Muscle Of Broiler Chickens Research Articles

Transcriptome analysis of post-hatch breast muscle in legacy and modern broiler chickens reveals enrichment of several regulators of myogenic growth.

Agriculture provides excellent model systems for understanding how selective pressure, as applied by humans, can affect the genomes of plants and animals. One such system is modern poultry breeding in which intensive genetic selection has been applied for meat production in the domesticated chicken. As a result, modern meat-type chickens (broilers) exhibit enhanced growth, especially of the skeletal muscle, relative to their legacy counterparts. Comparative studies of modern and legacy broiler chickens provide an opportunity to identify genes and pathways affected by this human-directed evolution. This study used RNA-seq to compare the transcriptomes of a modern and a legacy broiler line to identify differentially enriched genes in the breast muscle at days 6 and 21 post-hatch. Among the 15,945 genes analyzed, 10,841 were expressed at greater than 0.1 RPKM. At day 6 post-hatch 189 genes, including several regulators of myogenic growth and development, were differentially enriched between the two lines. The transcriptional profiles between lines at day 21 post-hatch identify 193 genes differentially enriched and still include genes associated with myogenic growth. This study identified differentially enriched genes that regulate myogenic growth and differentiation between the modern and legacy broiler lines. Specifically, differences in the ratios of several positive (IGF1, IGF1R, WFIKKN2) and negative (MSTN, ACE) myogenic growth regulators may help explain the differences underlying the enhanced growth characteristics of the modern broilers.

Effects of Tannic Acid on Performance and Fatty Acid Composition of Breast Muscle in Broiler Chickens Under Heat Stress

One hundred twenty day-old broiler chicks (Cobb 500) were randomly assigned into 4 treatment groups to investigate the effects of tannic acid supplementation (TA) on fatty acid composition in breast muscle of broilers under chronic heat exposure conditions. Five pen replicates of 6 chicks each were assigned to each of the following 4 dietary treatments: i) basal diet containing no TA at 25°C (CL); ii) basal diet containing no TA at 35°C (CH); iii) basal diet supplemented with 1% TA at 25°C (TL); and iv) basal diet supplemented with 1% TA at 35°C (TH). At the end of the 5-week experiment, breast muscle samples were collected to examine the fatty acid composition. Results showed that temperature, TA and their interaction effect significantly decreased body weight gain and feed intake. In addition, feed conversion ratio (FCR) significantly increased under high temperature, and addition of TA under high temperature did not improve the FCR. The effects of temperature, TA and their interaction on the saturated and unsaturated fatty acids were not significant (P<0.05). However, monounsaturated fatty acids significantly reduced by adding TA to the diet. Generally, TA improved the fatty acid profile of breast muscle of broilers under heat stress in comparison to the heat stressed chickens, which did not receive TA. Hence, it seems that dietary TA supplementation can be applied as a biological antioxidant for poultry nutrition in hot climatic conditions.

Estimation of Heavy Metal Levels in the Muscle, Gizzard, Liver and Kidney of Broiler, Layer and Local (Cockerel) Chickens Raised within Awka Metropolis and Its Environs, Anambra State, South Eastern Nigeria

65 chickens (layer, broiler and cockerel) from different farms within Awka metropolis and its environs were purchased, processed and analyzed for the levels of heavy metals (Pb, As, Cd, Ni, Cr, Hg, V and Cu) in the internal organs (muscle, gizzard, liver and kidney) of the chickens using flame atomic absorption spectrometer after nitric/perchloric acid digestion. The ranges of mean concentrations of the metals in the internal organs of the chickens in mg/g were Pb; (0.046 - 0.478) As; (0.053 - 0.318), Cd; (0.027 - 0.649), Cr; (0.045 - 0.234), Hg; (0.052 - 0.740), Ni; (0.038 - 0.534), V; (0.037 - 0.053), and Cu; (0.146 - 0.445). About 10% - 40% of Pb, Cd and Hg exceeded the permissible level of 0.5 ppm set for these metals in the liver and kidney of the chickens. Anova analysis revealed significance of the heavy metals in the internal organs of the chickens at p < 0.05.

The Effect of Breed Line and Age on Measurements of pH-value as Meat Quality Parameter in Breast Muscles (m. Pectoralis Major) of Broiler Chickens

The objective of this study was to determine the effect of breed line and age on pH in broiler chicken breast muscles. pH values of m. pectoralis major muscle were compared within 6 groups - each line (Cobb, Ross, Hubbard) was divided into two groups aged 42 and 50 days. pH values were recorded 15minutes, 24 and 48hours after slaughtering. Older broilers showed significantly lower pH than younger ones. Interactions between breed line and age were found, except for pH after 24hours. Meat quality of broilers can be estimated quickly by determining the pH-value of breast meat.

干酪乳杆菌L. casei Zhang对肉鸡屠宰性能及肌肉品质的影响

本试验旨在研究添加不同剂量的L. casei Zhang对肉鸡的屠宰性能及肌肉品质的影响，进一步探讨其作为一种新型饲料益生菌的可行性。试验以玉米和大豆粕为主要原料配制日粮，采用单因子随机试验设计方法，选择1日龄雌雄各半的健康AA肉仔鸡180只，称重后随机分为3个组，其中1个对照组和2个L. casei Zhang组，每个组6个重复，每个重复10只鸡，各组鸡的初始体重经方差检验差异均不显著(P > 0.05)。对照组肉鸡不饲喂L. casei Zhang，L. casei Zhang组饮水饲喂L. casei Zhang，添加水平分别是为2 × 105 cfu/ml和2 × 106 cfu/ml。试验期42天。本试验研究结果表明，添加L. casei Zhang可显著提高肉鸡全净膛率、胸肌率和宰后36h pH (P The present experiment was conducted to study the effects of dietary L. casei Zhang on intestinal structure of broiler chicken. In the experiment, a total of 180 1-day-old AA mixed-sex broiler chickens with similar body weight were randomly allotted into 3 treatments with 6 replicates in each treatment, with 10 broilers in each replicate. The trial period was 42 d. The basal diet was mainly composed of corn and soybean. Broiler chickens were fed four levels of L. casei Zhang (0, 2 × 105 cfu/ml and 2 × 106 cfu/ml respectively) in drinking water in a single factorial arrangement. The results showed that adding L. casei Zhang can significant increase dressing rate, brisket rate and pH after slaughter of 36 h (P < 0.05), as well as carcass traits. The additive dosage of 2 × 106 cfu/ml in the treatment group is better than others. However L. casei Zhang does not improve the flesh color and keep the water force for muscle of broiler chickens, showing that L. casei Zhang doesn’t have significant beneficial modulation for the meat quality of broiler chickens.

Effects of Fasting and Refeeding on Expression of Atrogin-1/MAFbx in Cardiac Muscle of Broiler Chickens

Effects of Fasting and Refeeding on Expression of Atrogin-1/MAFbx in Cardiac Muscle of Broiler Chickens

Вміст амінокислот і поліамінів у грудному м’язі курчат-бройлерів за умов застосування екстракту селезінки з метою нівелювання передзабійного стресу

The results on the Adrenocorticotropic hormone (ACTH) level in blood, amino acids and polyamines content in pectoral muscle of broiler chickens under using spleen extract for decreasing pre-slaughter stress are presented. The spleen extract (70% alcohol solution in volume 1.4 ml per chicken) was added to the diet of broiler chi­ckens of experimental groups by using aerosol method. This extract was obtained with and without the ultrasound application. 70% alcohol solution in the same volume and the same method was used to the diet of broiler chickens of control group five days before slaughter. The content of polyamines, such as putrescin, spermine and spermidin in pectoral muscle of broiler chi­ckens was determined. The total amount of polyamines and spermine specifically of both experimental groups in broiler chickens pectoral muscle was reliable higher compared to the control. The level of putrescin, spermine and spermidin was the lowest in pectoral muscle of broiler chickens of control group. The putrescin content in the pectoral muscle was reliablely highest in broiler chickens of the first experimental group after addition to the diet of the spleen extract with the ultrasound application. The concentration of amino acids, except of serine, in broiler chickens pectoral muscle was reliablely highest in broiler chickens of both experimental group, compared to control. The amount of polyamines and spermine specifically of both experimental groups in pectoral muscle of broi­ler chickens was reliablely higher, compared to control. After using of spleen extract, obtained with and without the ultrasound application, ACTH level in blood of broiler chi­ckens was reliablely lower compared to control, that caused a decrease at the pre-slaughter stress. The amino acids content in pectoral muscle of broiler chickens was reliablely the highest in broiler chickens of both experimental group after addition of the spleen extract to the diet that caused a raise in biological quality of poultry meat.

Effect of Different Dietary n-6 to n-3 Fatty Acid Ratios on the Performance and Fatty Acid Composition in Muscles of Broiler Chickens.

The objective of this study was to investigate the different dietary ratios of n-6 to n-3 (n-6/n-3) fatty acid (FA) on performance and n-6/n-3 FA in muscles of broiler chickens. A total of 300 one-day-old Cobb chicks were randomly assigned to 3 treatments of 10 replicates in each (10 birds/replicate). Birds were fed on a corn-soybean meal-based diet containing 1% oil during starter (day 1 to 21) and 2% oil during finisher (day 22 to 39) phases, respectively. Treatments of high, medium and low dietary n-6/n-3 FA were formulated by replacing rice bran oil with linseed oil to achieve n-6/n-3 FA close to >20:1, 10:1 and 5:1, respectively. Average daily gain, average daily feed intake, and feed conversion ratio were similar (p>0.05) among the treatments. Serum glucose, cholesterol and triglycerides concentrations were not affected (p>0.05) by dietary treatments. In breast, concentration of C18:3n-3 was significantly greater (p = 0.001) for medium and low vs high n-6/n-3 FA, while concentrations of C20:5n-3, C22:6n-3, total n-3 FA, and n-6/n-3 FA were significantly higher for low vs medium, and medium vs high dietary n-6/n-3 FA. In contrast, concentrations of C18:2 and mono-unsaturated FA (MUFA) were lower for low vs high dietary n-6/n-3 FA. In thigh muscles, concentrations of C20:5n-3 were higher (p<0.05) for medium and low vs high dietary n-6/n-3 FA, and concentrations of C18:3n-3, C22:6, and n-3 FA were greater (p<0.05) for medium vs high, low vs medium dietary n-6/n-3 FA. However, concentrations of C18:1, MUFA, n-6/n-3 were lower (p<0.05) for low and medium vs high dietary n-6/n-3 FA. In conclusion, lowering the dietary n-6/n-3 FA did not affect the performance of chickens, but enhanced beneficial long-chain n-3 FA and decreased n-6/n-3 FA in chicken breast and thigh, which could be advantageous for obtaining healthy chicken products.

Effects of the replacement of corn oil with linseed oil on fatty acid composition and the expression of lipogenic genes in broiler chickens

The effect of dietary 18:2n-6/18:3n-3 ratio (by the replacement of corn oil with linseed oil) on n-3 polyunsaturated fatty acids (PUFA) enrichment in breast muscle of broiler chickens and the expression of lipogenic genes were investigated. Broiler chickens were fed ad libitum with diets containing 5% corn oil (CO), 3.75% corn oil + 1.25% linseed oil (CL1), 2.5% corn oil + 2.5% linseed oil (CL2), and 5% linseed oil (LO) based on the basic diets, respectively. Dietary 18:2n-6/18:3n-3 ratio did not affect 42-day body weight and 0&amp;ndash;42-day feed conversion efficiency (feed/gain, P &amp;gt; 0.05) of broiler chickens, however, 5% linseed oil significantly increased 0&amp;ndash;21-day feed conversion efficiency (feed/gain, P &amp;lt; 0.05) and decreased breast muscle weight (by 16%, P &amp;lt; 0.05) of broiler chickens. With the decrease of dietary 18:2n-6/18:3n-3 ratio, the enrichment of total n-3 PUFA, 18:3n-3, 20:5n-3, and 22:5n-3 increased linearly (P &amp;lt; 0.01), while the enrichment of total n-6 PUFA and 18:2n-6 decreased linearly (P &amp;lt; 0.01) in breast muscle of broiler chickens. Dietary corn oil increased the enrichment proportion of 20:4n-6 in a dosage-independent manner. Replacing 1.5% corn oil with linseed oil increased the enrichment proportion of 22:6n-3 (P &amp;lt; 0.05), but continuing to increase dietary linseed oil could not further elevate its deposition. Real-time quantitative RT-PCR was used to determine the expression of the mRNA levels of related genes. Dietary PUFA had insignificant effect on the expressions of LPIN2, WD and tetratricopeptide repeats 1 (WDTC1) and △-6 fatty acid desaturase (FADS2) in both breast muscle and abdominal fat. The effect of dietary PUFA on the expression of LPIN1 gene showed clear tissue dependence. Equivalent adding of corn oil and linseed oil could up-regulate the mRNA level of LPIN1 in abdominal fat (P &amp;lt; 0.01). This study demonstrated that decreasing dietary 18:2n-6/18:3n-3 ratio promoted the deposition of desirable n-3 long chain PUFA in the edible tissue and influenced the expression of LPIN1 in a tissue-dependent manner. &amp;nbsp;

New Polymorphisms in Regulatory Region of CAPN3 Gene with no Effect on Gene Expression in Breast Muscle of Broiler Chickens

Abstract Calpains are enzymes that belong to calcium-dependent, non-lysosomal cysteine proteases. The CAPN3 gene encodes a major intracellular specific muscle protease with a high capacity for degradation of cytoskeletal and muscle fibre proteins. Therefore, they play an important role in fusion of myoblasts, proliferation, cell growth and migration. In chickens, the gene encoding for calpain 3 is localized on chromosome 5. Due to the function of encoded protein, the CAPN3 has beenchosen as a candidate gene for meat quality in chickens. Consequently, the aim of our study was to identify new polymorphisms in the regulatory region of CAPN3 gene and to investigate their impact on CAPN3 transcript abundance in breast muscles. The experiment used broilers of two genetic lines: fast- and slow-growing. The polymorphisms were identified by screening with High Resolution Melting (HRM) and sequencing based on the Sanger method. The CAPN3 gene expression was conducted by using succinate dehydrogenase complex, subunit A (SDHA) and 60S ribosomal protein L4 (RPL4) genes as endogenous controls. Four new polymorphisms were found: g.322176G&gt;A in promoter region (GenBank: AADN03004661.1), c.176*C&gt;T, c.144*G&gt;C and c.137*_147*delCAGCCCTGCTT in 3`UTR sequence. The new polymorphisms were identified by using restriction enzymes ScrFI, BslI, AcuI, HpyAV, respectively. The frequency of polymorphisms found in 3`UTR region was similar in both lines. According to polymorphisms identified in 3`UTR region the alleles with deletion, C and C (c.137*_147*del, c.144*G&gt;C and c.176*C&gt;T) were rare. The polymorphism identified in the promoter region and 3`UTR regions changed a few binding sites for transcription factors, but did not alter any binding sites for the other important translation regulators such as miRNA. Analysis of the effect of new polymorphisms on CAPN3 gene expression showed that in fast-growing line the chickens with GG genotype according to polymorphism g.322176G&gt;A inthe promoter region, were characterized by the highest CAPN3 transcript abundance. Other polymorphisms in 3&gt;UTR region seem to have no effect on CAPN3 gene expression.

Effects of Phytosterol in Feed on Growth and Related Gene Expression in Muscles of Broiler Chickens

Purpose: To investigate the effect of phytosterol in a feed on growth and gene expression of broiler chickens.Methods: Seven isonitrogenous diets with graded levels of polyhydroxy phytosterol(Castastesrone) (15, 20, and 25 g/kg diet) and hydroxyphytosterol (â-sitosterol) (25, 50, and 75 g/kg diet) were used to feed broiler chickens for 45 d.Results: The dietary phytosterol significantly improved (p &lt; 0.05) the body weight and feed intake of broiler chickens, especially with the 75 g/kg diet. In contrast, phytosterol supplementation was associated with significant (p &lt; 0.05) hypotriglyceridemic effects with concurrent modifications ofdepressed antioxidant defence systems in the broiler chickens. Myogen, eIF4E, and S6k1 gene expression levels in tissues were significantly (p &lt; 0.05) improved by dietary phytosterol. mTOR gene expression levels in muscle tissues were increased significantly (p &lt; 0.05), but myostatin (GDF-8) and ubiquitin levels were significantly decreased (p &lt; 0.05).Conclusion: These results suggest that giving immediate phytosterol feeding regimen to chicks is a good feeding program for appropriate morphological development of the pectoralis major muscle and the expression of genes necessary for muscle cell proliferation and differentiation. Furthermore, the data suggest that developmental decline in skeletal muscle protein synthesis, may be partly attributed to developmental regulation of the activation of growth factor and nutrient components.Keywords: Broiler chicken, Polyhydroxy phytosterol; Hydroxyphytosterol, Feed, Antioxidant status, Gene expression.

Effect of allele frequencies, effect sizes and number of markers on prediction of quantitative traits in chickens

The objective was to assess goodness of fit and predictive ability of subsets of single nucleotide polymorphism (SNP) markers constructed based on minor allele frequency (MAF), effect sizes and varying marker density. Target traits were body weight (BW), ultrasound measurement of breast muscle (BM) and hen house egg production (HHP) in broiler chickens. We used a 600K Affymetrix platform with 1352 birds genotyped. The prediction method was genomic best linear unbiased prediction (GBLUP) with 354564 single nucleotide polymorphisms (SNPs) used to derive a genomic relationship matrix (G). Predictive ability was assessed as the correlation between predicted genomic values and corrected phenotypes from a threefold cross-validation. Predictive ability was 0.27±0.002 for BW, 0.33±0.001 for BM and 0.20±0.002 for HHP. For the three traits studied, predictive ability decreased when SNPs with a higher MAF were used to construct G. Selection of the 20% SNPs with the largest absolute effect sizes induced a predictive ability equal to that from fitting all markers together. When density of markers increased from 5K to 20K, predictive ability enhanced slightly. These results provide evidence that designing a low-density chip using low-frequency markers with large effect sizes may be useful for commercial usage.

The effects of thermal and light exposure on the development of broiler chicken leg musculature

Modified incubation factors affect skeletal musculature development of broiler chickens during embryonic and postnatal periods of development. These changes appear to have great influence on the proliferation of myoblasts and muscle growth after hatching. In this study, the histomorphological and -morphometric parameters of broiler chicken leg musculature, after thermal and light treatments during embryogenesis, were examined. The applied treatments included thermal manipulation (exposure of fertilized eggs to increased temperature), light manipulation (exposure of fertilized eggs to monochromatic green light) and simultaneous thermal and light manipulations. Following the specific parameters that were observed, it was determined that in the late postnatal period of development, treated groups have a larger diameter and smaller nucleocytoplasmic ratio of muscle cells compared to those of the control group, in which fertilized eggs were incubated at a constant temperature of 37.8?C, without light. Diameter was increased by 4.20%, 3.77% and 4.55% on day 42 after hatching in thermal, light and combined thermal and light treated groups, respectively, compared to the control. The nucleocytoplasmic ratio was increased by 37.5% on day 42 after hatching in the control group compared to all treated groups. The volume density of the muscle connective tissue was approximately at the same level between the groups. It can be concluded that thermal and light treatments stimulate the proliferation of myoblasts and enhance development and growth of leg muscles in broiler chickens.

The effect of season of transportation on the welfare of broilers and selected parameters of broiler meat quality

During breeding, especially during transportation from the farm to the slaughterhouse, poultry is exposed to various stressful factors that influence post-mortem muscle metabolism and, consequently, the meat quality. The aim of this study was to investigate the effect of season of transportation on broiler welfare and broiler meat quality parameters: pH, colour and cooking loss t. For the purpose of the experiment, during the summer (July) and winter (November), twelve broilers were tested, reared on the same farm and belonged to the same flock of line hybrid Ross 308. Distance from the farm to the slaughterhouse was 130 km, and transport lasted 3 to 5 hours. Average values of temperature and relative humidity during transport in summer period were 20.60ºC and 65.64%, respectively, and in the winter period 14.42ºC and 69.14%, respectively. It was established that the samples of breast muscle and drumstick muscles of broiler chickens transported in summer had higher average L*(lightness) values. When the L*value of 56L* units, as the limit of PSE (pale, soft, exudative) meat, are applied on the results of the present study, it can be concluded that, in the summer, the share of pale meat in samples of breast and drumsticks was 75%, while in winter it was 33.34% for breasts and 16.67% for drumsticks. After transport, in the summer, pH values of breast and drumstick muscles (5.40 ± 0.20 and 5.71 ± 0.30, respectively) were significantly lower than the pH values measured after transport in winter (5.90 ± 0.18 and 6.46 ± 0.25, respectively). Lower values of cooking loss in the samples of breast muscle and drumstick samples (29.06 ± 2.80 and 29.69 ± 3.47, respectively) were found in broiler chickens transported in November, when exposed to lower temperatures. Between pH and cooking loss, and pH and L*values of samples of breast muscles and drumstick muscles studied after transport in summer and winter periods, negative correlation was determined.

Effects of tonic immobility (TI) and corticosterone (CORT) on energy status and protein metabolism in pectoralis major muscle of broiler chickens

Tonic immobility (TI), which can be divided into short (STI) or long (LTI) duration, is a character related to fear. Our previous study has demonstrated LTI phenotype and chronic corticosterone (CORT) administration retarded growth of breast muscle in broiler chickens. In order to investigate the mechanism behind the negative effects of LTI and CORT on growth, the level of mRNA transcription of several key genes linked to energy and protein metabolism was measured in muscle. LTI broilers showed lower levels of ATP, energy charge (EC) (p<0.01), and lower muscle glycogen content (p<0.05) but higher level of ADP (p=0.08) than STI birds. CORT treatment elevated EC level (p<0.05) and reduced liver glycogen content (p<0.05). Real-time PCR results showed that STI chickens had higher mRNA expression of PPAR α (p=0.06) and AMPK α (p=0.09) than LTI. CORT significantly down-regulated α-enolase mRNA expression in breast muscle compared to control (p<0.05). Neither TI nor CORT altered gene expression in Akt/mTOR/p70s6k cascade pathway in muscle (p > 0.05). However, western blot results showed that LTI chickens exhibited higher protein content of total Akt (p=0.05) and phosphorylated Akt (p=0.06) than STI. CORT treatment decreased the total protein content of Akt (p=0.09) and p70s6k (p=0.08). These results suggest that the retardation of muscle growth by LTI and chronic CORT administration parallels a strong alternation in energy status but slight changes of Akt/mTOR/p70s6k cascade, indicating that a decrease in muscle growth induced by LTI and CORT might not be mediated through mTOR-dependent signaling pathways.

Histological Changes in Liver and Pectoral Muscles of Broiler Chickens Slaughtered with and Without Naming of Allah

Histological Changes in Liver and Pectoral Muscles of Broiler Chickens Slaughtered with and Without Naming of Allah

Dietary alpha lipoic Acid improves body composition, meat quality and decreases collagen content in muscle of broiler chickens.

A total of 192 broiler chicks were used to evaluate the influence of dietary α-lipoic acid (ALA) on growth performance, carcass characteristics and meat quality of broiler chickens with the purpose of developing a strategy to prevent the occurrence of pale, soft, and exudative (PSE) meat and to improve the meat quality of broilers. At 22 d of age, birds were allocated to 4 ALA treatments (0, 400, 800, and 1200 ppm). The results showed that dietary ALA significantly decreased average feed intake (AFI), average daily gain (ADG), final live body weight (BW) and carcass weight (p<0.05), while no difference in feed conversion ratio (FCR) was detected among chickens fed with and without ALA. Abdominal fat weight significantly decreased (p<0.05) for broilers fed 800 and 1200 ppm ALA. However when calculated as the percentage of carcass weight there was no significant difference between control and ALA treatments. Meat quality measurements showed that dietary ALA regulated postmortem glycolysis and improved meat quality as evidenced by increased muscle pH and decreased drip loss of meat (p<0.05). Although ALA did not change the tenderness of meat as indicated by meat shear force, dietary ALA decreased collagen content and mRNA expression of COL3A1 gene (p<0.05). In conclusion, the results indicate that dietary ALA may contribute to the improvement of meat quality in broilers.

Influence of in ovo prebiotic and synbiotic administration on meat quality of broiler chickens

A trial was conducted to evaluate the effect of in ovo injection of prebiotic and synbiotics on growth performance, meat quality traits (cholesterol content, intramuscular collagen properties, fiber measurements), and the presence of histopathological changes in the pectoral muscle (PS) of broiler chickens. On d 12 of incubation, 480 eggs were randomly divided into 5 experimental groups treated with different bioactives, in ovo injected: C, control with physiological saline; T1 with 1.9 mg of raffinose family oligosaccharides; T2 and T3 with 1.9 mg of raffinose family oligosaccharides enriched with different probiotic bacteria, specifically 1,000 cfu of Lactococcus lactis ssp. lactis SL1 and Lactococcus lactis ssp. cremoris IBB SC1, respectively; T4 with commercially available synbiotic Duolac, containing 500 cfu of both Lactobacillus acidophilus and Streptococcus faecium with the addition of lactose (0.001 mg/embryo). Among the hatched chickens, 60 males were randomly chosen (12 birds for each group) and were grown to 42 d in collective cages (n = 3 birds in each 4 cages: replications for experimental groups). Broilers were fed ad libitum commercial diets according to age. In ovo prebiotic and synbiotic administration had a low effect on investigated traits, but depend on the kind of bioactives administered. Commercial synbiotic treatment (T4) reduced carcass yield percentage, and the feed conversion ratio was higher in T3 and T4 groups compared with other groups. The abdominal fat, the ultimate pH, and cholesterol of the PS were not affected by treatment. Broiler chickens of the treated groups with both slightly greater PS and fiber diameter had a significantly lower amount of collagen. The greater thickness of muscle fibers (not significant) and the lower fiber density (statistically significant), observed in treated birds in comparison with those of the C group, are not associated with histopathological changes in the PS of broilers. The incidence of histopathological changes in broiler chickens from examined groups was low, which did not affect the deterioration of meat quality obtained from these birds.

Skeletal muscle fatty acids shift from oxidation to storage upon dexamethasone treatment in chickens

The effect of an exogenous glucocorticoid on the lipid metabolism and fatty acid pattern of skeletal muscle in broiler chickens (Gallus gallus domesticus) was investigated in vivo and in vitro. Male Arbor Acres chickens were subjected to dexamethasone (DEX) treatment for 3days. We found that DEX retarded body growth, facilitated lipid accumulation in adipose and skeletal muscle tissues, and elevated the thigh monounsaturated fatty acids (MUFA) to saturated fatty acids (SFA) ratio at fasted state. DEX-treated chickens exhibited increased stearoyl-CoA desaturase-1 (SCD1) activity and decreased carnitine palmitoyltransferase-1 (CPT1) activity in the thigh muscle under fasting conditions and in primary cultured myoblasts. Phosphorylation of AMP-activated protein kinase alpha at Thr172 did not occur in vivo but was increased in vitro by DEX. In cells exposed to DEX, fatty acid transport protein-1 mRNA expression and fatty acid storage were enhanced while fatty acid oxidation was repressed. In conclusion, in oxidative muscle of fasted chickens, DEX stimulated uptake of myocellular fatty acids which was stored with the modified MUFA to SFA ratio in a process that maybe involved SCD1 activation. The altered fatty acid composition together with the inactivation of CPT1 showed an increased tendency towards fatty acid accumulation as opposed to oxidation. These findings provide important insight concerning the influence of glucocorticoids on lipid metabolism.

Betaine: a promising antioxidant agent for enhancement of broiler meat quality

1. Antioxidant and methyl donor effects of betaine in experimental animal models have recently been demonstrated. The present study was therefore designed to examine the antioxidant effects of betaine on the antioxidant status and meat quality of breast muscles in broilers. 2. Cobb broilers were randomly divided into Control, Methionine low, Methionine low plus betaine, and Betaine groups. 3. The activity of the main antioxidant enzyme (glutathione peroxidase) in the Betaine and the Methionine low plus betaine groups significantly increased compared to the Methionine low and Control groups. Catalase and superoxide dismutase activities were significantly higher in the Betaine group compared to the Methionine low group, and lipid peroxidation was significantly higher in the Control and the Methionine low groups. 4. The present study indicates that adding betaine (1 g/kg) to a diet deficient in methionine can significantly improve antioxidant defences and meat quality, decreasing lipid peroxidation in the breast muscles of broiler chickens.