Dissertation > Agricultural Sciences > Livestock, animal medicine,hunting,silkworm,bee > General Animal Science > Feed

Effects of Chromium Nanocomposite on BodyComposition, Gene Expression of Insulin Receptor in Muscle and Relative Biochemistry Serum Index in Sprague-Dawley Rats

Author GuLiangYing
Tutor XuZuoRong
School Zhejiang University
Course Animal Nutrition and Feed Science
Keywords Chromium Nanocomposite SD rats Body composition Inlusin Insulin receptor Gene expression
CLC S816
Type Master's thesis
Year 2007
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The research was conducted to investigate the effects of different doses of chromium nanocomposite (CrNano) administration on growth performance, body composition, serum indexes and insulin receptor gene expression of muscle cells in Sprague-Dawley rats, and approach to the mechanism of the effects.Seventy male Sprague-Dawley weanling rats weighing 80±5g were randomly divided into seven groups with ten rats each. The groups received the same basal diets supplemented with 0,750,150,300,450,600,1200ppb Cr from CrNano respectively. The feeding experiment lasted 36 days after a week’s acclimation. Feed and water were ad libitum throughout the experiment. Meanwhile, body weight and diets consumption were measuredrecorded weekly.At the end of the trial, rats were fasted for 24h.Then, three rats were randomly chosen from each group to anaesthesia assess body weight, lean body mass, body fat mass, and percentage of body fat by means of dual energy X-ray absorptiometry.Then all rats were slaughtered after anaesthwtizing. The blood was colleted to prepare serum and muscles of hind leg were quickly frozen in liquid nitrogen, heart, liver, spleen and kidney,pancreas, testis and hind leg muscle were weighed and collected for laboratory analysis.The results of feeding trial indicated that adding CrNano enhanced average daily gain(ADG) of all rats,and the ADG of the group supplemented 75 ppb increased by 14.89%(P<0.05), and the feed efficiency (FE) was elevated significantly in groups of 75,300,450 ppb.The results of dual energy X-ray absorptiometry showed that the percentage of body fat of groups supplemented with 150ppb,300ppb,450ppb and 600ppb was decreased by 23.40%(P<0.05),24.46%(P<0.05),25.24%(P<0.05),24.32%(P< 0.05) respectively.Analysis results of Cr sediment in tissues and excretions exhibited that the sediment content of Cr in liver and kidney increased significantly in groups supplemented with 150ppb、300ppb、450ppb、600ppb、1200ppb, however, the sediment content of Cr in hind leg muscle was only elevated significantly in groups supplemented with 300ppb、450ppb、600ppb. The results of serum analysis were listed as follows:(1) The serum high density lipoprotein (HDL) and triglyceride (TG) in SD rats were significantly affected by CrNano. Compared with the control group, HDL increased by 26.50%(P<0.05), 20.96%(P<0.05),22.19%(P<0.05) adn 23.42%(P<0.05) in group supplemented 75,150,300 and 450 ppb, and TG decreased by 34.31%(P<0.05),33.24%(P<0.05), 47.34%(P<0.05) and 45.48%(P<0.05), respectively. (2) Compared with the control group, the concentration of total protein (TP) in CrNano supplemented group was elevated by 29.12%(P<0.05),26.39%(P<0.05),25.18%(P<0.05),25.26%(P< 0.05),20.98%(P<0.05) and 14.23%(P>0.05). (3) Glucose (Glu) content in serum decreased significantly by 31.25%,31.70%, and 31.90% in group supplemented with 75,150 and 300 ppb, respectively. (4) In group supplemented 150,300 and 450 ppb, the insulin content in serum reduced by 40.40%(P<0.05),45.38%(P<0.05) and 40.78%(P<0.05), respectively.(5) The content of insulin growth-like-factor-I (IGF-I) in serum was significantly elevated by 67.87%(P<0.05),66.45%(P<0.05),54.42 %(P<0.05),78.69%(P<0.05),72.76%(P<0.05) and 60.79%(P<0.05) in group of supplemented 75,150,300,450,600 and 1200 ppb, respectively. (6) Free triiodothyronin (T3) in serum increased by 35.86% in group supplemented 1200 ppb.The results showed that gene expression content of insulin receptor in muscle increased significantly in groups supplemented 300ppb,450ppb,600ppb and 1200ppb by 38.78%(P< 0.05),46.06%(P< 0.05),42.66%(P< 0.05),54.69%(P<0.05)and 58.67%(P<0.05), respectively.The results implicate:supplementation of CrNano to the diet of rats was significantly increased growth positively alter body composition,increase Cr deposit in tissues.decrease the insulin content in serum and increase gene expression content of insulin receptor in muscle.

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