Acute toxicity bioassays are essential tools for assessing the ecotoxicological risks of chemical pollutants in aquatic environments. Among these, the Artemia nauplii immobilization test offers a rapid, cost-effective, and standardized approach for screening toxic substances. This study evaluated the acute toxicity of four heavy metal sulfates (copper, zinc, cadmium, and lead) using Artemia salina nauplii, with potassium dichromate as the reference toxicant. Artemia cysts were hatched under optimized conditions, including controlled salinity (35 ppt), pH (8.0-8.5), temperature (28°C), and continuous aeration to ensure maximum hatching success and larval viability. Toxicity tests were conducted using stage II nauplii, selected for their enhanced sensitivity to environmental contaminants, exposed to serial dilutions of each heavy metal for 24 hours following standardized protocols. Mortality rates were recorded to determine acute toxicity parameters, including 24 h LC₅₀ and LC₁₀₀ values. The results indicated that copper was the most toxic heavy metal tested, followed by lead, cadmium, and zinc, with the toxicity ranking as follows: Cu > Pb > Cd > Zn. The LC₅₀ values demonstrated that Artemia nauplii exhibited differential sensitivity to heavy metals, with copper and lead showing significantly higher toxicity compared to cadmium and zinc. Despite this differential toxicity, Artemia nauplii demonstrated considerable tolerance to heavy metal exposure across all the tested concentrations. These findings contribute to the classification and comparative assessment of heavy metal toxicity in aquatic invertebrates and underscore the utility of the Artemia bioassay as a first-tier screening tool for environmental risk assessment.

Climate change and microplastic pollution are emerging environmental stressors that increasingly threaten marine ecosystems and filter-feeding organisms. The Mediterranean mussel, Mytilus galloprovincialis, is particularly vulnerable due to its ecological and economic importance. This study explored how elevated seawater temperature and microplastic exposure alone or/in combination affect the expression of key antioxidant and stress-related genes: catalase (cat), superoxide dismutase 1 (sod1), superoxide dismutase 2 (sod2), and heat shock protein 70 (hsp70). Mussels (27.04 ± 6.45 g; 4.02 ± 0.21 cm) were assigned to four treatments: (1) control (18 °C, synthetic seawater), (2) elevated temperature (24 °C), (3) microplastics (0.06 mg L⁻¹), and (4) combined elevated temperature and microplastics. After 21 days, gill and digestive gland tissues were analyzed using quantitative PCR (qPCR). Exposure to higher temperature caused a marked increase in hsp70 expression and moderate upregulation of antioxidant genes, suggesting the activation of protective mechanisms against oxidative and proteotoxic stress. Microplastic exposure alone triggered a milder antioxidant response, consistent with particle-induced oxidative imbalance. The combined treatment produced the strongest transcriptional activation, particularly in sod2 and hsp70, indicating synergistic effects between thermal and microplastic stressors. Overall, the findings suggest that climate-driven warming can intensify the harmful effects of microplastic pollution, compromising the mussel’s oxidative defense capacity. Understanding such multi-stressor interactions is essential for predicting the resilience of marine bivalves under future ocean conditions.

The present study aimed to investigate correlations between the environmental variables, coat characteristics, and physiological responses of Caracu young bulls. Forty-eight Caracu young bulls (mean±SD: 283±23 days old; 240±38 kg body weight) participated in the experiment conducted at Sertãozinho, Brazil, in October 2025, on two days separated by a 13-day interval. Data collection was conducted in the morning and lasted approximately 2 h 30 min. Data on the variables sweating rate (g/m²/h), respiratory rate (num./min), and rectal temperature (°C) were collected and the exact time at which each animal was sampled was recorded. Then, these data were combined with the relative humidity (RH, %), air temperature (AT, °C), and the Temperature and Humidity Index (THI) of that moment. Thermal environment variables at each 20 min point were obtained from the local weather station (CIIAGRO). Data were analyzed using descriptive statistics, non-parametric tests, and correlation analysis. During data collection, the mean AT was 28°C (range: 23.3-30.7°C), UR averaged 49.7% (range: 33.8-75.7%), and ITU averaged 76.4 (range: 70-79.9). The sweating rate showed a positive correlation with rectal temperature (r=0.30; p=0.005), AT (r=0.39; p<0.001), and THI (r=0.32; p=0.002) and a negative correlation with RH (r=-0.27; p=0.01). The respiratory rate showed a positive correlation with rectal temperature (r=0.22; p=0.04) and a negative correlation with RH (r=-0.30; p=0.004), indicating that higher humidity tends to reduce heat loss through respiratory pathways. The results highlight the relevance of the thermoregulatory behaviour of Caracu cattle under tropical conditions. Selecting animals with efficient physiological responses, along with strategic management during high-THI periods, can contribute to resilience and productive efficiency in tropical beef cattle farming. We conclude that young Caracu bulls are affected by a challenging thermal environment and activate physiological responses that are also influenced by environmental conditions. Sweating rate and respiratory rate responses were found to decrease with increasing relative humidity.

Introduction

In several species, individual variation in sperm freezability has been documented, categorizing males by the response of their sperm to cryopreservation as either “good freezers” and “bad freezers”. Because sperm cryotolerance has been poorly described in goats, the objective of this study was to compare sperm freezability in this species using a recently developed tool, Sperm Quality Index (SQI).

Methods

A total of 124 ejaculates from seven Saanen goat bucks were collected weekly using an artificial vagina over one year. After semen assessment, samples were frozen using a conventional method, stored in LN₂, and thawed at 37°C. Thawed sperm were assessed for motility, viability, acrosome integrity, capacitation status, and membrane fluidity. After freeze-thawing, sperm quality significantly decreases; some sperm variables, such as motility, decrease, while others increase, such as acrosome-reacted spermatozoa. Thus, two SQIs were produced, SQI–1 included decreasing variables (progressive motility, viability, CTC–F, and acrosome integrity), whereas SQI–2 included increasing variables (CTC–AR and hyper-fluid membranes). Possible differences between males were analyzed statistically.

Results

Significant differences (p<0.05) were detected between males 1 and 6 for SQI–1 (male 1: 28.1±2.16^a; male 2: 32.2±1.98^ab; male 3: 34.7±1.73^ab; male 4: 34.7±1.64^ab; male 5: 33.5±1.76^ab; male 6: 39.9±1.82^b; male 7: 38.3±2.26^ab). Similarly, significant differences were found between male 1 and males 6 and 7 for SQI–2 (male 1: 73.0±2.28^a; male 2: 66.4±2.55^ab; male 3: 67.0±2.20^ab; male 4: 65.7±2.22^ab; male 5: 66.7±2.09^ab; male 6: 60.9±1.08^b; male 7: 64.4±2.22^b).

Conclusion

Differences observed in both SQI–1 and SQI–2 (specifically between male 1 and male 6, and between male 1 and males 6 and 7, respectively) indicated a reduced cryotolerance in male 1. These findings could be associated with a variation in seminal plasma and/or sperm plasma membrane composition. The results support decision making regarding the selection of “good freezers” in ARTs or the implementation of specific modifications in cryopreservation protocols for “bad freezers”.

This 12 weeks study examined effects of supplemental vitamins C and E on the hen day production (HDP), egg quality characteristics (EQCs) and ovarian morphometry (OM) of improved Fulani ecotype (IFE) hens. A total of 400 hens (17 weeks old) were divided into four groups, each had 100 birds and five replications of 20 birds. Hens in group 1 were fed a basal diet (control). Hens in groups 2, 3 and 4 were fed a diet with supplemental vitamin C (VC - 500 mg/kg), vitamin E (VE - 400mg/kg) and VC+VE (500+400mg/kg), respectively. The study applied a completely randomized design and HDP was calculated on teh basis of the treatment. The EQCs determined included egg weight (EWT), shell weight (SWT), yolk weight (YWT), yolk height (YH), albumen height (AH) and albumen weight (AWT), while Haugh unit (HU) was estimated using a standard formula. Four hens from each replicate were sacrificed and their reproductive organs harvested to determine oviduct length, oviduct weight, ovary weight and stroma weight. The number of follicles and diameter of large yellow (>10mm), small yellow (<5mm) and white follicles were determined, respectively. Data were subjected to an analysis of variance, and Tukey's HSD test was used to compare the difference between means. HDP (%) and OM were not influenced (p>0.05) by the antioxidants. A lower EWT (p<0.05) was observed in the control group (49.58g) compared to the VC (57.14g) and VE groups (58.03g). A pattern similar to that of EWT was observed in SWT, while a heavier YWT was observed in the VE group (19.54g). The AH of the VC (7.63mm), VE (7.55mm) and VC+VE (7.70mm) groups were better than the control (7.00mm). Alower AWT (p<.0.05) was recorded in the control group (27.90g) compared to the VC (32.08g) and VE (32.04g) groups. HU was higher (p<.0.05) in VC+VE group (88.95) compared to control (86.56) and VE (87.20) groups. This study concludes that supplemental VC and VE could enhance some internal and external EQC of IFE Hens.

Introduction and objectives:

Equine piroplasmosis (EP) is a parasitic disease caused by Theileria equi, Babesia caballi, and, to a lesser extent, Theileria haneyi. It is transmitted by hard ticks, mainly belonging to the genera Dermacentor, Haemaphysalis, Rhipicephalus, and Hyalomma. The aim of the present study was to determine the seroprevalence of EP in sport horses in Spain and to identify its associated risk factors.

Methodology:

A total of 1,022 serum samples collected in 2023 (n = 356), 2024 (n = 353), and 2025 (n = 313) from healthy horses of various breeds residing in 16 autonomous communities across Spain were analyzed. The samples were tested using two commercial cELISA kits (VMRD® Inc., Pullman, WA, USA). Apparent and true seroprevalence were calculated, and a risk factor analysis was performed using binary logistic regression to evaluate different variables, including year, sex, age group, breed group, geographical area (north or south), use/purpose, and paddock access.

Results and discussion:

Results showed an overall true seroprevalence of EP (T. equi and/or B. caballi) of 30.3% (95% CI: 27.5%–33.2%), with a decreasing trend over the three years for both T. equi and B. caballi. Older age (p < 0.001) and breed (crossbred and Iberian horses, p < 0.001) were identified as significant risk factors. The southern region of Spain showed a significantly higher EP seropositivity compared to the northern region (p = 0.018). Neither the horse’s use/purpose (p = 0.66) nor paddock access (p = 0.19) was identified as a risk factor.

Conclusions: Breed, age, and geographical location were identified as risk factors associated with the presence of EP in sport horses. Increasing the number of leisure horses included in the study, as well as collecting more detailed information on paddock access and other

management-related variables for all horses, could improve the assessment of potential risk factors associated with EP.

Egypt is one of the leading global producers of Nile tilapia, with aquaculture success closely related to water quality. The Tilapia Welfare Egypt Project aimed to enhance water quality management practices and improve fish welfare awareness among Egyptian tilapia farmers.

A comprehensive case study was conducted across 12 farms representing four major tilapia farming regions in Egypt, with three farms per region. Instrumented farms monitored water temperature and dissolved oxygen daily and measured total ammonia nitrogen (TAN), pH, nitrite, alkalinity, and Secchi disk visibility at defined intervals. Fish welfare was assessed using regular biometric and environmental indicators recorded through the FAI Tilapia Welfare App. The 12 farms under study were monitored for a full production cycle of 6 to 8 months.

According to the findings, farmers' understanding and perspectives on the significance of water quality in promoting fish health have significantly improved. Farms with monitoring equipment showed a greater ability to spot and address changes, leading to enhanced growth rates, lower mortality and more effective pond management. The results also showed that farmers' decisions on farm management were more based on results of water quality measures.

Overall, the study achieved measurable outcomes in fish performance and promoted a cultural shift towards proactive water quality management, playing a crucial role in promoting sustainable aquaculture practices and tilapia welfare throughout Egypt.

INTRODUCTION: Global warming has intensified the occurrence of heat waves, directly impacting animal reproduction, especially in cattle. Heat stress affects male reproductive efficiency. Increased body temperature compromises essential reproductive processes, particularly spermatogenesis. Understanding how heat interferes with testicular physiology and sperm quality in cattle is fundamental for the development of management strategies that minimize its negative effects on reproduction. This study aimed to evaluate, based on the scientific literature, how heat stress compromises testicular function in cattle. METHODOLOGY: The review was conducted in the PubMed and ScienceDirect databases, including original scientific articles published in English in the last 10 years, with full-text access. The descriptors used were heat-shock response, testis, cattle, thermoregulation, and spermatozoa. Initially, 21 studies were identified, of which 13 met the inclusion criteria. RESULTS: Evidence has shown that environmental heat stress promotes increased testicular temperature and alterations in blood flow, compromising scrotal thermoregulation. These alterations result in oxidative stress, sperm DNA damage, and epigenetic modifications. Significant reductions in sperm quality have been observed, including decreased motility, impaired sperm structural integrity, and Sertoli and Leydig cell dysfunction, negatively affecting spermatogenesis. Studies have also reported early diagnostic methods for heat-induced testicular changes. Furthermore, mitigation strategies, including ventilation, cooling systems, and chemical approaches, have proven effective in reducing thermal damage and preserving fertility. CONCLUSION: The studies demonstrate that heat stress reduces sperm quality parameters and alters the morphology and physiology of seminiferous tubules, ultimately leading to decreased fertility. Even moderate increases in testicular temperature are sufficient to significantly compromise sperm quality.