Quantities of ash, Ca, and P in metacarpals, metatarsals, and tibia are better correlated with total body bone ash in growing pigs than ash, Ca, and P in other bones

Differences in intestinal and renal Ca and P uptake in three different breeds of growing-finishing pigs

This study investigated the differences in bone growth and turnover and calcium (Ca) and phosphorus (P) uptake among three different breeds of growing-finishing pigs. Ninety healthy Duroc, Xiangcun black (XCB), and Taoyuan black (TYB) pigs (30 pigs per breed) at 35 day-old (D) with the average body weight (BW) of their respective breed were assigned and raised to 185 D. The results showed that Duroc pigs had higher bone weight and length than the XCB and TYB pigs at 80, 125, and 185 D and the bone index at 185 D (p < 0.05). Duroc pigs had higher bone mineral densities (femur and tibia) compared with the other two breeds at 80 D and 125 D, whereas TYB pigs had higher mineral content and bone breaking load (rib) compared with the other two breeds at 185 D (p < 0.05). The bone morphogenetic protein-2 and osteocalcin concentrations were higher, and TRACP5b concentration was lower in serum of TYB pigs at 125 D (p < 0.05). Meanwhile, 1,25-dihydroxyvitamin D3, parathyroid hormone, thyroxine, and fibroblast growth factor 23 concentrations were higher in serum of TYB pigs at 185 D (p < 0.05). The TYB pigs had higher apparent total tract digestibility of P at 80 D and 185 D and bone Ca and P contents at 185 D in comparison to the Duroc pigs (p < 0.05). Furthermore, gene expressions related to renal uptake of Ca and P differed among the three breeds of pigs. Collectively, Duroc pigs have higher bone growth, whereas TYB pigs have a higher potential for mineral deposition caused by more active Ca uptake.

Fermented Rapeseed Meal as a Dietary Intervention to Improve Mineral Utilization and Bone Health in Weaned Piglets

This study examined the effects of incorporating fermented rapeseed meal (FRSM) into the diet of newly weaned piglets on mineral digestibility and bone health. Experimental diets containing varying levels of FRSM (8%, 12%, 15%, and 25%) were introduced to the piglets at 18 days of age, prior to weaning at 28 days. These diets were continued until the piglets were euthanized at 42 days of age. Mineral absorption was assessed using the apparent total tract digestibility (ATTD) method and blood plasma element analysis, while bone mineral content and mechanical properties were evaluated through densitometry and three-point bending tests. The results showed that intermediate levels of FRSM (12-15%) significantly enhanced the digestibility of key minerals, including phosphorus, calcium, magnesium, copper, zinc, and iron. This improvement was linked to increased femoral mineral content and bone stiffness, as well as a higher yield point, likely due to enhanced collagen synthesis. Additionally, there was an increase in bone fracture load and fracture stress, potentially due to changes in the organization of the bone mineral phase, as no changes in bone mid-shaft mineral density or geometry were observed. These findings suggest FRSM as a promising dietary component for improving mineral bioavailability and bone health in piglets.

A New Biosynthetic 6-Phytase Added at 500 Phytase Unit/kg Diet Improves Growth Performance, Bone Mineralization, and Nutrient Digestibility and Retention in Weaned Piglets and Growing-Finishing Pigs

Two experiments were performed to evaluate the effect of a biosynthetic 6-phytase added at 500 phytase unit (FTU)/kg diet on growth performance, bone mineralization, and nutrient digestibility and retention in weaned piglets and growing-finishing pigs. Experiments were performed on 90 weaned male and female piglets with an average initial body weight (BW) at 7.7 ± 0.73 kg, 26 days of age) and 300 male and female growing pigs (initial BW: 21.0 ± 3.44 kg) for 43 and 98 days in experiments 1 and 2, respectively. In each experiment, the animals were assigned to one of three treatments according to a randomized complete block design. The treatments consisted of a positive-control (PC) diet formulated to meet nutrient requirements; a negative-control (NC) diet reduced similarly in calcium (Ca) and digestible P by 0.15 and 0.12% points in phases 1 and 2, respectively, in piglets and by 0.14, 0.11, and 0.10% points, respectively, in phases 1, 2, and 3 in growing-finishing pigs, compared with PC diet; and a NC diet supplemented with the new 6-phytase at 500 FTU/kg diet (PHY). The dietary P and Ca depletion reduced (p < 0.05) the final BW (-11.9%; -7.8%,), average daily gain (ADG, -17.8%; -10.1%), average daily feed intake (ADFI, -9.9%; -6.0%), gain-to-feed (G:F) ratio (-8.9%; -4.6%), and apparent total tract digestibility (ATTD) of P (-7.7% points; -6.7% points) in nursery piglets and growing pigs, respectively. It also decreased (p < 0.001) P and Ca retention by 6.1 and 9.4% points, respectively, in nursery pigs and ash, P, and Ca contents in metacarpal bones by 18.4, 18.4, and 16.8%, respectively, in growing pigs. Compared to animals fed the NC diet, phytase supplementation improved (p < 0.001) the final BW (+7.7%; +11.3%), ADG (+12.5%; +15.0%), G:F ratio (+8.4%; +5.8%), ATTD of Ca (+10.8% points; +7.2% points), and ATTD of P (+18.7% points; +16.6% points) in weaned piglets and growing pigs, respectively. In addition, phytase also increased (p < 0.001) P and Ca retention by 6.1 and 9.4% points, respectively, in nursery pigs and ash, P, and Ca contents in metacarpal bones by 17.7, 15.0, and 15.2%, respectively, in growing pigs. The final BW, ADG, G:F ratio, and bone traits in animals fed the NC diet supplemented with phytase were comparable to animals fed the PC diet. This finding indicates the ability of this novel biosynthetic phytase to restore performance and bone mineralization by improving the availability of P and Ca in piglets and growing pigs fed P- and Ca-deficient diets.

The effects of increasing dietary total Ca/total P ratios on growth performance, Ca and P balance, and bone mineralization in nursery pigs fed diets supplemented with phytase

The objective of this study was to investigate the effects of increasing dietary total Ca/total P ratios on growth performance, digestibility of Ca and P, bone mineralization, and concentrations of Ca and P in urine and plasma in nursery pigs. There were six diets in a randomized complete block design, including one positive control and five diets corresponding to five total Ca/total P ratios: 0.55, 0.73, 0.90, 1.07, and 1.24 (analyzed as 0.58, 0.75, 0.93, 1.11, and 1.30). These five diets were deficient in P but supplemented with 1,000 phytase units/kg feed. Each diet was fed to six pens of eight pigs (four barrows and four gilts per pen). All diets contained 3 g/kg TiO2, and fecal samples were collected from each pen on days 5-7 of trial. At the end, one pig per pen was sacrificed to collect the right tibia and urine in the bladder. The results showed that increasing dietary Ca/P ratio to 0.93 increased gain:feed but then gain:feed decreased as the Ca/P ratio was increased to 1.30 (linear and quadratic, P < 0.05). Although average daily gain and final BW were unaffected by changing Ca/P ratio in diet, dry bone weight; weights of bone ash, Ca and P; and bone Ca/P ratio increased linearly (P < 0.001) with increasing dietary Ca/P ratio. The percent bone Ca showed a tendency to increase (P = 0.064). Increasing dietary Ca/P ratio decreased apparent total tract digestibility (ATTD) of Ca and P linearly (P < 0.05) and the concentration of digestible P linearly (P < 0.001), but increased the concentration of digestible Ca (linear and quadratic effects: P < 0.01) and the digestible Ca/P ratio (linear effect: P < 0.001). In plasma, the concentration of Ca increased both linearly (P < 0.01) and quadratically (P = 0.051), whereas the concentration of P tended (linear and quadratic, P < 0.10) to decrease with increasing dietary Ca/P ratio. Similarly, in urine, the concentration of Ca increased both linearly and quadratically (P < 0.05), whereas the concentration of P decreased linearly (P < 0.01). In conclusion, increasing the dietary Ca/P ratio reduced feed efficiency but increased bone mass and the amounts of Ca and P deposited in bone of nursery pigs fed diets supplemented with 1,000 FYT/kg phytase. The increases in bone growth led to a reduction of urinary P excretion that exceeded the decreased digestible P supplied in diet with the widening dietary Ca/P ratios.

Effects of Exogenous 6-Phytase (EC 3.1.3.26) Supplementation on Performance, Calcium and Phosphorous Digestibility, and Bone Mineralisation and Density in Weaned Piglets

Phosphorus (P) is an essential mineral for growing piglets, which is poorly accessible in vegetable feedstuffs as it is stored as phytates. Thus, phytase supplementation is essential to increase P availability. Two experiments were conducted to evaluate a novel 6-phytase (EC 3.1.3.26) in weaned pigs fed low-P diets. In each experiment, one hundred and twenty piglets were fed a positive control (PC; adequate in Ca and P), a negative control (NC; limiting in Ca and P), or NC supplemented with 125, 250, or 500 FTU/kg of phytase (NC125, NC250, and NC500, respectively). P content was lower in diets of Experiment 1 than diets of Experiment 2. In Experiment 1, piglets offered PC or phytase diets had higher growth and efficiency compared with NC diets. In Experiment 2, similar effects were obtained, but the effects were less significant. In both experiments, P and Ca ATTD and bone density were significantly increased with phytase supplementation. Moreover, PC and NC500 had higher P concentrations and lower alkaline phosphatase activity in plasma than NC. To conclude, supplementation with the new 6-phytase at doses up to 500 FTU/kg enhanced P utilization, growth performance, and bone density in piglets fed P-limiting diets.