Satokar, V., Vickers, M., Bridge-Comer, P. et al. 2021. Emulsified gels: A refined vehicle for accurate and rapid oral administration of lipid based preparations to rats. Animal Technology and Welfare 20(2), 95-103.
Oro-gastric gavage is used to accurately administer nutritional substances or drugs to animals. However, it induces stress and has a substantial risk of mishap. Incorporation into edible gels is difficult for lipid-based preparations. We report a new methodology for producing emulsified oil-enriched gels, their effectiveness in pilot studies and subsequent larger experimental studies. Emulsified fish oil-enriched gels were produced using non-polar starch. Multiple gel types were made incorporating 0.05ml or 1ml oil doses, oxidised or unoxidised oil and with or without raspberry flavouring. The palatability and safety were assessed with i) 8 gel types in female SD rats consuming a chow diet (40 treatments) and ii) 3 gel types in rats consuming a high fat diet (45 treatments). Subsequently, palatability and safety were further assessed in a large cohort of pregnant rats (n=155; 4,242 treatments). Across both studies, all gels were eaten completely, whether the rats consumed a chow or high-fat diet. There was a 5-day period of acclimatisation. Raspberry flavoured gels were consumed more quickly than unflavoured gels. Rats exhibited positive behaviour towards receiving the gels and there were no ill-health effects. In subsequent experimental studies 4,242 doses were given to pregnant rats and all were completely consumed. Oil-enriched emulsified gels represent an easily administered highly acceptable, reliable and safe method of lipid delivery to rats, that we propose is superior to oro-gastric gavage.