Abstract in English:

ABSTRACT Eggs are a cornerstone of the food industry. They are a versatile ingredient used in a wide variety of products for their rich protein, vitamin and mineral contents. The use of efficient and high-quality eggs is of great importance in hatcheries, as well as in direct food consumption. The use of quality and efficient eggs in hatcheries has a strong impact on chick, egg, and white meat production. Artificial intelligence-based smart systems usage for product quality classification is growing steadily in productive sectors. In many of these systems, product images are used as input data. The use of such smart systems provides both fast and low-error quality control. Smart systems can quickly and accurately classify new products with algorithms trained by product images. In this study, an intelligent classification system using a machine learning algorithm, which is a subfield of artificial intelligence, was designed to classify the quality and efficiency of chick eggs in a chicken hatchery. Eggs are most commonly classified according to their size as either Large (L), Medium (M) or Small (S). In this study, 425 egg images were obtained using the image acquisition system designed on the hatchery belt system, and the data for each egg was recorded in a dataset. In the next stage, image processing methods (Morphological operations and Hough Transform) and the SVM machine learning algorithm were used together in the proposed model. According to our results, the classification of eggs into L, M, and S was successfully achieved at 98.0% using the SVM algorithm on the dataset.

Abstract in English:

ABSTRACT Salmonella spp. is one of the major bacterial causes of foodborne gastroenteritis in humans. The aim of this study was to investigate antimicrobial susceptibility to cephalosporins and quinolones, and to identify the genetic mechanisms related to this resistance in strains of Salmonella spp. Seventy chicken carcass samples were collected from slaughterhouses in the state of Rio de Janeiro, Brazil. The phenotypic profile was detected by the disk-diffusion method and the search for genes encoding betalactamases, and resistance to quinolones was evaluated by PCR. The search for mutations in gyrA and parC was carried out by sequencing these genes. Eleven strains of Salmonella spp. of different serotypes were isolated. All the strains were resistant to at least one of the antimicrobials tested, and 63.64% (7/11) showed resistance to three or more antimicrobials. In the phenotypic test for ESBL production, 36.36% (4/11) of the strains were considered positive. PCR detected the resistance genes bla CMY-2, qnrB, bla CTX-M, and bla TEM. Among the isolates, 45.45% (5/11) simultaneously presented the bla CTX-M, bla TEM, qnrB genes and a mutation (Thr-57→Ser) in parC. Point mutations in the parC gene were detected in all the analyzed samples. Genes such as bla SHV, qnrA, qnrC, qnrD, qnrS, aac(6’)-Ib, qepA, and oqxAB were not detected. The study identified Salmonella spp. resistant to cephalosporins and quinolones, with resistance genes and mutations in parC, highlighting concerns about the adoption of biosecurity measures, responsible use of antimicrobials, and surveillance of resistant strains in the poultry chain.

Abstract in English:

ABSTRACT The use of enzymes is a concrete fact in broiler feeding. The global economic situation has been undergoing major changes, especially in the cost of agricultural commodities such as corn and soybean meal, the main ingredients in broiler diets in many parts of the world. This study aimed to assess the effect of increasing doses of phytase by assigning an optimized non-linear increasing nutritional matrix to the diet of broilers from 1 to 42 days of age, using economic production indicators as response variables. 900 one-day-old chicks were distributed in a randomized block design with six treatments and ten replications. Different nutritional matrices were studied: a positive control diet without phytase; diets with increasing levels of this enzyme (350, 500, 1,000, 1,500 FTU); and a negative control diet (-100 kcal/kg EMA) without phytase supplementation. Performance from 1 to 42 days of age and economic viability were assessed. It was observed that the negative control and the overdose (1,500 FTU) of phytase showed worse feed conversion than the positive control diet. In the economic analysis, there was a reduction in feed costs with increasing doses of the enzyme, as well as lower production costs per carcass kilo. The data found in this study shows that performance indicators do not always reflect economic efficiency responses. Specifically, the production cost was lower in broiler diets (1 to 42 d) formulated with increasing doses of phytase (up to 1,500 FTU kg-1).

Abstract in English:

ABSTRACT The selection of an appropriate production system plays a crucial role in ensuring the health, welfare, and productivity of American Pekin ducks. The aim of this study was to investigate the influence of various rearing production systems on the performance of American Pekin Ducks. A total of 180 straight run ducklings (10 days old) were randomly allocated into three experimental groups: intensive production system (IPS), free-range production system (FRPS), and pool with yard production system (PYPS). The distribution was carried out following a completely randomized design. We investigated the morphological parameters, growth performance, serum chemistry, meat cholesterol and triacylglycerol, cellular immunity, intestinal morphology, and carcass traits of Pekin ducks. The results indicate that PYPS birds exhibited significantly better morphometric parameters compared to IPS and FRPS ones. Ducks raised in PYPS had the highest growth rate till the 75th day as compared to those reared in IPS and FRPS. Triacylglycerol, total lipids, blood and meat fat and triacylglycerol were higher in IPS; whereas albumin, AG ratio, total proteins, glucose, and globulin were higher in PYPS. Similarly, cellular immunity (phagocytic activity, eosinophils, basophils, and monocytes) was increased in PYPS. Intestinal morphology and overall carcass traits were better in birds reared under PYPS than in those of IPS and FRPS. American Pekin ducks raised in PYPS showed improved growth, serum chemistry, cellular immunity, and carcass traits. These results suggest that the PYPS could be a promising production system for raising ducks in sub-tropical regions.

Abstract in English:

ABSTRACT The apparent total tract digestibility (ATTD; trial 1) and the apparent (AID) and standardized (SID) ileal digestibility of the amino acids (AA) (trial 2) in canola meal (CM) were evaluated with the addition of exogenous multi-carbohydrase (MC) and phytase (Phy). A total of 80 28-day-old broilers were allotted in a completely randomized design to receive treatments up to 35 days of age. A 2 × 2 factorial design was used to determine the enzyme effects on the ATTD of dry matter, nitrogen, calcium, phosphorus and fibre; as well as energy use and the AID and SID of AA, in five replicate cages. Supplementation with exogenous enzymes showed a positive interaction (p<0.05) between MC and Phy for nitrogen and energy. The isolated inclusion of Phy or MC showed a favorable effect (p<0.05) for dry matter, calcium, phosphorus and fiber. The enzyme inclusion on the AID and SID of AA in CM, established by comparing the means, suggested a better response to the addition of MC or Phy. Supplementation with Phy or MC was shown to be a viable alternative to increase the ATTD of nutrients and energy. The isolated inclusion of Phy or carbohydrate resulted in higher apparent and standardized digestibility of AA from CM.

Abstract in English:

ABSTRACT The purpose of this study was to investigate the effects of acidifier on broilers’ performance. A total of 648-day-old broilers were assigned to four treatments (0, 1, 2, and 3 g/kg acidifier in the diet). In the grower period, the acidifier inclusion resulted in a higher average daily weight gain (ADWG) than in the control. On the 40th day of age, 3 g/kg of acidifier increased ADWG and average daily feed intake (ADFI). The highest ADWG was observed in the 3 g/kg of acidifier treatment for the whole period. Orthogonal contrast between acidifier and control indicated that cholesterol and high-density lipoprotein (HDL) concentration in the serum was lower in the acidifier-fed broilers. Inclusion of 2 and 3 g/kg of acidifier reduced Salmonella population in the ileum. Adding 2 and 3 g/kg acidifier to the diet increased crypt depth compared to other treatments. Weight and length of the tibia were also significantly increased by acidifier. The quadratic effect showed that the acidifier had a significant effect on the tibio-tarsal index. The mRNA expression of PPARγ and Toll-Like Receptor 4 (TLR4) genes in the ileum of broilers that were fed 3 g/kg acidifier was significantly higher than in other treatments. Fatty Acid-Binding Protein 1 gene showed a significant enhancement effect by the acidifier: with increasing levels of acidifier, its expression also increased. In conclusion, the acidifier improved the performance, upregulated the expression of ileal fatty acid-binding protein 1 (FABP1), TLR4, and PPARγ genes, as well as increased the tibia length, and reduced the Salmonella population in the ileum.

Abstract in English:

ABSTRACT This study investigated the impact of housing environment on performance parameters of the Lohmann LSL Classic (LW) and Lohmann Sandy (LS) strains. The deep litter (DL), free access to outdoor Mentha piperita (MP), Petroselinum crispum (PC), and Medicago sativa (MS) housing environments were examined. A total of 260 four-week-old birds were randomly allotted to DL and outdoor plant-associated groups, with four and three replicates, respectively, and 10 birds per replicate. Data collection for weekly feed intake began at 4 weeks until the end of the study. Weekly hen weights were measured from 4 weeks of age until the age of 50% egg production; and then later, at 52 weeks of age. From the day of the first egg until the last day of the study, eggs laid in each nest box tier (upper, middle, bottom, and floor) were recorded and weighed at 9:00 a.m., 12:00 noon, and 3:00 p.m. Housing environment influenced the age at first egg and 50% egg production, hen-day egg production, feed intake during the egg-laying period, feed conversion ratio, average egg weight, and egg size distribution (p<0.01; p<0.05). Age at first egg and 50% egg production, hen-day egg production, feed intake, average egg weight, and egg size distribution varied between strains (p<0.01; p<0.05). Most of the eggs were laid in the morning and on the upper nest box tier (p<0.01). Additionally, average egg weight varied among the egg-laying time and nest box tiers, and most of the eggs laid were in the large egg size (56-65 g) category (p<0.01). It was concluded that access to Medicago sativa offers hens the most ideal environment for production performance. The two strains were quite similar in terms of overall performance outcomes.

Abstract in English:

ABSTRACT This study determined the effect of layer age, egg-laying time, cage tier, and cage direction (outward-inward) on egg quality parameters of commercial layer chickens reared in enriched cages. A total of 944 layers (approximately 100 eggs every four weeks, from the 26 to the 58th week) obtained from Lohmann LSL-Classic layers reared at the Niğde Ömer Halisdemir University Ayhan Şahenk Agricultural Application and Research Centre were analyzed. Laying hen age significantly affected all the egg quality variables (p<0.01). Egg weight, shell-breaking strength, egg surface area, Haugh unit, and yolk color score differed across egg-laying time (p<0.05; p<0.01). There was variability in all the external egg quality traits among the cage tiers (p<0.05), but not for internal egg quality (p>0.05). Furthermore, it was found that cage direction had a significant effect on egg weight, shell thickness, egg surface area, and all the internal egg quality traits, except for yolk color score (p<0.05; p<0.01). In conclusion, our results highlight significant changes in egg quality traits due to layer age, egg-laying time, cage tier, and cage direction.

Abstract in English:

ABSTRACT Managing fertile eggs and minimizing seasonal impacts is crucial in poultry farming. This study evaluated the effects of the storage time of fertile eggs, broiler breeder strain, and age on hatchability and first-week broiler performance. Twelve treatments were carried out in a factorial arrangement with two broiler breeder strains (Cobb MV and Ross 308AP), two breeder age intervals (between 30-40 weeks and between 50-60 weeks), and three egg storage times (4, 7 and 9 days). The Ross 308AP strain showed the highest hatchability (91.74%) at 30-40 weeks, while Cobb MV had the greatest weight gain (162.75g) from days 1 to 7 at 50-60 weeks. Longer egg storage affected weight gain at 7 days for Cobb MV. Nine-day storage reduced chick weight (45.46g) from breeders aged 50-60 weeks. Lower first-stage embryonic mortality was observed in Ross 308 AP (3.83%) in breeders aged 30-40 weeks (4.13%), and in eggs stored for 4 days (4.01%). The Ross 308AP had the greatest percentage of infertile eggs (10.25%), and breeders aged 50-60 weeks showed greater percentages of infertility (10.14%). The Cobb MV had lower second-stage embryonic mortality but higher percentages of discarded chicks. Hatchability and first-week broiler performance depend on storage time, breeder age and strain.

Abstract in English:

ABSTRACT Considering the importance of backyard broiler production in Zambia, this study aimed to characterize this practice in the Serenje district (Zambia). A structured questionnaire was administered to 55 households. Results revealed a male predominance (56.36%) in broiler ownership, with most (69.09%) falling within the 30 to 50 years age group. Most (72.73%) had received at least secondary education. Notably, broiler producers primarily depended on farming (41.82%) and formal employment (32.73%) for income. Marketing channels predominantly involved direct sales to consumers (78.18%), minimizing intermediary involvement. The study highlighted the seasonal demand for broilers. Broiler consumption was common (90.91%) among producers, with most (85.45%) consuming broiler meat up to twice a week. Biosecurity practices varied, and mortality management predominantly involved burning or burial (67.27%). While most (96.36%) farmers practiced vaccinations, disease outbreaks persisted (92.73%), with limited consultation of veterinarians (67.27%). Access to information on broiler production primarily relied on agricultural agencies and organizations (49.09%). Common challenges included feed costs (94.55%), diseases (92.73%), and price fluctuations (87.27%). This study provides valuable insights into the dynamics of backyard broiler production in an urban setting, shedding light on its potential impacts on public health and the overall poultry industry.

Abstract in English:

ABSTRACT To determine the digestible valine (dVal) requirement and dVal to digestible lysine ratio (dVal: dLys) for laying hens, this experiment was performed on three hundred sixty Hy-Line W36 hens during the peak egg production phase (28 to 40 weeks of age), based on a completely randomized design with six treatments and five replicates of 12 birds each. The six dietary treatments were graded levels of dVal: dLys ratios: 0.82 (basal diet), 0.86, 0.90, 0.94, 0.98, and 1.02. The dVal: dLys ratio of 0.82 led to the lowest performance, indicating that valine is the first limiting amino acid in this ratio. The graded increase in the dietary dVal: dLys ratio improved egg weight (EW, p<0.01), egg mass (EM, p<0.05), and feed conversion ratio (FCR, p<0.01). The highest performance was observed at the dVal: dLys ratio of 0.94. Serum albumin, uric acid, and triglycerides were significantly (p<0.01) affected by the dVal: dLys ratio; the highest level of albumin, and the lowest levels of triglycerides and uric acid were observed at the ratios of 0.98, 0.98, and 0.94, respectively. The graded increase in dVal: dLys ratio improved (p<0.05) the egg quality traits (albumen and yolk height, Haugh unit, albumen ratio, and yolk color). Based on regression analysis, the response curves for EW and EM showed the best fit with the linear broken line (LBL) model, while the quadratic polynomial (QP) model was the best fit for FCR. In conclusion, the optimum dVal: dLys ratio was estimated at 0.93, which equals 695 mg dVal/ hen/ day.

Abstract in English:

ABSTRACT We evaluated the effect of alpha-hydroxycholecalciferol (1α-OH-D3) and phytase supplementation on the performance, carcass characteristics, blood factors, and the expression of vitamin D receptors (VDR) and Calbindin 28k (CaBP-D28k) genes in broiler chickens. In the current experiment, 400 one-day-old male chicks of the Cobb 500 strain were allocated into a completely randomized design with 4 treatments and 5 replicates (20 chicks per replicate). Experimental treatments were: 1- Control (no additional supplements), 2- Addition of 14 mg/kg DM 1α-OH-D3 to the diet, 3- Addition of 5 mg/kg phytase, and 4- Addition of 14 mg/kg 1α- OH-D3 + 5 mg/k phytase. Compared to the control diet, adding 1α-OH-D3 and phytase could significantly improve the feed conversion ratio and weight gain (p≤0.05). The combination also decreased alkaline phosphatase (ALP) activity relative to the control (p≤0.05) The relative expression of VDR and CaBP-D28k genes in the treatments that used 1α-OH-D3 and 1α-OH-D3 along with the phytase enzyme had a significant elevation compared to the control group (p<0.05). Overall, using 1α-OH-D3 along with the phytase enzyme can lead to a higher growth performance than using each one of them separately. The use of 1α-OH-D3 together with phytase led to a greater improvement of the growth performance and expression of the VDR and CaBP-D28k genes when compared to their separate use in broiler chickens’ diets.

Abstract in English:

ABSTRACT Methionine (Met) and cysteine (Cys) are nutrients in broiler diets, responsible for strengthening protein synthesis, immunity, and metabolic regulation. To estimate the ideal digestible Met + Cys:digestible Lysine (Lys) ratio for broilers under a lipopolysaccharide (LPS) inflammatory challenge, 384 male broilers were distributed in a completely randomized 4×2 factorial design, with four ratios of dig. Met + Cys:dig. Lys (0.69, 0.73, 0.77, and 0.81) and two conditions (with or without challenge). Each treatment had eight replicates, with six birds per experimental unit (EU). The evaluated parameters included broilers’ weight gain (WG), feed intake (FI), and feed conversion ratio (FCR); jejunum mRNA transcript levels of nuclear factor kappa-B (NF-Κb), glutathione peroxidase (GPX), superoxide dismutase (SOD), glutathione synthetase (GSS), and methionine adenosyltransferase 2 (MAT2); relative weights of liver and spleen, and fat mass (%) and lean mass (%). A linear regression model would estimate the ideal ratio if an effect had occurred. No interaction (p>0.05) was observed between the factors for all the data, nor did the different ratios had any effect (p>0.05) either. LPS-administered exhibited reduced performance, heavier liver and spleen, and lower GSS expression. Hence, the lowest dig Met + Cys:dig Lys ratio (0.69) was sufficient to maintain the performance parameters, the relative weight of lymphoid organs, fat and lean mass, and NF-Kb, GPX, SOD, GSS, MAT2, and CBS mRNA transcript levels in the jejunum.

Abstract in English:

ABSTRACT In this study, the performance characteristics and egg quality of brown (Hy-Line Brown (HB)) and white (Isa Tinted (IT)) laying hens housed in three different cage densities were investigated. Low (5 hens/cage LCD), medium (7 hens/cage MCD) and high (10 hens/cage HCD) cage densities were used in the research. A total of 396 laying hens were used in the experiment by placing 198 HB and 198 IT layers in cages. The performance characteristics, egg production (EP), feed consumption (FC) and livability (L) were recorded at the same time every day. Egg weight (EW) and feed conversion ratio (FCR) were measured weekly, while body weight (BW) was evaluated monthly. Monthly analyzes were performed to determine egg internal and external quality characteristics. According to the results of the research, as the cage density increased, the EP, EW, FC, FCR, BW and L of both hybrids decreased. However, the ratio of broken-cracked eggs was less in HCD. It has been determined that the performance characteristics of HB laying hens are better than ITs. The effect of cage density on egg internal and external quality parameters was insignificant (except for shape index). The shape index was found to be similar at MCD and HCD, both showing higher values than LCD. The effect of hybrid (HB, IT) on egg external quality parameters was found to be significant only on EW (HB: 63.60 g; IT: 62.50 g); while among the internal quality parameters, only the effect on egg yolk was found to be significant (IT>HB).

Abstract in English:

ABSTRACT This study aimed to determine the effect of three distinct cage densities (750 cm2/hen, 535 cm2/hen, and 375 cm2/hen) on the keel bone damage of brown (Hyline Brown, HB) and white (Isa Tinted, IT) laying hens by x-ray method. Moreover, osteocalcin (OC), calcitonin (CT), and parathormone (PTH) hormones were examined by taking blood from a total of 162 laying hens (54 laying hens from each period) at the 35th, 51st and 60th weeks. The research took place from laying hen ages of 20 to 60 weeks. A total of 396 laying hens (198 HB, 198 IT) were used in the research. Scoring was done at the end of the experiment, using the x-ray images of the chest area of the laying hens at the 35th, 51st, and 60th weeks (162 laying hens). A ‘0’ score was attributed to images with deviation and fracture; while those without them were attributed a score of ‘1’. The hormones examined were not affected by cage density. Only PTH hormone differed according to age (p<0.05) and genotype (IT > HB) (p<0.001). It was determined that keel bone damage (deviation, p=0.009) was greater at low cage density, and age had no effect on damage occurrence. The study showed that the cage density applied in conventional cage systems may affect keel bone damage.

Abstract in English:

ABSTRACT The research aimed to investigate the economic aspects of rearing male layer-type chickens to produce meat, so as to determine the production cost and propose a selling price for the products obtained. The experiment was conducted at the Institute of Animal Science - Kostinbrod, Bulgaria, using Lohmann Brown Classic cockerels. A total of 800 chickens were initially involved. The birds were slaughtered at 5 and 9 weeks of age. The costs incurred for the rearing were classified as fixed and variable, and calculated cumulatively for each week of the experiment (Option 1). Subsequently, we tested the second option of the experiment - rearing all the cockerels until 9 weeks of age (Option 2). In this scenario, the chickens were slaughtered at a random moment after 5 weeks and up to 9 weeks of age. Mathematical modelling was applied to compare the economic indicators of Option 1 and Option 2. The economic efficiency was determined for both rearing options, and was higher in the second one. The optimum age of slaughter in terms of profitability was found to be 9 weeks of age. Thus, based on the economic analysis, we propose an alternative to the currently applied practice of culling the 1 day-old layer cockerels. Furthermore, a minimum selling price of 9.85 EUR/kg has been suggested for the sale of the derived meat product.

Abstract in English:

ABSTRACT The current global trend to eradicate the use of antibiotic growth promoters (AGPs) from the poultry industry has led to the exploration of effective alternatives for sustainable poultry production and to overcome intestinal diseases in the post-AGP era. Therefore, medicinal plants and their extracts are being used as safe and natural substitutes. In this study, a research trial was conducted to explore the effect of different levels of mango seed kernel extract on the growth performance, carcass characteristics and gut microbiota of broiler birds, since mango is well known for its antioxidant, antibacterial and anti-inflammatory properties. Broiler birds (n=720) were allocated to six treatment groups under a completely randomized design; T1: positive control (basal diet with antibiotic), T2: negative control (basal diet without antibiotic), and T3, T4, T5 and T6 representing treatment groups supplemented with respectively 10 mL/kg, 20 mL/kg, 30 mL/kg and 40 mL/kg of feed of mango seed kernel extract (MSKE). Among the different levels of mango seed kernel extract, birds supplemented with 30 mL/kg and 40 mL/kg showed decreased total bacterial and differential bacterial counts, better Lactobacillus counts, and increased leg quarter and breast quarter weights. However, among the groups supplemented with 30 and 40 mL/kg, increased body weight gain and better FCR was observed in the 30 mL/kg group. Hence, it can be concluded that mango seed kernel extract given in broilers’ diet at the dose level of 30 mL/kg of feed can improve birds’ growth performance and function well as an AGP replacement, being a good option for sustainable poultry production.

Abstract in English:

ABSTRACT This study investigates the dynamics of spoilage microflora in duck meat packed in vacuum and air during 9 days of storage. In total, 72 duck carcasses were used in the study. Samples of meat (breasts and thighs, with or without skin) were analysed on days 1, 3, 6 and 9 after packaging in two different atmospheres, at a storage temperature of 3°C ± 1°C. Enterobacteriaceae, coliform bacteria, and E. coli, Total Viable Count, psychrotrophic microorganisms, Lactic Acid Bacteria, Pseudomonas spp. counts, and Brochothrix thermosphacta were determined. As expected, the type of sample and storage length had the greatest influence on microbiological quality (p<0.001). Lower significance (p<0.01) was observed for the place of sampling factor - i.e. duck breast or thigh. As expected, better microbiological parameters were achieved with vacuum-packed samples. The pH value increased during storage, but the increase was minimal for the vacuum-packed samples. In all the microbiological parameters monitored, the best results at the end of storage were obtained for duck breast muscles packed in vacuum.

Abstract in English:

ABSTRACT This study aimed to determine the prevalence of Eimeria spp., including the recently described Eimeria species Eimeria lata, Eimeria nagambie, and Eimeria zaria, on commercial broiler chicken farms (CBCFs) in the western region of the state of Santa Catarina, and to correlate their prevalence with the anticoccidial programs. Ninety-six fecal samples corresponding to 96 commercial broiler farms were examined by microscopic screening and genus-specific PCR (ITS-1 gene). All positive samples were subjected to genus-specific nested PCR (18S rRNA gene), followed by next-generation sequencing to identify the Eimeria species, and new Eimeria operational taxonomic units. Eimeria spp. were identified in 80.2% (77/96) of the samples. Next-generation sequencing revealed the following order of prevalence: Eimeria acervulina (70/77; 90.9%), Eimeria maxima (65/77; 84.4%), Eimeria mitis/mivati (17/77; 22.1%), and Eimeria praecox (37/77; 48.1%). Eimeria spp. were identified on 100% (62/62) and 44% (15/34) of the CBCFs employing treatment with salinomycin and nicarbazin, respectively. In conclusion, we observed a greater prevalence of Eimeria acervulina and Eimeria maxima; a lower prevalence of Eimeria mitis and Eimeria praecox; and the absence of Eimeria brunetti, Eimeria lata, Eimeria nagambie, Eimeria necatrix/tenella, and Eimeria zaria. There was lower positivity for Eimeria spp. on CBCFs employing treatment with nicarbazin.

Abstract in English:

ABSTRACT Chlorella vulgaris possesses antioxidant properties and a rich polyunsaturated fatty acid profile, which maintain intestinal health, improve nutrient absorption, and improve carcass characteristics and meat quality in broiler chickens. The objective of this study was to evaluate the carcass characteristics and meat quality of broiler chickens fed diets with different concentrations of Chlorella vulgaris (0, 0.25, 0.50, and 1%), without or without probiotics (0.02%), for 42 days. A completely randomized design was used in a 4 × 2 factorial arrangement (inclusion levels of Chlorella vulgaris × inclusion or absence of probiotic). Samples of the pectoralis major (n=16) were analyzed for color (L*, a*, and b*), pH, water-holding capacity (WHC), cooking loss, shear force, lipid oxidation rate, and fatty acid profile. The results showed that the addition of Chlorella vulgaris linearly increased the yellow intensity (b*) of meat. It also improved the α-linolenic acid content and the n-6/n-3 ratio. Arachidonic acid showed a quadratic effect, with a lower value when 0.5% Chlorella vulgaris was included. The addition of probiotics reduced WHC without compromising the other parameters of meat quality, and increased arachidic acid content. It was concluded that the addition of Chlorella vulgaris and/or probiotics did not influence carcass and cut characteristics. The probiotic did not improve meat quality, and Chlorella vulgaris provided more yellow color to the meat, and improved the fatty acid composition of broiler breast meat.