Czech Journal of Animal Science - In Press
Dietary yeast culture supplementation improves meat quality and fat metabolism-related gene expression in lambOriginal Paper
Jun Xiao, Xue Han, Wei Zhao, Xin Li, Zhiwen Xuan, Zhibao Wang, Qing He, Yang Gao, Tingwei Wang, Songze Li, Yuanhong Xia, Tao Wang, Zhe Sun, Yuguo Zhen, Xuefeng Zhang, Xue Chen
This study evaluated the effects of dietary yeast culture (YC) supplementation on lamb growth performance and meat quality. After 14 days of acclimation, 20 three-month-old lambs (30.46 ± 1.77 kg) were randomly assigned to the control (CON, basal diet) or YC-supplemented group (0.625 g/kg DM) for 50 days. While YC induced no significant improvements in growth parameters (average daily gain, average daily feed intake, and ratio of feed to gain; P > 0.05), it enhanced longissimus thoracis (LT) meat quality by elevating the L* (lightness) and a* (redness) values (P < 0.05), reducing shear force (P < 0.05), increasing intramuscular fat (EE, P < 0.05), and decreasing crude protein (P < 0.05). YC modified fatty acid profiles by reducing atherogenic saturated fatty acids (P < 0.05) and elevating C16:1 (P < 0.05). Transcriptional analysis revealed depot-specific regulation: YC suppressed subcutaneous adipogenesis via downregulation of PPARγ/SREBP-1/HSL and upregulation of LPL and promoted intramuscular fat deposition in LT through coordinated activation of PPARγ/SREBP-1/FAS/ACC and inhibition of LPL (P < 0.05). These findings demonstrate the capacity of YC to optimise meat sensory attributes and lipid healthfulness through tissue-specific metabolic modulation, supporting its application as a functional feed additive in precision lamb production.
The effect of cattle breed on the quality of intramuscular fatOriginal Paper
Natalie Klessy, Eva Straková
The aim of the study was to verify whether differences in intramuscular fat quality, evaluation based on fatty acid profile and ratios, occur between cattle genotypes – the combined performance cattle breed Czech Fleckvieh and the beef breed Aberdeen Angus – under identical rearing conditions (same pasture location and nutritional management) with extensive grazing. The results of observation show the difference in the quality of intramuscular fat of bulls with combined performance and bulls with meat performance in extensive pastoral farming. Breed differences were reflected by a statistically significantly higher mean intramuscular fat (P ≤ 0.05) in the beef cattle breed (149 ± 60.1 g/kg dry matter) compared to the combined performance breed (120 ± 51.8 g/kg dry matter). A higher saturated fatty acid (SFA) value of 53.4 ± 22.2 g/kg dry matter was observed in the beef cattle breed compared to SFA 40.8 ± 18.9 g/kg dry matter (P ≤ 0.05) in the combined performance cattle breed; a higher monounsaturated fatty acid (MUFA) value of 43.8 ± 26.3 g/kg dry matter compared to a MUFA value of 42.3 ± 20.8 g/kg dry matter (P > 0.05); and a higher value of polyunsaturated fatty acids n-3 (PUFA n-3) 0.76 ± 0.33 g/kg dry matter (P ≤ 0.05) compared to PUFA n-3 0.48 ± 0.21 g/kg dry matter in combined performance cattle breed. A higher value of polyunsaturated fatty acids n-6 (PUFA n-6) 3.66 ± 1.39 g/kg dry matter was found in the combined performance cattle breed compared to the meet meat cattle breed with PUFA n-6 3.54 ± 0.96 g/kg dry matter (P > 0.05). A more favorable n-6/n-3 PUFA ratio was observed in the Aberdeen Angus (P ≤ 0.05). The results suggest that the different genotypes of the bull breeds studied, reared on extensively used pasture, may influence the amount of intramuscular fat and its quality.
A systematic review on the modulation of heat shock protein 70 in broilers at different stages of growth under thermal stressReview
ABDULLAHI HUDU RAMALAN, AHMED ABUBAKAR ABUBAKAR, RAMIAH SURIYA KUMARI, HASSIM HASLIZA ABU, GOH YONG MENG
This systematic review synthesises evidence from published articles investigating nutritional strategies to modulate heat shock protein 70 (HSP70). A total of 1,616 records were identified from four databases and snowballing. After screening and eligibility assessment, 25 studies comprising 29 reports published between 2004 and 2025 were included. The analysis shows that targeted interventions particularly antioxidants (vitamins C, E, and selenium), amino acids and their derivatives (methionine, betaine), and phytogenic compounds effectively downregulate HSP70 expression in a dose or tissue-dependent manner. This modulation is associated with improved growth performance, enhanced redox balance, and normalised stress hormone profiles. Key findings indicate that synergistic combinations outperform single additives in suppressing HSP70 and improving carcass yield under chronic heat stress (32-38 °C); early-life nutrient delivery modulates HSP70 expression and influence post-hatch thermotolerance; and organic mineral or methionine hydroxy analogue, are more effective than inorganic forms. However, efficacy varies by life stage, with most studies focused on Ross and Cobb genotypes, and is influenced by gut microbiota interactions. Major research gaps remain, including defining stage-specific optimal HSP70 thresholds, clarifying links between HSP70 modulation, immunity or gut health, understanding long-term effects of early-life nutritional programming, and determining the influence of administration routes on nutrient efficacy.
Effects of manganese supplementation to diets containing flaxseed oil on performance, antioxidant status, serum lipids, and egg fatty acid profile in aged laying hensOriginal Paper
Israa Saddam Mohammed Al-Moussawi, Seyyed Ali Mirghelenj, Mohsen Daneshyar, Hamed Khalilvandi Behrouzyar, Hamzeh Ghaderi Chaparabad, Motaleb Ebrahimi
The present study was conducted to investigate the effect of manganese (Mn) methionine supplementation in diets containing different levels of flaxseed oil (FO) on performance, blood and liver antioxidant parameters, serum lipid parameters, and egg fatty acid profile in laying hens. For this purpose, 288 laying hens were used in a completely randomised design with a 2×3 factorial arrangement, comprising six replications with eight birds in each. The experimental treatments included diets containing three levels of FO (0, 1.5, and 3% of the diet) and two levels of Mn–methionine (0 and 80 mg/kg of the diet). The results showed that hens treated with 3% FO, with or without Mn, had the highest egg production and egg weight, which were significantly greater than those of hens fed diets without FO (P < 0.05). The synergistic effects of FO and Mn indicated that FO at concentrations of 1.5% and 3%, in combination with Mn, significantly reduced triglyceride and LDL levels (P < 0.05). Diets containing 1.5 and 3% FO decreased the total antioxidant capacity of the liver and serum, while the use of 80 mg Mn increased the aforementioned parameters. The percentage of polyunsaturated fatty acids (PUFA), the ratio of PUFA to saturated fatty acids, and the percentage of ω-3 fatty acids increased significantly with the higher inclusion levels of FO in the diet (P < 0.05). In general, the inclusion of 3% FO in the diet of laying hens is recommended to improve performance while reducing serum lipid parameters and enhancing the fatty acid profile of eggs; however, the supplementation of Mn as an antioxidant is necessary to prevent lipid peroxidation.