Search Results (6)

Heat stress is a critical constraint to poultry production in tropical regions, where the temperature–humidity index (THI) frequently exceeds thermoneutral thresholds. Despite growing interest in climate-resilient livestock, limited research has explored the genetic sensitivity of local chicken breeds to increasing THI levels. This study aimed to evaluate the genetic effects of increasing THI on growth performance traits in two tropical chicken breeds. The data included body weight (BW), average daily gain (ADG), and absolute growth rate (AGR) from 4,745 black-boned and 3,001 Thai native synthetic chickens across five generations. Growth data were collected from hatching to 12 weeks of age, whereas temperature and humidity were continuously recorded to calculate daily THI values. A reaction norm model was used to estimate genetic parameters and rate of decline of BW, ADG, and AGR traits under varying THI thresholds (THI70 to THI80). Results indicated that the onset of heat stress occurred at THI72 for black-boned chickens and at THI76 for Thai native synthetic chickens. Heritability estimates for BW, ADG, and AGR decreased as the THI increased in both chicken breeds. However, the Thai native synthetic chickens consistently exhibited higher genetic potential across all THI levels (average heritability: BW = 0.28, ADG = 0.25, AGR = 0.36) compared to the black-boned chickens (average heritability: BW = 0.21, ADG = 0.15, AGR = 0.23). Under mild heat stress (THI72), black-boned chickens showed sharp declines in all traits (average reduction in BW = −10.9 g, ADG = −0.87 g/day, AGR = −3.20 g/week), whereas Thai native synthetic chickens maintained stable performance. At THI76, both breeds experienced significant reductions, particularly in males. Estimated breeding values (EBVs) for AGR decreased linearly with THI, though Thai native synthetic chickens showed greater individual variability, with some birds maintaining stable or positive EBVs up to THI80—suggesting the presence of heat-resilient genotypes. In conclusion, Thai native synthetic chickens demonstrated superior thermotolerance and genetic robustness under increasing THI conditions. The identification of breed-specific THI thresholds and resilient individuals provides novel insights for climate-smart poultry breeding. These findings offer valuable tools for genetic selection, environmental management, and long-term adaptation strategies in response to global climate change. Full article

In this study, we evaluated genetic parameters and progress in growth traits and heat tolerance across four Thai native synthetic chicken lines—Kaimook e-san, Soi Pet, Soi Nin, and Kaen Thong—over seven generations. Growth traits, including body weight (BW), average daily gain (ADG), and breast circumference (BrC), were recorded and analyzed from hatching to 14 weeks of age, with heat stress assessed based on the temperature–humidity index (THI). Genetic parameters were estimated using a multi-trait animal model incorporating THI thresholds. Significant differences in growth traits were observed among the lines (p < 0.05). Kaimook e-san consistently exhibited superior performance, with males outperforming females, while Kaen Thong showed the lowest performance across all traits. Heritability estimates declined with age, with higher values observed in early growth stages, indicating stronger genetic influence during early development. Strong negative genetic correlations between heat tolerance and growth traits were observed in Kaimook e-san, while Kaen Thong showed weaker correlations, suggesting greater potential for simultaneous improvement in growth and heat tolerance. All lines demonstrated genetic progress in growth traits across generations, with Kaimook e-san achieving the highest gains, although these were accompanied by a decline in heat tolerance. The findings highlight the trade-offs between growth and thermal resilience and underscore the importance of multi-trait selection strategies for sustainable poultry breeding in tropical environments. Full article

A commonly observed chicken meat issue is its lipid oxidation that leads to deterioration of its organoleptic and nutritional properties and its further-processed products. Basil (Ocimum basilicum L.) is one of the traditional culinary herbs exhibiting food preservation properties. The current study investigated the essential oil composition, antioxidant activity and in vitro cytotoxic capacity of the essential oil of basil indigenous to Pakistan. GC–MS analysis of the essential oil revealed the presence of 59 compounds that constituted 98.6% of the essential oil. O. basilicum essential oil (OB-EO) exhibited excellent antioxidant activity, i.e., IC₅₀ 5.92 ± 0.15 µg/mL as assayed by the DPPH assay, 23.4 ± 0.02 µmoL Fe/g by FRAP, and 14.6 ± 0.59% inhibition by H₂O_2. The brine shrimp lethality assay identified an average mortality of ~18% with OB-EO at 10–1000 µg/mL, while that of the same concentration range of the standard drug (etoposide) was 72%. OB-EO was found to be non-toxic to HeLa and PC-3 cell lines. TBARS contents were significantly decreased with increase of OB-EO in chicken nuggets. The lowest TBARS contents were recorded in nuggets supplemented with 0.3% OB-EO, whereas the highest overall acceptability score was marked to the treatments carrying 0.2% OB-EO. The results suggest OB-EO as a promising carrier of bioactive compounds with a broad range of food preservation properties, and which has a sensory acceptability threshold level for chicken nuggets falling between 0.2-0.3% supplementation. Future research must investigate the antibacterial impact of OB-EO on meat products preserved with natural rather than synthetic preservatives. Full article

The rapid emergence of antibiotic resistance demands new antimicrobial strategies that are less likely to develop resistance. Augmenting the synthesis of endogenous host defense peptides (HDPs) has been proven to be an effective host-directed therapeutic approach. This study aimed to identify small-molecule compounds with a strong ability to induce endogenous HDP synthesis for further development as novel antimicrobial agents. By employing a stable HDP promoter-driven luciferase reporter cell line known as HTC/AvBD9-luc, we performed high-throughput screening of 5002 natural and synthetic compounds and identified 110 hits with a minimum Z-score of 2.0. Although they were structurally and functionally diverse, half of these hits were inhibitors of class I histone deacetylases, the phosphoinositide 3-kinase pathway, ion channels, and dopamine and serotonin receptors. Further validations revealed mocetinostat, a benzamide histone deacetylase inhibitor, to be highly potent in enhancing the expression of multiple HDP genes in chicken macrophage cell lines and jejunal explants. Importantly, mocetinostat was more efficient than entinostat and tucidinostat, two structural analogs, in promoting HDP gene expression and the antibacterial activity of chicken macrophages. Taken together, mocetinostat, with its ability to enhance HDP synthesis and the antibacterial activity of host cells, could be potentially developed as a novel antimicrobial for disease control and prevention. Full article

Heat stress is becoming a major problem because it limits growth in poultry production, especially in tropical areas. The development of genetic lines of Thai native chickens (TNC) which can tolerate the tropical climate with the least compromise on growth performance is therefore necessary. This research aims to analyze the appropriate growth curve function and to estimate the effect of heat stress on the genetic absolute growth rate (AGR) in TNC and Thai synthetic chickens (TSC). The data comprised 35,355 records for body weight from hatching to slaughtering weight of 7241 TNC and 10,220 records of 2022 TSC. The best-fitting growth curve was investigated from three nonlinear regression models (von Bertalanffy, Gompertz, and logistic) and used to analyze the individual AGR. In addition, a repeatability test-day model on the temperature-humidity index (THI) function was used to estimate the genetic parameters for heat stress. The Gompertz function produced the lowest mean squared error (MSE) and Akaike information criterion (AIC) and highest the pseudo-coefficient of determination (Pseudo-R²) in both chicken breeds. The growth rates in TSC were higher than TNC; the growth rates of males were greater than females, but the age at inflection point in females was lower than in males in both chicken breeds. The THI threshold started at 76. The heritability of the AGR was 0.23 and 0.18 in TNC and TSC, respectively. The additive variance and permanent environmental variance of the heat stress effect increased sharply after the THI of 76. The growth rate decreased more severely in TSC than TNC. In conclusion, the Gompertz function can be applied with the THI to evaluate genetic performance for heat tolerance and increase growth performance in slow-growing chicken. Full article

The epidermal growth factor receptor (EGFR) plays a central role in the progression of many solid tumors. We used this validated target to analyze the de novo design of EGFR-binding peptides and their application for the delivery of complex payloads via rational design of a viral vector. Peptides were computationally designed to interact with the EGFR dimerization interface. Two new peptides and a reference (EDA peptide) were chemically synthesized, and their binding ability characterized. Presentation of these peptides in each of the 60 capsid proteins of recombinant adeno-associated viruses (rAAV) via a genetic based loop insertion enabled targeting of EGFR overexpressing tumor cell lines. Furthermore, tissue distribution and tumor xenograft specificity were analyzed with systemic injection in chicken egg chorioallantoic membrane (CAM) assays. Complex correlations between the targeting of the synthetic peptides and the viral vectors to cells and in ovo were observed. Overall, these data demonstrate the potential of computational design in combination with rational capsid modification for viral vector targeting opening new avenues for viral vector delivery and specifically suicide gene therapy. Full article