Chicken FTO Gene: Tissue-specific Expression, Brain Distribution, Breed Difference And Effect Of Fasting

FTO gene (fat mass and obesity-associated gene) is the first gene we have found contributing to common forms of human obesity. Studies in mammalian have made certain progress, but chicken FTO study is still vacant. In present study, we tested FTO gene tissue-specific expresssion, especially chickens with different ages and strains. FTO mRNA distribution pattern in chicken hypothalamus and thalamus was examined, as well the PVN and VMN FTO expression comparison between different food intake status and breeds.1 FTO gene tissue specific expression in different ages and breeds of chickenHypothalamus, forebrain, cerebellum, muscle, liver and visceral fat were sampled from 1 week and 19 weeks old male Ross and Leghorn chicken. FTO gene expression in these tissue samples was tested with Real-time PCR. Our results showed that FTO gene was highly expressed in liver, hypothalamus, visceral fat and cerebellum. Although factors of age and strain did not affect the FTO expression pattern in different tissues very much, there are still some breed-specific and age-specific expressions in certain tissues.In breeds comparison, the FTO gene expression in 1 week old broiler liver is severely higher than 1 week layers (P<0.01); FTO expression in 1 week broiler visceral fat and cerebellum is significantly lower compared with 1 week layers (P<0.05). In ages comparison, FTO expression level in 19 weeks old layer liver and visceral fat were markedly higher than 1 week layers (P<0.01); FTO expression level in 19 weeks old broilers hypothalamus was higher than lweek layers(P<0.05), and in cerebellum was profoundly higher than 1 week layers (P<0.01).2 FTO mRNA distributions in hypothalamus and thalamusIn this study we examined the FTO mRNA distribution pattern in hypothalamus and thalamus with in situ hybridization (ISH). Our ISH result shows that FTO gene expressed in hypothalamic PVN (paraventricular nucleus) and VMN (ventromedial nucleus), and in thylamic DLA (nucleus dorsolateralis anterior), ALA (ansae lenticularis anterior), OM (Tractus occipitomesenphalicus), SCE (stratum cellulare externum), D (nucleus of Darkschewitsch), nl (nucleus intramedialis). These nucleuses relate to food intake, visual and reproductive rhythm function.3 Effects of fasting and breed on PVN and VMN FTO expression1 week old male Ross and Leghorn chicken were divided into broiler 24 hours fasting group, broiler control, layer 24 hours fasting group and layer control. Nucleus of PVN and VMN were collected from hypothalamus by punch, and FTO mRNA levels were determined by Real-time PCR. Our result shows FTO breed specific expression in chicken PVN, that FTO expression in 1 week old broiler PVN is significantly higher than 1 week layers (P<0.05); no breed specific expression was detected in chicken VMN.24 hours fasting didn't affect both hypothalamic PVN and VMN FTO expression in 1 week male broilers. After the feed restriction, FTO expression level in VMN was significantly reduced (P<0.05), while no difference was found in PVN.