| 1. |
- Mendoza, P., et al.
(författare)
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Starch and fiber intake effects on energy metabolism, growth, and carapacial scute pyramiding of red-footed tortoise hatchlings (Chelonoidis carbonaria)
- 2022
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Ingår i: Comparative Biochemistry and Physiology a-Molecular & Integrative Physiology. - : Elsevier BV. - 1095-6433. ; 265
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Tidskriftsartikel (refereegranskat)abstract
- Tortoise husbandry includes reports of excessive growth and carapace pyramiding, although triggers still remain to be fully elucidated. Juvenile red-footed tortoises (Chelonoidis carbonaria) were fed with two different diets, one high in fiber (HF; 14.2% crude fiber; 39.2% neutral detergent fiber, NDF; dry matter basis, DMB) and one high in starch (HS; 27.7% DMB), to assess effects on energy metabolism, nutrient digestibility, and growth. A total of 20 hatchlings (10 per diet) were used to evaluate: apparent digestibility coefficients (Da) of nutrients and gross energy (GE), passage times at 5 and 11 months of age; resting and post-prandial metabolic rates at 6 and 12 months of age; growth rates; pyramiding; and estimated body composition. Animals fed HS showed higher mass-specific intake of digestible energy (113.9 +/- 32.1 kJ kg(-1) day(-1) vs. 99.6 +/- 35.3 kJ kg(-1) day(-1); P < 0.05), digestible DM (6.1 +/- 1.8 g kg(-1) day(-1) vs. 5.0 +/- 1.8 g kg(-1) day(-1); P < 0.01), shorter transit (3 +/- 1 days vs. 4 +/- 1 days; P < 0.01) and retention times (8 +/- 2 days vs. 10 +/- 2 days; P < 0.01), and higher Da of DM, starch, NDF, and GE. Crude protein Da was higher for HF. Rest and post-prandial metabolic rates, and pyramiding degree were not affected by diets. At 13 months, the animals from HS presented wider plastrons and carapaces, and higher carapace width growth rates. In addition, these animals had lower body mineral content (1.88 +/- 0.15% vs. 2.15 +/- 0.19%; P < 0.01) and bone density (0.13 +/- 0.01 g mm(-2) vs. 0.15 +/- 0.02 g mm(-2); P < 0.02). Results provide evidence that highly digestible foods can accelerate shell growth and lower mineralization in this species.
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| 2. |
- Mendoza, P., et al.
(författare)
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Temperature effects on metabolism and energy requirement during the fast growth phase in the red-footed tortoise, Chelonoidis carbonaria
- 2023
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Ingår i: Journal of Comparative Physiology B-Biochemical Systems and Environmental Physiology. - 0174-1578. ; 193:6, s. 661-676
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Tidskriftsartikel (refereegranskat)abstract
- Early life is a challenging phase because of the high rates of morphophysiological development and growth. Changes in ambient temperature, which directly affect energy metabolism and digestive functions in ectotherms, may be of great impact during this phase. We addressed this issue in red-footed tortoise (Chelonoidis carbonaria) hatchlings kept in captivity. To this end, we investigated the effect of temperature (28 degrees C and 18 degrees C) on mass-specific gross energy intake ( GEI(m)), daily body mass gain (MG), daily intake of gross energy (GEI), digestible energy (DEI), resting metabolic rate (RMR), and specific dynamic action (SDA) components during different seasons in the first 13 months after hatching. Greater GEI(m) and MG were observed in spring (381.7 +/- 84.9 J.g(-0.86).day(-1) and 0.9 +/- 0.4 g.day(-1)) and summer (356.9 +/- 58.9 J.g(-0.86).day(-1) and 1.0 +/- 0.4 g.day(-1)). The highest and lowest RMRs at 28 degrees C were observed in spring (36.4 +/- 5.1 kJ.kg(-1).day(-1)) and winter (22.4 +/- 6.2 kJ.kg(-1). day(-1)), respectively. Regardless season, hatchlings showed greater GEI and DEI, O-2 consumption, CO2 production, RMR, maximum metabolic rate after feeding (FMRMAX), and heat increment ( FMRMAX- RMR) at 28 degrees C compared to 18 degrees C. In addition, the significant body mass influence showed allometric exponents of 0.62 at 28 degrees C and 0.92 at 18 degrees C for RMR. Our results indicate an important effect of environmental temperature on energy requirements and utilization in C. carbonaria hatchlings, which is seasonally influenced even in this early phase of life.
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