Repeated AAV-mediated gene transfer by serotype switching enables long-lasting therapeutic levels of hUgt1a1 enzyme in a mouse model of Crigler-Najjar Syndrome Type I.

Adeno-associated virus (AAV) -mediated gene therapy is a promising strategy to treat liver-based monogenic diseases. However, two major obstacles limit its success: first, vector dilution in actively dividing cells, such as hepatocytes in neonates/children, due to the non-integrating nature of the vector; second, development of an immune response against the transgene and/or viral vector. Crigler-Najjar Syndrome Type I is a rare monogenic disease with neonatal onset, caused by mutations in the liver-specific UGT1 gene, with toxic accumulation of unconjugated bilirubin in plasma, tissues and brain. To establish an effective and long lasting cure, we applied AAV-mediated liver gene therapy to a relevant mouse model of the disease. Repeated gene transfer to adults by AAV-serotype switching, upon neonatal administration, resulted in lifelong correction of total bilirubin (TB) levels in both genders. In contrast, vector loss over time was observed after a single neonatal administration. Adult administration resulted in lifelong TB levels correction in male, but not female Ugt1-/- mice. Our findings demonstrate that neonatal AAV-mediated gene transfer to the liver supports a second transfer of the therapeutic vector, by preventing the induction of an immune response and supporting the possibility to improve AAV-therapeutic efficacy by repeated administration.

Determination of the equation parameters of carbon flow curves and estimated carbon flow and CO2 emissions from broiler production.

The objective of this study was to determine the equation parameters of carbon (i.e., C) flow curves and to estimate C flow and carbon dioxide (i.e., CO2) emissions from the production of 1- to 49-day-old broilers from different genetic strains. In total, 384 1-day-old chicks were used, distributed into 4 groups: high-performance males (Cobb-M) and females (Cobb-F), and intermediate-performance males (C44-M) and females (C44-F), with 6 replicates/treatment according to a completely randomized study design. Carbon intake and retention were calculated based on diet and body C composition, and expired C was stoichiometrically estimated as digestible C intake-C retention-C in the urine. Litter C emission was estimated as initial litter C+C in the excreta-final litter C. Carbon flow curves were determined fitting data by nonlinear regression using the Gompertz function. Expired CO2 was calculated based on expired C. The applied nonlinear model presented goodness-of-fit for all responses (R2>0.99). Carbon dioxide production was highly correlated with growth rate. At 42 d age, CO2 expiration (g/bird) was 3,384.4 for Cobb-M, 2,947.9 for Cobb-F, 2,512.5 for C44-M, and 2185.1 for C44-F. Age also significantly affected CO2 production: to achieve 2.0 kg BW, CO2 expiration (g/bird) was 1,794.3 for Cobb-M, 2,016.5 for Cobb-F, 2617.7 for C44-M, and 3,092.3 for C44-F. The obtained equations present high predictability to estimate individual CO2 emissions in strains of Cobb and C44 broilers of any weight, or age, reared between 1 and 49 d age.

Effect of CLA on performance and immune response of weanling piglets.

An experiment was conducted to evaluate the effect of CLA on the immune response and performance of piglets when subjected to an immune challenge. A total of 32 weanling pigs (17 to 23 d of age) with an initial BW of 8.9 kg were allotted to a 3 × 2 factorial arrangement of treatments. There were 3 levels of dietary CLA (0%, 1%, and 2%) and 2 levels of lipopolysaccharide (LPS) challenge (unchallenged and challenged). Challenged pigs were challenged on d 7 and 21. On d 4 and 18, all pigs were inoculated with BSA for assessment of IgG production. There was no difference in growth performance among piglets receiving different CLA supplementation levels. However, LPS-challenged piglets had poorer BW (P < 0.05), ADFI (P < 0.01), and ADG (P < 0.001) compared with the control group at d 35 postweaning. Lipopolysaccharide-challenged piglets also had increased respiratory rate (P < 0.001) and rectal temperature (P < 0.001), and decreased plasma proteins, hematocrit, and white blood cell counts (P < 0.05). Production of IgG against BSA was increased in the 1% CLA supplementation group (P < 0.001), indicating that CLA has an immunomodulatory effect. Supplementation with CLA did not affect lymphocyte proliferation, percentage of CD4(+) and CD8(+) cells, plasma proteins, red and white blood cell count, respiratory rate, or rectal temperature after LPS challenge. Although CLA supplementation did not influence growth performance or certain immune system measurements, the increased IgG titers with 1% CLA dietary supplementation indicate that it has a beneficial effect on the humoral immune system of weaned piglets.