The current study aimed to investigate the effects of ageing on oral immunity using β-defensin (DEFB) 1/2 as a marker and evaluate the effects of curcumin (CUR) on these processes. The study sample included thirty male C57BL/6J mice divided into three groups based on the treatment method used. The young control (YC) and old control (OC) groups received 0·5 % methylcellulose-400 (CUR vehicle) orally for 5 days, whereas the CUR group of older mice received a CUR solution suspended in 0·5 % methylcellulose-400 (dose: 3·0 mg/kg body). DEFB1/2 and immune indicator levels were measured in the saliva and salivary glands post-treatment. The saliva volume and protein content were significantly reduced in the OC group compared with the YC group. CUR administration restored these parameters, decreased DEFB1 expression in the salivary gland and increased DEFB1/2 secretion and DEFB2 expression. These findings were supported by epigenetic gene regulation and partial cytokine activation from changes in WD40 repeat protein 5, TNF alpha and IL-1beta. CUR can partially restore age-related changes in oral immune responses and promote oral health, thereby preventing frailty in the older population through a nutritional therapeutic pathway.

Antimicrobial proteins are active against protozoans, fungi, viruses as well as gram-positive and gram-negative bacteria. In many cases, antimicrobial proteins are present as components of innate immunity and are capable of evading bacterial resistance mechanisms. Due to these characteristics, these proteins represent an appealing alternative to conventional antibiotic drugs. Considerable research has been conducted on antimicrobial proteins from invertebrate and mammalian sources. Within the last decade, over 20 novel antimicrobial proteins have been isolated from avian systems. The majority of these proteins has been isolated from the domestic chicken and therefore represents a minuscule fraction of the avian antimicrobial proteins that are potentially awaiting discovery. In this review, we elaborate on these discoveries and on the future of avian antimicrobial protein research.