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Effect of dietary iron on copper metabolism in sheep

Sefdeen, S.M. (2017) Effect of dietary iron on copper metabolism in sheep. Doctoral thesis, Harper Adams University.

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Abstract

A series of experiments were carried out to investigate the effect of dietary iron (Fe), sulphur (S) and breed on copper (Cu) metabolism and performance of growing lambs. In the first study (present ed in C hapter 3) , a basal diet containing 487.6 mg/kg DM Fe and 4 g/kg DM S, supplement ed with 0, 250, 500, and 750 mg/kg DM Fe were given to weaned Texel lambs to investigate effect s on Cu status, performance and nutrient balance . There was no effects of dietary treatments on lamb performance. Dietary supplemental Fe significantly reduced liver Cu storage but increased liver Fe storage of lambs with the greatest effect observed at 750 mg Fe/kg DM. Dietary supplemental Fe in this study had no effect on other Cu parameters measured. It was also observed that Fe suppl ementation significantly increased plasma Fe concentration but had no effect on other minerals concentration . Supplemental Fe significantly increased urinary Mo output in all lambs receiving Fe but had no effect on the urinary output of other minerals. In t he study present ed in C hapter 4, t hree levels of supplemental S (0, 1.5 and 3 g/kg DM ; basal S = 2.89 g/kg DM ) and two levels of supplemental Fe (0 and 800 mg/kg DM ; basal Fe = 302.3 mg/kg DM ) w ere given to weaned lambs to investigated the effect of diffe rent levels of S with or without Fe on Cu metabolism . Dietary Fe significantly reduced the plasma and liver Cu concentration of lambs after 12 weeks of supplementation . Liver and plasma Fe concentration increased significantly in groups given Fe supplement ed diets. Plasma Mo increased significantly in lambs fed supplemental Fe. Dietary S had no significant effect on liver, plasma or the biliary Cu, Fe, and Mn concentration, but significantly increased biliary Mo concentration in lambs. Ceruloplasmin activit y (Cp) and Cp:Pl - Cu ratio increased in Fe supplemented lambs but Cp activity decreased in group s given S supplemented diets . In the last series of studies ( present ed in C hapter 5) , the effect of dietary Fe and breed of sheep on Cu metabolism was investigat ed. Weaned Scottish Blackface and Texel lambs were fed a basal or Fe supplemented diets (800 mg Fe/kg DM ; basal Fe= 257.5 mg/kg DM ). Dietary Fe reduced plasma Cu but increased plasma Fe and Mo concentration. Scottish Blackface had higher plasma Cu concentr ation than Texel lambs, but Texel lambs had higher plasma Mo concentration than Scottish Blackface lambs. In the second part of this study (experiment 2) , w eaned Swaledale and Texel lambs were fed basal or Fe supplemented diet (368.7 mg/kg DM ; basal Fe= 53 2.4 mg/kg DM ) . Supplemental Fe significantly decreased liver Mo but had no effects on other the liver minerals concentration . Texel lambs retained significantly more Cu in their livers than Swaledale lambs after ten weeks feeding . Plasma Cu and Zn concentr ation decreased significantly in the lambs fed Fe supplements. These studies confirm that Fe is a potent Cu antagonist in sheep and highlights the differences between sheep breeds in their Cu metabolism and responses to antagonists.

Item Type: Thesis (Doctoral)
Divisions: Animal Production, Welfare and Veterinary Sciences
Depositing User: Ms Kath Osborn
Date Deposited: 21 Aug 2018 15:46
Last Modified: 22 Aug 2018 13:31
URI: http://hau.collections.crest.ac.uk/id/eprint/17316

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