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Adequate Ca intake is critical to preserve the integrity of the skeleton in growing animals and bone mineralization in later life of mammals largely depends on bone minerals accrual achieved during the early stages of growth and development. It has reported that phosphorus (P)-depleted pigs have the capacity to rapidly replace bone mass through compensatory bone mineralization. The objective of this experiment was to determine the effects of dietary calcium (Ca) levels on growth performance and bone development of growing and finishing pigs. A total of 150 crossbred pigs (37.0 ± 4.0 kg BW) were randomly assigned to 5 treatment groups: (1) low Ca levels in both grower and finisher phases (LL), (2) low Ca level in grower phase and high Ca level in finisher phase (LH), (3) medium Ca levels in both grower and finisher phases (MM), (4) high Ca level in grower phase and low Ca level in finisher phase (HL), and (5) high Ca levels in both grower and finisher phases (HH). The dietary phosphorus (P) levels were fixed. When the average pen BW reached approximately 60 kg, pigs were switched to finisher diets.
Pig performance was not affected by dietary treatments during either the grower or finisher phases. During the grower phase, bone mineral density (BMD) and bending moment of the fourth metacarpal and metatarsal bones were lower in pigs fed the low Ca diets than in those fed the medium Ca diets. During the finisher phase, P weight, BMD and bending moment of the fourth metacarpal and metatarsal bones were not different for pigs fed the LH and HL diets compared with pigs fed the HH diet. The bending moment of the fourth metacarpal bone and fat-free dry weight of the fourth metatarsal bone were lower in pigs fed the LH diet compared with those fed the MM diet.
In conclusion, a compensatory effect occurred in bone characteristics at the end of the finisher phase when the high Ca diet was introduced in the finisher phase, following a low-Ca diet during the grower phase. However, pigs fed LH diet did not surpass the level of bone mineralization achieved by pigs fed the MM diet.
L.L. Bai, F. Wu, H. Liu, L. Zhang, S. Zhang, L. Liu, X.S. Piao, Y.H. Liu, P.A. Thacker, F.L. Wang, (2016). Effects of dietary calcium levels on growth performance and bone characteristics in pigs in grower-finisher-transitional phase. Animal Feed Science and Technology. http://dx.doi.org/10.1016/j.anifeedsci.2016.12.014