Growth performance and starch utilization in common carp (Cyprinus carpio L.) in response to dietary chromium chloride supplementation

• Published in: Journal of trace elements in medicine and biology 2013-01, Vol.27 (1), p.45-51
• Main Authors: Ahmed, Arafat R., Moody, A. John, Fisher, Andrew, Davies, Simon J.
• Format: Article
• Language: English
• Subjects: Animal Husbandry; Animals; Blood Glucose - analysis; Carps - growth & development; Chlorides - administration & dosage; Chlorides - pharmacology; Chromium; Chromium - analysis; Chromium Compounds - administration & dosage; Chromium Compounds - pharmacology; Common carp; Dietary Supplements; Growth; Key liver enzyme (HK, G6PD and ALAT); Liver - drug effects; Liver - pathology; Liver and gut histology; Plasma glucose; Starch - chemistry; Starch - metabolism; Weight Gain - drug effects
• ISSN: 0946-672X; 1878-3252
• DOI: 10.1016/j.jtemb.2012.05.006

A nutrition trial was conducted on juvenile common carp (Cyprinus carpio), initial mean body weight 15±0.4g within a controlled facility at 25±0.5°C. Six diets containing various levels of supplementary Cr (0, 0.2, 0.5, 1.0, 1.5, and 2.0) mg Cr/kg of diet as Cr chloride hexahydrate were fed to carp for a period of 10weeks. Lower growth performance was observed in fish fed on the control diet and the diet supplemented with the highest level of Cr (2.0mg Cr/kg). Although fish fed 0.5mg Cr/kg showed the best growth performance, this was not significantly different (P>0.05) from fish fed 1.0mg Cr/kg. The regression of plasma glucose concentration was linear (R2=0.97 and P value=0.001) as the Cr content of the diet increased (up to 1.5mg Cr/kg). Cr carcass content was elevated with an increasing level of dietary Cr supplementation up to 1.5mg Cr/kg; but fish fed on the diet supplemented with the highest level of Cr (2.0mg Cr/kg) showed a decrease in Cr carcass content. Histological examination to evaluate the impact of different Cr supplementation on liver and gut tissues showed notable changes. The higher level of Cr (2.0mg Cr/kg) in the diet gave rise to elevated hepatocyte vacuolization and changes in gut tissue morphology. It appeared that Cr chloride significantly improved growth within a defined range (0.2–1.5) mg Cr/kg without any negative impact, while 2.0mg Cr/kg in carp diet seems to be the threshold for the initiation of toxicity.