Antibiotic effects on cytochromes P450 content and mixed-function oxygenase (MFO) activities in the American alligator,Alligator mississippiensis

There are no Food and Drug Administration (FDA)-approved antimicrobial agents for use in cultured American alligators (Alligator mississippiensis) destined for human consumption yet some producers administer antibiotics for prophylaxis. The cytochromes P450-dependent mixed-function oxygenases (MFO) catalyze the oxidation of xenobiotic compounds such as drugs, pesticides and polycyclic aromatic hydrocarbons. Herein, we describe the effects of oxytetracycline, ceftazidime and enrofloxacin on the MFO system of the American alligator, Alligator mississippiensis. Juvenile alligators (4 animals/treatment) were administered these antibiotics intraperitoneally in an effort to induce hepatic microsomal cytochromes P450. Alligators treated with enrofloxacin exhibited emesis and convulsive spasms within 5 min of the initial injection. Total hepatic cytochromes P450 contents were significantly decreased in oxytetracycline-and enrofloxacin-pretreated alligators. In vitro hepatic microsomal benzyloxyresorufin O-dealkylase (BROD) activity was significantly decreased by enrofloxacin pretreatment. Western blots of proteins from antibiotic-pretreated alligator hepatic microsomes incubated with several mammalian and fish cytochromes P450 (CYP) antibodies exhibited little or no induction of CYP1A1, 2B, 2C and 2E1. In vitro incubation with enrofloxacin and oxytetracycline caused a concentration-dependent decrease in alkyl-substituted phenoxazone dealkylase activities catalyzed by phenobarbital- and 3-methylcholanthrene-induced alligator hepatic microsomes.     

Fatty Acid Composition of Muscle, Liver, and Depot Fat of Wild and Cultured Common Snapping Turtles Chelydra serpentina

Abstract This study was conducted to compare the fatty acid composition of muscle, liver, and depot fat of common snapping turtles Chelydra serpentina from the wild with those of captive common snapping turtles fed a diet of known fatty acid composition. Total lipid from each tissue was separated by thin-layer chromotography, methylated, and analyzed by gas chromatography/mass spectrometry. The fatty acid composition of total lipid, polar lipid, and nonpolar lipid in muscle and depot fat of wild and captive turtles exhibited greater variability than liver polar lipid. Cultured turtles contained significantly lower levels of linolenic and arachidonic acids in liver polar lipid than wild turtles. Total n-9 fatty acids were significantly higher in whole-lipid and nonpolar fractions of muscle, liver, and depot fat of cultured turtles indicating de novo synthesis. Total polyunsaturated fatty acids were significantly lower in total lipid of muscle tissue from cultured turtles. Total polyunsaturated fatty acids were significantly lower in both depot fat and liver nonpolar lipid of cultured turtles, but did not differ (P > 0.05) in the polar lipid fractions of cultured and wild turtles.     

Effects of Dietary Energy: Protein Ratio and Stocking Density on Growth and Survival of the Common Snapping Turtle Chelydra serpentinal1

Although the common snapping turtle Chelydra serpentina is cultured commercially in the United States, little information is available on nutritional and culture requirements. This study was conducted to evaluate the effects of dietary energy: protein ratio and stocking density on survival, growth, feed consumption, feed conversion, liposomatic index, dress-out percentage, and productive protein value of cultured, common snapping turtles. Hatchling turtles were stocked at 29 and 58 animals/m² and fed one of seven prepared diets. Six diets contained 30, 35, or 40% protein at two digestible energy (DE) levels (7 or 9 kcal DE/g protein); the seventh was a reference diet (66% protein and 5 kcal DE/g protein) formulated to equal or exceed the whole-body essential amino acid composition of wild, common snapping turtles. Turtles stocked at 58/m² exhibited greater mortality, lower weight gain, higher feed consumption, less-efficient feed conversion, lower liposomatic index, and lower productive protein value than turtles stocked at 29/m² (P < 0.05). The reference diet produced the greatest weight gain (P < 0.001). The superior performance of turtles fed the reference diet suggests that: 1) the protein (amino acid) content and/or energy: protein ratio of the reference diet was superior to that of the other diets tested; 2) improvements in growth parameters can be made with dietary manipulation; and 3) high levels of plant protein can be used in prepared, snapping turtle diets.