Effect of fast-, medium- and slow-growing strains on meat quality of chickens reared under the organic farming method

Data-independent acquisition-based SWATH-MS proteomics profiling to decipher the impact of farming system and chicken strain and discovery of biomarkers of authenticity in organic versus antibiotic-free chicken meat

In the literature, there is a paucity of methods and tools that allow the identification of biomarkers of authenticity to discriminate organic and non-organic chicken meat products. Shotgun proteomics is a powerful tool that allows the investigation of the entire proteome of a muscle and/or meat sample. In this study, a shotgun proteomics approach using Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS) has been applied for the first time to characterize and identify candidate protein biomarkers of authenticity in post-mortem chicken Pectoralis major muscles produced under organic and non-organic farming systems (antibiotic-free). The proteomics characterization was further performed within two chicken strains, these being Ross 308 and Ranger Classic, which differ in their growth rate. From the candidate protein biomarkers, the bioinformatics enrichment analyses revealed significant differences in the muscle proteome between the two chicken strains, which may be related to their genetic background and rearing conditions. The results further provided novel insights on the potential interconnected pathways at interplay that are associated with the differences as a consequence of farming system of chicken strain, such as muscle contraction and energy metabolism. This study could pave the way to more in-depth investigations in proteomics applications to assess chicken meat authenticity and better understand the impact of farming systems on the chicken muscle and meat quality.

Markers for meat provenance and authenticity with an account of its defining factors and quality characteristics - a review

Provenance is becoming increasingly important in meat supply chains as it lends products higher perceived quality. However, its precise definition and interpretation along with its associated characteristics factors have remained somewhat elusive. This review meticulously defines meat provenance while dissecting the essential factors and associated quality attributes that constitute its essence and are subsequently employed to establish pertinent markers for provenance. Meat provenance emerges as a multi-dimensional construct stemming from the adept management of a constellation of factors relating to geographical origin, farm production system, traceability, and authenticity. Through intricate interactions, these factors unveil innate originality that not only forges a distinct reputation but also imparts a unique typicity to the meat product. Gaining insights into a meat product's provenance becomes attainable by scrutinizing its pertinent composition and organoleptic quality traits. Trace elements and stable isotopes stand out as provenance markers, forging a direct connection to both geographical origin and dietary sources. While somewhat less direct in linkage, other markers such as plant biomarkers, fatty acid composition, pH levels, flavour and aromatic compounds along with organoleptic characteristics contribute to the overall understanding of provenance. Additionally, the identification of animal species and breeds serves as key markers, particularly in the context of protected geographical indications. The study findings are useful for the various stakeholders of how the information for meat provenance can be linked with intrinsic and extrinsic factors for meat quality and protecting the integrity of the supply chain with special reference to traceability and authenticity. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Processing of beef rumen with ultrasonic waves

The article discusses the main trends in processing animal products, the development of technologies to improve their quality and technologies to preserve the quality indicators of the product over time. A review of the effects of ultrasound treatment on beef rumen is presented, and the main directions of ultrasound application are determined. The advantages of ultrasonic processing and its influence on the characteristics of raw meat were researched. The modes and parameters (frequency, intensity and duration) of ultrasound treatment of muscle tissue were established based on the results. This study evaluated the effect of ultrasound treatment on beef rumen's physical, microstructural and organoleptic characteristics. The physicochemical, mineral, microbiological, vitamin and amino acid composition of beef rumen and reticulum were also studied. Based on the results of the presented review, it can be concluded that the development of technologies for processing beef rumen with ultrasound is of potential interest. The optimal parameters are 400 and 600 W/m2, with a frequency of 40 kHz, for 50-60 minutes.

Intake of nutrients (polyunsaturated fatty acids, tocols, and carotenes) and storage efficiency in different slow-growing chickens genotypes reared in extensive systems

An extensive rearing system (ERS) for poultry requires an outdoor run, which enhances the foraging activity of chickens. Slow-growing (SG) strains are more adapted to ERS than fast-growing (FG); and generally, have higher levels of bioactive compounds in their meat. The aim of this paper was to assess the storage efficiency of n-3 and n-6 polyunsaturated fatty acids (PUFA), tocols and carotenes in the meat of seven commercial SG genotypes (SG1-7). One hundred SG chicks/strain of both sexes were included and their walking activity (High- or Low-W) was classified: SG1-4, HW comprised more than 10% of the time budget, and SG5-7, less than 10% (LW). Chickens were reared in pens (4 pens/strain) with indoor (0.10 m2/bird) and outdoor (4 m2/bird) areas, and they were fed the same diet ad libitum (starter feed for 1-21 d, grower feed from 22 d to slaughter at 81 d). The chickens were weighed weekly; feed consumption and grass intake were also estimated. At 81 days of age, 32 chickens/genotype were selected on the basis of the average weight (1:1, M:F) and slaughtered. The breast, thigh and drumstick meat were excised from 30 carcasses/genotype, sampled and stored at -20°C until analysis. Nutrients (e.g., n-3, n-6, carotenes and tocols) of feed, grass and meat were analyzed. The storage efficiency of nutrients was estimated as the ratio between the amount deposited in the body muscles (OUT) and the dietary intake (feed and grass, IN). The genotype affected chickens foraging behavior and the intake of nutrients. For SG1, SG2 and SG3, more than 50% of the intake of n-3 came from grass, whereas in the other genotypes, less than 20%. Accordingly, chickens that foraged more showed better meat nutritional profiles (less fat, more n-3 and antioxidants), which, in ERS, was ascribed to grass ingestion. However, the storage efficiency of nutrients into meat was inversely correlated with the grass intake: strains with higher grass intake (SG1, SG2, and SG3) had lower storage rates. Several hypotheses were proposed to explain these trends.

Indexing of Fatty Acids in Poultry Meat for Its Characterization in Healthy Human Nutrition: A Comprehensive Application of the Scientific Literature and New Proposals

Chicken meat is becoming the most consumed in the world for both economic and nutritional reasons; regarding the latter, the lipid profile may play positive or negative roles in the prevention and treatment of diseases. In this study, we define the state of the art of lipid-based nutritional indexes and used the lipid content and fatty acid profile (both qualitative and quantitative) of breast meat of two poultry genotypes with different growth rates and meat traits. Further, we summarize and review the definitions, implications, and applications of nutritional indexes used in recent years and others of our own design to provide a useful tool to researchers working in the field of meat quality (not only in poultry) to select the most appropriate index for their own scientific purposes. All indexes show advantages and disadvantages; hence, a rational choice should be applied to consider the nutritional effect of meat on human health and for a possible assessment of the most suitable rearing systems (genotype, feeding, farming system or postmortem handling).

The g.4290 C>G Polymorphism in the FADS2 Gene Modifies the Fatty Acid Profile of the Pectoralis Superficialis Muscle of Ross 308 Broiler Chickens

The effect of the g.4290 C>G substitution in the FADS2 gene and g.285 C>T in the FABP4 gene on carcass quality, meat quality, and fatty acid profile of the pectoralis superficialis muscle of 238 male broiler chickens reared up to 45 days of age was analyzed. A significant influence of g.4290 C>G in the FADS2 gene on the pectoralis superficialis muscle fatty acid profile was demonstrated. Chickens with the GG genotype were characterized by the highest content of conjugated linoleic acid, amino acids, eicosapentaenoic acids, docosapentaenoic acid, docosahexaenoic acids. and the lowest value of the linoleic acid/alpha-linolenic acid ratio. The FABP4 polymorphism determined only the content of C18:1n-9, C18:2n-6 and docosahexaenoic acid. There was no effect of the studied genotypes on final body weight, carcass quality traits, or quality of broiler pectoral muscles.

Breast Meat Fatty Acid Profiling and Proteomic Analysis of Beijing-You Chicken During the Laying Period

The disparity in fatty acids (FA) composition exhibits a significant impact on meat quality, however, the molecular regulatory mechanisms underlying this trait in chicken are far from clear. In this study, a total of 45 female Beijing-You chicken (BYC) hens, fed on the same diet, were collected at the slaughter age of 150, 300, or 450 days (D150, D300, and D450) from sexual maturation stage to culling stage (15 birds per age). Gas chromatography-mass spectrometry (GC-MS) and tandem mass tag labeling technology based on liquid chromatography mass spectrometry (TMT-LC-MS/MS) analysis strategies were applied to profile FA compositions and to compare differential expressed proteins (DEPs) between these different slaughter ages, respectively. The FA profiling showed that increasing hen ages resulted in increased contents of both saturated and unsaturated fatty acids. Proteomic analyses showed a total of 4,935 proteins in chicken breast muscle with the false discovery rate (FDR) < 1% and 664 of them were differentially expressed (fold change > 1.50 or < 0.67 and P < 0.01). There were 410 up- and 116 down-regulated proteins in D150 vs. D300 group, 32 up- and 20 down-regulated in D150 vs. D450 group, and 72 up- and 241 down-regulated in D300 vs. D450 group. A total of 57 DEPs related to FA/lipid-related metabolisms were obtained according to the enrichment analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). These DEPs were involved in 21 significantly enriched (P < 0.05) pathways, including well-known pathways for FA synthesis (metabolism, desaturation, and elongation) and the signaling pathways for lipid metabolism (PPAR, adipocytokine, calcium, VEGF, MAPK, and Wnt). In addition, there existed several representative DEPs (FABP, FABP3, apoA-I, apoA-IV, apoC-III, apoB, VTG1, and VTG2) involved in the regulation of FA/lipid transportation. The construction of the interaction networks indicated that HADH, ACAA2, HADHA, ACSL1, CD36, CPT1A, PPP3R1, and SPHK1 were the key core nodes. Finally, eight DEPs were quantified using parallel reaction monitoring (PRM) to validate the results from TMT analysis. These results expanded our understanding of how the laying age affects the FA compositions and metabolism in hen breast meat.

Poultry Meat and Eggs as an Alternative Source of n-3 Long-Chain Polyunsaturated Fatty Acids for Human Nutrition

The beneficial effects of n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) on human health are widely known. Humans are rather inefficient in synthesizing n-3 LC-PUFA; thus, these compounds should be supplemented in the diet. However, most Western human diets have unbalanced n-6/n-3 ratios resulting from eating habits and the fact that fish sources (rich in n-3 LC-PUFA) are not sufficient (worldwide deficit ~347,956 t/y) to meet the world requirements. In this context, it is necessary to find new and sustainable sources of n-3 LC-PUFA. Poultry products can provide humans n-3 LC-PUFA due to physiological characteristics and the wide consumption of meat and eggs. The present work aims to provide a general overview of the main strategies that should be adopted during rearing and postproduction to enrich and preserve n-3 LC-PUFA in poultry products. The strategies include dietary supplementation of α-Linolenic acid (ALA) or n-3 LC-PUFA, or enhancing n-3 LC-PUFA by improving the LA (Linoleic acid)/ALA ratio and antioxidant concentrations. Moreover, factors such as genotype, rearing system, transport, and cooking processes can impact the n-3 LC-PUFA in poultry products. The use of a multifactorial view in the entire production chain allows the relevant enrichment and preservation of n-3 LC-PUFA in poultry products.

Performance and meat quality traits of slow-growing chickens stimulated in ovo with galactooligosaccharides and exposed to heat stress

In vivo performance, carcass and meat quality traits of slow-growing chickens stimulated in ovo with trans galactooligosaccharides (GOS) and exposed to heat stress were evaluated. On d 12 of egg incubation, 3,000 fertilized eggs (Hubbard JA57) were divided into prebiotic group (GOS) injected with 3.5 mg GOS/egg, saline group (S) injected with physiological saline (only to assess the hatchability rate) and an uninjected control group (C). After hatching, 600 male chicks (300 from GOS and 300 from C) were housed on floor pens (6 pens/treatment, 25 birds/pen) and reared under neutral (TN) or heat stress conditions (HS, 30°C from 36 to 50 d). BW, daily feed intake (DFI), daily weight gain (DWG), feed conversion rate (FCR), and mortality were measured. At 50 d of age, 15 randomly selected birds/treatment/environmental conditions were slaughtered and the pectoral muscle (PM) was collected for analyses. Hatchability was similar among groups. BW of the newly hatched chicks was lower (P < 0.01) in GOS compared to C. Final BW, DWG, DFI, and FCR were not affected (P > 0.05) by GOS. HS reduced final BW (−12.93%, P < 0.001). During finisher phase, DFI and DWG were lower (P < 0.001) and FCR was higher (P < 0.01) in HS compared to TN. Mortality was not affected (P > 0.05) by GOS and HS. Meat from GOS chickens had a higher (P < 0.01) pH and was darker (P < 0.05) compared to C. Proximate composition, cholesterol content, fatty acid profile, and intramuscular collagen properties of PM were not affected by GOS. The HS group showed a lower (P < 0.05) content of both collagen and monounsaturated fatty acids than TN group. Significant interactions between GOS and temperature were found for FA composition. In conclusion, the differences in performance have had an impact on the responses to HS in Hubbard chickens, but not on mortality rate. GOS did not relieve the negative effect of HS on chickens’ performance.

Soybean vs. Pea Bean in the Diet of Medium-Growing Broiler Chickens Raised under Semi-Intensive Conditions of Inner Mediterranean Areas: Growth Performance and Environmental Impact

The effects of Glycine max L. (SOY) vs. Pisum sativum L. (PEA) in the diet were investigated on in vivo performance of two medium-growing broiler genotypes and on environmental impact. Sixty Kabir Red Plus and sixty New Red chickens were randomly allocated in 20 pens (n = 6 birds per pen). Each pen, i.e., experimental unit, received 1.18 kg dry matter (DM) including soybean (3.39%) in SOY, or pea bean (6.78%) in PEA groups. DM intake, DM refusals and bodyweight (BW) were recorded on pen basis, and average daily gain (ADG) and feed conversion rate (FCR) were calculated. Data on in vivo performance were processed by ANOVA General Linear Model followed by Student−Newman−Keuls post hoc test. Greenhouse gas (GHG) emissions were evaluated on a year basis by GLEAM-i software. The diet did not affect (p > 0.05) DM intake and DM refusals, BW, ADG and FCR. Diet x genotypes affected (p < 0.05) DM intake and DM refusals. PEA diet, cheaper than SOY diet, allowed the reduction in total GHG and CO2, and of meat emission intensity. However, an increase in total CH4 and N2O emissions was observed. The replacement of soybean with pea bean can represent a possible management strategy to reach trade-off between good farming practices and environmental protection on small-scale poultry farms of inner Mediterranean areas.

Lipid metabolism analysis in liver of different chicken genotypes and impact on nutritionally relevant polyunsaturated fatty acids of meat

Humans and mammalian species are unable to synthesize significant amounts of polyunsaturated fatty acids (PUFA), which therefore must be introduced with the diet. In birds, lipogenesis takes place primarily in the liver, whereas adipose tissue serves as the storage site for triacylglycerols (TG, composed by 80-85% esterified fatty acids). However, both the nature (unsaturation level, n-3, or n-6 series) and the allocation (such as constituents of complexed lipids) of PUFA are very important to evaluate their function in lipid metabolism. The objective of the present investigation was to study the liver lipid metabolism, with particular attention to non-esterified fatty acids (NEFA), TG, phospholipids (PL), FADS2 gene expression, and Δ6-desaturase activity of three chicken genotypes, Leghorn (Leg), Ross 308 (Ross), and their crossbreed (LxR), by LC/MS analysis. The concentration of single fatty acids in muscle was quantified by GC-FID. The results showed that the Ross has a lipid metabolism related mainly to storage and structural roles, exhibiting higher levels of TG, phosphatidylethanolamine (PE) and phosphatidylcholine (PC) that are largely unsaturated. Meanwhile Leg showed a relevant amount of n-3 NEFA characterized by a higher phosphatidylserine (PS) unsaturation level, FADS2 gene expression and enzyme activity. The LxR seem to have a moderate trend: n-6 and n-3 NEFA showed intermediate values compared with that of the Ross and Leg and the TG trend was similar to that of the Ross, while PE and PC were largely unsaturated (mainly 6 and 7 UNS most of the metabolic energy for storage fatty acids in their tissues (TG) whereas, the Leg birds were characterized by different lipid metabolism showing in their liver a higher content of n-3 NEFA and higher unsaturation level in PS. Furthers details are needed to better attribute the lipid energy to the different metabolic portion.

Effects of β-alanine and L-histidine supplementation on carnosine contents in and quality and secondary structure of proteins in slow-growing Korat chicken meat

Carnosine enrichment of slow-growing Korat chicken (KRC) meat helps differentiate KRC from mainstream chicken. We aimed to investigate the effects of β-alanine and L-histidine supplementation on the carnosine synthesis in and quality and secondary structure of proteins in slow-growing KRC meat. Four hundred 21-day-old female KRC were used, and a completely randomized design was applied. The chickens were divided into 4 experimental groups: basal diet (A), basal diet supplemented with 1.0% β-alanine (B), 0.5% L-histidine (C), and 1.0% β-alanine combined with 0.5% L-histidine (D). Each group consisted of 5 replicates (20 chickens per replicate). On d 70, 2 chickens per replicate were slaughtered, and the levels of carnosine, anserine, and thiobarbituric acid reactive substances were analyzed. Biochemical changes were monitored using synchrotron radiation-based Fourier transform infrared microspectroscopy; 5 chickens per replicate were slaughtered, and the meat quality was analyzed. Statistical analysis was performed using ANOVA and principal component analysis (PCA). Group D chickens exhibited the highest carnosine meat content, followed by those in groups B and C. However, amino acid supplementation did not affect anserine content and growth performance. Higher carnosine levels correlated with increasing pH_{45 min} and decreasing drip loss, cooking loss, shear force, and lipid oxidation. PCA revealed that supplementation with only β-alanine or L-histidine was related to increased content of β-sheets, β-turns, and aliphatic bending groups and decreased content of α-helix groups. This study is the first to report such findings in slow-growing chicken. Our findings suggest that KRC can synthesize the highest carnosine levels after both β-alanine and L-histidine supplementation. Higher carnosine contents do not adversely affect meat quality, improve meat texture, and alter the secondary structures of proteins. The molecular mechanism underlying carnosine synthesis in chickens needs further study to better understand and reveal markers that facilitate the development of nutrient selection programs.

In pursuit of a better broiler: carcass traits and muscle myopathies in conventional and slower-growing strains of broiler chickens

Selection for accelerated growth rate and high breast yield in broiler chickens have been associated with an increase in myopathies, including wooden breast (WB) and white striping (WS). To investigate effects of growth rate on carcass traits and incidence of myopathies, 14 strains were evaluated, encompassing 2 conventional (CONV; strains B and C: ADG0-48 > 60 g/d) and 12 slower-growing (SL) strains. The latter were categorized based on growth rate: FAST (strains F, G, I and M; ADG0-62=53-55 g/d), MOD (strains E, H, O and S; ADG0-62=50-51 g/d), and SLOW (strains D, J, K and N; ADG0-62<50 g/d). In a randomized incomplete block design, 7,216 mixed-sex birds were equally allocated into 164 pens (44 birds/pen; 30 kg/m2), with each strain represented in 8 to 12 pens over 2 to 3 production cycles. From each pen, 4 males and 4 females were processed at 2 Target Weights (TWs) based on their expected time to reach 2.1 kg BW (TW 1: 34 d for CONV; 48 d for SL strains) and 3.2 kg BW (TW 2: 48 d for CONV; 62 d for SL strains). Weights and yields for the carcass, breast, drumsticks, thighs, and wings were obtained; breast fillets were assessed to determine the presence and severity of WB and WS. At both TWs, breast yield was higher as growth rate increased (P < 0.001), with CONV having greater breast yield than other categories. Strain F had the greatest breast yield at both TWs (P < 0.001) within the FAST category. At TW 2, CONV had the greatest incidence of WB and WS (P < 0.001). However, within FAST, strain F had the greatest incidence of myopathies (P < 0.001) at both TWs, exhibiting values as high or as greater than CONV birds. The incidence of WB and WS in strains with differing growth rates but high breast meat yield suggests that the latter may play a major role in the occurrence of these myopathies.

Fatty acid profile in the breast and thigh muscles of the slow- and fast-growing birds under the same management system

The aim of the study was to assess the effect of feeding the same diet to different breeds of chickens and at different ages on fatty acid (FA) composition of the breast and thigh muscles. A total of 150 chickens comprising 50 each of red jungle fowl (RJ) and village chicken (VC), the slow-growing birds, and the commercial broiler (CB), fast-growing birds, were used for this study. Ten chickens from each breed were serially euthanized at days 1, 10, 20, 56, and 120 post hatch, and pectoralis major and bicep femoris were harvested to represent the breast and thigh muscles respectively. It was revealed that the breast muscle concentrations of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and total polyunsaturated fatty acids (PUFA) are significantly different (p<0.05) among the breeds. Also, the FA composition of breast and thigh muscles among RJ, VC, and CB at various ages studied varied significantly (p<0.05) but without a definite pattern. The composition of MUFA was lower, but that of PUFA was higher in the RJ and VC than in the CB breast muscles. Within the breeds, the composition of total MUFA decreased, while that of PUFA increased with age. The total MUFA and PUFA showed no significant difference (p>0.05) between the breast and thigh muscles at different ages evaluated. This study suggests that slow-growing birds (RJ and VC) might be better sources of desirable FA than the fast-growing birds, CB.

Extensive Rearing Systems in Poultry Production: The Right Chicken for the Right Farming System. A Review of Twenty Years of Scientific Research in Perugia University, Italy

Simple Summary

The aim of this review paper was to retrace the research journey of the researchers of the Department of Agricultural, Food, and Environmental Science at the University of Perugia, Italy that lasted twenty years and draw updated guidelines regarding the best synergy between chicken type and environment in extensive rearing systems in order to optimize animal welfare, quality, and environmental impact, linked with economical sustainability.

Abstract

The demand for poultry meat, being cheaper than red meat, will drive worldwide production of this product. Accordingly, an increase in production up to 16% is expected in 2025, most of which will occur in developing countries. Most poultry meat production is realized with intensive production systems, and extensive rearing systems (ERS) of poultry (organic, free-range, and low-input) represent only a small portion of poultry production in the EU (about 5%). However, there is an increasing interest in such rearing systems to maintain the good image of product and environmental sustainability, improved animal welfare, and meat quality with an annual trend of growth of about 10%. The aims of this work were to summarize the activities and the viewpoint of the researchers of the Department of Agricultural, Food, and Environmental Science of the University of Perugia (Italy). One of the most important goals of the research unit was the challenge of identifying the best poultry genotypes for ERS, which are important not only for the food industry but also for the improvement of human nutrition. Only the definition of the best genotypes adapted to ERS through the measurement of a wide panel of traits—genetic, physiologic, and behavior—and not only relying on daily weight gain will allow us to achieve this goal.

Commensal Escherichia coli Antimicrobial Resistance and Multidrug-Resistance Dynamics during Broiler Growing Period: Commercial vs. Improved Farm Conditions

Simple Summary

This experiment was designed to evaluate the differences in antimicrobial and multidrug resistance dynamics in broilers reared under two different farm conditions (commercial vs. improved) during the growing period, using Escherichia coli as sentinel bacterium. Although no antibiotics were applied during rearing for two different management conditions tested, high rates of antimicrobial and multidrug-resistant bacteria were observed throughout rearing, with the percentages of resistant bacteria observed being of particular concern in day-old chicks on arrival day and in chickens at the end of the growing period, just before delivery to the slaughterhouse.

Abstract

New measures applied to reduce antimicrobial resistances (AMR) at field level in broiler production are focused on improving animals’ welfare and resilience. However, it is necessary to have better knowledge of AMR epidemiology. Thus, the aim of this study was to evaluate AMR and multidrug resistance (MDR) dynamics during the rearing of broilers under commercial (33 kg/m² density and max. 20 ppm ammonia) and improved (17 kg/m² density and max. 10 ppm ammonia) farm conditions. Day-old chicks were housed in two poultry houses (commercial vs. improved), and no antimicrobial agents were administered at any point. Animals were sampled at arrival day, mid-period and at slaughter day. High AMR rates were observed throughout rearing. No statistical differences were observed between groups. Moreover, both groups presented high MDR at slaughter day. These results could be explained by vertical or horizontal resistance acquisition. In conclusion, AMR and MDR are present throughout rearing. Moreover, although a lower level of MDR was observed at mid-period in animals reared under less intensive conditions, no differences were found at the end. In order to reduce the presence of AMR bacteria in poultry, further studies are needed to better understand AMR acquisition and prevalence in differing broiler growing conditions.

Breast meat quality in males and females of fast-, medium- and slow-growing chickens fed diets of 2 protein levels

The aim of this study was to evaluate the effects of genotype, sex, dietary protein level, and their interactions on select carcass characteristics and meat quality of fast- (Ross 308), medium- (Hubbard JA757) and slow-growing (ISA Dual) chickens (n = 2,520). The diet of the low-protein group of chickens had 6% lower CP than the commercial diet fed to the control group. When the chickens reached an average live weight of 2 kg, 10 males and 10 females of each genotype and the diet were selected for slaughter and breast meat–quality analysis. The dressing out and breast percentages were lower in the JA757 (−2.0 and −5.9%, respectively) and ISA Dual chickens (−9.9 and −14.3%, respectively) than those in the Ross 308 chickens. The ISA Dual chickens had higher abdominal fat percentage, higher DM and protein contents and lower ether extract content and shear force value in breast meat than the other genotypes. Significant interaction effects of genotype, sex, and diet were found on the color of breast skin. Among the various combinations of genotype, sex, and diet group, Ross 308 females fed the low-protein diet had the highest redness and yellowness of breast skin, highest pH45 value, and largest fibers, whereas ISA Dual females had the lowest color parameters and pH45 value, and ISA Dual males had the smallest muscle fibers. The low-protein diet was associated with decreased abdominal fat percentage and changes in meat quality parameters, including increased darkness, meat color intensity, drip loss, and muscle fiber area, in all genotypes. The results indicated greater differences in meat quality owing to genotype than to sex or dietary protein level.

Comparison of performance and carcass composition of a novel slow-growing crossbred broiler with fast-growing broiler for chicken meat in Australia

Slow-growing broilers offer differentiation in the chicken meat market for consumers who have distinct preferences based on perceived higher welfare indices and willingness to pay a higher price for the product. Although breeding for slow-growing broilers is relatively advanced in Europe and the United States, it is limited in Australia. Crossbreeding is one of the approaches taken to developing slow-growing broiler strains. Thus, the aim of this study was to compare performance, immune response, leg health, carcass characteristics, and meat quality of a novel crossbred slow-growing broiler breed (SGB) with the conventional, fast-growing Cobb 500 broiler (CB) to assess their suitability as an alternative for chicken meat production in Australia. A total of 236 one-day-old broiler chicks (116 SGB and 120 fast-growing CB) were reared on standard commercial diet in an intensive production system. Birds and feed were weighed on a weekly basis and feed intake and feed conversion ratio calculated. At 21 d of age, a 2% suspension of sheep red blood cells was injected subcutaneously into 8 broilers of each breed to compare their antibody response. Birds from both breeds were grown to a final live weight of 2.0–2.2 kg, before a latency-to-lie (LTL) test, carcass analysis and apparent metabolizable energy (AME) assay were performed. The SGB reached the target weight at 55 d of age compared with 32 d in CB. However, SGB stood for longer during LTL, had higher thigh, drumstick, and wing yields (as a percentage of carcass weight) as well as darker and redder meat in comparison with the CB. The CB had better feed conversion efficiency, higher antibody (IgM) production, higher AME, heavier breast yield, and lower meat drip loss than the SGB. Although fast-growing CB outperformed the SGB for traditional performance parameters, the crossbred in this study was comparable with other slow-growing broiler breeds and strains across different countries and is thus a suitable candidate for a slow-growing alternative in Australia.

Fatty acid profile, oxidative status, and content of volatile organic compounds in raw and cooked meat of different chicken strains

Chicken meat is rich in unsaturated fatty acids. Therefore, it is more susceptible to lipid oxidation and production of volatile organic compounds (VOC). In this study, we evaluated the fatty acids, antioxidants, and VOC profiles of raw and cooked meat samples derived from 4 strains of chicken differing in their growth rates, which were as follows: slow-growing (SG, Leghorn), medium-growing (MG, Hubbard and Naked Neck), and fast-growing (FG, Ross). The VOC profile of meat was measured using proton-transfer reaction–mass spectrometry (PTR–MS). The VOC were identified using PTR–time of flight-MS (PTR-ToF-MS). The data were analyzed using both univariate and multivariate models. Twenty main VOC were identified, which were classified into the following chemical categories: aldehydes, alkadienes, alkenes, furans, amides, alcohols, and other compounds. Our results revealed that the chicken genotype and the method of cooking strongly influenced the VOC profile of the meat. Identifying the relationships between these traits allowed us to highlight the trade-off of the main substrates such as n-3 and n-6 polyunsaturated fatty acids (PUFA), protective substances (antioxidants), and degradation products (VOC) of the poultry meat produced during cooking. The extent of VOC production and n-3 loss was found to be higher for the SG genotype. Reduction of n-6 was higher in MG, whereas small losses in antioxidants and PUFA were observed in the FG genotype, consequently, resulting in the lowest production of VOC. The SG and MG are genotypes more active from a kinetic point of view respect to the FG ones. For this reason, in the FG genotypes, the antioxidants are less involved in the oxidative stress induced by the movement; thus, they were available to protect the lipid of the meat during the cooking process. These results suggested that the use of SG and MG genotypes requires a specific dietary protocol (i.e., increasing the antioxidants content) to counteract the lipid oxidations in all the phases: in vivo, postmortem, and during/after cooking.

Lipid Assessment, Cholesterol and Fatty Acid Profile of meat from broilers raised in four different rearing systems

Evaluated lipid and cholesterol concentration and fatty acid profile of raw breast, thigh and drumstick meat from broilers raised in different rearing systems. Were used 200 male broiler carcasses from four different rearing systems (n=50 from conventional intensive; n=50 from organic; n=50 from free-range; and n=50 from antibiotic-free) distributed in a completely randomized design with four rearing systems and 50 replications (carcasses). Breast meat from conventional broilers showed higher lipid (1.47) and cholesterol (34.13) concentration. Thigh and drumstick meat from free-range broilers had higher lipid (7.53/4.73) and cholesterol (45.55/53.65) concentration. Fat contained in breast, thigh and drumstick meat from free-range broilers showed higher levels of polyunsaturated fatty acids. Fat from breast and thigh meat from free-range broilers showed higher total concentration of ω3 and ω6 fatty acids. Fat from thigh meat from organic broilers showed higher levels of EPA (C20:5n3) and DHA (C22:6n3). Fat from drumstick meat from free-range broilers showed higher total concentration of ω3 and ω6 fatty acids. Meat from chickens raised in alternative rearing systems offers less risk to cardiovascular health because it presents lower concentrations of lipids and cholesterol, greater amounts of polyunsaturated fatty acids, which are beneficial for human health.

Suitability of dual-purpose cockerels of 3 different genetic origins for fattening under free-range conditions

The utilization of male chickens for fattening constitutes a potential advantage of the dual-purpose concept. In addition to the use of commercial hybrids, producers could introduce alternative chicken genotypes or further develop local breeds. To gain more information about the genetic effect on growth performance, carcass characteristics, physicochemical meat traits, and sensory attributes, 60 cockerels belonging to Les Bleues (developed from the French breed Bresse Gauloise), Canarian (Spanish local breed), and Dominant Red Barred D459 (DRB D459; commercial dual-purpose hybrid) genotypes were reared under free-range conditions in a warm tropical climate and slaughtered at 15 wk of age. The major findings were as follows: (i) Les Bleues chickens exhibited the best growth rate and the body weight of 2.44 kg reached by this strain at 15 wk would be gained only after 18 to 19 wk with DRB D459 and it would take even 2 wk longer for Canarian breed, according to the growth modeling using the Morgan equation, although the body weights between the latter were statistical similar at 15 wk; (ii) Les Bleues strain had a good capability in terms of meat production performance, presenting carcasses with significantly heavier commercial cuts, and higher fleshiness than the other 2 genotypes; (iii) although significant differences among genotypes appeared in the physical characteristics of the breast meat, especially those concerning the skin and meat color and water-holding capacity, which was significantly reduced for Canarian chickens, no significant differences were detected in the chemical composition and fatty acid profile of the breast meat; (iv) trained panelists (n = 8) pointed out that leg meat of none of the genotypes is better in terms of global appreciation, but untrained consumers (n = 99) perceived that the Les Bleues leg meat was significantly more palatable than the DRB D459 leg meat.

Selected freshness indices of skin and wings from organic chicken packaged in modified atmosphere

This study is part of a project aiming to optimize storage conditions for organic chicken meat. Selected indices of skin and wings from organic chicken were evaluated. A total of 24 samples were packaged in MAP-O2 (80% O2/20% CO2), 24 samples in MAP-N2 (70% N2/30% CO2) and 48 samples as a control. The samples were analysed on days 2, 7, 10 and 14 of storage during a 14-day storage period at 2 ± 2 °C. The surface colour of skin (L*a*b*), ammonia content, thiobarbituric acid reactive substances content (TBARS) and antioxidant capacity were assessed. The lightness values (L*) for chicken skin in MAP-O2 were increased on days 7 and 10 of the storage period, and were significantly (P < 0.05) higher than in the samples in MAP-N2 and the control. Significant increases of TBARS were observed in the samples in MAP-O2 from day 7 and these values continued to increase until the end of the storage period. The antioxidant capacities of the samples in MAP-O2 were mostly lower than those of the samples in MAP-N2. Our results indicate that MAP-O2 only had a positive effect on skin colour, whereas MAP-N2 maybe preferable for shelf-life prolongation.

Performance and Meat Quality of Dual-Purpose Cockerels of Dominant Genotype Reared on Pasture

Simple Summary

One-day-old laying cockerels are killed after hatching because they do not reach the growth rate of broiler chickens, and their fattening would be economically disadvantageous. A possible variant of the use of these cockerels could be organic or free-range farming, where it is desirable that the animals are fattened for a longer period of time, are more physically active, and graze pasture vegetation. Another possibility is dual-purpose genotype breeding, where hens are used for egg production and cockerels are fattened for meat. In the present study, three genotypes of dual-purpose cockerels Dominant were compared. All three genotypes showed the ability to graze with resulting improvements in meat quality. The Dominant 102 cockerels have the greatest prerequisites for use in extensive fattening, mainly due to higher performance, willingness to graze and vitamin E content, which protects the fat from becoming rancid.

Abstract

The culling of layer cockerels due to economic inefficiency is an ethical problem. Organic or free-range fattening of these cockerels or dual-purpose genotypes breeding is a possible solution to this problem. The aim of the study was to assess the differences in performance and meat quality characteristics in dual-purpose cockerels Dominant of three genotypes (Dominant Sussex D 104, Dominant Brown D 102 and Dominant Tinted D 723, 100 cockerels per genotype) with access to pasture. The cockerels were housed in mobile boxes on the pasture herbage from the 50th to 77th day of age (stocking density: 0.108 m²/bird). The highest body weight on the 77th day of age (p < 0.001) and the nonsignificantly lowest feed conversion was achieved by Dominant Brown D 102 cockerels (1842 g and 2.79, respectively). Non-significantly higher pasture herbage intake on the 70th day of age was recorded in genotype Dominant Brown D 102 (7.41 g dry matter (DM)/bird/day) and Dominant Tinted D 723 (7.52 g DM/bird/day). The pasture herbage contained 56.9 mg/kg DM α-tocopherol, 170.3 mg/kg DM zeaxanthin and 175.0 mg/kg DM lutein and had a favourable n6/n3 ratio (0.26). The boiled meat of cockerels Dominant Tinted D723 showed the highest tenderness based on both the sensory evaluation (p = 0.022) and the value of shear force (p = 0.049). This corresponds with a higher (p < 0.001) cross-sectional area and muscle fibre diameter in these chickens. The highest content of n3 fatty acids (eicosapentaenoic, clupanodonic and docosahexaenoic acids) in breast meat were found in Dominant Sussex D104 chickens (p < 0.001). In contrast, a significantly higher α-tocopherol content (p < 0.001) and higher oxidative stability (p = 0.012) were found in Dominant Brown D102 (4.52 mg/kg and 0.282 mg/kg) and Dominant Tinted D 723 chickens (4.64 mg/kg and 0.273 mg/kg) in comparison with the Dominant Sussex D104 genotype (3.44 mg/kg and 0.313 mg/kg). The values of the atherogenic and thrombogenic indexes were the lowest (p < 0.001) in meat from Dominant Brown D102 chickens. Moreover, a lower cholesterol content (p < 0.001) was recorded from the genotypes Dominant Brown D102 (396 mg/kg) and Dominant Tinted D723 (306 mg/kg) chickens, contrary to the Dominant Sussex D104 cockerels (441 mg/kg). It can be concluded that cockerels Dominant Brown D102 are a suitable genotype for free-range rearing due to higher performance and higher pasture herbage intake, which positively influences meat quality, whereas the meat of Dominant Sussex D104 cockerels shows higher amounts of n3 fatty acids and lower n6/n3 ratios.

The dynamic of antibiotic resistance in commensal Escherichia coli throughout the growing period in broiler chickens: fast-growing vs. slow-growing breeds

Antimicrobial resistance (AMR) is an important threat to public health worldwide. Furthermore, different studies have demonstrated a close association between antibiotic use in animal production and AMR in humans. It is well known that it is necessary to reduce antibiotic administration in farms by finding effective alternative treatments, using more resistant breeds and improving animal welfare. However, to be able to assess the alternatives proposed, it is essential to study the epidemiology of AMR under production conditions. Hence, the aim of this study was to investigate the AMR dynamic in 2 genetic poultry breeds during the growing period. The study was performed in 2 experimental poultry houses to simulate real production conditions, and no antibiotics were administered during the growing period. In addition, 2 poultry breeds were used, fast-growing and slow-growing. To evaluate AMR evolution, Escherichia coli was selected as indicator bacterium. To this end, animals from each experimental group were sampled at different times: on day of arrival, at mid-period, and at slaughter day. In the laboratory, cecal content was removed and inoculated in selective media. Then, biochemical tests were performed to confirm E. coli. Finally, antibiotic susceptibility was assessed according to Decision 2013/653. At the onset of the cycle, significant differences were observed between breeds, as the E. coli strains isolated from fast-growing 1-day-old-chicks showed higher AMR rates. However, at the end of the period, no significant differences were found between breeds and their presence of resistant bacteria (above 95%). Therefore, although no antibiotics were administered during the growing period, a high level of AMR at slaughter day was demonstrated. Further studies are necessary to determine the main risk factors that increase the level of AMR throughout the productive cycle in broiler chickens. In conclusion, it is important to highlight that although it is crucial to control both antibiotic use and animal welfare during the growing period, measures should be taken at all levels of the production chain.

Gaping of pectoralis minor muscles: magnitude and characterization of an emerging quality issue in broilers

Recently, a certain number of broiler abattoirs located in different Countries around the World have signaled an emerging quality issue termed "gaping" because of the separation of the fiber bundles affecting the external portion of the bipinnate pectoralis minor muscle. Thus, after defining the criteria to classify the muscles as Normal (NORM), Moderate (MOD), or Severe (SEV) cases, the incidence of gaping under commercial conditions was assessed on a total of 8,600 P. minor obtained from broiler chickens belonging to 43 flocks during a 6-mo period. Then, a total of 180 P. minor were selected based on previously defined criteria to evaluate the main quality traits (pH, color, water-holding/-binding capacity and tenderness), proximate composition, water mobility, and thermal properties as well as metabolic profile through 1H-Nuclear Magnetic Resonance spectroscopy. The average incidence of gaping defect was found to be 16.8% (8.8 and 8.0% MOD and SEV cases, respectively). As for the main quality traits, a reduction in ultimate pH was observed as the severity of the gaping defect increased, with SEV muscles displaying significantly lower values in comparison with NORM (5.96 vs. 6.02; P < 0.01), while MOD showed intermediate values (5.99). Concurrently, if compared with their NORM counterpart, MOD and SEV exhibited higher lightness (53.6 and 54.2 vs. 51.8; P < 0.01) coupled with higher (P < 0.05) cooking losses and longer (P < 0.05) transversal relaxation time of extra-myofibrillar water fraction. Overall, no significant differences were found concerning proximate composition and thermal properties. With regard to the metabolic profile, a significantly lower (P < 0.001) glutamine concentration was found in MOD and SEV muscles that, concurrently, revealed significant (P < 0.05) variations in the metabolites involved in energy-generating pathways. Overall, these findings evidenced that the gaping defect affecting broilers' P. minor muscles have strong similarities with the pale-soft-exudative condition previously described in poultry and likely results from the biochemical processes taking place during the post-mortem conversion of muscle to meat.

Effects of Slaughter Age on Muscle Characteristics and Meat Quality Traits of Da-Heng Meat Type Birds

Simple Summary

The current work evaluated the breast muscle performance, meat quality traits, and myofiber characteristics of Da-Heng meat type birds with 60, 90, 120, 150, 180 days of age. Older chickens often presented a higher pH, lower drip loss, higher shear force, darker, and redder breast meat. The correlation coefficients showed that myofiber characteristics played an important role in breast pH values, drip loss, and meat color.

Abstract

Due to the increasing demand for producing chickens with high meat quality, there is a need to determine its mode of action on chicken meat quality traits across a wider age spectrum. In this study, five groups of 200 male Da-Heng meat type birds were reared until slaughter age of 60, 90, 120, 150, 180 days old and breast muscle performance, meat quality traits, and myofiber characteristics were evaluated. The larger body weight and breast weight of chicken are based on larger myofiber diameter and area, less myofiber density for the older birds than younger birds. There was an age effect on all meat quality traits of chicken breast muscle (p < 0.05). Older chickens often presented a higher pH, lower drip loss, higher shear force, darker, and redder breast meat. The correlation coefficients showed that myofiber characteristics played an important role in breast pH values, drip loss, and meat color (p < 0.05). Besides, significant correlations were also found between meat quality traits (p < 0.05). Further studies are needed to explore the biochemical character and potential molecular mechanism of chicken breast muscle to determine the factors that causes these age-related differences in meat quality in the current study.

Efficacy of In Ovo Delivered Prebiotics on Growth Performance, Meat Quality and Gut Health of Kuroiler Chickens in the Face of a Natural Coccidiosis Challenge

A study was carried out to assess the efficacy of prebiotic delivered in ovo on performance, carcass traits, meat quality and gut health in the face of a natural coccidiosis infection in Kuroiler chickens. On d 12 of incubation, 150 fertile eggs were divided into a prebiotic group injected with trans-galactooligosaccharides (Bi²tos) and a control group uninjected. Hatched chicks from each group were further divided: One group received antibiotic chick formula while the other was left untreated, giving rise to 4 groups-Control (C), Antibiotic (A), Bi²tos (B), and Bi²tos + Antibiotic (AB). Prebiotic improved growth performance at six weeks of age, AB birds were the heaviest at the end of the rearing period. The highest intestinal lesion scores and oocyst counts were recorded in C birds. B group had a slightly higher carcass weight and cuts yields tended to be higher in treated groups compared to C. Meat from B group displayed a higher amount of polyunsaturated fatty acids compared to C and a positively lower n-6/n-3 ratio compared to C and A. In conclusion, prebiotics with or without antibiotics reduced severity of intestinal lesions and oocyst excretion induced by natural infection with Eimeria, with positive effects on Kuroiler chicken productive traits.

Perfil lipídico da carne de frangos de corte de diferentes cruzamentos criados em sistema alternativo

RESUMO Objetivou-se avaliar o perfil lipídico da carne de frangos de diferentes genótipos. O delineamento foi inteiramente ao acaso (DIC), disposto em esquema fatorial (5x2), sendo cinco genótipos (New Hampshire ˗ NHS; Gigante Negra de Jersey ˗ GNJ; Índio Gigante ˗ IG; cruzamento entre as raças IG e NHS ˗ IG x NHS; e entre as raças IG e GNJ ˗ IG x GNJ) e dois sexos, com cinco repetições, sendo cada uma representada por três aves, totalizando 150 aves, abatidas aos 105 dias. As análises de perfil lipídico foram realizadas no peito e na coxa. Foram calculadas as estimativas das atividades enzimáticas, os índices de aterogenicidade e de trombogenicidade. Os genótipos IG e IG x NHS apresentaram maiores teores de ácido araquidônico e DHA. Foram observados maiores teores de ácidos graxos saturados e monoinsaturados no peito para os genótipos IG x NHS e NHS, respectivamente. Maiores médias de ácidos graxos poli-insaturados e ômega 3 foram observadas para os genótipos IG e IG x NHS. O genótipo IG x NHS e as fêmeas apresentaram melhores características de qualidade de carne, por oferecerem uma maior fonte de ômega 3.

Association Between Arachidonic Acid and Chicken Meat and Egg Flavor, and Their Genetic Regulation

In Japan, the majority of chicken meat is obtained from fast-growing broiler chickens. Because most Japanese chicken breeds have a low meat yield and egg production, many of these breeds are endangered. Recently, the palatability of meat and eggs of native chickens has been reevaluated in the Japanese market. Jidori, which means chicken from the local, is an indigenous local chicken that is more delicious, firmer in texture, and more expensive than the broiler chickens. Most Japanese consumers recognize that the meat of Jidori chicken is richer in flavor than that of the broiler chicken. However, the reason for this rich flavor of the meat of Jidori chicken has not been elucidated. Recently, we found that arachidonic acid (AA) (C20:4n-6), a polyunsaturated fatty acid, is associated with the rich flavor of the meat and eggs of Jidori chicken. The present paper summarizes the discovery of the involvement of AA in the flavor characteristic of the meat and eggs of chicken, and also the genetic regulation of the AA content in the meat and eggs of Jidori chicken.

Meat quality of chicken of different crossings in alternative system

ABSTRACT The purpose was to evaluate the effects of gender and of different genotypes of chickens on the physicochemical parameters and centesimal composition, related to the quality of meat. The design was completely randomized arranged in 5x2 factorial scheme, five genotypes (Índio Gigante - IG; New Hampshire - NHS; Gigante Negra de Jersey - GNJ; poultry from the crossing between the IG and NHS breeds - IG x NHS; and between the IG and GNJ breeds - IG x GNJ) and two genders, with five repetitions and each one represented by three poultry, totaling 150 animals, slaughtered at 105 days. The parameters evaluated on the breast and thigh were: centesimal composition (moisture, ether extract - EE, protein and ash), ultimate pH, color (L*- luminosity, a*- redness, b* -yellowness, C* - chroma index and h* - hue angle), weight loss by cooking (WLC) and shear force (SF). The IG genotype had the highest average of ultimate pH of the breast (6.03). The NHS and IG x NHS genotypes showed, respectively, higher average of L * (58.93) and a* (1.92) of the breast. The IG, IG x NHS and IG x GNJ showed the highest values of b* of the breast (12.53, 13.37 and 12.69, respectively). The IG poultry showed high average of SF of the breast and thigh (4.79 and 5.01kgf, respectively). The IG x NHS and IG x GNJ genotypes showed the lowest ultimate pH values of the thigh (6.13 and 6.02, respectively). The IG x GNJ genotype showed a high average of b* of the thigh (14.94) and the NHS had a high average of WCL (24.65%). The females showed higher averages of EE on the breast and ash on the thigh (1.03 and 1.11%, respectively). The IG x NHS and IG x GNJ poultry showed higher averages of EE of the breast (1.21 and 1.38 %, respectively). The poultry of IG breed and those from the crossing with NHS and GNJ presented meat quality characteristics more desirable by the consumer in relation to physicochemical parameters and centesimal composition, while genders showed no influence on these aspects.

A comparison of the effects of post-mortem aging on breast meat from Cobb 500 and Hubbard ISA broilers

We compared the physical and chemical characteristics of the pectoralis major muscle from Cobb 500 and Hubbard ISA broilers and evaluated the effect of aging process for up to 7 days on meat quality. We used breast samples from male Cobb 500 (42 days of age; n = 60) and Hubbard ISA (85 days of age; n = 60) broilers. Twenty samples of each genotype were analysed 4 h post-slaughter (Control group). Another 20 samples of each genotype were aged in an incubator (2 ± 0.5°C) for 3 and for 7 days. Breast fillets were 23% heavier in the Cobb 500 group (306 g vs 248 g; P = 0.0009). Before aging, meat from Hubbard ISA broilers had higher (P < 0.001) water-holding capacity, which promotes the production of less exudate and possibly reduces nutritional losses during storage, which may be beneficial to the poultry industry. Despite being initially less tender, breast meat from Hubbard ISA broilers showed, during the aging process, a reduction (P < 0.05) of shear force (48.46–15.04 N), total collagen amount (6.0–4.8 g/kg) and myofibrillar fragmentation index (150.17–97.42) and had the same (P = 0.134) fat concentration (0.87 g/100 g) as that of breast meat from Cobb 500 broilers (0.93 g/100 g, respectively). Breast meat from Hubbard ISA broilers had a higher (P < 0.001) polyunsaturated fatty acid concentration, especially docosahexaenoic acid, which is beneficial to human health. Aging breast fillets for 3 days at 2°C is sufficient to tenderise the meat without reducing its juiciness, which suggests that the aging process can add value to free-range meat.

Breast meat quality of chickens with divergent growth rates and its relation to growth curve parameters

Abstract. The effects of the increase of body weight of contemporary broilers during growth on functional meat quality and color characteristics of the chicken breast muscle are controversially debated. Therefore, male chickens (n = 264) of a fast-growing commercial broiler (Ross 308) and two slow-growing experimental meat-type chicken lines were compared at equal age and at similar body weight in order to investigate the effect of growth rate on selected functional breast meat traits and meat color. Additionally, the breast meat characteristics of birds with different growth profiles were compared within lines. When the body weight of commercial broilers reached about 40 to 60 % of their growth potential, they exhibited particularly high ultimate pH values compared with slow-growing lines. The ability of the meat of fast-growing broilers to retain water during cooking was impaired (5 to 16 percentage points increased cooking loss compared to slow-growing lines), which, in contrast to pH, was only marginally affected by body weight and/or age at slaughter. No unfavorable correlations of breast meat quality traits with the growth profile, represented by growth curve parameters derived from the Gompertz–Laird equation, were detected within any of the investigated chicken lines. It is noteworthy that the associations of ultimate pH and cooking loss with maximum growth speed indicate a non-linear relationship. Thus, some of the functional characteristics of breast meat of the fast-growing broiler resembled the white-striping defect described for poultry meat, but the hypothesis that selection on increased growth rates is detrimental for meat quality per se could not be confirmed. In fact, an elevated growth potential in particular, i.e., body weight at maturity, could have some beneficial effects for the water-holding capacity of breast meat, regardless of the genotypic growth rate.

QUALIDADE DA CARNE DE AVES DA RAÇA RODHE ISLAND RED CRIADAS EM SISTEMA ALTERNATIVO

Resumo Objetivou-se caracterizar a qualidade da carne de aves da raça Rodhe Island Red em função da diferença do tipo de corte e sexo. Foram utilizadas 30 aves em delineamento inteiramente casualizado em esquema fatorial (2 x 2), sendo dois cortes (peito e coxa) e dois sexos, com cinco repetições por tratamento. As aves foram abatidas aos 105 dias para realização das análises físico-químicas, composição centesimal e perfil lipídico do peito e coxa. A coxa apresentou maior média de pH final, teor de vermelho (a*) e força de cisalhamento (FC). Para luminosidade (L*), o peito obteve a maior média e as fêmeas maior média de FC. A coxa apresentou maior teor de extrato etéreo (EE) e umidade. O peito apresentou maior média de ácidos graxos saturados. As fêmeas obtiveram maior quantidade de ω3 e menor relação ω6/ω3. Foi observado maior índice de trombogenicidade no peito. A coxa mostrou menor conteúdo de ácidos graxos saturados e menor índice de trombogenicidade. As fêmeas apresentaram maior teor de ω3. O tipo de corte demonstrou maior influência que o sexo sobre os parâmetros estudados e a coxa apresentou melhores aspectos físico-químicos e de perfil lipídico para carne de aves neste sistema de produção relacionados à qualidade de carne desejável pelos consumidores.

Thai native chicken meat: an option to meet the demands for specific meat quality by certain groups of consumers; a review

Native chickens are slowly growing indigenous chicken (Gallus domesticus) breeds; many of them were developed from jungle fowl, which is found in every part of Asia. These breeds are disease resistant, easy adapting to tropical climates, and have a low mortality. In Thailand, a distinct sector of consumers prefers to eat meat from native chickens rather than that from broilers because it is more tasty and chewy. In addition, studies have shown that it has a low content of fat which may be helpful for people susceptible to coronary heart diseases. This review also compiles evidence for further indicators of a special meat quality such as more oxidative (Type I) muscle fibres, a higher collagen content (promoting the preferred chewiness), an elevated content of certain flavor-relevant compounds, as well as high ratio of polyunsaturated to saturated fatty acids.

Microbial Populations in Naked Neck Chicken Ceca Raised on Pasture Flock Fed with Commercial Yeast Cell Wall Prebiotics via an Illumina MiSeq Platform

Prebiotics are non-digestible carbohydrate dietary supplements that selectively stimulate the growth of one or more beneficial bacteria in the gastrointestinal tract of the host. These bacteria can inhibit colonization of pathogenic bacteria by producing antimicrobial substances such as short chain fatty acids (SCFAs) and competing for niches with pathogens within the gut. Pasture flock chickens are generally raised outdoors with fresh grass, sunlight and air, which represents different environmental growth conditions compared to conventionally raised chickens. The purpose of this study was to evaluate the difference in microbial populations from naked neck chicken ceca fed with commercial prebiotics derived from brewer’s yeast cell wall via an Illumina MiSeq platform. A total of 147 day-of-hatch naked neck chickens were distributed into 3 groups consisted of 1) C: control (no prebiotic), 2) T1: Biolex^® MB40 with 0.2%, and 3) T2: Leiber^® ExCel with 0.2%, consistently supplemented prebiotics during the experimental period. At 8 weeks, a total of 15 birds from each group were randomly selected and ceca removed for DNA extraction. The Illumina Miseq platform based on V4 region of 16S rRNA gene was applied for microbiome analysis. Both treatments exhibited limited impact on the microbial populations at the phylum level, with no significant differences in the OTU number of Bacteroidetes among groups and an increase of Proteobacteria OTUs for the T1 (Biolex^® MB40) group. In addition there was a significant increase of genus Faecalibacterium OTU, phylum Firmicutes. According to the development of next generation sequencing (NGS), microbiome analysis based on 16S rRNA gene proved to be informative on the prebiotic impact on poultry gut microbiota in pasture-raised naked neck birds.

Fatty acid composition of chicken breast meat is dependent on genotype-related variation of FADS1 and FADS2 gene expression and desaturating activity

In Western countries the dietary guidance emphasizes the need to decrease the intake of saturated fatty acids and to replace them with polyunsaturated fatty acids (PUFA), particularly long chain n-3 PUFA (LC-PUFA). The production of poultry meat having a lower fat content and healthier fatty acid (FA) profile is a hot topic for the poultry industry, and the possibility to identify genotypes able to produce meat with a higher LC-PUFA content deserves attention. The aims of the present study were to evidence in chicken (i) a genotype-related different expression of the desaturating enzymes delta-6 (Δ6, EC 1.14.99.25), delta-5 (Δ5, EC 1.14.19.) and delta-9 (Δ9, EC 1.14.19.1); (ii) the impact of the hypothesized different expression on the meat FA composition; (iii) the distribution of desaturase products in the different lipid classes. Slow (SG), medium (MG) and fast (FG) growing chickens fed the same diet were evaluated either for the relative expression of FADS1, FADS2 and SCD1 genes in liver (by q-PCR), or for the FA composition of breast meat. MG and particularly SG birds showed a greater expression of FADS2 and FADS1 genes, a higher Δ6 and Δ5 activity (estimated using desaturase indices), and consequently a higher LC-PUFA content in the breast meat than FG birds. The relationship between genotype and desaturating ability was demonstrated, with a significant impact on the PUFA content of breast meat. Due to the high consumption rate of avian meat, the identification of the best genotypes for meat production could represent an important goal not only for the food industry, but also for the improvement of human nutrition.