Influence of phytase added to a vegetarian diet on bone metabolism in pregnant and lactating sows

Abstract

The purpose of the study was to find out if the supplementation of phytase to a diet of gestating and lactating sows has any effects on performance and bone parameters of the animals. Forty primiparous gilts were assigned into four groups: group A with phytase [4.2 g total phosphorus (P)/kg (gestation) and 4.5 g total P/kg (lactation)], group B without phytase (with phytase supplementation in diet for rearing) and same P content as group A, group C without phytase and higher P contents [5.0 g total P/kg (gestation) and 5.5 g total P/kg (lactation)] and group D with the same diet as group B (no phytase during the rearing). A 6-phytase was used in this trial (750 FTU/kg diet). The four diets were fed during gestation and lactation. Faeces were collected to determine apparent digestibility of minerals. Blood samples were taken to analyse minerals and bone markers. After weaning the sows were slaughtered and the bones of one hind leg were prepared to measure bone mineral density (BMD) and bone mineral content (BMC) of the tibia. Bone ash and mineral content of the phalanx III were determined. Mean P concentrations in serum decreased during gestation and lactation. But there were no significant differences between the groups. Bone formation marker bone-specific alkaline phosphatase decreased at the beginning of lactation whereas bone resorption marker serum crosslaps increased. The BMD and BMC of the tibia were slightly higher in the groups fed higher concentrations of P and phytase. The ash and mineral contents of the phalanx were the highest for the group fed the highest concentration of P. The apparent digestibility of P increased during gestation mostly in group A (57%--> 69%). In conclusion, high P content and addition of phytase to the diet induced a slightly higher ash content of the bones. It is of high importance, that sows during gestation absorb enough P, to avoid lamenesses and sudden fractures. As not many studies with phytase have been performed during gestation and lactation in sows yet, we can recommend, that phytase as supplement can be used to keep P in the diet at a lower level without negative consequences for bone health.

Impact of parity on bone metabolism throughout the reproductive cycle in sows

“…In the period between day 84 and 129, CTX increases and OC graphically decreases, except for a similar decrease of CTX and OC at parturition and a similar increase of CTX and OC until 3 days postpartum. At this reproductive phase, despite the increased absorption efficiency, the minerals absorbed from feed may not meet the increased nutrient requirements to facilitate Ca and P demands for foetal development and milk production (Liesegang et al, 2005;Counotte et al, 2009;Donangelo and King, 2012). In other studies, serum Ca concentrations decreases consequently and stimulates PTH and 1,25-(OH) 2 D 3 secretion to support Ca transport and mobilisation (Liesegang et al, 2000;Taylor et al, 2008;Counotte et al, 2009), thereby increasing bone resorption and decreasing bone formation (Halloran and DeLuca, 1980;Liesegang et al, 2005 and2006).…”

“…This test is based on a two-site immunoradiometric assay for the measurement of intact and N-terminal midregion OC fragment in serum (Liesegang et al, 2005 and. Serum CTX concentrations were determined using a one-step ELISA (Osteometer BioTech A/S, Herlev, Denmark).…”

“…This test is based on two specific monoclonal antibodies against the amino acid sequence of the CTX. The second antibody is oxidase-conjugated (Liesegang et al, 2005 and. Serum HYP was determined using competitive ELISA (Porcine Hydroxyproline (HYP) Elisa kit, E07H0014; BlueGene Biotech CO., Shanghai, China).…”

“…Increased mineral requirements at the end of gestation and during lactation change the mineral absorption and bone metabolism throughout the reproductive cycle of mammals (Liesegang et al, 2005 andCounotte et al, 2009). These processes are largely regulated by parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D 3 (1,25-(OH) 2 D 3 ) hormone secretion (Peterson et al, 2005;Liesegang et al, 2006;Taylor et al, 2008).…”

“…The latter hormone increases an active calcium (Ca) and phosphorus (P) intestinal epithelial transport and mobilisation. The changes in bone metabolism stimulate the mobilisation of Ca and P from bone to enable foetal skeletal mineralisation during gestation and milk production during lactation (Fukuda and Iida, 1993;Liesegang et al, 2005 and2006).…”