Zn requirement is usually not met without dietary Zn supplementation

Transcription

1 Bioavailability of zinc sources in piglets and broilers: a meta-analysis Schlegel P., Sauvant D. and Jondreville C.

2 Introduction ZINC (Zn) o Heavy metal, polluant toxic for plants and microorganisms o Non renewable ressource o Essential nutrient in pigs and poultry Zn requirement is usually not met without dietary Zn supplementation For an efficient and sustainable use of Zn in monogastric nutrition, two main strategies are recommended: o Dietary Zn «safety margins» o Dietary Zn bioavailability 2

3 Introduction Dietary Zn bioavailability Major limiting dietary factor: Zn antagonism from phytate Ca Reduce plant phytate content. OPO 3 H - - HO 3 PO 2+ Zn Supplement Zn supposed not to interact with phytate (organic Zn sources). - HO3 PO 6 1 OPO 3 H 2 2 OPO amidon 5 4 OPO Fe Hypothesis: Organic Zn sources are more bioavailable than inorganic Zn sources. 3

4 Material and method Two databases (broiler, weaned piglets): Criteria for the choice of experiments: o Minimum one treatment with an inorganic and one with an organic Zn source Criteria for the choice of experimental treatment: o Microbial phytase: FTU/kg (piglets); < 5 FTU/kg (broiler) o No other experimental factor than trace elements (amino acids, org. acids, ) 4

5 Material and method Two databases (broiler, weaned piglets): Broilers: 28 experiments, 175 treatments Diets: synthetic, cereal-soybean meal, corn-soybean meal based Dietary Zn content: mg/kg Inorganic Zn: oxide (8), sulfate (55), acetate (3), nitrate (1) Organic Zn sources: Piglets: 34 experiments, 159 treatments Diets: cereal-soybean meal, corn-soybean meal based Dietary Zn content: mg/kg Inorganic Zn: oxide, sulfate acide aminé protéine ou peptide polysaccharide 5

6 Material and method: phase 1 Dose-response effect of dietary Zn Y Zn bioavailability is measured within the dose-response effect of a dependent variable. Ymax => Determination of X1 is necessary X1 DZNTOT Mathematical model: Non linear model (curvilinear-plateau) If DZNTOT wx X1, Y wx = Ymax w * (a + b*dzntot wx + c*dzntot wx2 ) +ɛ wx If DZNTOT wx > X1, Y wx = Ymax w DZNTOT: Dietary Zn content Y wx : Result from a dependent variable Y observed in experiment w with DZNTOT x X1: DZNTOT value from when Y is maximized (Ymax) b: slope a: 1 + 4*c*b 2 c: -b / 2*X1 ɛ: residual error 6

7 Results: phase 1 Dose-response effect of dietary Zn (example for plasma Zn and bone Zn) Plasma Zn [mg / l] Bone Zn [mg / kg DM] Plasma Zn = *DZNTOT -.275*DZNTOT 2 (X1 = 88; Ymax = 2.1; R² =.58; r.m.s.e =.158) Dietary Zn [mg / kg] Bone Zn = *DZNTOT -.233*DZNTOT 2 (X1 = 9; Ymax = 199; R² =.77 ; r.m.s.e = 13.2) Dietary Zn [mg / kg] Plasma Zn [mg / l] Bone Zn [mg / kg DM] Plasma Zn = *DZNTOT -.749*DZNTOT 2 (X1 = 117; Ymax = 1.3; R² =.49; r.m.s.e =.122) Dietary Zn [mg / kg] Bone Zn = *DZNTOT -.15*DZNTOT 2 (X1 = 1; Ymax = 111; R² =.51; r.m.s.e = 9.96) Dietary Zn [mg / kg]

8 Material and method: phase 2 Bioavailability of Zn sources within dose-response effect Mathematical model: General linear model Y wxyz = a + a w + b*dznn wx + c* wy + d* wz + f*dznn 2 wx + g* 2 wy + h* 2 wz + i*dznn wx * wy + j*dznn wx * wz +ε wxyz Y DZNN: native Zn source : supplemented inorganic Zn : supplemented organic Zn x, y, z : concentration de DZNN,, Y wxyz : Result from a dependent variable Y observed in experiment w, with Zn level x, y or z a: intercept a w : Experiment effect b, c, d: linear coefficients f, g, h: quadratic coefficients i, j: coefficients for interactions ɛ: residual error Removal of experimental treatments for phase 2: o When DZNTOT > X1 (Phase 1) DZNTOT o When combined supplementation of and o When and were not iso-dosed 8

9 Results: phase 2 Bioavailability of Zn sources within dose-response effect Model Coefficient P-value Coefficient P-value Intercept DZNN 2 2 DZNN x DZNN x N data R 2 r.m.s.e. vs 2 vs 2 DZNN x vs DZNN x RBV: relative bioavailability of to Plasma Zn [mg/l] Bone Zn [mg/kg DM].692 *** ** 3.35 ***.493 *** 4.78 ***.446 *** 5. *** *** -.41 *** *** *** ** *** RBV average Plasma Zn [mg/l] Bone Zn [mg/kg DM] Total Zn [mg/kg] Total Zn [mg/kg] 9

10 Results: phase 2 Bioavailability of Zn sources within dose-response effect [mg/l] [U/l] [mg/kg DM] [mg/kg DM] [mg] Model Coeff. P-value Coeff. P-value Coeff. P-value Coeff. P-value Coeff. P-value Intercept.58 *** 61.3 *** 251 *** 92.7 *** 44.4 * DZNN *** * *** ***.757 ***.871 ***.214 ***.125 *** 6.61 ***.736 **.874 ***.25 *** *** * * N data r.m.s.e R 2 Plasma Zn ALP Liver Zn Bone Zn vs 2 vs Absorbed Zn RBV RBV: relative bioavailability of to 12 4 Plasma Zn [mg/l] Total Zn [mg/kg] Bone Zn [mg/kg DM] Total Zn [mg/kg] Absorbed Zn [mg / kg diet ingested] Total Zn [mg/kg] 1

11 Discussion / conclusions Bioavailability of Zn sources in broilers and piglets Bioavailability of native Zn (DZNN) o In broilers: highly available supplemented Zn. o In piglets: availability was reduced with increasing contents, most probably due to Zn antagonism from diet components such as phytate Bioavailability of supplemented Zn sources ( vs. ) o In broilers: similar bioavailability o In piglets: similar bioavailability Possible reason (could not be tested in the present dataset) odznn from plant origin is at least partially bound to phytate (ex. Rodrigues-Filho et al., 25) oincreased dietary plant phytate reduces DZNN bioavailability, especially in piglets (ex. Linares et al., 27; Schlegel et al., 21) oplant phytate does not interact with supplemental Zn (ex. Schlegel et al., 21) oa soluble Zn source, such as ZnSO 4 is therefore highly bioavailable in broilers and in piglets (ex. Schlegel et al., 21) 11

12 Thanks a lot for your attention 12