Interactive effects of calcium, vitamin D3, and exogenous phytase on phosphorus utilization in male broiler chickens from 1 to 21 days post-hatch: A meta-analysis approach

Effects of 1,25-Dihydroxycholecalciferol Glycoside Supplementation on the Growth, Intestinal Health, and Immunity of Broilers from Breeders Supplemented or Not with the Same Additive

This study aimed to investigate the effects of 1,25-Dihydroxycholecalciferol glycoside (1,25(OH)2D3-G) supplementation on the performance, biochemical blood, bone health, intestinal histomorphometry, and gene expressions in broilers from breeders supplemented or not with 1,25(OH)2D3-G. A total of 1152 one-day-old, male Ross 308 AP chicks were distributed in a completely randomized design with a 2 × 3 factorial arrangement. One factor was the inclusion or not of 1,25(OH)2D3-G in the breeders' diets from 21 to 62 weeks of age. The other factor involved three levels (0, 50, and 100 mg/kg) of 1,25(OH)2D3-G inclusion in the broilers' diets from 1 to 21 days of age. The study totaled six treatments, with eight replicates and 24 birds per experimental unit. Breeders supplemented with of 1,25(OH)2D3-G resulted in heavier broiler chicks at hatch, better feed conversion, and higher concentrations of calbindin D28K, interleukin 10, and interleukin 1β at 21 days of age. Villus height and absorption area in the jejunum showed interactions between breeder supplementation and broiler diets. The inclusion of this additive in both diets was not sufficient to increase villus height and absorption area in broilers at 21 days of age. It is concluded that supplementation in breeders improves growth and immunity in broilers.

Effect of 25-hydroxycholecalciferol and high phytase doses on performance, vitamin D status, bone mineralization, and mechanistic target of rapamycin gene expression of broilers

The use of exogenous phytase and vitamin D3 metabolites such as 25-hydroxycholecalciferol (25-OH-D3) for poultry is well consolidated, but the potential for additive effects when supplementing both requires further investigation. This study investigated possible interactions between supplementation of 25-OH-D3 and high doses of phytase for broilers fed Ca- and P-deficient diets. A total of 1 200 one-d-old male broiler chicks were randomly allocated from one of four dietary treatments in a 2 × 2 factorial arrangement: 600 or 2 000 phytase units (FYT)/kg and with or without the inclusion of 25-OH-D3 at 69 µg/kg, with 12 replicates of 25 broilers each. Two feeding phases were stablished (1-to-21 and 22-to-42 d) and all diets contained commercial levels of vitamin D3 (100 µg/kg) with total Ca and available P respectively set to 0.6 and 0.3%. Supplementation with 25-OH-D3 increased body weight gain (BWG) and reduced feed conversion ratio (FCR) from 1 to 21 d (P < 0.05), as well as increased BWG from 1 to 42 d (P < 0.05). Serum 25-OH-D3 levels at 21 and 42 d were increased with 25-OH-D3 (P < 0.001). Phytase did not affect growth performance from 1 to 21 d, but a higher dose (2 000 FYT/kg) reduced feed intake and FCR from 22 to 42 d compared to 600 FYT/kg, also reducing FCR in the total period (P < 0.05). The mRNA expression of mechanistic target of rapamycin in breast muscle assessed at 42 d was enhanced with 2 000 FYT/kg (P < 0.001). Bone weight, bone contents of ash, Ca, and P, and bone breaking strength of tibia bone measured at 42 d were not affected by any dietary treatment. Although both additives are known to improve dietary Ca and P utilization, there were no detected additive or synergic effects. The results suggested that the inclusion of 25-OH-D3 and phytase combined with regular vitamin D3 levels can help minimize losses of performance and bone mineralization of broilers fed Ca- and P-deficient diets. Furthermore, vitamin D status is refined with dietary 25-OH-D3 and potential improvements on breast meat yield can be obtained with a high phytase dose of 2 000 FYT/kg.

Effects of phytase and 25-Hydroxycholecalciferol supplementation in broilers fed calcium-phosphorous deficient diets, with or without Eimeria challenge, on growth performance, body composition, bone development, and gut health

The study evaluated the effects of nutritional strategies on broilers challenged with Eimeria from d 14 to 26. A total of 840 Cobb male broilers were fed five diets in a 2 × 5 factorial arrangement: 1) nutrient adequate diet (PC; 0.84% calcium [Ca], 0.42% available phosphorus [avP]); 2) Ca-P deficient diet (NC; 0.64% Ca, 0.22% avP); 3) NC + 1500 FTU/kg phytase of diet (NC + PHY); 4) NC + 5000 IU/kg 25-Hydroxycholecalciferol of diet (NC + 25OHD); and 5) NC with both supplements (NC + PHY + 25OHD), with and without Eimeria challenge. All treatments had six replicate cages with 14 birds per cage. At 5 days post inoculation (DPI), the challenged birds exhibited higher serum fluorescein isothiocyanate-d (FITC-d) levels than the unchallenged birds (P < 0.001). The NC + PHY and NC + PHY + 25OHD groups exhibited lower FITC-d levels compared to the NC + 25OHD group (P = 0.012). Significant interaction effects between Eimeria challenge and dietary treatments were observed on various parameters. During 0 to 6 and 0 to 12 DPI, Eimeria challenge resulted in decreased the body weight gain (BWG) (P < 0.05) but had a negative effect on the feed conversion ratio (FCR) in birds compared to the unchallenged group (P < 0.05). Reducing Ca and avP levels in the diet (NC) did not adversely affect BWG, but negatively impacted FCR, bone ash weight, ash concentration, and femur bone microstructure parameters (P < 0.05). On 12 DPI, Eimeria challenge led to decreased tibia bone weight, bone volume, fat-free bone weight (FFBW), and ash weight of birds (P < 0.05). Supplementation with phytase alone or in combination with 25OHD improved growth performance, gut permeability, bone ash and bone microstructure parameters in birds (P < 0.05). However, the group fed 25OHD alone showed enhancements on growth performance, mineral apposition rate (MAR), bone ash concentration and ash percentage of the birds (P < 0.05). In conclusion, lowering Ca and avP levels in the diet negatively affected FCR and bone development but did not affect intestinal integrity in broilers. Dietary supplementation of phytase, 25OHD, or phytase in combination of 25OHD could enhance the growth performance and bone quality of broilers infected with Eimeria. Notably, the benefits of phytase supplementation were generally more pronounced than those associated with 25OHD supplementation; however, the combination of phytase and 25OHD could induce optimum effects.

Unlocking Phytate with Phytase: A Meta-Analytic View of Meat-Type Chicken Muscle Growth and Bone Mineralization Potential

The inclusion of exogenous phytase in P- and Ca-deficient diets of broilers to address the growing concern about excessive P excretion into the environment over the years has been remarkably documented. However, responses among these studies have been inconsistent because of the several factors affecting P utilization. For this reason, a systematic review with a meta-analysis of results from forty-one studies published from 2000 to February 2024 was evaluated to achieve the following: (1) quantitatively summarize the size of phytase effect on growth performance, bone strength and mineralization in broilers fed diets deficient in P and Ca and (2) estimate and explore the heterogeneity in the effect size of outcomes using subgroup and meta-regression analyses. The quality of the included studies was assessed using the Cochrane Collaboration's SYRCLE risk of bias checklists for animal studies. Applying the random effects models, Hedges' g effect size of supplemented phytase was calculated using the R software (version 4.3.3, Angel Food Cake) to determine the standardized mean difference (SMD) at a 95% confidence interval. Subgroup analysis and meta-regression were used to further explore the effect size heterogeneity (PSMD ≤ 0.05, I2 > 50%, n ≥ 10). The meta-analysis showed that supplemental phytase increases ADFI and BWG and improves FCR at each time point of growth (p < 0.0001). Additionally, phytase supplementation consistently increased tibia ash, P and Ca, and bone strength (p < 0.0001) of broilers fed P- and Ca-deficient diets. The results of the subgroup and meta-regression analyses showed that the age and strain of broiler, dietary P source, and the duration of phytase exposure significantly influence the effect size of phytase on growth and bone parameters. In conclusion, phytase can attenuate the effect of reducing dietary-available phosphorus and calcium and improve ADFI, BWG, and FCR, especially when added to starter diets. It further enhances bone ash, bone mineralization, and the bone-breaking strength of broilers, even though the effects of bone ash and strength can be maximized in the starter phase of growth. However, the effect sizes of phytase were related to the age and strain of the broiler, dietary P source, and the duration of phytase exposure rather than the dosage.