Search Results (1,056)

The objective of this study was to evaluate the effects of chromium propionate (Cr-Pr) and zilpaterol hydrochloride (ZH) supplementation on growth performance, performance-derived estimates of dietary energy utilization, body composition, carcass traits, wholesale cut distribution, and meat quality of finishing lambs. Forty intact male Dorper × Katahdin lambs were blocked by initial body weight (38.21 ± 1.72 kg) and assigned to a 2 × 2 factorial arrangement (n = 10/treatment): Control (0 Cr-Pr + 0 ZH), ZH (0 Cr-Pr + 7.2 mg ZH/lamb/d), Cr-Pr (1.2 mg elemental Cr/lamb/d + 0 ZH), and Cr-Pr + ZH (1.2 mg elemental Cr/lamb/d + 7.2 mg ZH/lamb/d). The experimental period lasted 45 d; Cr-Pr was supplemented throughout d 1–45, whereas ZH was administered during d 15–42, followed by a 3 d withdrawal period (d 43–45). Under the conditions evaluated, Cr-Pr, ZH, and their interaction did not affect growth performance or performance-derived estimates of dietary energy utilization (p > 0.05); however, both compounds produced specific changes in body composition and carcass traits. Supplementation with Cr-Pr reduced omental, visceral, and perirenal fat by 21.8, 18.6, and 18.7%, respectively (p ≤ 0.044), and increased longissimus muscle area (LMA) by 5.3% (p = 0.013). An interaction between Cr-Pr and ZH was detected for rib fat thickness (FAT) (p = 0.050), with the ZH and Cr-Pr individual treatments showing lower FAT than Control and Cr-Pr + ZH. Supplementation with ZH increased dressing percentage by 7.2% (p = 0.048). Regarding wholesale cuts, classified according to Institutional Meat Purchase Specifications (IMPS), Cr-Pr increased shoulder (IMPS 206) and loin (IMPS 231) proportions by 10.3 and 10.6%, respectively, and reduced shoulder (IMPS 207) by 3.3% (p = 0.043), whereas ZH increased breast (IMPS 209) weight by 15.0% and its proportion of cold carcass weight (CCW) by 9.7% (p ≤ 0.042). Interactions between Cr-Pr and ZH were also detected for ribs (IMPS 209A) and flank (IMPS 232) weights (p ≤ 0.047). Supplementation did not affect meat quality traits (p ≥ 0.217). Overall, Cr-Pr was associated with reduced internal fat deposition and increased LMA and loin (IMPS 231) proportion, whereas ZH modified dressing percentage and breast (IMPS 209) weight and proportion of CCW. These responses occurred without changes in growth performance or performance-derived estimates of dietary energy utilization and without detectable changes in the evaluated meat quality traits. The interactions observed for FAT, ribs (IMPS 209A), and flank (IMPS 232) were trait-specific and did not indicate a consistent benefit of the combination. Full article

This experimental trial assessed raw cowpea seed (CPS; Vigna unguiculata [L.] Walp.) inclusion effects in finishing pigs’ diet on growth performance, blood chemistry, meat quality, and fatty acid profile (FAs). A number of 54 crossbred male pigs ([♀F1 Topigs Large White × Norsvin Landrace] × ♂ Duroc) with an initial average body weight of 60.3 ± 3.20 kg (mean ± SD calculated across individual pigs) were divided into three groups of 18 pigs each comprising six pens of three pigs per treatment. The control group (CON) was fed a standardized SBM-based complete feed. In the experimental groups, the SBM was replaced with increasing levels of cowpea seeds (100 and 200 g/kg: CPS10 and CPS20 groups). Iso-nitrogenous and iso-caloric diets were designed with comparable levels of total lysine, sulphury amino acids (methionine + cysteine), calcium, and phosphorus. At the end of the experiment (49-day finishing period), all pigs were slaughtered. To evaluate physicochemical traits and the fatty acid profile, samples of the Longissimus dorsi (LD) muscle were collected. Incorporating CPS into pig diets produced no significant effects on growth performance (final BW, ADG, ADFI, FCR) or carcass characteristics. Overall, CPS inclusion did not affect blood biochemical indices or most meat quality parameters; however, a 20% CPS level decreased fat content, and both CPS treatments reduced the pH at 24 h post mortem, without affecting meat color or drip loss. Chewiness and resilience were lower in CPS10 group compared to CON group. Finally, the inclusion of CPS into the pigs’ diet ensured (p = 0.032) higher relative proportions of n-3 PUFAs within total muscle FAMEs, in the LD muscle, including, in particular, α-linolenic acid (p = 0.043), docosapentaenoic acid (p = 0.047), and docosahexaenoic acid (p = 0.044), which allowed for an increase in the hypo-/hypercholesterolemia ratio (p = 0.044) and a reduction in the n-6/n-3 PUFAs ratio (p = 0.037) compared with the CON group. In conclusion, raw Aura 26 cowpea seeds could partially replace soybean meal in fattening pig diets without adversely affecting productive performance while favorably altering the relative fatty acid composition of LD muscle lipids. Full article

L-malic acid (L-MA) is a naturally occurring organic acid abundant in fruits and traditional plant-based foods. L-MA, chemically identical to the natural form, has potential for optimizing energy metabolism and strengthening the antioxidant system in animal production. Objective: This research evaluated the impacts of dietary L-MA on nursery piglets’ growth performance, carcass traits, and muscle development. Forty castrated male crossbred piglets (BW: 8.06 ± 0.43 kg) were randomly assigned into five groups and provided a basal diet containing 0%, 0.25%, 0.5%, 1%, or 2% L-MA for a 56-day feeding trial. Dietary 0.5–2% L-MA enhanced final BW, ADG, and ADFI. All L-MA (0.25–2%) groups showed increased carcass weight, muscle length, and loin eye area, as well as higher pH value and color, and reduced drip loss and cooking loss of muscle tissues. An increased muscular abundance of oxidative fibers was observed in response to L-MA, accompanied by upregulated MyHCI and MyHCIIa and downregulated glycolytic-fiber-related gene expressions. Additionally, L-MA enhanced muscular SOD, GSH-Px, and CAT activities and upregulated SOD, GSH-Px, CAT, and NRF2 expressions, accompanied by a reduced MDA content. Furthermore, L-MA elevated plasma and muscular SDH and MDH activities and suppressed LDH activity. Moreover, L-MA augmented transcription of the myogenic markers (Myf6 and MyoD) and mitochondrial-related genes (COX4, Cytc, TFAM, NRF1, PGC-1α, and Sirt1), increased mitochondrial abundance, as evidenced by enhanced TOM20 intensity and upregulated expressions of COX4, Cytc, TFAM, NRF1, PGC-1α, and Sirt1. These changes were accompanied by transcriptional alterations in the AMPK/SIRT1/PGC-1α/NRF1 signaling axis. Significant enhancement effects were observed at L-MA supplementation levels of 0.5% and 2%. In summary, dietary L-MA improves ADG, ADFI, and final BW of nursery piglets, as well as muscle characteristics relevant to subsequent pork quality by enhancing antioxidant capacity, stimulating oxidative metabolism, and promoting slow muscle fiber formation. The observed effects may be partially associated with the AMPK/PGC-1α signaling pathway at the transcriptional level, as well as an increase in mitochondrial abundance. While these findings suggest a potential enhancement of mitochondrial biogenesis, definitive proof would require functional assays. Collectively, these findings underpin the potential of L-MA as a functional nutrient, a natural-identical source for improving performance and muscle quality characteristics in pig production systems. In addition, this study also contributes to the development of high-quality pork. Full article

Background: The final days before slaughter represent one of the most stressful periods in commercial broiler production, during which acute stress stimulates endocrine, oxidative, and inflammatory responses that may compromise animal welfare and slaughter outcomes. This study evaluated the effects of short-term dietary supplementation with a phytogenic additive containing Passiflora incarnata and Stevia rebaudiana extracts (Passiflora–Stevia phytogenic additive; PSPA) during the final five days before slaughter on carcass characteristics, physiological stress, oxidative status, inflammatory responses, tissue composition, and bone morphology in broilers. Methods: A total of 106,240 Ross 308 broilers were assigned to either a control group or a PSPA-supplemented group (1 kg/t) during the final five days before slaughter (days 38–42). Carcass characteristics, breast muscle and liver composition, serum corticosterone, inflammatory cytokines, oxidative stress biomarkers, and bone morphology using three-dimensional geometric morphometrics were evaluated. Results: PSPA supplementation significantly reduced serum IL-1β, IL-6, TNF-α, corticosterone, total oxidant status, and oxidative stress index, while increasing IL-10 concentrations (p < 0.05). Total antioxidant status was unaffected. After adjustment for pre-slaughter live weight, carcass weight was significantly higher in the PSPA group (p = 0.002), whereas carcass yield remained unchanged. PSPA-treated broilers also showed favorable numerical trends in carcass quality, including a higher proportion of Grade A carcasses and fewer carcass defects, although these differences were not statistically significant. Breast muscle and liver composition were unaffected, and only limited treatment-related differences were detected in bone morphology. Conclusions: Short-term PSPA supplementation improved physiological resilience by attenuating corticosterone secretion, oxidative stress, and inflammatory responses before slaughter. Although carcass quality was not significantly altered, the favorable numerical trends and improved physiological biomarkers suggest that targeted preslaughter phytogenic supplementation may represent a practical nutritional strategy to mitigate preslaughter stress in broiler chickens. Longer-term studies are warranted to determine whether these physiological benefits translate into improvements in bone characteristics and slaughter outcomes. Full article

Genetic background affects lamb growth, carcass characteristics, and meat quality and may determine the potential for producing well-marbled lamb meat. This single-site study compared growth performance, slaughter traits, and meat quality in 36 clinically healthy male lambs aged 3 months (n = 12 per genotype) from three crossbred genotypes: Kazakh Finewool × Suffolk, Kazakh Finewool × Dorper, and Kazakh Finewool × Edilbay. The lambs underwent 90 days of intensive fattening under identical housing and feeding conditions at DARA&CO LLP, Almaty Region. Growth performance, slaughter characteristics, physicochemical properties, color, pH, fatty acid, amino acid, mineral composition, and histological characteristics of the Longissimus dorsi muscle were evaluated. Marbling was assessed according to NY/T 630-2002. Kazakh Finewool × Suffolk lambs showed the highest average daily gain (294 g/day), dressing percentage (52.16%), marbling score (4.88 points), muscle area (16.40 cm²), and intramuscular fat content (11.44%) compared with Dorper and Edilbay crosses. Their meat also contained significantly higher levels of protein, zinc, and magnesium than the Dorper and Edilbay crosses (p < 0.05), with favorable pH (5.71) and color characteristics. Overall, the Kazakh Finewool × Suffolk cross showed the highest growth, carcass yield, and intramuscular fat deposition among the three crossbred groups evaluated. Because each group was represented by a single sire housed in a single pen, these findings should be interpreted as characteristics of the specific crossbred groups studied rather than as definitive breed-level effects, pending confirmation using multiple sires and replicated pens. Full article

This study aimed to determine whether greater weight gains in crossbred calves fed whole milk adjusted to 14% total solids during the preweaning phase persist into the postweaning and finishing phases and influence carcass grading. Eighty Holstein × beef calves (male and female) were randomly assigned to receive either pasteurized whole milk with 11% total solids (11%TS) or pasteurized whole milk supplemented with milk replacer to achieve 14% total solids (14%TS). Calf nutrition was modified only during the preweaning phase (<60 d). Calves fed the 14%TS diet received more nutrients than those fed the 11%TS diet, resulting in greater ADG (971 ± 16 vs. 851 ± 29 g; p < 0.01) and weaning weight (98.0 ± 1.29 vs. 93.2 ± 1.85 kg; p < 0.05). After weaning, and over a 49-week period, the gap in cumulative ADG in favor of the 14%TS group (+120 g) gradually decreased over time (only −5.6 g per month), yet consistently remained higher than that of the 11%TS group, resulting in a greater (p < 0.05) final BW (+17.5 kg) for calves in the 14%TS group than the control group (520.4 ± 3.6 vs. 502.9 ± 7.4 kg). In addition, a greater (p < 0.05) proportion of animals was assigned to higher-quality lots (sale lot assignment; 30/40; 75% in lot type 1 for 14%TS vs. 20/40; 50% for 11%TS) and a greater numerical proportion of carcasses was classified as Choice (27/40; 67.5% for 14%TS vs. 20/40: 50% for 11%TS), as determined by USDA-approved automatic grading. Ultimately, these advantages translated into greater estimated revenue per animal (USD 117 per calf) for the 14%TS group than the 11%TS group under USDA beef-grading scenario. In conclusion, the results of this study demonstrate that providing enhanced nutrition to beef-on-dairy calves improves growth performance during the preweaning phase, compared with the control group. This improvement persists over time, reflecting in favorable slaughter outcomes and numerical responses in carcass grading, thereby increasing revenue per animal and reinforcing the strategic value of beef-on-dairy systems. In addition, the financial advantages of implementing a payment method based on USDA beef grading classification are highlighted. Full article

In ruminant nutrition, functional feed additives are defined as non-nutritive or bioactive substances added to diets to intentionally alter rumen microbial populations, enhance nutrient digestibility, or modulate metabolic pathways beyond standard baseline nutrition. This review evaluates four additive classes used to address the feed-efficiency gap in sheep: gluconeogenic precursors, β-adrenergic agonists (β-AAs), exogenous enzymes, and phytochemicals. We place specific emphasis on their comparative productive performance, carcass and meat quality, economic feasibility, environmental impact, and regulatory status. Among the compounds reviewed, calcium propionate and zilpaterol hydrochloride yield the largest increases in growth rate and lean yield, though these effects remain breed-, diet-, and dose-dependent. Exogenous enzymes and phytochemicals offer smaller performance gains but generally face fewer regulatory restrictions; notably, phytochemicals reduce enteric methane emissions by 10–25% and improve meat oxidative stability, aligning well with modern sustainability goals. While combination strategies across additive classes show mechanistic promise, they remain empirically under-tested. To guide practical adoption, this review provides a cross-additive synthesis alongside qualitative cost–return profiles. Addressing critical research gaps—specifically multi-additive interactions, breed-specific validation, and the development of on-farm tools from precision-nutrition biomarkers—will determine the long-term viability of these strategies under growing market and environmental pressures. Full article

This study aimed to evaluate the effects of milk replacer (MR) feeding on carcass characteristics, meat quality, and fatty acid profile in suckling goat kids through a meta-analysis. The electronic databases Scopus, Web of Science, PubMed, and Google Scholar were used to identify the articles required for the meta-analysis using the PRISMA methodology. The data used in this meta-analysis were obtained from 13 English-language articles published in peer-reviewed journals between January 2005 and May 2026. All data were analyzed using random-effects models. Feeding with MR did not affect (p > 0.05) body weight at slaughter, hot carcass weight, or hot carcass yield of suckling kids. However, a lower renal fat weight (p < 0.05) was observed in kids fed MR. On the other hand, feeding with MR did not affect (p > 0.05) meat pH at 24 h, lightness (L*), redness (a*), yellowness (b*), Chroma (C*), Hue (H°), Warner-Bratzler shear force, or the moisture, protein, fat, collagen, and ash content in the meat of suckling kids. Nevertheless, a lower water-holding capacity (p < 0.05) was observed in the meat of kids fed MR. Feeding with MR did not affect (p > 0.05) the concentration of caproic, caprylic, lauric, myristic, myristoleic, palmitoleic, heptadecanoic, oleic, alpha-linolenic, arachidonic acid, behenic acids, total saturated fatty acids, total monounsaturated fatty acids, and total polyunsaturated fatty acids. However, lower concentrations (p < 0.05) of capric, pentadecanoic, palmitic, stearic, and arachidic acids were observed in the meat of suckling kids fed MR. In contrast, higher concentrations (p < 0.05) of linoleic acid were observed in the meat of suckling kids fed MR. In conclusion, the use of milk replacer in suckling kids preserves growth, carcass traits, and most meat quality attributes, while reducing renal fat deposition and selectively modifying the fatty acid composition toward a higher linoleic acid content. Full article

This study aims to assess the impact of different forms of feed and their processing methods on growth performance, nutrient absorption, and carcass quality in pigs across both growing and finishing stages. A total of 440 crossbred (Yorkshire × Landrace × Duroc) pigs were used in two experiments. Experiment 1 (Exp. 1) included 220 growing pigs (63 days of age; initial body weight [BW], 25.06 ± 1.82 kg), while Experiment 2 (Exp. 2) included 220 finishing pigs (105 days of age; initial BW, 54.80 ± 3.66 kg). In both experiments, pigs were assigned to four dietary treatments arranged in a 2 × 2 factorial design with 11 replicates with five pigs (two gilts and three barrows)/pen. In Exp. 1, growing pigs were either fed mash and/or crumble diets with or without 5% PKM for 6 weeks. Herein, corn, soybean meal (SBM), and PKM were all processed into both mash and crumble forms. In Exp. 2., finishing pigs were fed with mash (extruded) and crumble (non-extruded) diets with and without PKM for 10 weeks. At the end of week 6, growing pigs fed neither mash nor crumble with and without PKM diets showed no significant (p > 0.05) changes in their growth performance and nutrient digestibility. Similarly, no notable (p > 0.05) changes were observed on the growth performance, nutrient digestibility, and carcass grade quality in finishing pigs at the end of week 10. In summary, the present study had insufficient (less than 80%) statistical power to show possible differences between the treatment groups suggesting that current findings are preliminary evidence regarding the use of PKM and different feed-processing strategies in pig diets; however, further studies with greater experimental replication are warranted to validate these findings to clarify potential treatment effects. Full article

The aim of this study was to evaluate the effect of plant proteases on the oxidative stability as well as the physicochemical and sensory properties of horse meat derived from different age groups during marination. The experimental material consisted of samples of the longissimus thoracis muscle obtained from 24 horse half-carcasses, with 12 half-carcass representing horses aged 2–5 years and 12 half-carcass representing horses aged 8–12 years. Meat samples were treated with papain (P), bromelain (B), and actinidin (A) solutions at a concentration of 25 mg/100 g, as well as with a 0.5% culinary tenderizer solution (MT). The applied treatments significantly improved meat quality by reducing shear force, hardness, stiffness, and chewiness, and by affecting color parameters, including increased lightness (L*) and redness (a*) in both age groups (p < 0.05). At the same time, decreases in TBARS values, oxidation–reduction potential (ORP), and forced drip loss were observed, alongside an increase in cooking loss with extended marination time. Higher TBARS values were recorded in meat obtained from older animals, indicating a greater susceptibility to lipid oxidation. Prolonged marination, particularly up to 48 h, contributed to a reduction in lipid peroxidation processes. Full article

In post-mortem genetic identification, teeth represent one of the most reliable sources of nuclear DNA when other biological samples are unavailable, owing to their ability to protect genetic material from autolysis, microbial degradation, and environmental insults. The present study describes a forensic veterinary case report involving a Staffordshire Bull Terrier litter in which the appearance of blue-coated offspring from a phenotypically black sire and a blue dam prompted parentage verification. The sire died before formal ante-mortem sampling could be carried out. In accordance with Regulation (EC) No. 1069/2009, Article 15, the carcass was interred in the owner’s garden. Before burial, two teeth were collected as the sole biological material available for identification by the official veterinarian, ensuring an unambiguous chain of custody from death certification to laboratory analysis. DNA extraction was performed using two independent protocols: Method A, a silica-membrane-based purification (QIAamp DNA Kit, Qiagen), applied to dental pulp, and Method B, a decalcification-based workflow (T-Bone Ex Kit) followed by DNA extraction using EZ2 Connect Instruments (Qiagen). Quantification of the DNA samples obtained were done by fluorometry. Short Tandem Repeat (STR) genotyping was performed using the Canine Genotypes™ Panel 1.1 by Applied Biosystems (Thermo Fisher Scientific, Waltham, MA, USA) targeting the 18 autosomal ISAG-recommended microsatellite loci. Parentage assignments were carried out against reference STR profiles obtained from peripheral blood of the dam and offspring. The two methods, considering a different biological matrix and different operating conditions, allowed us to obtain the STR profile, but Method B showed quality electropherograms, improving the confidence and interpretation of all the markers analyzed. The differences observed between the two approaches may reflect a combination of factors, including the different dental matrices analysed, the quantity and quality of the starting material, tooth identity and tissue preservation, and differences inherent to the extraction procedures themselves; therefore, in this case, the more complete and clearer STR profile obtained with Method B should be considered a case-specific observation rather than evidence of a direct effect of the extraction method. Overall, regardless of the DNA extraction method used, the results did not exclude the biological paternity of the blue-mantled offspring. Furthermore, this case report provides practical methodological guidance for DNA recovery from canine teeth and supports their use as a reliable source of post-mortem DNA for STR-based parentage testing. Full article

This study evaluated a rumen-derived Streptococcus macedonicus isolate in Barki lambs using in vitro and in vivo approaches. The isolate was characterized for antibacterial activity and antimicrobial susceptibility. In vitro, a control diet was incubated for 24 h with 0, 0.002, 0.004, 0.008, or 0.016 g of S. macedonicus, and fermentation and digestibility were determined. In vivo, 40 Barki lambs were assigned to four dietary treatments for 210 d: control, control plus 1 g/d commercial probiotic, or control plus 1 or 2 g/d S. macedonicus. Feed intake, nutrient digestibility, growth performance, carcass traits, and meat quality were evaluated. The isolate showed antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus. In vitro, S. macedonicus increased dry matter digestibility (52.9% to 56.7%; p = 0.042) and total gas production (p < 0.0001). In vivo, dry matter digestibility increased from 66.3% to 75.2% (p = 0.002). Supplemented lambs had greater final body weight, average daily gain, and an improved feed conversion ratio (p < 0.001). Supplementation also improved carcass yield, dressing percentage, longissimus muscle area, lean proportion, water-holding capacity, and meat redness while reducing carcass fat percentage. Overall, rumen-derived S. macedonicus improved nutrient utilization, growth performance, and carcass and meat quality traits. Full article

Intramuscular fat (IMF) deposition drives premium beef value, but phenotypic selection is costly and slow. Although genome-wide studies have linked the KIRREL3 region to meat quality, whether intronic variants directly affect carcass traits and retain predictive power across physiological stages remains unproven. We genotyped two intronic SNPs (g.29756010C>T and g.29756149C>T) in Woking cattle, a high-quality beef breed developed in Jilin Province, China (n = 473; 226 and 206 heifers at 36 and 48 months, respectively, plus an independent validation cohort of n = 41), assessed for fatty acid composition, meat quality, and multi-tissue gene expression. Both loci were polymorphic and in Hardy–Weinberg equilibrium. At 36 months, TT individuals showed higher dressing percentage, rib thickness, and meat grade than CC at both loci. By 48 months, the 63-bp locus retained broader associations with carcass traits, whereas the 203-bp locus effects weakened. In the validation group, CC animals had higher IMF and muscle KIRREL3 expression than TT, yet received lower meat grades. Five fatty acids differed significantly among genotypes after Benjamini–Hochberg correction (q < 0.05), whereas the dominant fatty acids (C16:0, C18:1n9c, C18:0, C18:2n6c) showed no proportional differences. KIRREL3 was most highly expressed in the kidney among eight tissues examined. These findings identify the 63-bp site as a candidate marker for meat quality in local Chinese cattle, with potential for marker-assisted selection pending confirmation in larger cohorts and functional studies. Full article

The North American Corriente (NAC) is a Criollo-derived cattle breed raised primarily in the Southwestern and Great Plains regions of the United States for rodeo sports and beef production. Despite the substantial practical knowledge surrounding the breed, available information on the genomic makeup of NAC cattle remains limited. To address this gap, a comprehensive genomic analysis of two commercial NAC herds in northeastern New Mexico, United States, was conducted using a ~64 K SNP microarray. A total of 97 NAC cattle were initially sampled; after quality control, relatedness filtering, and population structure analysis, 52 animals were retained for downstream analysis. Population structure and admixture analyses point to a certain degree of genetic differentiation in the NAC population, which could be consistent with a distinct Criollo cattle lineage. This interpretation remains preliminary, however, and would benefit from additional sampling across independent and geographically representative herds. The overlap between functional enrichment results and known quantitative trait loci is consistent with the possibility that some genomic regions associated with movement, fertility, immune response, and carcass and milk traits may have been subject to selection. While informal, anecdotal observations of some of these phenotypic traits have been noted, further research with larger sample sizes and functional validation would be needed before drawing firmer conclusions. This study supports ongoing efforts to genetically characterize, promote, and conserve Criollo cattle populations across the Americas. Full article

This study investigated the effects of dietary nano-selenium (nano-Se) levels and Se sources on growth performance, blood parameters, meat quality, and tissue Se deposition in broilers. In Experiment 1, 480 broilers were assigned to five treatments (0, 0.10, 0.20, 0.30, and 0.40 mg/kg nano-Se) to assess the dose-dependent effects of nano-Se, with 0.20–0.22 mg/kg identified as the optimal dose through quadratic regression. In Experiment 2, 480 broilers received either a control diet or diets supplemented with 0.20 mg/kg Se from nano-Se, sodium selenite (SS), or two organic Se sources (Se-enriched yeast 1 and 2, SY1 and SY2). Supplementation with 0.20–0.30 mg/kg nano-Se improved (p < 0.05) antioxidant status, carcass yield, muscle redness at 45 min post-slaughter, and Se concentration in serum. At 0.20 mg/kg, nano-Se, SY1, and SY2 showed greater improvements in carcass traits, and antioxidant status than SS (p < 0.05), with comparable efficacy between nano-Se and organic sources. Nano-Se, organic Se sources, and SS increased Se deposition in serum and breast muscle compared to the control (p < 0.05). In conclusion, 0.20 mg/kg nano-Se is recommended for broiler diets, demonstrating superior bioefficacy to inorganic Se and comparable effects to organic Se sources. Full article