Growth performance, nutrient digestibility, bone mineralization, and hormone profile in broilers fed with phosphorus-deficient diets supplemented with butyric acid and Saccharomyces boulardii

Abstract

The present study evaluated the effects of butyric acid supplementation and Saccharomyces boulardii (alone or in combination) on growth performance, nutrient digestibility, bone mineralization, and blood hormones of male broiler chickens fed a diet including reduced levels of nonphytate phosphorus ( NPP ). The chickens were allocated to 6 dietary treatments: 1) positive control diet with adequate amounts of NPP ( PC ; 0.48, 0.43, and 0.39% in the starter, grower, and finisher period, respectively); 2) negative control diet with low amounts of NPP ( NC ; 0.38, 0.33, and 0.29% in the starter, grower, and finisher period, respectively); 3) NC plus 500 FTU/kg microbial phytase ( PHY ); 4) NC plus 0.2% butyric acid ( BA ); 5) NC plus 1 × 10 8 cfu/kg S. boulardii ( SB ); 6) NC plus butyric acid and S. boulardii ( BA+SB ). Each treatment had 5 pen replicates of 25 birds. After 6 wk, the body weight and ADG in birds fed with any of the diets were higher ( P < 0.001) than those in birds fed with the NC diet, where the birds fed with the PHY and BA+SB diets had the highest values. However, only the PHY diet improved ( P = 0.041) overall F:G. All diets, except the SB diet, resulted in the increased apparent ileal digestibility coefficient ( AIDC ) of CP, AME n , and tibia ash content and decreased serum alkaline phosphatase level compared with the NC diet ( P < 0.05). Broiler chickens fed with the PHY, SB, and BA+SB diets also had increased AIDC of phosphorus ( P = 0.017) than those fed with the NC and PC diets. Feeding PC, PHY, and BA+SB diets increased ( P = 0.007) the tibia phosphorus content but decreased ( P = 0.033) serum parathyroid hormone concentration. Overall, the present data indicate that the simultaneous inclusion of butyric acid plus S. boulardii in the low-NPP diets was beneficial for improving growth rate and bone mineralization, but not for feed efficiency.

Effect of Feeding a High Calcium: Phosphorus Ratio, Phosphorous Deficient Diet on Hypophosphatemic Rickets Onset in Broilers

“…The inconsistency may be due to different batches of chicks and the change of environmental conditions caused by different experiment times. Consistent with our result, F:G is not very sensitive to low dietary phosphorous by comparison with FI and ADG [11]. The BW and FI at day 3 worsened increasingly as the Ca:TP ratio increased from 1.41 to 2.69 and 3.08 in our trials.…”

“…These gait characteristics of lame chicks were consistent with previous reports of hypophosphatemic rickets [8]. Low P diets are known to be capable of reducing tibia ash and tibia P [10,11], likely one of the main reasons for the birds' poor gait scores.…”

“…Agriculture 2021, 11, x FOR PEER REVIEW 6 of 13 gait characteristics of lame chicks were consistent with previous reports of hypophosphatemic rickets [8]. Low P diets are known to be capable of reducing tibia ash and tibia P [10,11], likely one of the main reasons for the birds' poor gait scores. Hypophosphatemic rickets was further identified in the gross anatomy of chicks (Figure 1B-F,B'-F').…”

“…The rapidity of impact reflected the greater impact of a Ca:P imbalanced diet on tibia bone mineral density and ash content, and therefore, bone-breaking strength, compared with a Ca:P balanced, P-deficient diet [26]. This may be because a high dietary Ca:AP ratio causes the formation of insoluble Ca-P complexes in the intestines [27], reducing the true digestibility of Ca [17], increasing Ca excretion, and decreasing plasma P concentration [16], thus leading to poor tibial mineralization [10,11]. In our study, no consistent difference was observed in lesions of visceral organs (heart, liver, spleen, kidney, bursal, gizzard, gut, thymus, and abdominal fat) between healthy chicks and lame chicks.…”

“…In growing poultry, rickets most often results from feed mixing errors resulting in changes in dietary vitamin D, calcium, or phosphorus (P) concentrations [3]. Calcium (Ca) and P deficiency are well-known factors affecting bone strength, bone mineralization, and growth performance [4][5][6][7][8][9][10][11]. Vitamin D plays a role in maintaining the homeostatic balance between calcium and phosphorus in birds [12], affecting bone growth and mineral deposition [13].…”