.081 ± 0.033, 5.092 ± 0.021 and 7.102 ± 0.146 (mg/kg) respectively. The concentration on Mn in eggs was slightly above the maximum residual limits of 5.0 mg/kg. The high mean concentrations of Mn and Fe found in the study are of great public health concern because these metals are bioaccumulation and with continuous consumption, may pose a serious threat to public health.

Impact of deep pectoral myopathy on chemical composition and quality parameters of chicken breast fillet

One of the current myopathies affecting the chicken meat industry is deep pectoral myopathy (DPM), also known as green muscle disease or Oregon disease, the condition is considered a major problem in poultry processing lines. Thus, the present study proposes to examine the meat quality of the Pectoralis major muscle (breast fillet) from carcasses of broilers affected by DPM in Pectoralis minor muscle (tender) and from a control group. Breast fillets samples were harvested from Ross AP95 broilers that were slaughtered at 42 days of age and were selected to the occurrence of the myopathy (score 2 and score 3) and from a control group without (score 0) the presence of myopathy. Chemical composition, cholesterol, fatty acid profile, pH, color, water-holding capacity, cooking loss, shear force, sarcomere length, and collagen were analyzed in the breast fillet. And with the results it was observed the samples classified as DPM score 2 had a higher moisture and a lower protein percentage. The higher values lipid was found in the samples from broilers affected by DPM. There was no difference (P > 0.05) fatty acid profile only to C10:0, C15:0, C17:0, C20:0, and C18:2c9,t11. Differences were detected (P < 0.05) for the pH, WHC, SF, and sarcomere length of the samples from broilers affected by DPM. The higher pH observed in the samples from birds classified as DPM score 2 and the higher WHC values were observed in the samples affected by DPM (score 2 and 3). The SF (P < 0.05) among samples, with the most tender samples (lower SF values) being those unaffected by the condition DPM (score 0). The dorsal side surface, where the Pectoralis major muscle is in contact with the Pectoralis minor muscle, higher L* values were found in the meat affected by the myopathy. Although deep pectoral myopathy affects the Pectoralis minor muscle of broilers, it can also alter the qualitative characteristics and chemical composition of the breast fillets (Pectoralis major muscle).

Spaghetti Meat Abnormality in Broilers: Current Understanding and Future Research Directions.

Spaghetti meat (SM) is a recent muscular abnormality that affects the Pectoralis major muscle of fast-growing broilers. As the appellative suggests, this condition phenotypically manifests as a loss of integrity of the breast muscle, which appears soft, mushy, and sparsely tight, resembling spaghetti pasta. The incidence of SM can reach up to 20% and its occurrence exerts detrimental effects on meat composition, nutritional value, and technological properties, accounting for an overall decreased meat value and important economic losses related to the necessity to downgrade affected meats. However, due to its recentness, the causative mechanisms are still partially unknown and less investigated compared to other muscular abnormalities (i.e., White Striping and Wooden Breast), for which cellular stress and hypoxia caused by muscle hypertrophy are believed to be the main triggering factors. Within this scenario, the present review aims at providing a clear and concise summary of the available knowledge concerning SM abnormality and concurrently presenting the existing research gaps, as well as the potential future developments in the field.

Evaluation of Chemical Composition and Meat Quality of Breast Muscle in Broilers Reared under Light-Emitting Diode.

Simple SummaryThe present study was designed to investigate the role of three different light-emitting diode (LED) light color temperatures (Neutral, Cool, and Warm) on the growth performance, carcass characteristics, and breast meat quality of broilers. No significant differences were observed in carcass yield in any of the experimental conditions. The changes observed in physical and chemical properties of breast meat samples suggest that LED light was not able to modify the quality of the products; therefore, it could represent a good alternative technology to traditional light sources.The present study was designed to investigate the role of three different light-emitting diode (LED) light color temperatures on the growth performance, carcass characteristics, and breast meat quality of broilers. In our experimental condition, 180 chicks were randomly distributed into four environmentally controlled rooms (three replicates/treatment). The experimental design consisted of four light sources: neon (Control), Neutral (Neutral LED; K = 3500–3700), Cool (Cool LED; K = 5500–6000), and Warm (Warm LED; K = 3000–2500). Upon reaching the commercial weight (3.30 ± 0.20 kg live weight), 30 birds from each group were randomly selected, and live and carcass weight were evaluated to determinate the carcass yield. Following the slaughtering, samples of hemibreast meat were collected from each group and analyzed for physical and chemical properties, fatty acids composition, and volatile compounds. Live weight and carcass weight were negatively influenced by the Warm LED; however, no significant differences were observed in carcass yield in any of the experimental conditions. Higher drip loss values were detected in breast meat samples obtained by broilers reared under Neutral and Cool LEDs. In regard to the meat fatty acids profiles, higher polyunsaturated fatty acids (PUFA) values were detected with the Warm LED; however, the ratio of PUFA/saturated fatty acids (SFA) did not change in any group. The evaluation of volatile profiles in cooked chicken meat led to the identification of 18 compounds belonging to the family of aldehydes, alcohols, ketones, and phenolic compounds, both at 0 (T0) and 7 (T7) d after the cooking. The results of the present study suggest that the LED represents an alternative technology that is cheaper and more sustainable than traditional light sources, since it allows economic savings for poultry farming without significant alterations on the production parameters or the quality of the product.

Angiopoietin-like protein 4 regulates breast muscle lipid metabolism in broilers

The objective of this study was to determine the effects of angiopoietin-like protein 4 (ANGPTL4) on breast muscle lipid metabolism in broilers. In experiment 1, 36 thirty-five-day-old male Arbor Acres broilers were randomly allocated into 6 treatment groups with 6 birds in a completely randomized design. The broilers were subjected to intravenous injection of His-SUMO-ANGPTL4 at the dose of 0 (injection of normal saline [NS]), 20, 100, 500, 2,500, or 12,500 ng/kg BW, respectively. The results showed that broilers at 30 min after His-SUMO-ANGPTL4 at the level of 12,500 ng/kg BW intravenous injection had higher (P < 0.05) concentrations of triglyceride and non-esterified fatty acid in the serum, higher (P < 0.05) adipose triglyceride lipase and carnitine palmitoyltransferase 1 mRNA expression in the breast muscle, but lower (P < 0.05) lipoprotein lipase (LPL) mRNA expression in the breast muscle. In experiment 2, 18 thirty-five-day-old male Arbor Acres broilers were randomly allocated into 3 treatment groups with 6 birds in a completely randomized design. The broilers were subjected to intravenous injection of NS, His-SUMO, or His-SUMO-ANGPTL4 (12,500 ng/kg BW) in order to rule out the effect of His-SUMO tag. It's confirmed that ANGPTL4 could increase (P < 0.05) concentrations of triglyceride and non-esterified fatty acid in the serum, enhance (P < 0.05) adipose triglyceride lipase mRNA expression in the breast muscle, and decrease (P < 0.05) LPL mRNA expression in the breast muscle. In experiment 3 and 4, co-culture experiments of chicken primary myoblasts and NS, His-SUMO, or His-SUMO-ANGPTL4 (250 pg/mL, physiological dose) were set up to monitor the cytotoxicity of ANGPTL4 and the changes of lipid metabolism-related genes expression. It was found that cell viability was not affected but LPL mRNA expression in chicken primary myoblasts was highly reduced (P < 0.05) by ANGPTL4. In conclusion, ANGPTL4 could promote lipodieresis and inhibit LPL in the breast muscle of broilers.

Effect of stocking density on performance, meat quality and cecal bacterial communities of yellow feather broilers

Totally, 315 42-day-old male Xueshan chickens were allocated into 3 caging densities, 14, 21 and 28 birds/m2. Each treatment was represented by 5 replicates. The body weight (BW), slaughter performance, meat quality, behavioral assessment, and the cecal microorganisms were detected at the market age. The results showed that the BW of broilers in the low- and medium-density groups was significantly higher (p < 0.05) than that of the high-density group from the age of 10 weeks. Only the feather quality of the broilers in the low-density group improved significantly (p < 0.05) compared with those of the other two groups. And, the abdominal fat percentage and the fat content of thigh muscle of broilers in the low- and medium-density groups were higher (p < 0.05) than those in the high-density group. No significant difference (p > 0.05) was noted in the other traits. The abundance of some microbial like Akkermansiaceae, Lactobacillaceae and Faecalibacterium may be correlated with the BW and fat content of broilers. The findings of this study suggest that increasing the stocking density decreased the final BW, fat content and the feather quality, whereas no evidence was found that stocking density caused changes in other parameters.

Physical, Chemical and Histological Characterization of Pectoralis major Muscle of Broilers Affected by Wooden Breast Myopathy.

Simple SummaryWooden breast myopathy is a muscle abnormality resulting from the genetic improvement practiced by the poultry industry and which is widespread throughout the planet. Recent research has tried to unravel this myopathy for years and how the quality of the meat is affected, in search of its etiology and the solution to this problem. Unfortunately, the problems related to the myopathies of the affected birds will only be solved when the cause of the abnormality is in fact unveiled and controlled; in the meantime, it is up to us researchers to contribute scientifically to research on this type of meat that is fit for consumption but that, for often presenting non-standard appearance for sale in the form of whole fillets, is discarded.This study aimed to characterize the effects of wooden breast myopathy (WBM) on quality of broiler chicken breast meat. Normal samples (absence of myopathy), moderate-degree samples (hardness only in one area of the breast fillet) and severe-degree samples (hardness throughout the breast fillet) were classified. In macroscopic analysis, the pectoral muscle affected by the WBM showed, in general, pale color with stiff, irregular and reddish regions (suffusions and petechiae), with the presence of white striations. In microscopic analysis, the myopathy was characterized by loss of the polygonal aspect of the muscle fibers. Samples with moderate degree of the myopathy showed greater (p = 0.0266) water retention capacity. There was an increase (p = 0.004) in total collagen concentration in samples from the severe-degree group 0.29% in normal samples to 0.43% and 0.48% in samples from moderate- and severe-degree groups, respectively. Samples of chicken breast affected by the severe-degree WBM showed lower (p < 0.0001) myofibrillar fragmentation index (64.51) and lower (p = 0.0002) fat concentration (2.17%) than normal chicken samples (80.45 and 3.79%, respectively). Samples affected by WBM are larger and heavier and present poorer physical quality when compared to normal chicken meat. Histologically it is possible to observe loss of the polygonal aspect of muscle fibers.

Protective effects of dietary synbiotic supplementation on meat quality and oxidative status in broilers under heat stress.

This study evaluated protective effects of synbiotic on meat quality and oxidative status of breast muscle in heat-stressed broilers. Twenty 2-day-old broilers were allocated in a 2×2 factorial design, and the main factors consisted of synbiotic level (0 (basal diet) or 1.5 g/kg synbiotic) and temperature (thermoneutral or high temperature), resulting in 4 treatments. From 22 to 42 days, chickens were raised at thermoneutral temperature (22 °C) or subjected to cyclic high temperature (heat stress, HS) by keeping them at 32-33 °C for 8 h and 22 °C for rest 16 h daily. Cyclic HS decreased relative weight, redness (45 min), and pH values (45 min and 24 h) but increased contents of moisture and ether extract, lightness (45 min and 24 h), drip loss (24 h and 48 h), and cooking loss in breast muscle of broilers compared with those under thermoneutral temperature. It also increased malondialdehyde content and mRNA abundances of heat shock protein 70 (HSP70) and HSP90 but decreased glutathione (GSH) concentration and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as mRNA abundances of nuclear factor (erythroid 2)-like 2 (Nrf2), NAD(P)H quinone dehydrogenase 1 (NQO1), GSH-Px, and copper and zinc superoxide dismutase in breast muscle in broilers. Dietary synbiotic supplementation was effective in increasing weight and reducing lightness (45 min), drip loss (24 h and 48 h) and cooking loss of breast muscle in heat-stressed broilers compared with those fed the basal diet. It also reduced malondialdehyde content and HSP70 mRNA abundance and increased GSH-Px activity, GSH content, and mRNA abundances of Nrf2, NQO1 and GSH-Px in breast muscle of heat-stressed broilers. These results suggested that synbiotic supplementation at a level of 1.5 g/kg could ameliorate compromised meat quality and oxidative status in broilers under cyclic HS.

Dietary Beta-Hydroxy-Beta-Methyl Butyrate Supplementation Affects Growth, Carcass Characteristics, Meat Quality, and Serum Metabolomics Profile in Broiler Chickens.

This study aimed to explore the effects of beta-hydroxy-beta-methyl butyrate (HMB) on serum metabolic profiles and meat quality of muscles in Wenshi broiler chickens. Birds were fed a basal diet with an additional 0, 0.05, 0.10, or 0.15% HMB, respectively. Results showed that dietary HMB quadratically increased the average daily gain (P = 0.058) and decreased feed:gain (P < 0.05) mainly in the starter phase. At 51 days of age, birds receiving 0.10% HMB diet exhibited less abdominal fat and more breast yield than the control (P < 0.05). Moreover, dietary HMB quadratically decreased the L∗ value and drip loss in selected muscles (P < 0.05) and increased the a∗ value in breast muscle (P < 0.05). Serum metabolome profiling showed that the most differentially abundant metabolites are lipids and lipid-like molecules, including phosphatidylcholines. It was concluded that HMB improved growth performance and meat quality of muscle in broilers.

The excretion of 241Am and 137Cs from the broilers organs after long-term application

Data, despite being crucial for internal dose assessment, is lacking on the transfer of artificial radionuclides from the environment to the food supply. Expanding the available information on these factors is important for the improvement of dose models for specific scenarios.This paper describes the results of a 70 day field experiment with broiler chickens on the dynamics of excretion of 137Cs and 241Am from the muscle, liver and bone of broilers after a 30 day application of contaminated feed.The radionuclide concentrations in the feed and the thigh muscle, thigh bone and liver of 54 chickens divided between grass meal and soil contaminated feed groups were evaluated by gamma spectrometry for 241Am and 137Cs.The obtained results confirm previous data on the dynamics of the excretion of cesium from organs, which can be described with a fast and a slow exponential curve of excretion.On the 70th day, following the 30-days application, 2–8% of the first-day activity concentrations of 137Cs in organs (muscle, liver, bone) were detected. In the first two days, activity concentration of 241Am decreases twofold in both liver and bone. 35% of the maximum activity concentration of 241Am remained in bone and 15% in liver on the last day of the experiment.

Research Note: Evaluation of the incidence of white striping and underlying myopathic abnormalities affected by fast weight gain in commercially fed broiler chickens

Significant improvements in genetics, nutrition, and food efficiency have had a great impact on the rapid growth of broilers, notably with increases in muscle mass. However, with rapid growth, the broiler industry has been negatively impacted by the increased incidence of myopathies, including white striping. White striping affects the pectoralis major muscle of broilers, particularly the larger breasts of rapidly growing modern commercial broiler lines. In this study, we documented the growth process of commercial broiler chickens from hatching to market weight at 6 wk. Gross pathology and histopathology analyses were performed on pectoralis major muscle collected weekly from birds culled from 1 to 6 wk. The severity of both gross and histologic pathologies in the breast muscle increased over time. White striping was initially observed at week 2, with a rise in the incidence and severity through the sixth week. Mild histopathology was noted in week 2, characterized by macrophage infiltration and limited phagocytosis of the muscle. Muscle condition deteriorated with age and weight gain, with more prevalent macrophages, phagocytosis, and interstitial fibroblasts. By week 5 and 6, there was severe myopathy including regions of obliterated muscle tissue. Linear regression models show a positive correlation between white striping, gross pathology, and histopathology relative to weight and age.

Growth performance, carcass characteristics, and fatty acid composition of breast and thigh meat of broiler chickens fed gradually increasing levels of supplemental blueberry extract.

The effect of gradually increasing supplemental levels of blueberry extract on growth performance, carcass characteristics, and fatty acid composition of breast and thigh muscles of broiler chickens was investigated. One hundred ninety-two 7-day-old chickens were randomly distributed into four groups having four replicates with 12 birds in each replicate. Basal diets were prepared for starter (days 8 to 21) and finisher (days 22 to 42). Basal diets were offered to the control group only, whereas other treatments received basal diets fortified with 0.5, 1, and 2% blueberry extract (BB0.5, BB1, and BB2 groups, respectively). The duration of experiment was 35days (days 8 to 42). During finisher and overall growth phases, broilers in the BB2 group had greater body weight gain than those in the BB0.5 and control groups, whereas the BB1 group had higher body weight gain than the control group (P < 0.001). Body weight gain remained unaffected during the starter phase. Feed intake was greater in the BB2 group than in the control group at days 8 to 21, 22 to 42, and 8 to 42 (P = 0.002, P = 0.035, and P = 0.001, respectively). The control group had poor FCR than the BB2 group in the starter phase (P = 0.034). At days 22 to 42, feeding blueberry extract (BB0.5, BB1, and BB2) improved the FCR of broilers compared with the control group, whereas the BB2 group had better FCR than the BB0.5 group (P < 0.001). At 8 to 42days, broilers in the control group had poor FCR compared with the BB1 and BB2 groups, whereas the BB0.5 group had poor FCR than the BB2 group (P < 0.001). Slaughter weight was lower in the control group than in the blueberry extract groups, whereas the BB2 group had greater slaughter weight than the BB0.5 group (P < 0.001). Dressing percentage of broilers in the control and BB0.5 groups was lower than that in other groups (P < 0.001). Gizzard yield was higher in the BB0.5 and BB2 groups than in the control group (P = 0.021). In addition, feeding 2% blueberry extract increased the concentration of different fatty acids in breast and thigh meat of broiler chickens. Findings suggest that feeding 2% blueberry extract may improve growth performance, carcass characteristics, and fatty acid composition of breast and thigh muscles of broilers.

Evaluation of Muscle Chemical and Amino Acids Composition in Broiler Chicks Fed Sorghum or Sorghum-Pea Diets

ABSTRACT The study evaluated the chemical and amino acids (AA) composition of breast and thigh muscle in broilers fed sorghum and sorghum-pea diets, as partial substitute of corn and soybean meal (SBM). A total of 540 3-wk-old broilers (Cobb 500) randomly assigned to three groups were fed with corn-SBM control diet (C), corn-sorghum-SBM diet (S) and corn-sorghum-peas-SBM diet (SP) for finisher phase. At slaughter, muscle samples were collected for chemical analyses. The results showed that dietary sorghum or sorghum-pea inclusion did not affect (p>0.05) the chemical composition (dry matter, protein, fat and ash) of broilers muscle tissue. The total AA (TAA), essential AA (EAA) or flavour-related AA (FAA) concentrations from breast or thigh muscle did not differ (p>0.05) between treatments. A significant effect (p<0.05) was found for some individual EAA. The valine and phenylalanine concentrations were higher, and cysteine and methionine levels were lower in both muscles than the C group. The higher deposition (p<0.05) was found for most AA, except glycine and arginine, in the breast vs thigh, as an effect of muscle tissue. As results, the TAA, EAA, NEAA, FAA and EAA/NEAA ratio increased in the breast vs thigh muscle. Interactions between diets and muscle tissue were noticed for serine, threonine, methionine, isoleucine, phenylalanine, lysine, arginine, TAA and EAA. In conclusion, sorghum or sorghum-peas can partially substitute the corn and SBM in broiler diets, with no adverse effects on chemical composition and beneficial nutrients, such as EAA and FAA that are important for the nutritional quality of meat.

Effects of guanidinoacetic acid supplementation on zootechnical performance and some biometric indices in broilers challenged with T3-Hormone

The objective was to elucidate the effects of dietary guanidinoacetic acid (GAA) supplementation on broiler performance, serum enzymes, oxidative biomarkers, mitochondrial activities, carcase traits, gross lesion of cardiac muscle and liver histopathology in broilers challenged with T3-hormone. A total-of-192 one-day-old mixed sexed broilers were randomly assigned in a two factorial design, including two dietary treatments; control diet supplemented with or without T3-hormone (1.5 ppm) and GAA diet (0.06%) supplemented with or without T3-hormone (1.5 ppm). Each group was subdivided into eight replicates. Results showed interactions between GAAxT3-hormone. GAA diet significantly mitigated the negative effect of T3-hormone on serum total creatine kinase (CK), cardiac muscle (CK-MB), liver malondialdehyde (MDA) and superoxide dismutase (SOD), mitochondrial activities of cardiac muscle and liver histopathological lesion. In conclusion, GAA at a rate of 0.06% may have the potential to mitigate the negative effect of dietary T3-hormone but could not reduce the ascites mortality at such inclusion rate. HIGHLIGHTS GAA protected heart muscle. GAA mitigated the oxidative radicals in T3-hormone challenged birds. GAA modulated the mitochondrial activities in T3-hormone challenged birds.

The role of histidine dipeptides on postmortem acidification of broiler muscles with different energy metabolism

It is generally held that the content of several free amino acids and dipeptides is closely related to the energy-supplying metabolism of skeletal muscles. Metabolic characteristics of muscles are involved in the variability of meat quality due to their ability to influence the patterns of energy metabolism not only in living animal but also during postmortem time. Within this context, this study aimed at establishing whether the concentration of histidine dipeptides can affect muscle postmortem metabolism, examining the glycolytic pathway of 3 chicken muscles (pectoralis major, extensor iliotibialis lateralis, and gastrocnemius internus as glycolytic, intermediate, and oxidative-type, respectively) selected based on their histidine dipeptides content and ultimate pH. Thus, a total of 8 carcasses were obtained from the same flock of broiler chickens (Ross 308 strain, females, 49 d of age, 2.8 kg body weight at slaughter) and selected immediately after evisceration from the line of a commercial processing plant. Meat samples of about 1 cm3 were excised from bone-in muscles at 15, 60, 120, and 1,440 min postmortem, instantly frozen in liquid nitrogen and used for the determination of pH, glycolytic metabolites, buffering capacity as well as histidine dipeptides content through 1H-NMR. Overall results suggest that glycolysis in leg muscles ceased already after 2 h postmortem, whereas in breast muscle continued until 24 h, when it exhibited significantly lower pH values (P < 0.05). However, considering its remarkable glycolytic potential, pectoralis major muscle should have exhibited a greater and faster acidification, suggesting that its higher (P < 0.05) histidine dipeptides' content might have prevented a potentially stronger acidification process. Accordingly, breast muscle also showed greater (P < 0.05) buffering ability in the pH range 6.0–7.0. Therefore, anserine and carnosine, being highly positively correlated with muscle's buffering capacity (P < 0.001), might play a role in regulating postmortem pH decline, thus exerting an effect on muscle metabolism during prerigor phase and the quality of the forthcoming meat. Overall results also suggest that total histidine dipeptides content along with muscular ultimate pH represent good indicators for the energy-supplying metabolism of chicken muscles.

Hydrogen peroxide–induced oxidative stress impairs redox status and damages aerobic metabolism of breast muscle in broilers

Oxidative stress has always been a hot topic in poultry science. However, studies concerning the effects of redox status and glucose metabolism induced by hydrogen peroxide (H2O2) in the breast muscle of broilers have been rarely reported. This study was aimed to evaluate the impact of intraperitoneal injection of H2O2 on oxidative damage and glycolysis metabolism of breast muscle in broilers. We also explored the activation of the nuclear factor erythroid 2–related factor 2 (Nrf2) signaling pathway to provide possible mechanism of the redox imbalance. Briefly, a total of 320 one-day-old Arbor Acres chicks were randomly divided into 5 treatments with 8 replicates of 8 birds each (noninjected control, 0.75% saline-injected, 2.5, 5.0, and 10.0% H2O2-injected treatments). Saline group was intraperitoneally injected with physiological saline (0.75%) and H2O2 groups received an intraperitoneal injection of H2O2. The dosage of the injection was 1.0 mL/kg BW. All birds in the saline and H2O2 groups were injected on days 16 and 37 of the experimental period. At 42 d of age, 40 birds (8 cages per group and one chicken per cage) were selected to be stunned electrically (50 V, alternating current, 400 Hz for 5 s each one), and then immediately slaughtered via exsanguination. The results showed that broilers in the H2O2 injection group linearly exhibited higher contents of reactive oxygen species, carbonyl and malondialdehyde, and lower total antioxidant capacity and glutathione peroxidase activities. With the content of H2O2 increased, the H2O2 groups linearly downregulated the mRNA expressions of GPX, CAT, HMOX1, NQO1, and Nrf2 and its downstream target genes. In addition, H2O2 increased serum activities of creatine kinase and lactate dehydrogenase. Meanwhile, in the pectoral muscle, the glycogen content was linearly decreased, and the lactate content was linearly increased in muscle of broilers injected with H2O2. In addition, the activities of glycolytic enzymes including pyruvate kinase, hexokinase, and lactate dehydrogenase were linearly increased after exposure to H2O2. In conclusion, H2O2 injection could impair antioxidant status and enhance anaerobic metabolism of breast muscle in broilers.

Effect of DL-Methionine Supplementation on Tissue and Plasma Antioxidant Status and Concentrations of Oxidation Products of Cholesterol and Phytosterols in Heat-Processed Thigh Muscle of Broilers.

Simple SummaryThe occurrence of oxidative stress is a general problem in high-yielding farm animals. Oxidative stress not only affects animal health, but free radicals generated under oxidative stress conditions can also promote the oxidation of lipids in animal products which are detrimental for the consumer, such as lipid oxidation products. Therefore, prevention of oxidative stress by improving the antioxidant system has high priority in farm animal management. Methionine (Met) is a precursor of glutathione, one of the major antioxidants in the body. Therefore, we investigated the hypothesis that feeding diets with an excess of Met in relation to the requirement for optimum growth improves the antioxidant status by enhancing the formation of glutathione in broilers. We observed that broilers fed diets with an excess of Met had higher concentrations of glutathione in liver and thigh muscle, indicative of an improved antioxidant status, and moreover had lower concentrations of cholesterol oxidation products in heat-processed thigh muscle, in comparison to broilers of the control group. This effect is favorable with respect to animal health and quality of broiler meat.In this study, the hypothesis that supplementation with methionine (Met) as DL-Met (DLM) in excess of the National Research Council (NRC) recommendations improves the antioxidant system in broilers was investigated. Day-old male Cobb-500 broilers (n = 72) were divided into three groups which were fed a control diet or diets supplemented with two levels of DLM in which the concentrations of Met + Cys exceeded the recommendations of NRC by 15–20% (group DLM 1) or 30–40% (group DLM 2), respectively. The three groups of broilers did not show differences in body weight gains, feed intake, and feed conversion ratio. However, broilers of groups DLM 1 and DLM 2 had higher concentrations of glutathione (GSH) in liver and thigh muscle and lower concentrations of cholesterol oxidation products (COPs) in heat-processed thigh muscle than broilers of the control group. Concentrations of several oxidation products of phytosterols in heat-processed thigh muscle were also reduced in groups DLM 1 and DLM 2; however, the concentration of total oxidation products of phytosterols was not different between the three groups. The study shows that DLM supplementation improved the antioxidant status due to an increased formation of GSH and reduced the formation of COPs during heat-processing in thigh muscle.