Lactic acid bacteria (LAB)-based probiotics are widely recognized as effective and sustainable alternatives to antibiotic growth promoters due to their ability to improve intestinal integrity, modulate host immunity, and enhance productive performance in poultry. This study evaluated the effects of Pediococcus acidilactici (1 × 10 8 CFU/g) administered via drinking water on the productive performance, egg quality characteristics, hatching traits, serum biochemical indices, and immune responses of broiler breeder hens. A total of 240 hens (29 weeks old) were randomly assigned to four treatment groups receiving 0.0, 0.1, 0.2, or 0.3 g of Pediococcus acidilactici per liter of drinking water, with six replicates of ten birds each. All birds were maintained under standardized management and environmental conditions for an eight-week experimental period. Supplementation at 0.2 and 0.3 g/L significantly increased egg production, egg weight, and egg mass, while also improving feed efficiency ( P < 0.05) without affecting feed intake, final body weight, or livability ( P > 0.05). These inclusion levels also enhanced reproductive performance—including settable eggs, fertility, hatchability, and hatch of fertile eggs—while reducing embryonic mortality ( P < 0.05). In terms of egg quality, hens receiving 0.2 and 0.3 g/L exhibited significant improvements in egg length, egg width, and Haugh unit scores ( P < 0.05), whereas other internal and external egg quality parameters remained statistically unchanged ( P > 0.05). Furthermore, probiotic supplementation at these levels significantly reduced serum triglyceride concentrations and elevated antibody titers against Newcastle disease and infectious bronchitis viruses ( P < 0.05). Taken together, these findings demonstrate that supplementing drinking water with PA, particularly at a concentration of 0.2 g/L, can effectively enhance the productivity, reproductive performance, and immune status of breeder hens. Future research should explore the long-term effects of PA across different genetic strains and production stages, while also integrating gut microbiota profiling and metabolic studies to better elucidate the underlying biological mechanisms.

Summary: This study investigated the effects of soybean oil nanoemulsion compared with conventional soybean oil under different dietary energy levels on the performance, metabolism, nutrient utilization, and meat quality of broiler chickens. A total of 360 male Ross 308 broilers were allocated to a 3 × 2 factorial arrangement, comprising two oil sources (soybean oil nanoemulsion vs. conventional soybean oil) and three dietary energy levels (recommended, −50, and −100 kcal/kg), in a completely randomized design with six treatments, four replicates, and 15 birds per replicate. Across 42 days, growth performance (weight gain, feed intake, feed conversion ratio, and mortality) did not differ among treatments. Carcass yield was unaffected, although breast yield increased at −100 kcal/kg, abdominal fat was elevated at −50 kcal/kg, and digestive tract proportion decreased at −100 kcal/kg (P<0.05). Lipid metabolism showed distinct oil × energy interactions: low-density lipoprotein spiked with nanoemulsion at −50 kcal/kg, triglycerides increased with nanoemulsion at −100 kcal/kg, while soybean oil maintained lower levels. Energy reduction increased high-density lipoprotein but reduced alkaline phosphatase activity (P<0.05). Intestinal morphology revealed elongated villi at −100 kcal/kg without changes in crypts. Nutrient digestibility and metabolizable energy were enhanced by nanoemulsion only at standard energy; these benefits were lost under restriction (P<0.05). Regarding meat quality, nanoemulsion improved oxidative stability under reduced energy, lowering malondialdehyde values (P<0.05), while energy reduction increased pH but did not alter water‑holding capacity or proximate composition. Soybean oil nanoemulsion can enhance nutrient utilization and meat oxidative stability in broilers, but its advantages are strongly dependent on adequate dietary energy supply.

Worldwide, billions of day-old male chicks are culled each year in the egg industry due to the low market value of layer-type males. As a result of public pressure on this ethical issue, some countries banned the practice, leading to changes in animal welfare legislation. In addition to the use of dual-purpose chicken for egg and meat production, technologies for in-ovo sex determination, aiming to cull male embryos during early development and prior to the onset of pain perception, are feasible alternatives. However, the temporal onset of pain perception in chick embryos is still unknown, and its determination is challenging. Here we embed a review of the existing literature of in-ovo pain research under the country-specific umbrella of societal discussions and culling alternatives. Recently, a study on nociception measured first signs of responses by the embryo at day 13 of incubation. Still, neither the depiction of nociceptive pathways nor an EEG, which includes signals of general muscle contraction, provide definitive proof of the perception of pain. We urge that more knowledge about the development of pain perception in chick embryos is key to the ethical framework that should underpin policy decisions.