Nutrition utilization by and diet preference of American white pelicans (Pelecanus erythrorhynchos) when offered diets of channel catfish and (or) grass carp

Citation

Ferguson T, Rude B, Tommy King, D. 2009. Nutrition utilization by and diet preference of American white pelicans (Pelecanus erythrorhynchos) when offered diets of channel catfish and (or) grass carp. In Ward A, Treiber K, Schmidt D, Coslik A, Maslanka M, Eds. Proceedings of the Eighth Conference on Zoo and Wildlife Nutrition, AZA Nutrition Advisory Group, Tulsa, OK.

Abstract

Twelve pelicans (Pelecanus erythrorhynchos) captured in northeast Mississippi were used to determine nutrient metabolism when consuming channel catfish (Ictalurus punctatus) and(or) grass carp (Ctenopharyngodon idella). Another objective was to determine the dietary preference of pelicans when allowed to consume catfish and carp. For the 7-day metabolism trial pelicans were allotted to one of three treatment diets (4 birds/diet): catfish only, carp only or both (50 % catfish and 50% carp). Feces, samples of fish offered and orts were collected and analyzed for nutrient content to determine nutrient metabolism. Pelicans receiving catfish or both (4.41 % and 5.10 % body weight/day (BW/day), respectively) consumed less (P = 0.0107) dry matter as a percent of body weight than pelicans receiving carp (6.06 % BW/day). Pelicans consuming catfish metabolized less (P < 0.05) dry matter, organic matter and energy (42.2, 52.0, 74.4 %, respectively) compared to pelicans consuming both (54.8, 64.1, 81.2 %, respectively) or carp (60.0, 68.0, 83.4 %, respectively). Pelicans eating only catfish (2.5%) tended to metabolize less (P = 0.0579) protein than pelicans eating only carp (28.1%). However pelicans eating both (22.5 %) were intermediate to those eating catfish or carp for protein metabolism. For the 2-day preference trial the four pelicans that were allotted to the diet consisting of both catfish and carp for the metabolism trial were used to determine preference for catfish or carp (based on intake). Pelicans preferred (P = 0.001) carp (89 % of diet) compared to catfish (11 % of diet). Pelicans ate more carp and digested nutrients from carp more efficiently than they did for catfish.

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