Di Santo Ludmilla G, Braos Lucas B, Vitta-Takahashi Amanda, Borges Monique Harumi S, Pacheco Letícia G, de Paula Cerdan Isaura, Carciofi Aulus C
School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, São Paulo, Brazil.
Federal Institute of Education, Science and Technology of South of Minas Gerais - IFSULDEMINAS, Inconfidentes, Brazil.
Arch Anim Nutr. 2025 Apr;79(2):124-138. doi: 10.1080/1745039X.2025.2542144. Epub 2025 Aug 19.
The comprehension of the digestive strategy of red-footed tortoises () is necessary for effective dietary practices, which prevent metabolic disorders often seen in captivity. The present study evaluated the effects of three extruded diets (high in fibre [Control], high in starch [Starch], and high in fat [Fat]) on the tortoises' preference, nutrient digestibility, faeces quality, fermentation products, and gastrointestinal transit time (GTT). Eighteen adult red-footed tortoises (9 males and 9 females) were used to compare diet palatability. Tortoises were randomly divided into three groups of six, balanced for sex and assigned to one of the experimental diets. The total tract apparent digestibilities (TTAD) of nutrients and energy was measured using chromium oxide (0.25%) as a marker, while GTT was assessed with ferric oxide (2.5%). Faeces were collected for analysis of short and branched-chain fatty acids, lactate, ammonia, and pH. Data were analysed using analysis of variance (ANOVA), and means were compared using Tukey's test ( < 0.05). Diet preference was evaluated with paired t-test, and first-choice preferences by the Chi-square test ( < 0.05). The tortoises showed preference for the Starch and Fat diets, consuming less of the Control diet, high in fibre ( < 0.05). The TTAD of dry matter, organic matter, and gross energy was highest for the Starch diet, intermediate for the Fat diet, and lowest for the Control diet ( < 0.05). The TTAD of fat was lowest for the Fat diet, which resulted in faeces with a high fat content (33.9 ± 2.64% faecal DM; < 0.05). Tortoises fed the Control diet showed a trend towards a longer GTT, nearly three days longer than those on the other diets ( = 0.075). Short- and branched-chain fatty acids, and faecal lactate, were similar across diets ( > 0.05), though ammonia concentration was lower in the Control diet compared to the Starch diet ( < 0.05). In conclusion, red-footed tortoises showed a preference for diets high in starch and fat over the high fibre formulation. Fat TTAD was limited, decreasing with higher fat intake. Faecal concentrations of fermentation products remained consistent across diets, suggesting extensive absorption of these compounds due to the tortoises' long GTT and the reverse peristalsis.
了解红腿陆龟的消化策略对于有效的饮食管理至关重要，这可以预防圈养环境中常见的代谢紊乱。本研究评估了三种挤压饲料（高纤维[对照]、高淀粉[淀粉]和高脂肪[脂肪]）对陆龟的偏好、营养物质消化率、粪便质量、发酵产物和胃肠道转运时间（GTT）的影响。使用18只成年红腿陆龟（9只雄性和9只雌性）比较饲料适口性。陆龟被随机分为三组，每组6只，性别均衡，并分配到一种实验饲料中。使用氧化铬（0.25%）作为标记物测量营养物质和能量的全消化道表观消化率（TTAD），同时用三氧化二铁（2.5%）评估GTT。收集粪便分析短链和支链脂肪酸、乳酸、氨和pH值。数据采用方差分析（ANOVA）进行分析，均值采用Tukey检验进行比较（P<0.05）。饲料偏好通过配对t检验评估，首选偏好通过卡方检验（P<0.05）。陆龟表现出对淀粉和脂肪饲料的偏好，对照饲料（高纤维）的摄入量较少（P<0.05）。淀粉饲料的干物质、有机物质和总能的TTAD最高，脂肪饲料居中，对照饲料最低（P<0.05）。脂肪饲料的脂肪TTAD最低，导致粪便脂肪含量较高（粪便干物质的33.9±2.64%；P<0.05）。喂食对照饲料的陆龟显示出GTT延长的趋势，比其他饲料的陆龟长近三天（P=0.075）。不同饲料的短链和支链脂肪酸以及粪便乳酸含量相似（P>0.05），尽管对照饲料中的氨浓度低于淀粉饲料（P<0.05）。总之，红腿陆龟对高淀粉和高脂肪饲料的偏好高于高纤维配方饲料。脂肪TTAD有限，随着脂肪摄入量的增加而降低。不同饲料的粪便发酵产物浓度保持一致，表明由于陆龟较长的GTT和反向蠕动，这些化合物被大量吸收。
