INTRODUCTION .. . . . . . . . . . . . ...... . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . ........ . . . . . . . .. . . . . . . . . . . . 122 THIOMOLYBDATES: NUTRITIONAL DOUBTS AND CERTAINTIES .... 123 Qualitative Evidence for Thiomolybdate Formation in vivo . .. ..... . . . . . . . . . . . . .. . . . . . . . . 123 Qualitative Evidence for Thiomolybdate Inhibition of Copper Absorption ... . . . . . . . . . 123 Qualitative Evidence for Absorption of Thiomolybdates ......... . . . . . . . . . . . . . . . . . . . . . . . . . 124 Quantitative Evidence for Thiomolybdate Excretion in Feces... . . . . . . . . . 124 Systemic Effects of Thiomolybdates . . . . . . . . . . . . . . . . . . . . . . . . . 125 Conclusions on Physiological Importance of Thiomolybdates... .... . . . . . . . . . . . . . . . . . . . . . 129 NUTRITIONAL VARIABLES AFFECTING THE RUMEN INTERACTION . . ... . . . ... 130 Sulphur....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 Molybdenum 131 Copper . ... 131 Undigested Organic Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 Sulphide-Trapping Agents ..... 131 Copper-Trapping Agents .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Post-RuminaIInteractions 132

The interactions between copper, molybdenum, and sulphur in ruminant nutrition.

A study was conducted to determine the effects of copper (Cu) depletion by feeding diets high in either iron (Fe) or molybdenum (Mo) on performance and Cu status of beef cows and calves. Thirty-eight 2-yr-old beef heifers, entering the last one-third of gestation, were randomly assigned by expected calving date to one of four diets: 1) control (CON; corn silage-soybean meal-based diet, 4 mg of Cu/kg), 2) control + 600 mg of Fe (as FeCO3)/kg, 3) control + 5 mg of Mo (as Na2MoO4)/kg, and 4) control + 10 mg of Cu (as CuSO4)/kg. From d 28 until after the end of the calving season (d 125), heifers receiving supplemental Cu had higher (P < .05) plasma Cu levels and ceruloplasmin activities than heifers fed the other diets. By d 224, plasma Cu concentrations of heifers fed the CON and Fe diets had increased to levels similar to those observed in the Cu-supplemented heifers, whereas the Mo heifers exhibited the lowest (P < .05) plasma Cu of the four treatments from d 168 through the remainder of the 280-d trial. Plasma Cu concentrations and ceruloplasmin activities were greater (P < .05) in Cu-supplemented than in non-Cu-supplemented calves (diets 1, 2, and 3) from d 168 onward, and the Fe- and Mo-supplemented calves did not differ in either measurement at any time during the trial. Rate of gain did not differ among calves fed the CON, Fe- or Cu-supplemented diets, whereas the Mo-supplemented calves gained at a much slower (P < .05) rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of dietary copper, iron, and molybdenum on growth and copper status of beef cows and calves.

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 VARIABLES INFLUENCIN G INTESTINAL SOLUBILITY OF TRACE ELEMENTS 175 Dietary Phytate, Calcium, and Trace Metals...... .. . . . . . . . . . . . .. . . . . . . .. . . . ... . . . . . . ..... . . 175 Absorption and Metabolism of Copper . . . .. . . . . . . . . . . . . . . ..... . . . . . . . . . . . . . . . . . . 177 IMBALANCES IN VOLVIN G IRON S UPPLY OR UTILI ZATION ... . . . . . . . . . . . . . . . . . . . . . 1 80 Zinc and the Metabolism of Iron and Copper ...... . . . . . . . . . . . . . . . . .... .. . . . . . . . . . . . . . . . . . . . 1 80 Effects of Iron Deficiency on Trace Metal Metabolism . . . . . . . . . . ...... . . ..... 1 8 1 Effects of a High Iron Status .. .. .. . . . .. . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 83 Iron Metabolism in Deficiencies of Nickel and Lead . . . . . . . . . . . . . . ...... . . . . . . . . . . . . . . . . . . . 1 85 M ETAB OLIC RES PONSES TO M ULTIPLE DEFICIENCIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 85 Modified Responses to Zinc Deficiency 1 85 Interrelated Effects of Selenium, Copper, and Manganese Deficiencies . . . . . . .... . . . . . . 1 86 CONCLUSION . .. . . . . . . . . . ....... ... . . . . . . . . . . . .... ....... .. . . . . . . . . .. . . . . . . ... ...... . . . . . . . .. ..... . . . 187

Dietary interactions involving the trace elements.

Regarding the hygienic aspects of the production and use of animal wastes, further research on the following aspects is essential: pathogenic agents present in residues of animal production in the context of transmissible multifactorial diseases and the epidemiology of pathogens under different ecological conditions; recycling of toxic agents, e.g., copper, selenium and iodine, in animal wastes in the context of the food chain from soil to humans; hygienic effects of animal wastes on water as regards the standards required by medical authorities; effects of agents used to increase animal production, or used for medicinal purposes, which are present as residues in animal excreta and may be hazardous to public health; effects of animal excreta on microbiological processes in the soil; effects of dust and airborne microbial emissions from animal production, and finally, processes of self-disinfection of manure and livestock slurry during storage as a means of reducing the amounts of chemical disinfectants used, of reducing environmental pollution, and of studying the application of biotechnological methods to disinfect manure and livestock slurry, this study being of particular importance.

Hygienic aspects of the production and agricultural use of animal wastes.

Plasma Cu concentrations and ceruloplasmin (a Cu metalloenzyme) activity were used to assess relative Cu bioavailability from different Cu sources for growing cattle. In Exp. 1, 18 calves (average BW 207 +/- 7.7 kg) that had been fed Cu-deficient diets since birth were randomly assigned to treatment. Treatments consisted of control (n = 3) or 30 mg/d of supplemental Cu (n = 5/treatment) from Cu oxide (CuO), Cu sulfate (CuSO4), or Cu lysine. Blood samples were obtained for plasma Cu and ceruloplasmin activity on d 0, 7, 14, and 21. Plasma Cu and ceruloplasmin activity were greater (P < .05) on d 7, 14, and 21 for calves supplemented with CuSO4 than for controls. Copper status of calves fed Cu lysine did not differ from that of calves fed CuSO4. Compared with d-0 values, plasma Cu concentrations by d 21 had increased by 95 and 98% in calves supplemented with CuSO4 and Cu lysine, respectively. Copper oxide supplementation did not increase Cu status above that observed in control calves. In Exp. 2, 36 calves (average BW 211 +/- 4.4 kg) were used to compare the relative bioavailability of Cu from CuO and CuSO4 when supplemented to corn silage-based diets high in the Cu antagonists iron (Fe) or molybdenum (Mo). Treatments consisted of no supplemental Cu or 8 mg of supplemental Cu/kg diet from either CuSO4 or CuO. Within each Cu treatment, diets were supplemented with 600 mg of Fe or 5 mg of Mo/kg diet. In calves fed 5 mg of Mo/kg, plasma Cu was lower (P < .05) in those fed no supplemental Cu or CuO compared with calves fed CuSO4 by d 91 and at subsequent sampling dates throughout the 154-d study. Plasma ceruloplasmin activity was decreased (P < .01) by Mo and was increased (P < .05) by CuSO4 compared with CuO. Based on plasma Cu and ceruloplasmin activity, CuSO4 and Cu lysine were similar in bioavailability, but CuO was essentially unavailable.

Bioavailability of feed-grade copper sources (oxide, sulfate, or lysine) in growing cattle.

Four repletion experiments were carried out to clarify the roles of molybdenum, sulphur and iron in the inhibition of copper absorption by ingested soils. In each experiment, groups of four to six hypocupraemic Scottish Blackface ewes were repleted for 21 days with diets containing CuSO4 and/or soil Cu and the responses in plasma Cu used to assess the availability of the Cu supplied.In Expts 1 and 2, three soils varying in Mo but high in Fe content and derived from Lower Lias Clay, Namurian Shale and Weald loam were added at 100 g/kg D.M. to diets of low (1·0) and high (4·1 g/kg D.M.) S contents: they provided 3·1, 2·8 and 0·1 mg Mo/kg D.M. respectively. When compared with groups given no soil, each soil increased plasma Cu repletion in the low S experiment and decreased it in the high S experiment. Inhibition was thus not completely dependent on soil Mo but dependent upon dietary S.Soils varying in Fe content were compared in the manner of the above experiments in Expts 3 and 4. Two Fe-rich soils, developed from the Upper Chalk and a Barton Clay and providing 2·8 and 1·5 g Fe/kg D.M., impaired Cu repletion on the high S diet but not on the low S diet. A soil, developed on a sand from the Bagshot Beds and providing only 0·15 g Fe/kg D.M., did not impair repletion but FeSO4, providing 0·8 g Fe/kg D.M. did so, irrespective of dietary S content. Ingestion of Fe-rich soils in a high S diet caused three-fold increases in rumen sulphide concentrations 5 and 24 h after feeding. It is suggested that soil ingestion impairs Cu absorption in sheep by trapping S as heavy metal sulphides such as FeS and releasing sulphide in the acid abomasum.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0021859600043343

N. F. Suttle

Papers

The role of a soil × dietary sulphur interaction in the impairment of copper absorption by ingested soil in sheep