Effects of temperature on growth, food uptake and retention time of juvenile nile crocodiles (Crocodylus niloticus)

Kanui, Titus I.; Mwendia, C; Aulie, Arnfinn; Wanyoike, MM

doi:10.1016/0300-9629(91)90032-8

Cited by 17 publications

(9 citation statements)

References 7 publications

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“…Possibly, heat was a high-priority resource to geckos raised in the absence of diurnal temperatures. Contrary to expectations (Regal, 1966;Gatten, 1974;Harlow et al, 1976;Waldschmidt et al, 1986;Lillywhite, 1987;Lutterschmidt and Reinert, 1990;Kanui, 1991), there was no postprandial increase in Tp. This pattern is not unique; several studies report the absence of postprandial thermophily in ectothermic reptiles (see Brown and Brooks, 1991).…”

Section: Discussioncontrasting

confidence: 56%

Behavioral Thermoregulation Increases Growth Rate in a Nocturnal Lizard

Autumn¹,

Nardo²

1995

Journal of Herpetology

142

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We tested the hypothesis that thermoregulation increases growth rate in nocturnal lizards. Leopard geckos (Eublepharis macularius) maintained from hatching at 25 C grew at a rate of 0.11 g/day, while geckos allowed to thermoregulate at preferred body temperatures (30 C for 13.5 h per day) grew 1.5 times as fast (0.16 g/day). Long-term thermal treatment had a significant reverse acclimation effect on preferred body temperature (Tp): Tp was 1.2 C lower in thermoregulatory individuals than in those kept at 25 C. Feeding and time of day also had significant but minor effects on Tp. Despite their nocturnal ecology, leopard geckos seem to be typical among lizards in requiring a diurnal heat source for maximal growth. This result provides a physiological explanation for the observation that some nocturnal lizards thermoregulate in burrows during the day, and may have implications for the biogeography of nocturnal ectotherms.

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Section: Discussioncontrasting

confidence: 56%

Behavioral Thermoregulation Increases Growth Rate in a Nocturnal Lizard

Autumn¹,

Nardo²

1995

Journal of Herpetology

142

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“…Warm temperatures are necessary for normal physiologic processes such as digestion, growth, reproduction, and immune function (Kanui et al, 1991;Dickinson and Fa, 1997). Warm temperatures are necessary for normal physiologic processes such as digestion, growth, reproduction, and immune function (Kanui et al, 1991;Dickinson and Fa, 1997).…”

Section: Temperaturementioning

confidence: 99%

Biology and Diseases of Reptiles

O’Rourke

Lertpiriyapong

2015

Laboratory Animal Medicine

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“…Although various possibilities have been proposed, none have been thoroughly investigated. Proposed factors associated with runting include egg incubation conditions; 38,69 poor yolk absorption posthatching; 22,32 inappropriate diet or problems with diet assimilation; 11,22,26,55 posthatching environment, including temperature, stocking density, and behavior of conspecifics; 26,32,39,48,58 and failure to adapt to the captive environment. 3,64 Poor growth has been found to be clutch related in that some clutches produce relatively high numbers of runts.…”

mentioning

confidence: 99%

Pathology of Runting in Farmed Saltwater Crocodiles (Crocodylus porosus) in Australia

et al. 2014

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Extremely poor growth of some individuals within a birth cohort (runting) is a significant problem in crocodile farming. We conducted a pathological investigation to determine if infectious disease is associated with runting in farmed saltwater crocodiles (Crocodylus porosus) and to look for evidence of other etiologies. In each of 2005 and 2007, 10 normal and 10 runt crocodiles, with an average age of 5.5 months and reared under identical conditions, were sampled. Laboratory testing included postmortem; histological examination of a wide variety of tissues (with quantitation of features that were noted subjectively to be different between groups); hematology; serum biochemistry (total protein, albumin, globulins, total calcium, phosphorus, and iron); bacterial culture of liver and spleen (2005 only); viral culture of liver, thymus, tonsil, and spleen using primary crocodile cell lines (2007 only); and serum corticosterone (2007 only). The only evidence of infectious disease was mild cutaneous poxvirus infection in 45% of normal and 40% of runt crocodiles and rare intestinal coccidia in 5% of normal and 15% of runt crocodiles. Bacterial and viral culture did not reveal significant differences between the 2 groups. However, runt crocodiles exhibited significant (P < .05) increases in adrenocortical cell cytoplasmic vacuolation and serum corticosterone, decreased production of bone (osteoporosis), and reduced lymphoid populations in the spleen, tonsil, and thymus. Runts also exhibited moderate anemia, hypoalbuminemia, and mild hypophosphatemia. Taken together, these findings suggest an association between runting and a chronic stress response (hyperactivity of the hypothalamic-pituitary-adrenal axis).Keywords adrenocortical hyperplasia, crocodile, farmed, histopathology, inanition, lymphoid atrophy, runting, stressIn the crocodilian farming industry, extremely poor growth of some hatchlings compared with their birth cohort (runting) is a major problem worldwide, affecting up to 30% of animals. 3,21,32,33,48,49,55,58 Runting is a cause of major economic loss, in an industry where juvenile growth and survival are important economic factors. 33The cause of runting in farmed crocodiles is unknown. Although various possibilities have been proposed, none have been thoroughly investigated. Proposed factors associated with runting include egg incubation conditions; 38,69 poor yolk absorption posthatching; 22,32 inappropriate diet or problems with diet assimilation; 11,22,26,55 posthatching environment, including temperature, stocking density, and behavior of conspecifics; 26,32,39,48,58 and failure to adapt to the captive environment.3,64 Poor growth has been found to be clutch related in that some clutches produce relatively high numbers of runts. 26,33,48,58 However, future crocodile runts are not identifiable at hatching, since body size at hatching is a poor predictor of posthatching growth. 26,34,38,69 There is limited information on diseases and pathology exhibited by runt crocodiles. A few studies mention b...

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Effects of temperature on growth, food uptake and retention time of juvenile nile crocodiles (Crocodylus niloticus)

Cited by 17 publications

References 7 publications

Behavioral Thermoregulation Increases Growth Rate in a Nocturnal Lizard

Behavioral Thermoregulation Increases Growth Rate in a Nocturnal Lizard

Biology and Diseases of Reptiles

Pathology of Runting in Farmed Saltwater Crocodiles (Crocodylus porosus) in Australia

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