Abstract：
The present work aimed to study whether a high sugar diet can alter immune responses and the gut microbiome in green iguanas. Thirty-six iguanas were split into four treatment groups using a 2×2 design. Iguanas received either a sugar-supplemented diet or a control diet, and either a lipopolysaccharide (LPS) injection or a phosphate-buffered saline (PBS) injection. Iguanas were given their respective diet treatment through the entire study (∼3 months) and received a primary immune challenge 1 and 2 months into the experiment. Blood samples and cloacal swabs were taken at various points in the experiment and used to measure changes in the immune system (bacterial killing ability, lysis and agglutination scores, LPS-specific IgY concentrations), and alterations in the gut microbiome. We found that a sugar diet reduces bacterial killing ability following an LPS challenge, and sugar and the immune challenge temporarily alters gut microbiome composition while reducing alpha diversity. Although sugar did not directly reduce lysis and agglutination following the immune challenge, the change in these scores over a 24-h period following an immune challenge was more drastic (it decreased) relative to the control diet group. Moreover, sugar increased constitutive agglutination outside of the immune challenges (i.e. pre-challenge levels). In this study, we provide evidence that a high sugar diet affects the immune system of green iguanas (in a disruptive manner) and alters the gut microbiome.
摘要：
本工作旨在研究高糖饮食是否可以改变绿鬣蜥的免疫反应和肠道微生物组。使用2x2设计将36只鬣蜥分成四个处理组。Iguanas接受糖补充饮食或控制饮食，并接受脂多糖(LPS)注射或磷酸盐缓冲液(PBS)注射。在整个研究过程中（〜3个月），对iguanas进行了各自的饮食治疗，并在实验中接受了1个月和2个月的初次免疫攻击。在实验的各个点采集血样和泄殖腔拭子，用于测量免疫系统的变化（细菌杀伤能力，裂解和凝集评分，LPS特异性IgY浓度），和肠道微生物组的改变。我们发现，糖饮食会降低LPS攻击后的细菌杀灭能力，和糖和免疫挑战暂时改变肠道微生物组组成，同时减少α多样性。虽然糖在免疫攻击后没有直接减少裂解和凝集，与对照饮食组相比,免疫攻击后24小时内这些评分的变化更为剧烈(下降).此外，糖在免疫挑战之外增加了组成性凝集(即，挑战前水平)。在这项研究中,我们提供的证据表明，高糖饮食会影响绿鬣蜥的免疫系统（以破坏性的方式）并改变肠道微生物组。
