The aim of this study is to determine the effect of abrupt and gradual light/dark switching on growth performance, behavior, villus development, meat characteristics, and immunity of broilers. A total of 270 daily male broiler chicks were used in the experiment. The study comprised three groups based on whether the transitions between light and dark periods were abrupt or gradual. No significant differences were observed among the examined groups in terms of body weight, weight gain, mortality rate, feeding, pecking, relaxing, and feather preening behaviors, carcass, and breast meat quality characteristics. Total body weight gain, total feed consumption, total feed utilization ratio, and mortality rates of broilers during the 6‐week fattening period did not differ compared to the abrupt transition. Broilers in the group with gradual transition exhibited less movement, more sitting, and sleeping behaviors. It was determined that the IgG was higher in the gradual transition group. The transitions between light and dark periods influenced the characteristics of thigh meat. Villus height and crypt depth were higher in the group where a 1‐h gradual transition was applied. As a conclusion, gradual transition is more appropriate in broiler rearing.

Background: In recent years, research has increasingly focused on the role of light exposure in stimulating embryonic development of broilers, particularly regarding how different lighting conditions during incubation may affect growth and performance outcomes. Objectives: This research examined the effects of continuous green LED lighting (560 nm, 15 lux) throughout incubation on embryo growth, hatching performance, post‐hatch growth, intestinal morphology, and carcass traits. Methods: In this study, 600 Ross‐308 hatching eggs were divided into two groups: a control group incubated in darkness and a group exposed to continuous green LED light (560 nm, 15 lux) throughout incubation. Results: Results showed no significant differences in embryo weight, length, or yolk sac usage between groups at day 19 (p > 0.05). Green LED lighting reduced relative heart weight (p < 0.01) and chick weight at hatch (p < 0.05) while significantly shortening incubation time (p < 0.001). Embryonic mortality and hatchability were not affected (p > 0.05). By day 42, broilers incubated under green LED light exhibited lower body weight and cumulative weight gain (p < 0.05), though feed conversion ratios remained similar across groups (p > 0.05). Carcass analysis revealed no significant differences in yield, but relative liver weight was higher in the green LED group (p < 0.01). Subtle changes in intestinal morphology, particularly in the jejunum, were observed with age. Conclusion: While green LED lighting did not affect hatching performance, it negatively impacted body weight, heart weight, and liver development.

This study was aimed at the assessment of the reliability and performance of the Brix refractometer for the determination of colostral IgG concentrations in sheep. A total of 190 colostrum samples were collected from 150 ewes of various breeds. Out of the colostrum samples, 101 were taken at parturition, 10 at 6 h postpartum, 6 at 8 h postpartum, 2 at 10 h postpartum, 65 at 12 h postpartum and 6 at 24 h postpartum. The Brix percentages of the colostrum samples were determined using a Brix refractometer, and the colostral IgG concentrations were measured with the radial immunodiffusion (RID) technique. Correlation coefficients were calculated between the Brix percentages and RID‐IgG values. Receiver operating characteristics (ROC) analyses were performed to determine the optimal Brix thresholds for the prediction of colostral IgG concentrations using <20, <50, <75 and <100 g/L thresholds. The misclassification cost term (MCT) analyses were performed to test the robustness of the Brix thresholds based on the relative costs of misclassifications. The mean IgG concentration and Brix percentage of the ewe colostrum samples were determined as 62.7 g/L and 27.2%, respectively. A high correlation was detected between the colostral RID‐IgG concentrations and Brix percentages ( r = 0.83). Brix percentages of ≤25.0%, ≤25.9%, ≤27.5% and ≤31.9% indicated IgG concentrations of <20, <50, <75 and <100 g/L, respectively. The Brix refractometer was demonstrated to be a low‐cost, practical and reliable tool for the determination of colostrum quality in sheep. It is recommended that the four Brix thresholds determined in this study be used strategically in feeding lambs in need of colostral supplementation due to inadequate or poor‐quality colostrum production by their dams.

Background: During incubation, the formation of fundamental anatomical and physiological structures of broilers makes this period highly sensitive to environmental factors.Objectives: This study examined the effects of green LED lighting (560 nm, 15 lux) during incubation on the quality characteristics of broiler breast meat.Methods: Meat samples were analysed for pH, colour (L*, a*, b*), cooking loss, water holding capacity, proximate composition (dry matter, crude protein, fat, and ash), fatty acid composition, amino acid profile, and antioxidant properties.Results: Green LED lighting had no significant impact on ultimate pH, meat colour, cooking loss or water holding capacity (P>0.05) but resulted in a higher initial pH (p < 0.05). Nutrient composition was found similar between groups (p > 0.05). It increased certain saturated fatty acids (C17:0, C20:0, C23:0), DHA (C22:6n3), asparagine and glutamine (p < 0.05), which may enhance nutritional value. Although TAS levels were elevated, higher TOS and OSI values indicate increased oxidative stress (p < 0.05).Conclusion: These findings suggest that green LED lighting during incubation can positively influence certain meat quality traits, particularly fatty acid and amino acid composition. Future studies should focus on optimising lighting protocols during the incubation to enhance meat quality while minimising oxidative stress.