Ready, steady, chop! Investigating the impact of chop size on zoo food nutritional quality

It is common for animal keepers to chop food up for their animals into small pieces, yet there is limited information as to why this practice is done. Anecdotally, many collections also prepare their zoo animal diets the day before feeding, and store them in the fridge overnight. The potential impact of these food preparation and storage methods on food nutritional quality is unknown. To address this, this study investigated the impact of preparing six types of produce into four sizes (0.5, 2, and 4 cm3 cubes, or whole) on the desiccation, browning and pH scores. Samples were stored either under ambient, room temperatures, or stored in a fridge and analysis was conducted over a 24-hour period. The most severe desiccation levels occurred in finely chopped feeds, for both ambient and fridge-stored samples. Time significantly affected the rate of desiccation and browning, and food chop size was a significant predictor of both browning and pH. These results suggest that serious nutritional changes occur in chopped feeds, especially when they are finely chopped and especially when food is stored for more than a couple of hours prior to feeding. Practitioners who care for animals should consider whether their animals benefit from finely chopped feeds, and should avoid the practice of storing chopped food overnight.