Nutrient digestibility, rumen parameters and (cannabinoid) residues in sheep fed a pelleted diet containing green hemp (Cannabis sativa L.) biomass

The feeding value for ruminants of green hemp biomass, from the low Δ⁹-tetrahydrocannabinol (Δ⁹-THC) variety of Cannabis sativa L., is unknown. Twelve Merino ewes were individually penned and randomly allocated on a stratified liveweight basis to one of two pelleted dietary treatments, control (0% hemp, n = 6) or hemp (42% green hemp biomass, n = 6) that delivered a diet meeting the nutrient requirements of the animals. The experimental period consisted of 17 d dietary and housing adaptation, followed by 7 d total urine and feces collection for determination of apparent nutrient digestibility. A ruminal fluid sample was collected on day 27 and assessed for pH, ammonia, volatile fatty acid (VFA), and cannabinoid concentrations. A blood sample from the jugular vein and incisional subcutaneous fat biopsy from an area around the base of the tail were collected on day 28 with additional fat biopsies taken 35 d and 140 d post-feeding to measure cannabinoids. The dry matter (DM), organic matter (OM), and crude protein (CP) digestibilities, along with total VFA concentration did not differ (P = 0.713) between the two diets; however, acid detergent fiber (ADF) and neutral detergent fiber (NDF) digestibilities (P < 0.001), water intake (P = 0.023), and fecal water output (P < 0.001) were significantly lower for the sheep-fed Hemp. Rumen pH did not vary (P = 0.256) between diets, but ruminal ammonia concentration was significantly lower (P = 0.024) for sheep consuming Hemp. Sheep-fed Hemp had significantly greater molar proportions of butyric (P = 0.039) and hexanoic (P = 0.012) acids and lower molar proportions of propionic acid (P = 0.003). There were no differences between diets for N intake (P = 0.175), fecal N output (P = 0.253), and N balance (P = 0.695), with all sheep in positive N balance; however, there was significantly lower (P = 0.001) urinary N output for sheep-fed Hemp. Cannabidiolic acid (CBDA) and tetrahydrocannabinolic acid (THCA) were detected in plasma of all sheep-fed Hemp. ∆⁹-tetrahydrocannabinol was present in the subcutaneous fat of four of the six sheep on the final day of being fed Hemp, and in all (six) sheep 35 d post-feeding and one sheep 140 d post-feeding Hemp. No cannabinoids were detected in the corresponding samples taken from the sheep-fed Control. Thus, despite green hemp biomass being nutritionally a suitable feed for ruminants, under current Food Standards in Australia, the presence of these cannabinoid residues restricts its use in ruminant diets.

The legacy of structural racism: Associations between historic redlining, current mortgage lending, and health

Structural racism, which is embedded in past and present operations of the U.S. housing market, is a fundamental cause of racial health inequities. We conducted an ecologic study to 1) examine historic redlining in relation to current neighborhood lending discrimination and three key indicators of societal health (mental health, physical health, and infant mortality rate (IMR)) and 2) investigate sustained lending disinvestment as a determinant of current neighborhood health in one of the most hypersegregated metropolitan areas in the United States, Milwaukee, Wisconsin. We calculated weighted historic redlining scores from the proportion of 1930s Home Owners' Loan Corporation residential security grades contained within 2010 census tract boundaries. We combined two lending indicators from 2018 Home Mortgage Disclosure Act data to capture current neighborhood lending discrimination: low lending occurrence and high cost loans (measured via loan rate spread). Using historic redlining score and current lending discrimination, we created a 4-level hierarchical measure of lending trajectory. In Milwaukee neighborhoods, greater historic redlining was associated with current lending discrimination (OR = 1.73, 95%CI: 1.16, 2.58) and increased prevalence of poor physical health (β = 1.34, 95%CI: 0.40, 2.28) and poor mental health (β = 1.26, 95%CI: 0.51, 2.01). Historic redlining was not associated with neighborhood IMR (β = -0.48, 95%CI: -2.12, 1.15). A graded association was observed between lending trajectory and health: neighborhoods with high sustained disinvestment had worse physical and mental health than neighborhoods with high investment (poor physical health: β = 5.33, 95%CI: 3.05, 7.61; poor mental health: β = 4.32, 95%CI: 2.44, 6.20). IMR was highest in 'disinvested' neighborhoods (β = 5.87, 95%CI: 0.52, 11.22). Our findings illustrate ongoing legacies of government sponsored historic redlining. Structural racism, as manifested in historic and current forms of lending disinvestment, predicts poor health in Milwaukee's hypersegregated neighborhoods. We endorse equity focused policies that dismantle and repair the ways racism is entrenched in America's social fabric.

Abstract P873: Structural Racism in Columbus, Ohio Associated With Stroke Prevalence

Introduction: Racial disparities exist in stroke and stroke outcomes. However, the fundamental cause for these disparities are not biological differences, but structural racism. Using the Home Owners’ Loan Corporation (HOLC) ‘redlining’ scores, as indicator of structural lending practices from middle of the last century, we hypothesize that census tracts with high historic redlining are associated with higher stroke prevalence.

Methods: Weighted historic redlining scores (HRS) were calculated using the proportion of 1930s HOLC residential security grades contained within 2010 census tract boundaries of Columbus, Ohio. Stroke prevalence (adults >=18) was obtained at the census tract-level from the CDC’s 500 Cities Project. Sociodemographic factors, as measured by census tract level information (American Community Survey 2014-2018), were considered mediators in the causal association between historic redlining (measured in 1936) and stroke prevalence (measured in 2017) and were not controlled for in regression analysis. The functional form of the association was non-linear, so stroke prevalence within quartiles of the HRS were compared using linear regression instead of a continuous score.

Results: Higher HRS, representing greater redlining, were associated with greater prevalence of stroke when comparing the highest to the lowest quartile of HRS (Figure). Census tracts in the highest quartile of HRS had 1.48% higher stroke prevalence compared to those in the lowest quartile (95% CI: 0.23-2.74). No other interquartile differences were observed.

Conclusions: Historic redlining practices are a form of structural racism that established geographic systems of disadvantage and consequently, poor health outcomes. Our findings demonstrate disparate stroke prevalence by degree of historic redlining in census tracts across Columbus, Ohio. While ecologic, this study demonstrates the need to acknowledge that racism, not race, drive stroke disparities.

The intersectional effect of poverty, home ownership, and racial/ethnic composition on mean childhood blood lead levels in Milwaukee County neighborhoods

Environmental conditions that contribute to childhood lead exposure are spatially patterned. Socioeconomic and racial inequities in childhood lead exposure have been well documented, however childhood lead exposure in Milwaukee is understudied. As a segregated rustbelt metropolitan area with childhood lead exposure concerns, Milwaukee is uniquely positioned to evaluate the synergistic effects of racial and economic drivers of childhood lead exposure. Using surveillance data from the Wisconsin Department of Health Services, Division of Public Health and the US Census Bureau, this cross-sectional study determined the intersectional effect of poverty, home ownership, and racial/ethnic composition on childhood lead exposure in Milwaukee County neighborhoods using linear regression adjusting for average census tract housing age and number of children. The final analytical sample consisted of 48,393 individual childhood blood lead levels aggregated to 215 Milwaukee County census tracts. Census tracts with mean childhood blood lead levels greater than or equal to 5 μg/dL were predominantly low home ownership, high poverty, and majority non-White census tracts. The effects of low home ownership, high poverty, and majority non-White census tracts were synergistic, producing 1.78 (95% CI: 1.44, 2.11) μg/dL higher mean childhood blood lead level than high home ownership, low poverty, and majority White census tracts (referent). This research reveals that social determinants at the neighborhood level co-occur and interact to produce inequities in childhood lead exposure. Lead prevention efforts should align with equity-focused housing and economic policies that target primary prevention in neighborhoods disproportionately burdened by childhood lead exposure.