Date of Defense
24-2-2026 12:00 AM
Location
F3-110
Document Type
Dissertation Defense
Degree Name
Doctor of Philosophy in Nutritional Sciences
College
CMHS
Department
Nutrition & Health
First Advisor
Amita Attlee
Keywords
autism, zinc homeostasis, gut microbiome, ASD-relevant behavior, hair mineral, gut morphology, inflammation-related outcome.
Abstract
Background: Autism spectrum disorder (ASD) has been associated with altered zinc homeostasis and disruptions in the gut microbiota. Zinc is a vital trace mineral involved in multiple biological processes such as inflammatory regulation, intestinal integrity, and neurobehavioral function, and has an important role in influencing microbial activity along the gut–brain axis. Both deficiency and excess of zinc can alter microbial balance. However, their collective effects on behavior, overall physiology, and mineral status in ASD-relevant models are not yet fully understood.
Aim: This comprehensive study explored the effect of dietary zinc variation on body weight, food intake, behavior, gut microbiota composition, and inflammation-related outcomes in BTBR T+Itpr3tf/J (BT) and C57BL/6 (B6) mice. Method: Male mice (8 weeks of age) of each strain were allocated to zinc-deficient (0 ppm), zinc-adequate (30 ppm), or zinc-excess (150 ppm) diets (n = 8 per group). The experiment was run eight weeks with 3-time intervals (Time 0, Time 4, and Time 8 weeks). Behavioral assays, including hole-board, repeat-dip, and marble-burying tests, were conducted at the mentioned 3 time points, along with fecal collection for 16S rRNA sequencing. Body weight and food intake were recorded weekly. Colon, cecum, blood, and hair samples were collected at the endpoint for histological, biomarker, and mineral analyses. Statistical analysis was done using generalized linear models (GLM), analysis of variance, and PERMANOVA.
Results: In the gut microbiota of both strains, Firmicutes dominated, with Lactobacillus species being the core taxa. In general, BT mice showed higher microbial variability than B6 mice, and zinc doses significantly influenced the community structures in BT mice in relation to time (PERMANOVA, p< 0.01), while B6 microbiota remained comparatively stable. Similarly, physiological and behavioral results showed strain-dependent patterns. The body weight of BT mice consistently was higher throughout than B6 mice, and zinc sufficiency was associated with improved body weight and food intake in comparison to zinc deficiency. Behavior-wise, BT mice displayed greater exploratory head-dip and marble-burying compared to B6 mice; head-dip behavior in BT changed over time, and the level of these changes varied by zinc doses. On the other hand, B6 behavior remained largely stable. Markers of inflammation were predominately strain influenced, rather than rather being than zinc dose dependent. Colonic histology analysis showed that the mucosal architecture was strain- and zinc-dependent. Zinc deficiency induced changes in crypt morphology and increased neutrophilic presence. Finally, altered hair mineral profiles too were observed in zinc-deficient BT mice, as evidenced by elevated concentrations of essential and non-essential metals including aluminum, arsenic, and lead.
Conclusions: In conclusion, dietary zinc dose- and strain-dependent effects on microbiota composition, behavior, colonic structure, inflammatory markers, and mineral homeostasis. The elevated sensitivity of BT mice to zinc dyshomeostasis reflects features of microbial and physiological vulnerability to ASD, whereas B6 mice demonstrated greater physiological resilience across varying dietary zinc conditions.
Included in
ZINC IMBALANCE AND ITS EFFECT ON NUTRITIONAL STATUS, BEHAVIOR, GUT MICROBIOTA, AND INFLAMMATORY BIOMARKERS IN BTBR T+Itpr3tf/J AND C57BL/6J MICE: INSIGHTS INTO AUTISM SPECTRUM DISORDER
F3-110
Background: Autism spectrum disorder (ASD) has been associated with altered zinc homeostasis and disruptions in the gut microbiota. Zinc is a vital trace mineral involved in multiple biological processes such as inflammatory regulation, intestinal integrity, and neurobehavioral function, and has an important role in influencing microbial activity along the gut–brain axis. Both deficiency and excess of zinc can alter microbial balance. However, their collective effects on behavior, overall physiology, and mineral status in ASD-relevant models are not yet fully understood.
Aim: This comprehensive study explored the effect of dietary zinc variation on body weight, food intake, behavior, gut microbiota composition, and inflammation-related outcomes in BTBR T+Itpr3tf/J (BT) and C57BL/6 (B6) mice. Method: Male mice (8 weeks of age) of each strain were allocated to zinc-deficient (0 ppm), zinc-adequate (30 ppm), or zinc-excess (150 ppm) diets (n = 8 per group). The experiment was run eight weeks with 3-time intervals (Time 0, Time 4, and Time 8 weeks). Behavioral assays, including hole-board, repeat-dip, and marble-burying tests, were conducted at the mentioned 3 time points, along with fecal collection for 16S rRNA sequencing. Body weight and food intake were recorded weekly. Colon, cecum, blood, and hair samples were collected at the endpoint for histological, biomarker, and mineral analyses. Statistical analysis was done using generalized linear models (GLM), analysis of variance, and PERMANOVA.
Results: In the gut microbiota of both strains, Firmicutes dominated, with Lactobacillus species being the core taxa. In general, BT mice showed higher microbial variability than B6 mice, and zinc doses significantly influenced the community structures in BT mice in relation to time (PERMANOVA, p< 0.01), while B6 microbiota remained comparatively stable. Similarly, physiological and behavioral results showed strain-dependent patterns. The body weight of BT mice consistently was higher throughout than B6 mice, and zinc sufficiency was associated with improved body weight and food intake in comparison to zinc deficiency. Behavior-wise, BT mice displayed greater exploratory head-dip and marble-burying compared to B6 mice; head-dip behavior in BT changed over time, and the level of these changes varied by zinc doses. On the other hand, B6 behavior remained largely stable. Markers of inflammation were predominately strain influenced, rather than rather being than zinc dose dependent. Colonic histology analysis showed that the mucosal architecture was strain- and zinc-dependent. Zinc deficiency induced changes in crypt morphology and increased neutrophilic presence. Finally, altered hair mineral profiles too were observed in zinc-deficient BT mice, as evidenced by elevated concentrations of essential and non-essential metals including aluminum, arsenic, and lead.
Conclusions: In conclusion, dietary zinc dose- and strain-dependent effects on microbiota composition, behavior, colonic structure, inflammatory markers, and mineral homeostasis. The elevated sensitivity of BT mice to zinc dyshomeostasis reflects features of microbial and physiological vulnerability to ASD, whereas B6 mice demonstrated greater physiological resilience across varying dietary zinc conditions.