Transfer of immune factors via the egg may represent a maternal adaptation enhancing offspring survival. Lysozyme is a major component of maternal antibacterial immunity which is transferred to the eggs in birds. In a population of barn swallows (Hirundo rustica), lysozyme activity declined during the prelaying and laying periods in females but not in males. Egg hatching failure decreased with maternal lysozyme activity. The first eggs in a clutch contained more lysozyme and produced nestlings with larger lysozyme activity when 5 days old than last-laid ones. In a cross-fostering experiment where brood size was manipulated, nestling origin but not post-manipulation brood size affected lysozyme activity. Hence, maternal lysozyme varies during the breeding season and may differentially enhance antibacterial immune defence of the eggs and nestlings in relation to laying order. These findings suggest that offspring innate immunity is influenced by early maternal effects.

Bacteriophages, or phages, which are viruses with specifically restricted tropism for bacteria, have regained interest in the last few decades as alternative therapeutic agents against antibiotic-resistant pathogenic bacteria in animals and humans worldwide. In this context, bacteriophage therapy has been developed to treat bacterial infections of cultured fish, shellfish, and crustaceans. Nowadays, aquaculture is the only feasible solution to meet the continuously growing global demand for high-quality seafood. As such, it is crucial to focus on controlling the spread of pathogenic bacteria, as they have a significant economic impact on aquaculture systems. Overall, the documented research supports the application of bacteriophage therapy in aquaculture, but also underlies the need for additional studies, as it is still mostly in the scientific stage. This review aims to highlight and critically examine recent advancements in the application of bacteriophages to treat the most common bacterial infectious diseases in both freshwater and saltwater aquaculture species, providing topical perspectives and innovative advances.

Beginning at the end of March 1999, a syndrome characterized by severe depression, anorexia, fever, and respiratory and enteric symptoms appeared in flocks of turkeys and, to a lesser extent, of chickens in the densely populated poultry-rearing regions of northeast Italy. The disease was characterized by sinusitis, tracheitis, peritonitis, and pancreatitis. The mortality varied between 5% and 90%. The disease was diagnosed as low pathogenic avian influenza, H7N1 serotype. After a summer period of declining cases, the disease reappeared in autumn exclusively in turkeys. Since the middle of December 1999, many farms of chickens, turkeys, and guinea fowl were abruptly affected by a highly pathogenic H7N1 virus, with very severe depression and mortality up to 100% in a few days. By the end of March 2000, nearly 500 farms, representing over 15 million birds, were affected or depopulated. To date, control measures have focused on improved biosecurity measures. Vaccine was not allowed, but its use was debated.