Biochemical and haematological blood parameters of sows during pregnancy and lactation fed the diet with different source and activity of phytase

Abstract

The aim of the study was to estimate the influence of microbial phytase supplementation to mixtures with low (425 ± 25 PU kg −1) or high (1075 ± 75 PU kg −1) native phytase on haematological and biochemical indices as well as contents of chosen mineral components in blood of sows during pregnancy and lactation. In two experiments conducted on 75 sows in each one, all the animals were randomized to three experimental groups. Diets with low content of native phytase used in experiment 1 were based on barley, wheat, oat and rapeseed meal. Diets with high native phytase level used in experiment 2 contained triticale, rye, oat and rapeseed meal. Additionally, lactating diets were supplemented with soybean meal. The experimental design was analogical in both experiments. The diet of group I (positive control) was supplemented with the standard mixture of nutrients, containing Ca and P according to NRC recommendations (1998). Sows from group II (negative control) were fed a mixture without inorganic phosphorus supplementation. In group III, the animals were fed the same mixture as in group II, but with microbial phytase addition (500 PU kg −1 of mixture). Blood samples were taken on 8th and 14th week of pregnancy and 21st day of lactation. The following indices in whole blood were determined: hematocrit (Ht), haemoglobin (Hb) level, erythrocyte (RBC) and leukocyte (WBC) number. In the blood the activity of AP, ALT, AST, LDH, Na +K +ATP-ase has estimated and concentration of P, Ca, Na, K, Mg, Fe, Cu and Zn. Supplementing diet with the microbial phytase increased the availability of Ca, Fe, Zn in both experiments and P, Cu in experiment with high native phytase activity (experiment 2). The microbial phytase addition to the high native phytase diets diminished WBC number and increased Hb level in blood. The levels of the rest haematological indices were not changed by the exogenous microbial phytase. The increase of the phosphorous availability in the diet affected by the addition of microbial phytase is in line with the increased AP activity. The higher level of native phytase increased Mg and P, Ca, Cu and Zn availability and activity of the following enzymes: AP, ALT and LDH. Irrespective of phytase activity in diet, a higher content of sodium and the elevated RBC and Ht levels, higher AP and LDH activity but lower activity of ALT and ATP-aseNa +K + in the blood of sows during pregnancy in comparison with lactation was noted.