Ab. Batal et al., Zinc bioavailability in tetrabasic zinc chloride and the dietary zinc requirement of young chicks fed a soy concentrate diet, POULTRY SCI, 80(1), 2001, pp. 87-90
Three chick assays were conducted to determine a bioavailable Zn requiremen
t and to establish a Zn relative bioavailability (RBV) value for tetrabasic
Zn chloride [TBZC, i.e., Zn5Cl2(OH)(8)]. In Assay 1, 8-d-old chicks were f
ed a Zn-deficient soy concentrate diet (8.8 mg/kg bioavailable Zn) suppleme
nted with 0, 5.81, 10.81, 15.10, and 20.25 mg Zn/kg from ZnSO4. 7H(2)O for
14 d to establish a linear response range and estimate a bioavailable Zn re
quirement. Weight gain of chicks increased linearly (P < 0.01; r(2) = 0.99)
when the first three levels of Zn were fed. Broken-line analysis of the we
ight gain data indicated a bioavailable Zn requirement of 22.4 mg/kg. In As
say 2, RBV of Zn in TBZC was determined by multiple-linear regression slope
-ratio methodology. The Zn-deficient basal diet was supplemented with 0, 5.
81, and 10.81 mg Zn/kg from ZnSO4<bullet>7H(2)O to produce a linear growth
response as determined in Assay 1. The same basal diet was supplemented wit
h 5.38 and 10.81 mg Zn/kg from TBZC. The RBV of Zn in TBZC was found to be
102%, which was not different (P > 0.10) from 100%. A third assay was condu
cted as described for Assay 2, and the RBV of Zn in TBZC was 111%, which wa
s not different from 100%. In summary, the RBV of Zn in TBZC was not differ
ent from that of ZnSO4.H2O, and the minimal bioavailable Zn requirement for
chicks 1 to 3 wk of age fed a soy concentrate diet was estimated at 22.4 m
g/kg.