Advances in organ-on-chip technology allowed the recapitulation of two or more organs interaction thanks to dedicated microbioreactors interconnected by microfluidic network. Here, we developed pancreas-liver coculture model in a microfluidic biochip, using rat Langerhans islets and hepatocytes. The behavior and functionality of the model were compared to islets and hepatocytes (with/without insulin) monocultures. We confirmed the insulin, glucagon and C-peptide secretions by islets monoculture and coculture. Furthermore, C-peptide and insulin secretions were higher in coculture after 5 days of culture. The islets coculture presented downregulation of Pdx1, Glut2, Gcg, App, Ins1, Neurod, Neurog3 and Gcgr genes, compared to monocultures. In hepatic compartment, the monocultures without insulin were negative to CK18 staining and displayed a weaker production of albumin when compared to monocultures with insulin. They also presented a moderate protein expression of CYP3A2, GLUT2, INSR and modulation of several hepatic genes. In coculture model, hepatocytes displayed albumin productions similar to those in monoculture with insulin. The hepatocytes cocultures were highly positive to INSR, GLUT2, CK18 and CYP3A2 immunostaining and allowed to recover mRNA levels similar to monoculture with insulin (Gcgr, Insr, Hnf4a, Igfbp1 and Alb). The result illustrated that islets can produce insulin to supplement the culture medium and recover hepatic functionality. We believe that our model illustrated the potential of organ-on-chip technology to reproduce cross-talk between liver and pancreas.

A case control study was conducted to estimate the prevalence of feather-damaging behavior and evaluate the correlation with risk factors among pet psittacine birds in Japan. Although feather-damaging behavior among pet parrots is frequently observed in Japan, its prevalence and potential risk factors have not been investigated. Therefore, we conducted an online questionnaire survey on parrot owners throughout Japan to examine regional differences in feather-damaging behavior and associated risk factors. In total, 2,331 valid responses were obtained. The prevalence of feather-damaging behavior was 11.7%, in general agreement with prior studies. The highest prevalence was among Cockatoos (Cacatua spp., etc.; 30.6%), followed by Lovebirds (Agapornis spp.; 24.5%) and African grey parrots (Psittacus erithacus; 23.7%). Multivariate logistic regression was carried out to calculate the adjusted odds ratio (ORadj) for potential risk factors and adjust the confounding of the variables. The odds of feather-damaging behavior were significantly higher for Conures (Aratinga spp., Pyrrhura spp., Thectocercus acuticaudatus, Cyanoliseus patagonus) (ORadj = 2.55, P = 0.005), Pacific parrotlets (Forpus coelestis) (ORadj = 3.96, P < 0.001), African grey parrots (ORadj = 6.74, P < 0.001), Lovebirds (ORadj = 6.79, P < 0.001) and Cockatoos (ORadj = 9.46, P < 0.001) than Budgerigars (Melopsittacus undulatus), and for young adults (ORadj = 1.81, P = 0.038) and adults (ORadj = 3.17, P < 0.001) than young birds, and for signs of separation anxiety (ORadj = 1.81, P < 0.001). Species, bird age and signs of separation anxiety were significantly higher risk factors for feather-damaging behavior than any other potential risk factors. Our findings, which include broad species diversity, are a good source of data for predicting risk factors for feather-damaging behavior and could be useful in preventing declines in welfare.

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