Intake, apparent digestibility, and digesta passage in leopard tortoises (Geochelone pardalis) fed a complete, extruded feed

Physically Effective Fiber Threshold, Apparent Digestibility, and Novel Fecal Microbiome Identification of the Leopard Tortoise (Stigmochelys pardalis)

“…The DM, OM, ash, AIA, aNDF, and sADF of the pelleted CNTRL diet is similar to that determined for the same formula as an extruded diet (Lickel, 2010), although sADF was slightly lower than expected in the CNTRL diet, and lower than that determined by Lickel (2010) (Table 9). This may be due to typical variation in raw ingredient composition or human error during analysis, although duplicate results were very consistent.…”

“…Measured GE of the CNTRL diet was slightly higher than previously measured for the same formula in an extruded form (18.18 kJ/g; Lickel, 2010). Since all diets in this study, and that of Lickel (2010), were ground and pelleted using the same procedure for GE determination via bomb calorimetry, the original form of the diet (pelleted versus extruded) should not be a factor in the difference.…”

“…Retention time is the average amount of time a digestive marker spends in the gut (Stevens and Hume, 1998). Digesta passage rate for reptiles is longer than birds or mammals, typically spanning several days (Barboza, 1995;Stevens and Hume, 2004;Tracy et al, 2006 (Lickel, 2010). At a constant 30°C ambient temperature, Hailey (1997) demonstrated retention time of 6 hinge-back tortoises (Kinixys spekii) and 6 S. pardalis individuals to be 2.2 d and 3.8 d, respectively, when fed looped polyester thread markers (2.0 cm circumference) with kale leaves.…”

“…Since all diets in this study, and that of Lickel (2010), were ground and pelleted using the same procedure for GE determination via bomb calorimetry, the original form of the diet (pelleted versus extruded) should not be a factor in the difference. It was expected that GE of the celluloseadded diets (2.0 and 0.2 mm) would be more similar to one another than to the CNTRL due to their expected nutrient concentration similarities.…”

“…Captive tortoise diets have traditionally varied in composition, containing domestic produce, hay, and commercial dog and cat foods (Davis, 1979;Donoghue and McKeown, 1999;Lickel, 2010;Ritz et al, 2012). These diets pose two concerns, 1) nutrient imbalance, which may result in nutritional disorders (Donoghue and McKeown, 1999;Fledelius et al, 2005;Ritz et al, 2012), and 2) most extant herbivorous reptiles lack teeth (Spellerberg, 1982;Norman and Weishampel, 1985;Stevens and Hume, 1998), and may be adapted to larger ingesta particles than what these diets provide.…”