Calcium and phosphorus utilization in growing sheep supplemented with dicalcium phosphate

Abstract

SUMMARYThe objective of the current study was to evaluate the utilization of calcium (Ca) and phosphorus (P) in growing sheep consuming increasing amounts of dicalcium phosphate. Eighteen growing sheep, aged 8 months, were fed a basal diet supplemented with 0, 12·5 and 25 g of dicalcium phosphate/day. During the experiment, animals were injected intravenously with 7·4 MBq of 45 Ca and 32 P and samples of plasma, faeces and urine were subsequently taken daily for 1 week after injection. Rumen fluid was sampled on days 4-7 after injection. Specific radioactivity in plasma and in faeces were used to determine true absorption of Ca and P, whereas plasmatic and ruminal specific radio-activities were used to determine endogenous P flow into the rumen and turnover time of rumen P. Increasing dicalcium phosphate intake led to linear increases in faecal excretion of endogenous Ca and P (P < 0·05), suggesting that surpluses of ingested Ca and P were voided through secretion to the gut. True absorption coefficients for 0, 12·5 and 25 g of dicalcium phosphate ingested daily were 0·54, 0·41 and 0·38 for Ca, and 0·66, 0·62 and 0·64 for P, respectively. Flows of endogenous P into the rumen increased linearly and ruminal turnover time of P decreased linearly (P < 0·01) as P intake was increased. Concentrations of Ca and P in bone were not affected by the increased amounts of these minerals ingested (P < 0·05). In conclusion, increasing ingestion of dicalcium phosphate increases faecal excretion of Ca and P, thus decreasing the efficiency of utilization of both minerals. Moreover, increasing levels of dietary P increased endogenous P excretion, contributing to the amount of P disposed of in the environment.

Phosphorus utilization in broilers fed with diets supplemented with different feed ingredients

“…and blood by colorimetry using the vanadate molybdate reagent (Fiske and Subbarow, 1925;Sarruge and Haag, 1974) and a method adapted from the Association of Official Analytical Chemists (1995), described in detail by Dias et al (2013). Excreta were collected daily and frozen until analysis.…”

Minimum Effects of Sampling Time on the Apparent Digestibility of Nutrients and Blood Protein Catabolites in Light Lambs

“…Furthermore, it has been described that faeces are the principal pathway of P excretion in ruminants, and it is directly correlated with the diet P content [ 24 ]. However, according to Dias et al [ 25 ], the faecal loss of P may be overestimated because of salivary P secretion, suggesting that the true available P was probably greater in both dietary treatments. Assuming that the urinary loss of this mineral is minimal, the metabolic P requirements may be related to the mineral proportion of skeletal body weight gain [ 26 ].…”

Influence of Fossil Shell Flour Supplementation on Feed Preference, Body Condition Scores and Wool Parameters of Dohne Merino Wethers

“…It has been reported that Na in the form of sodium chloride in the diets of sheep in uences the feed preference through the taste and avor of the diets [54,55]. In the same way, [56] and [57] reported that Mg, which cannot be stored in the body are involved in energy generating reaction in the tissue of sheep, while Calcium and Potassium are involved in metabolism and body electrolytes balance that secure the health status of the animal vis-à-vis feed intakes. This agrees with the ndings of [58] and [59] who both reported that mineral supplementation has positive effects on feed preference vis-a vis the feed intake and the DMI.…”