Template-Type: ReDIF-Article 1.0 Author-Name: Ondřej Šťastník Author-Workplace-Name: Department of Animal Nutrition and Forage Production, Faculty of AgriSciences, Mendel University in Brno, Czech Republic Author-Name: Dana Zálešáková Author-Workplace-Name: Department of Animal Nutrition and Forage Production, Faculty of AgriSciences, Mendel University in Brno, Czech Republic Author-Name: Jakub Novotný Author-Workplace-Name: Department of Animal Nutrition and Forage Production, Faculty of AgriSciences, Mendel University in Brno, Czech Republic Author-Name: Vojtěch Kumbár Author-Workplace-Name: Department of Technology and Automobile Transport, Faculty of AgriSciences, Mendel University in Brno, Czech Republic Author-Name: Andrea Roztočilová Author-Workplace-Name: Department of Animal Nutrition and Forage Production, Faculty of AgriSciences, Mendel University in Brno, Czech Republic Author-Name: Eva Mrkvicová Author-Workplace-Name: Department of Animal Nutrition and Forage Production, Faculty of AgriSciences, Mendel University in Brno, Czech Republic Author-Name: Leoš Pavlata Author-Workplace-Name: Department of Animal Nutrition and Forage Production, Faculty of AgriSciences, Mendel University in Brno, Czech Republic Title: Different particle sizes of laying hens diets and it's effect on blood biochemical parameters, ileal digesta viscosity and nitrogen retention Abstract: The aim of this work was to evaluate the effect of different particle sizes of hens diets on blood biochemical parameters, ileal digesta viscosity and nitrogen retention. In the experimental part, the effects of different physical structure were investigated on two groups of laying hens of the Bovans Brown hybrid from 76 to 80 weeks of age. A finely ground mash diet [geometric mean diameter (GMD), 632 µm] and a coarsely ground mash diet (GMD, 1 258 µm) with the equal nutritional content were used. In the experiment, the particle sizes of the feed mixtures were analysed and compared with the particle size of unaccepted feed residues using a feed separator. Furthermore, feed consumption, live weight of laying hens, blood biochemical parameters, digestive viscosity and nitrogen retention coefficient were assessed. The study revealed that the particle sizes of hens' diets significantly influenced the nitrogen retention coefficient, with higher values observed in the finely ground diet as compared to the coarsely ground diet (30.3 vs 24.0%; P < 0.05). However, no significant differences were observed in feed intake, live weight, blood biochemical parameters, or digesta viscosity between the dietary groups (P > 0.05). This finding highlights the potential of diet structure optimisation to improve nutrient utilisation efficiency, which is particularly relevant for reducing nitrogen excretion and its environmental impact. These novel insights provide a foundation for further research on the effects of feed structure on productivity and organ health. Keywords: chromium oxide, geometric mean diameter, ileal viscosity, nutrition, poultry Journal: Czech Journal of Animal Science Pages: 183-193 Volume: 70 Issue: 5 Year: 2025 DOI: 10.17221/11/2025-CJAS File-URL: http://cjas.agriculturejournals.cz/doi/10.17221/11/2025-CJAS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjs-202505-0001.txt Handle: RePEc:caa:jnlcjs:v:70:y:2025:i:5:id:11-2025-CJAS Template-Type: ReDIF-Article 1.0 Author-Name: Jan Tyl Author-Workplace-Name: International Poultry Testing Station Ústrašice, Tábor, Czech Republic Author-Workplace-Name: Department of Animal Science, Faculty of Agrobiology, Food and Natural Resources, University of Life Sciences Prague, Prague, Czech Republic Author-Name: Eva Tůmová Author-Workplace-Name: Department of Animal Science, Faculty of Agrobiology, Food and Natural Resources, University of Life Sciences Prague, Prague, Czech Republic Author-Name: Darina Chodová Author-Workplace-Name: Department of Animal Science, Faculty of Agrobiology, Food and Natural Resources, University of Life Sciences Prague, Prague, Czech Republic Title: Effects of two protein levels on the performance of chicken males with different growth intensities Abstract: At present, genetic selection programs produce chicken genotypes with different growth intensities, which might have variable requirements for dietary protein. The objective of this study was to compare the response of three different genotypes to two levels of crude protein in feed mixtures. Cockerels of fast-growing Ross 308, medium-growing Hubbard JA 757 and slow-growing ISA Dual chickens were used in the study. Each genotype was fed diets that differed in protein level: the control group (C) received commercial feed, and the experimental group was fed a diet with a 6% lower protein content (LP). The daily weight gain (DWG) and feed conversion ratio (FCR) were significantly affected by the interaction of genotype and feed protein level. A greater percentage of DWG depression was observed in fast-growing cockerels than in medium-growing cockerels (10% and 6%, respectively), whereas the percentage of slow-growing cockerels negligibly increased (2%). A low-protein diet impaired the FCR only in fast-growing birds (-5%), whereas in the medium- (-2%) and slow-growing groups (+2%), the differences were not significant. Carcass composition significantly influenced only genotype and thigh meat pH. In terms of meat colour, significant interactions revealed that in fast-growing Ross 308 chickens, redness and yellowness did not differ according to diet group; however, in both genotypes with slower growth, significantly greater redness and yellowness were detected in the low-protein diet group than in the control group. The results indicate that genotypes with slower growth have lower protein requirements for growth performance, but lower diet protein has an effect on physical meat quality parameters in these genotypes. Keywords: carcass composition, cockerels, feed protein, physical meat quality, strain Journal: Czech Journal of Animal Science Pages: 194-201 Volume: 70 Issue: 5 Year: 2025 DOI: 10.17221/44/2025-CJAS File-URL: http://cjas.agriculturejournals.cz/doi/10.17221/44/2025-CJAS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjs-202505-0002.txt Handle: RePEc:caa:jnlcjs:v:70:y:2025:i:5:id:44-2025-CJAS Template-Type: ReDIF-Article 1.0 Author-Name: Beatriz Carracelas Author-Workplace-Name: Extensive Livestock Production System, National Agricultural Research Institute, INIA Las Brujas, Canelones, Uruguay Author-Name: Pablo Peraza Author-Workplace-Name: Extensive Livestock Production System, National Agricultural Research Institute, INIA Las Brujas, Canelones, Uruguay Author-Name: Brenda Vera Author-Workplace-Name: Extensive Livestock Production System, National Agricultural Research Institute, INIA Las Brujas, Canelones, Uruguay Author-Name: Silvia Llambi Author-Workplace-Name: Animal Genetics and Breeding Unit, Department of Animal Production and Health Production Systems, Veterinary Faculty, University of the Republic (UdelaR), Montevideo, Uruguay Author-Name: Gabriel Ciappesoni Author-Workplace-Name: Extensive Livestock Production System, National Agricultural Research Institute, INIA Las Brujas, Canelones, Uruguay Title: Genetic diversity and population structure of a Creole sheep flock from Uruguay Abstract: Since 2020, the National Agricultural Research Institute (INIA) has conserved a Creole sheep flock at INIA Las Brujas. This study genetically characterised this population and compared it with six others: San Miguel National Park Creoles, commercial farms Creoles, Brazilian Creoles, Corriedale, Merilin and Soay sheep. The analysis included 628 individuals and 31 392 autosomal SNPs. Soay and San Miguel National Park Creoles exhibited the lowest genetic diversity (Ho = 0.266 and 0.279) and highest inbreeding (FHOM: 0.283 and 0.249; FROH: 0.199 and 0.202). Merilin and Corriedale showed the highest genetic diversity (Ho = 0.351 and 0.364), while Brazilian Creoles had the highest Ho (0.327) among Creoles. Short runs of homozygosity (ROH) segments (≤4 Mb) predominated, with San Miguel National Park and INIA Las Brujas Creoles exhibiting the highest numbers of ROH (22 773 and 16 762, respectively). Fixation index (Fst) and Reynolds distances highlighted INIA Las Brujas Creoles and Soay as the most distinct (0.318 and 0.321, respectively). INIA Las Brujas Creoles also showed notable differentiation from San Miguel National Park Creoles (Fst = 0.269; Reynolds = 0.272). Principal component analysis (PCA) revealed clear clustering, with Corriedale and Merilin closely related (Fst = 0.060; Reynolds = 0.068). Admixture analysis indicated distinct ancestries for Soay, Corriedale and San Miguel National Park Creoles, while commercial and Brazilian Creoles showed significant admixture. INIA Las Brujas Creoles exhibited a distinct ancestry with traces of Corriedale. Phylogenetic analysis confirmed the divergence between Creole and Corriedale/Merilin populations. Results suggest the historical genetic exchange among INIA Las Brujas Creoles, Corriedale, and commercial farms Creoles, while high differentiation of San Miguel National Park Creoles reflects their closed status since 1929. Keywords: inbreeding coefficient, local sheep breed, model-based clustering, observed heterozygosity, phylogenetic tree Journal: Czech Journal of Animal Science Pages: 173-182 Volume: 70 Issue: 5 Year: 2025 DOI: 10.17221/93/2024-CJAS File-URL: http://cjas.agriculturejournals.cz/doi/10.17221/93/2024-CJAS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjs-202505-0003.txt Handle: RePEc:caa:jnlcjs:v:70:y:2025:i:5:id:93-2024-CJAS Template-Type: ReDIF-Article 1.0 Author-Name: Nur Liyana Akmal Harun Author-Workplace-Name: Laboratory of Sustainable Animal Production and Biodiversity, Institute of Tropical Agriculture and Food Security, University Putra Malaysia, Serdang, Selangor, Malaysia Author-Name: Anjas Asmara Samsudin Author-Workplace-Name: Laboratory of Sustainable Animal Production and Biodiversity, Institute of Tropical Agriculture and Food Security, University Putra Malaysia, Serdang, Selangor, Malaysia Author-Workplace-Name: Department of Animal Science, Faculty of Agriculture, University Putra Malaysia, Serdang, Selangor, Malaysia Author-Name: Awis Qurni Sazili Author-Workplace-Name: Department of Animal Science, Faculty of Agriculture, University Putra Malaysia, Serdang, Selangor, Malaysia Author-Workplace-Name: Halal Products Research Institute, University Putra Malaysia, Putra Infoport, Serdang, Selangor, Malaysia Author-Name: Yong Meng Goh Author-Workplace-Name: Laboratory of Sustainable Animal Production and Biodiversity, Institute of Tropical Agriculture and Food Security, University Putra Malaysia, Serdang, Selangor, Malaysia Author-Workplace-Name: Department of Veterinary Preclinical Science, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Selangor, Malaysia Title: Effect of polyphenol-rich oil palm empty fruit bunch extract on in vitro rumen fermentation, fatty acid profile and microbial population Abstract: The aim of this study was to evaluate the effect of oil palm empty fruit bunch (OPEFB) extract on in vitro rumen fermentation, fatty acid profile, and microbial population. Rumen fluid was obtained from three female dairy goats fed a similar diet of 60% Napier grass and 40% commercial pellets. The substrate used for the fermentation was a Napier grass and commercial pellet mixture (60 : 40 in dry matter) and the treatment diets were: CON (substrate without OPEFB extract), OPEFB-5 (substrate with 5% of OPEFB extract), OPEFB-10 (substrate with 10% of OPEFB extract). The characteristics of rumen fermentation including pH, fermentation kinetics, total gas production, volatile fatty acid (VFA) production, fatty acid (FA) production, and microbial populations were examined. Results showed that OPEFB supplementation decreased rumen acetate concentration, increased isoacid concentrations as well as palmitic acid concentration. Meanwhile, the population of total bacteria, protozoa, and B. fibrisolvens decreased with the OPEFB supplementation. OPEFB-5 resulted in a moderate amount of acetate, isobutyrate, isovalerate concentration, insoluble fraction of gas production (but degradable), estimated potential gas production as well as B. fibrisolvens population when compared with the control and OPEFB-10 diet. Therefore it is suggested that the supplementation of OPEFB extract at 5% is suitable and practical to be used in ruminant feed without causing an imperative effect on rumen fermentation. Keywords: B. fibrisolvens, empty fruit bunch extract, fermentation kinetics, protozoa population, volatile fatty acids, total gas production Journal: Czech Journal of Animal Science Pages: 161-172 Volume: 70 Issue: 5 Year: 2025 DOI: 10.17221/180/2024-CJAS File-URL: http://cjas.agriculturejournals.cz/doi/10.17221/180/2024-CJAS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjs-202505-0004.txt Handle: RePEc:caa:jnlcjs:v:70:y:2025:i:5:id:180-2024-CJAS