Effect of early exposure to maternal docosahexaenoic acid on memory and cognition in weaned foals

s / Journal of Equine Veterinary Science 33 (2013) 321-399 364 Effect of early exposure to maternal docosahexaenoic acid on memory and cognition in weaned foals T.L. Hansen, A.M. Adkin, and L.K. Warren Department of Animal Sciences, University of Florida, Gainesville, Florida, USA Maternal docosahexaenoic acid (DHA) status has been shown to influence cognitive development in infants and children. Improvements in learning ability might enhance trainability of horses, which could lead to better athletic performance and decreased behavioral problems. To assess the cognitive benefits of early exposure to DHA, offspring of mares fed a fat supplement containing an algae source of DHA (n1⁄410) or a placebo fat supplement (CON, n1⁄410) from d 250 of gestation through 74 d of lactation were evaluated. Using operant conditioning, foals had been taught to touch a target object with their nose upon verbal command at 2 mo of age. This study evaluated memory recall of previous training, as well as performance on new, more complex tasks using the same target training technique in weaned foals (mean SEM, 185 2 d of age). We hypothesized that weanlings exposed to DHA would have better memory recall and progress further and with greater ease through a series of new tasks than weanlings exposed to CON. With researchers blinded to treatment, weanling response times, performance scores, and the number of cues needed to successfully complete each behavior were recorded during 11 training sessions conducted over 6 d. Data were analyzed using a two-tail t-test or zero inflated Poisson model. Memory recall of previous training was evaluated during the first 2 sessions by repeating the original targeting behaviors. Based on performance scores, all foals demonstrated recall of previous training (P< 0.0001). Mean response time during session 1 was slower (P 1⁄4 0.031) than session 2, indicating optimal recall may not be achieved when first re-exposed. Memory recall was not affected by DHA exposure or sex of the foal. New behavior training (sessions 3-11) was comprised of targeting tasks that progressed in difficulty, including walking from point A to B, performing target behaviors in an open environment, walking over novel objects (black stall mat and wooden platform), and loading into a livestock-hauling trailer. Overall, weanlings exposed to DHA were more likely to score lower (P 1⁄4 0.016) than CON weanlings on new training tasks. DHA weanlings scored lower (P 1⁄4 0.013) and required more cues (P 1⁄4 0.037) to successfully complete the platform task compared to CON weanlings, whereas performance on all other individual tasks was unaffected by maternal diet. When performance on the platform was excluded from analysis, DHA weanlings showed a trend to score higher (P 1⁄4 0.0997) on all tasks than CON weanlings. Performance on all tasks was similar between colts and fillies. Results indicate that exposure to DHA via maternal supplementation in late gestation and early lactation did not enhance memory recall of previous training. Although some positive responses were noted for performance on new training tasks, additional study is needed before concluding that maternal DHA supplementation augments cognitive function of young horses. Molecular investigation and diagnosis of three genetic diseases in Arabian horses from Middle East and North American populations A.M. Khanshour, R. Juras, L. Stelly, and E.G. Cothran Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Science, Texas AM Severe Combined Immunodeficiency Disorder (SCID), Lavender Foal Syndrome (LFS) and Cerebellar Abiotrophy (CA). The associated gene for each of these diseases in Arabians has been described (Brault et al. 2011; Brooks et al. 2010; Shin et al. 1997). The aims of this study are to determine if the mutant alleles for the three diseases occur in the Syrian horse population, and to compare the frequency of each of these diseases among both Middle Eastern and North American populations, as well as other Arabian horse populations we have sampled. We extracted the total DNA using the PUREGENE DNA purification kit from 250 healthy Arabians collected from Syria, Saudi Arabia, Iran and the USA. Custom Taqman SNP Genotyping Assays from Life TechnologiesTM were used for the genotyping. Probes and primers were designed based upon the gene sequences of each disease reported in the literature. The primarily scan of the Syrian samples showed that none of them has the SCID, LFS and CA mutant alleles. The absence of the SCID carriers have been reported in other Arabians such as Polish Arabians (Terry et al. 1999) and Iranian Arabians (Seyedabadi et al. 2011). Our primarily results compared with some other studies (Brault and Penedo 2011; Brooks et al. 2010; Piro et al. 2008) suggest that the Syrian Arabians might not be the source of any of the SCID, LFS and CA mutant allels in the USA Arabians. The other horses of USA-Arabians and some horses from Saudi Arabia and Iran are still under investigation and results will be ready soon. Furthermore, additional Syrian samples might be added to this study.