Kwanseob Shim

Early post-hatch feeding strategies supplementing nutrients, particularly functional amino acids, have been proposed to enhance gastrointestinal tract (GIT) maturation and health in broilers in the post-antibiotic era. However, reported effects on performance and gut morphology remain inconsistent. Hence, this meta-analysis synthesized and clarified the efficacy pattern of supplemental FAA (Arg, Gln, Gly) evidence on growth performance, gut morphology, and lymphoid organ development. From a search spanning 2015 to September 2025, data were extracted from 23 eligible studies among 582 reports identified and pooled from five online databases. Standardized mean differences (SMDs) were calculated using Hedges’ g estimator with 95% confidence intervals, and heterogeneity was explored using subgroup and meta-regression procedures. Internal validity and reliability of included studies and publication bias were also assessed. The random-effects meta-analyses revealed that the FAA increased BWG (SMD = 1.01; p = 0.0006) and reduced feed conversion ratio (SMD = −0.45; p < 0.0001). Likewise, they enhanced intestinal architecture in both the jejunum and ileum. This was characterized by increased villus height (p < 0.05), reduced crypt depth (p < 0.05), and an elevated villus-to-crypt ratio (p < 0.0001), with the ileum exhibiting the greatest morphological response. In contrast, supplementation had no significant effect on spleen weight (SMD = 0.24; p = 0.2483) or bursa weight (SMD = 0.31; p = 0.1575). These effects, however, can be influenced by dosage used, dietary crude protein level, and broiler strain. In addition to enhancing the small intestine morphology early on, longer supplementation increased feed efficiency. Specifically, L-arginine and glycine efficaciously stimulated BWG, while L-glutamine and L-arginine enhanced morphology. Overall, early dietary supplementation with arginine, glutamine, or glycine is an effective post-antibiotic nutritional strategy to alleviate early post-hatch physiological stress and support broiler growth and intestinal development. However, to optimize nutrient utilization and sustain growth performance comparable to that achieved with standard CP diets, these FAAs in practical broiler nutrition should be strategically integrated into low-CP formulations.

Muscle satellite cells are integral to muscle growth and regeneration, making them critical for cultured meat production. However, the influence of anatomical origin on porcine muscle satellite cells (PMSCs) for food applications remains underexplored. Here, we compared PMSCs from neck, back, and leg muscles to identify the optimal cell source for cultured meat. Transcriptomic analysis showed region-specific gene expression, including differential HOX gene expression. Neck-derived PMSCs exhibited the highest proliferation, whereas back-derived PMSCs maintained the highest PAX7 and MYOD expressions during long-term culture. Back-derived PMSCs also exhibited superior differentiation, forming thicker myotubes with the highest fusion index, favoring fast-twitch fibers, and showing the highest protein content. In contrast, neck-derived PMSCs favored slow-twitch fibers and displayed the lowest protein content. These findings underscore the significance of cell source selection in optimizing muscle tissue engineering for scalable cultured meat production, contributing to the advancement of sustainable and alternative food technologies.

Journal of Animal Science and Technology (JAST) is a peer-reviewed, open access journal publishing original research, review articles and notes in all fields of animal science. Topics covered by the journal include: genetics and breeding, physiology, nutrition of monogastric animals, nutrition of ruminants, animal products (milk, meat, eggs and their by-products) and their processing, grasslands and roughages, livestock environment, animal biotechnology, animal behavior and welfare.

Transportation, environmental changes, and overcrowding can induce short-term stress in livestock, leading to physiological imbalances even within a short period. Cortisol is a stress-response hormone and its concentration in the blood can rapidly fluctuate depending on the individual and situation. This study evaluated the short-term effects of cortisol by applying blood cortisol concentrations that mimicked the normal and stress-induced levels observed in Korean native cattle (Hanwoo) to the culture medium of Hanwoo muscle stem cells (HWSC). Treatments were designed with five cortisol concentrations (0, 5, 10, 30, and 70 ng/mL) and four treatment times (0.5, 1, 2, and 3 h), based on the CCK-8 and viable cell count results. The expression levels of cortisol receptor-related genes (NR3C1, HSP70, and HSP90AA1) increased and reached a peak at 30 min post-treatment. After 30 min, the expression of these genes gradually decreased. However, in the case of HSP70, expression tended to increase again after 3 h of treatment. This could be seen as the regulation of cortisol inflow into the HWSC. Upon examining the oxidative effects of cortisol on superoxide dismutase 1 (SOD1), glutathione peroxidase (GPX), catalase (CAT), and oxygen consumption rate (OCR), the expression of antioxidant factors increased and peaked at 30 min of treatment. Following this peak, their levels generally began to decrease. However, in the 70 ng/mL group, the expression of these factors remained at a high level compared to the control group even after 30 min. In addition, the cellular respiration index and ATP production increased as the treatment prolonged, regardless of the concentration, as shown by the OCR analysis. These results can be considered a phenomenon corresponding to the accumulation of oxidative by products, such as Reactive Oxygen Species (ROS), caused by cortisol. The gene expression of apoptosis factors (p53, BAX, Caspase-3) temporarily increased at 30 min but then decreased. Caspase-3 protein activity was elevated at 30 min in the 70 ng/mL group, which later reduced. These results suggested that short-term cortisol administration had no effect on apoptosis in muscle cell culture. Therefore, the study findings elucidating the effects of short-term cortisol treatment on HWSC suggest that short-term stress may not have a significant negative effect on Hanwoo muscle. However, as this study was limited to muscle stem cells derived from Hanwoo, further investigation is required to determine whether the observed responses are consistent across different species and in vivo environments.

Jeong Eun Lee, Sang Hoon Yoon, Kwan Seob Shim, Jeong Tae Do. IJSC -0001;0:. https://doi.org/10.15283/ijsc25037

We aimed to determine the effects of oleic acid (OA) and palmitic acid (PA), alone or in combination, on proliferation, differentiation, triacylglycerol (TAG) content, and gene expression in porcine muscle satellite cells (PMSCs). Results revealed that OA-alone- and PA + OA-treated PMSCs showed significantly increased viability than those in the control or PA-alone-treated groups. No significant effects on apoptosis were observed in all three treatments, whereas necrosis was significantly lower in OA-alone- and PA + OA-treated groups than in the control and PA-alone-treated groups. Myotube formation significantly increased in OA-alone and PA + OA-treated PMSCs than in the control and PA-alone-treated PMSCs. mRNA expression of the myogenesis-related genes MyoD1 and MyoG and of the adipogenesis-related genes PPARα, C/EBPα, PLIN1, FABP4, and FAS was significantly upregulated in OA-alone- and PA + OA-treated cells compared to control and PA-alone-treated cells, consistent with immunoblotting results for MyoD1 and MyoG. Supplementation of unsaturated fatty acid (OA) with/without saturated fatty acid (PA) significantly stimulated TAG accumulation in treated cells compared to the control and PA-alone-treated PMSCs. These results indicate that OA (alone and with PA) promotes proliferation by inhibiting necrosis and promoting myotube formation and TAG accumulation, likely upregulating myogenesis- and adipogenesis-related gene expression by modulating the effects of PA in PMSCs.

Rumen-protected linoleic acid-enriched calcium salts (LAE-Ca salts) and oleic acid-enriched calcium salts (OAE-Ca salts) were examined for their effects on total lipids, fatty acids, and lipid metabolism gene expression in Korean steers. A total of 30 animals with a mean body weight of 597 ± 5 kg were divided into three treatment groups: Control, control diet without additional fat (n = 10); LAE-Ca salts fed 50% LAE-Ca salts (n = 10); and OAE-Ca salts, fed 50% OAE-Ca salts (n = 10); 100 g/d/animal on dry matter required basis (DMR). Results revealed that lipid content was substantially lower in the OAE-Ca salts group. Total poly-unsaturated fatty acid (PUFA), ω6, and ω3 were substantially higher in the OAE-Ca salts group but the percentage of saturated fatty acids (SAF), mono-unsaturated fatty acids (MUFA), and unsaturated fatty acids (USFA) was not affected. Up-regulation of leptin gene expression was observed in the LAE-Ca salts group. The mRNA levels of genes related to lipogenesis, including lipoprotein lipase (LPL), fatty acid synthase (FAS), and stearoyl-CoA desaturase (SCD), were not statistically different between groups. However, acetyl CoA carboxylase (ACC), lipolytic adipose triglyceride lipase (ATGL), and fatty acid binding protein (FABP4) were substantially higher in the LAE-Ca salt group; hormone-sensitive lipase (HSL) was higher in the OAE-Ca salt group. Therefore, our findings indicate that fatty acid-enriched calcium salt diets affect total lipids, fatty acids, and the expression of certain lipid metabolism genes in Korean cattle.

Background: Pre-slaughter process during transportation, handling, and lairage causes stress in pigs, affecting animal welfare and meat quality. Therefore, lairage factors are important for relieving stress. A total of 24 LYD (Landrace × Yorkshire × Duroc) barrows were used to investigate the effect of 6 and 20 h lairage time (LT) on cortisol, serotonin, and catecholamine in blood and physiological factors in muscle, and to verify the causal relationship between these factors. Results: The results revealed that cortisol was increased (0.064 ± 0.007 µg/ml), and epinephrine (0.020 ± 0.002 µg/ml) and norepinephrine (1.518 ± 0.071 µg/ml) were lower at a LT of 20 h than those at 6 h, and there was no significant effect on the muscle and carcass characteristic factors. In addition, cortisol and norepinephrine showed a negative correlation (r = -50,346, p = 0.0121), epinephrine and glycogen had a positive correlation (r = 0.4417, p = 0.0307), and serotonin and heat shock protein 70 (HSP70) were positively correlated (r = 0.4715, p = 0.0200). Path analysis indicated that the increase in LT had a direct effect on cortisol, epinephrine, and norepinephrine, and an indirect effect on muscle glycogen. Conclusion: This study confirmed the effect of the increase in LT from 6 to 20 h in the lairage room on the stress response of pigs. These findings support the legal requirements that advocate for shorter lairage times, in alignment with enhanced animal welfare standards.