In-Ovo injection of melittin into Alexandria chicken eggs: a way for early immune acceleration

Effects of In Ovo Administration of Freeze-Dried Royal Jelly on Hatchability, Blood Parameters, and Organ Weights of Day-Old Chicks

Royal jelly renowned for its robust nutritional, functional, and biological properties, is a pivotal product derived from honeybees. The purpose of this investigation was to assess the theory that in ovo injection of freeze-dried royal jelly (FDRJ) solutions at varying concentrations can influence the hatchability, blood properties and hatching characteristics of day-old chicks. A total of 480 eggs (54.81 ± 0.187 g) were allocated into four experimental groups: negative control (NC), without injection, positive control (PC), administered with regular saline, a low FDRJ dose group (9 mg/egg), and a high FDRJ dose group (18 mg/egg). The in ovo injections were administered on Day 18 of incubation, and the experiment was subsequently continued until the incubation period concluded at 21 days. Results revealed that the lower FDRJ dose (9 mg/egg) significantly improved hatchability percentages compared to other treatments. Conversely, the higher FDRJ dose (18 mg/egg) and control groups (NC and PC) resulted in significantly higher chick yield percentages than the lower FDRJ and PC groups. The NC group showed the supreme yolk sac (YS) percentage, whereas the yolk-free body mass (YFBM) percentages displayed an inverse trend. Furthermore, the in ovo FDRJ injection did not affect haematological values or the relative organ weight of day-old chicks. In conclusion, in ovo FDRJ injection demonstrated beneficial effects on hatchability and chick weight, as evidenced by the studied parameters.

Yolkin, a Polypeptide Complex from Egg Yolk, Affects Cytokine Levels and Leukocyte Populations in Broiler Chicken Blood and Lymphoid Organs after In Ovo Administration

Yolkin is a polypeptide complex isolated from hen egg yolk that exhibits immunomodulating properties. The aim of the present study was to determine whether in-ovo-delivered yolkin affects leukocyte populations and cytokine levels in broiler chickens. The experiment was carried out on eggs from Ross 308 broiler breeder birds. Yolkin was administered in ovo on the 18th day of incubation, once, at the following three doses: 1, 10, or 100 µg/egg. The immunological parameters were assessed in 1-, 7-, 14-, 21-, 28-, 35-, and 42-day-old birds kept under farming conditions and routinely vaccinated. The leukocyte populations were determined in the thymus, spleen, and blood. The cytokine (IL-1β, IL-2, IL-6, and IL-10) levels were determined in the plasma of the broiler chickens. Each experimental group included eight birds. The most pronounced effect of yolkin was an increase in the population of T cells, both CD4+ and CD8+, mainly in the blood. This effect on the lymphocyte subsets may be valuable regarding chicken immune responses, mainly against T-dependent antigens, during infection or after vaccination.

Bee Products for Poultry and Rabbits: Current Challenges and Perspectives

Poultry and rabbit production are important and rapidly growing agricultural subsectors, particularly in several developing countries. To ensure the sustainability of poultry and rabbit production, realistic poultry and rabbit farming practices must be improved. Apitherapy is a traditional alternative medicine that involves the prevention and treatment of some diseases with several bee products including propolis, royal jelly, pollen, and venom. More feeding investigations on the numerous benefits of bee products for poultry and rabbits are crucial to be addressed. Poultry and rabbit production has recently experienced numerous challenges, including climate change, disease spread, and antibiotic misuse. Improving animal welfare, health, and production is a top priority for all livestock farms, as is supplying consumers with safe and healthy products. Therefore, this review aims to collect and investigate recent relevant literature on the use of bee products, as feed additives, drinking water supplements, and injections, for poultry and rabbits to improve animal health and production. From the current findings, bee products can improve the growth and immunological performance of small-livestock animals, such as poultry and rabbits, by activating digestive enzymes, maintaining microbial balance, and promoting vitamin synthesis. Therefore, bee products could be a promising natural alternative to growth promoters, reproductive stimulants, and immunological enhancers in poultry and rabbit farms to provide safe and healthy products for humans.