WWW.WAS.ORG • WORLD AQUACULTURE • MARCH 2016 65 Alligator lengths and weights were averaged by tank and compared by t-test to determine if statistically significant differences existed between feeding treatments. At termination of the feeding trial, the pooled final mean length was 89.5 cm and weight was 2,209 g. Findings Feed consumption of alligators fed to apparent satiation once per day averaged 3.2 percent of body weight during the first 34 days of feeding, then declined to 2.7 percent of body weight by day 68 (average body weight of all animals in the trial at that time was 813 g) and remained at that level for the final 100 days of the study (Fig. 1). Feed consumption of alligators fed to apparent satiation twice per day averaged 4.0 percent of body weight during the first 34 days of feeding, then declined to 3.5 percent of body weight by day 68 and 3.2 percent of body weight by day 99 (average body weight of all alligators in the trial at that time was 1,285 g), where it remained until the end of the study. Daily feed consumption of alligators fed twice per day, at 0800 and 1400 h, was less than one percent greater than feed consumption of alligators fed once per day and weight gains were essentially equal in both groups (Fig. 2). Although results indicated no growth-related benefit to a second daily feeding in this study, it is possible that a different feeding regimen (e.g., longer interval between feedings) could have produced a different result. Length-weight data collected during the study were used to establish a growth curve (Fig. 3), from which we developed a formula for calculating body weight. The approximate lengthweight relationship was: W = 0.00285 (L3), where W is body weight in grams and L is length (tip of snout to tip of tail) in centimeters. This formula predicted body weights within 93-103 percent of observed values, indicating that it could be used to provide a good approximation of body weight for the purpose of calculating feed allotments. The formula could be used in a spreadsheet to determine approximate starting points for feeding alligators of different sizes. For example, a 100-cm alligator would be estimated to weigh approximately 2,850 g by this formula. With a three-percent feeding rate, an appropriate daily feed allotment would be 86 g of diet per animal. Initial feed allotments can be adjusted as necessary to meet individual producer preferences and production conditions. Because production practices differ among farms, customized feeding tables that reflect typical alligator growth rates on individual farms could be created if sufficient length and weight data are available. Such information might be obtained during sorting operations or at other times when opportunities to weigh and measure large samples of animals are available. Results of the research indicated that feed consumption of alligators weighing 300 g to 2,200 g was 3-4 percent of body weight per day at temperatures of 30-31 C during a 169-day growth trial. Feeding alligators twice per day, with a 6-h interval between feedings, provided no growth-related benefit. The formula W = 0.00285 (L3), where W is body weight (g) and L is length (cm), provided a good estimate of alligator body weight under conditions of this study. Feed allotments based on body weight estimations are recommended to minimize overfeeding, improve water quality in the production environment, and reduce alligator production cost. Notes Robert C. Reigh and Millie B. Williams, Aquaculture Research Station, Louisiana State University Agricultural Center, 2410 Ben Hur Road, Baton Rouge, LA 70820-6103 USA Email: rreigh@agcenter.lsu.edu Acknowledgments This research was funded in part by the Louisiana Department of Wildlife and Fisheries (Contract CMFS# 706908), the Louisiana Agricultural Experiment Station (Project LAB94014), and by Cargill Animal Nutrition. Publication has been approved by the Director of the Louisiana Agricultural Experiment Station as Manuscript Number 2015-*****. References Asa, C.S., G.D. London, R.R. Goellner, N. Haskell, G. Roberts and C. Wilson. 1998. Thermoregulatory behavior of captive American alligators (Alligator mississippiensis). Journal of Herpetology 32:191-197. Johnson, C.R., W.G. Voigt and E.N. 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Dietary energy sources for the American alligator, Alligator mississippiensis (Daudin). Aquaculture 89:245-261. Because production practices differ among farms, customized feeding tables that reflect typical alligator growth rates on individual farms could be created if sufficient length and weight data are available.
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