Circulating growth hormone and prolactin concentrations in turkeys and chickens infected withhistomonas meleagridis

Abstract

1. Histomonas meleagridis was inoculated into young chickens and turkeys and the effect of the infection (blackhead) on circulating growth hormone (GH) and prolactin concentrations determined. 2. During the course of the infection in turkeys there was a marked increase in plasma GH concentration which correlated with the severity of the disease, as judged by liver and caecal characteristics. The infection was less severe in chickens and no correlation between plasma GH and the degree of infection was observed. 3. The concentration of plasma prolactin was increased in the chicken, but not in the turkey, during the invasive period of infection.

The Role of Chicken Prolactin, Growth Hormone and Their Receptors in the Immune System

“…Meanwhile, PRL levels alters in different chicken breeds (Mo et al, 2022 ). When chickens are infected with pathogens, such as Histomonas meleagridis (Chadwick et al, 1980 ), E. tenella (Chadwick et al, 1985 ), and ALV-J (Mo et al, 2021 ), the plasma PRL levels have changed compared with the uninfected chickens. These results indicate that PRL levels is not only affected by individual own growth cycle but also controlled by external factors.…”

“…In poultry, PRL and GH are related to growth, development, and reproduction (Nie et al, 2005 ; Qin et al, 2013 ; Wilkanowska et al, 2014 ). However, some studies have shown that after chicken infected with some pathogens, such as Eimeria tenella ( E. tenella ) (Chadwick et al, 1985 ; Davison et al, 1985 ), Histomonas meleagridis (Chadwick et al, 1980 ), infectious bronchitis virus (IBV) (Nii et al, 2015 ), Newcastle disease virus (NDV) (Rehman et al, 2020 ), infectious bursal disease virus (IBDV) (He et al, 2018 ; Yu et al, 2019 ), Marek's disease virus (MDV) (Liu et al, 2001 ) and avian leukosis virus (ALV) (Carter and Smith, 1983 , 1984 ; Dai et al, 2019 ; Mo et al, 2021 , 2022 ), it is found that the hormone levels are changed, and they are involved in regulating the body immune response (Allen et al, 1997 ; Breuel et al, 2004 ; Hartwell et al, 2014 ; Yu et al, 2020 ; Hu et al, 2021 ). These evidences suggest that hormones are involved in the immune responses under specific conditions, which present an often-overlooked challenge to the conventional idea that hormone merely as endocrine hormone.…”