1. Effects of dietary arginine on endocrine growth factors of channel catfish, Ictalurus punctatus.
- Author
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Pohlenz C, Buentello A, Miller T, Small BC, MacKenzie DS, and Gatlin DM 3rd
- Subjects
- Animals, Diet, Fisheries, Ictaluridae blood, Intercellular Signaling Peptides and Proteins blood, Weight Gain, Arginine administration & dosage, Dietary Supplements, Fish Proteins blood, Ictaluridae growth & development, Somatomedins metabolism, Thyroid Hormones blood
- Abstract
Thyroid (TH) and growth (GH) hormones, and insulin-like growth factor I (IGF-I) are anabolic regulators in fish and responsive to nutrient intake. A study was conducted to determine if previously reported growth effects of dietary arginine (ARG) in channel catfish were related to the activation of endocrine axes. In a first experiment, catfish were fed incremental levels of ARG (0.5 - 4% of diet) for 6 weeks and sampled at 2-week intervals. In a second experiment, fasted (48h) fish were fed a single ration of ARG (0.5 or 4% of diet) and sampled at various intervals (0 to 72h postprandial, PP). Experiment 1 did not reveal any influence of ARG on circulating TH, GH, or IGF-I despite the significantly increased growth of fish fed ARG-enriched diets. In experiment 2, feeding the 4% ARG diet significantly increased the amplitude of pulsatile plasma GH levels and also significantly increased IGF-I mRNA in liver and muscle, (at 2h PP) and plasma IGF-I levels (at 6h PP). Although relatively infrequent sampling failed to reveal alterations in TH or GH levels in response to ARG-induced growth activation, PP high frequency sampling unveiled high amplitude pulsatile GH secretions and may be important in activating IGF production in target tissues. Additionally, expressed and secreted IGF-I exhibited discernible patterns which closely correlate with ARG-induced growth effects in catfish., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2013
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