Perfil renal e excreção fracionada urinária de cálcio, fósforo e magnésio de cordeiros alimentados com teores diferentes de fósforo

Bianca Paola Santarosa,Daniela Marques Maciel Dabus,Matheus Ribeiro Coelho,Eduardo Gorzoni Fioratti,Raimundo Souza Lopes,Naiana Da Silva Branchini,Danilo Otávio Laurenti Ferreira,Soraya Regina Sacco Surian,Roberto Calderon Gonçalves,Henrique Barbosa Hooper

doi:10.21708/avb.2021.15.4.10228

Abstract

Obstructive urolithiasis is common in confined sheep, and a predominant factor predisposing animals to this condition is nutritional management. The objective of this study was to evaluate the effect of different concentrations of phosphorus (P) on urinalysis, serum urea and creatinine, and serum and urine concentrations of calcium (Ca), P, and magnesium (Mg), as well as to establish the fractional excretion (FE) of these elements in confined lambs. Thirty male Santa Inês x Ile de France sheep at four months of age were divided into two groups according to the diet: Group 1 (G1, n = 15), with 0.43% P in their feed; and Group 2 (G2, n = 15) with 0.65% P. The diets consisting of 10% Coast-cross hay and 90% of a concentrate of soybean meal, wheat, and crushed corn were provided for 90 consecutive days, with water ad libitum. The time points (M) of blood and urine collection were determined as M0, immediately before the beginning of the diet, and at 15-day intervals: M1, M2, M3, M4, M5, and M6. Phosphorous-rich diets favored the appearance of triple phosphate crystals in both groups, causing calculogenesis in more than one third of the animals (11/30), emphasizing the relevance of conducting laboratory tests to aid in urolithiasis diagnosis. In addition, FE revealed an increased renal excretion of excess minerals in the diet, and therefore a greater predisposition for stone formation in relation to nutritional management.

Highlights

Urolithiasis is a multifactorial pathological process characterized by the presence of stones in the urinary system, which has a high incidence in confined sheep (RIET-CORREA; SIMÕES; VASCONCELOS, 2008; GUIMARÃES et al, 2012)
Intensive breeding systems with a Ca: P imbalance or plants containing a large amount of silica or oxalate can trigger the disease (RIET-CORREA; SIMÕES; VASCONCELOS, 2008)
Non-castrated, crossbred from the Ile de France and Santa Inês breeds from commercial flocks, recently weaned with an average age of 120 days and average live weight (LW) of 18.7 ± 1.2 kg were identified, separated, and randomly distributed into two groups of 15 animals (G1 and G2)

Summary

Introduction

Urolithiasis is a multifactorial pathological process characterized by the presence of stones in the urinary system, which has a high incidence in confined sheep (RIET-CORREA; SIMÕES; VASCONCELOS, 2008; GUIMARÃES et al, 2012). Intensive breeding systems with a Ca: P imbalance or plants containing a large amount of silica or oxalate can trigger the disease (RIET-CORREA; SIMÕES; VASCONCELOS, 2008). The chemical imbalance results in increased excretion of P in the urine, which in ruminants is normally alkaline, rendering the P insoluble, causing precipitation and consequent formation of crystals (FERREIRA et al, 2014; MACIEL et al, 2017). In intensive farming systems using diets containing a high concentration of grains and low roughage, saliva production is reduced, and a higher concentration of P is eliminated by the kidneys, contributing to the formation of uroliths (EMERICK; EMBRY, 1963; LOUVADINI; VITTI, 1994)

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