Different sources of calcium for starter pig diets

The study was conducted to determine the true Ca absorption coefficients and growth performance of piglets fed diets containing different sources of Ca. In the metabolism study, 30 piglets uncastrated, with initial weight averages of 20.52 ± 1.84 kg, were assigned to 5 treatments with 6 piglets per treatment in a randomized complete block design. A basal diet was formulated to meet the piglets nutritional requirements, except to Ca (0.09%), and was supplemented with different source of Ca (limestone, monodicalcium phosphate, calcined bone meal, and oyster meal) to provide 0.64% total Ca. A low-Ca diet (0.018%) and 6 additional piglets were used to estimate the endogenous Ca excretion in the feces. Total feces and urine were collected to determine the apparent and true absorption of Ca. After the adaptation period (7 d), the excreted feces were collected twice daily, weighed, stored in plastic bags in freezer (−18 °C) until the end of the collection period (5 d). The volume of the urine collected for 24 h was measured and a 20% aliquot was stored in glass containers in refrigerator (3 °C) until the end of the collection period (5 d). Experimental diets, feces and urine were analyzed for Ca. To determine the effect of different Ca sources on the growth performance, 160 piglets were assigned, to 2 sexes (males intact and females) and 4 sources of Ca (the same ones used in the metabolism study), in a 2 × 4 factorial arrangement and randomized complete block design with 4 pens per treatment and 5 intact males or 5 females per pen. At the end of the study (22 d), blood samples were collected of the all piglets and 5 piglets per treatment were selected randomly regardless of sex to collect samples of organs. All samples were stored at −18 °C. Response criteria were: weight gain, feed intake, feed efficiency, Ca deposition in organs, bone strength, weight and size of the third metatarsal bone, and serum in Ca. The sources of Ca and direct or indirect collection method did not affect the absorption coefficients. There was no interaction among the sources of Ca and sex of the piglets for the performance variables. The piglets growth performance was similar among treatments. Calcined bone meal and oyster meal resulted in a greater content of mineral matter in the kidney (P = 0.013). The bone meal resulted in a greater Ca concentration in the piglets hearts (P < 0.001). The sources are equally effective as a source of Ca for young piglets.