Effects of Low-Phosphorus Diets Supplemented with Phytase on the Production Performance, Phosphorus-Calcium Metabolism, and Bone Metabolism of Aged Hy-Line Brown Laying Hens

Dietary calcium and non-phytate phosphorus levels affect performance, follicular development, and egg quality of native chicken at peak laying period: Calcium and non-phytate phosphorus affect performance

The experiment aimed to study effects of dietary calcium (Ca) and non-phytate phosphorus (NPP) levels on performance, follicular development, egg quality and serum biochemical indices in native bird-Beijing You Chicken (BYC). A 3 × 3 factorial design was adopted, dietary Ca levels were 2.8 %, 3.2 % and 3.6 %, dietary NPP levels were 0.33 %, 0.38 % and 0.43 %. A total of 972, 28-wk-old BYC laying hens were randomly divided into 9 groups with 4 replicates per group, and 27 birds per replicate. The trial was conducted after 2 wks of pre-adaptation. The performance was determined during 30∼35 wks, 36∼41 wks and 30∼41 wks; follicular development, egg quality and serum biochemical indices were determined at 41 wks of age. The results showed that dietary Ca and NPP levels alone and the interaction affected feed egg ratio (FER) of BYC during 30∼35 wks (P < 0.05), the FER was the lowest (2.65±0.05) and the egg-laying rate was the highest (77.45±3.19 %) in the group with 3.6 % Ca and 0.43 % NPP. Dietary 0.33 % NPP and 0.43 % NPP increased the number of small yolk follicles (P < 0.05). Dietary 3.6 % Ca deepened the yolk color (YC) (P < 0.001), dietary NPP level affected the YC, Haugh unit (HU), relative yolk weight (RYW) and relative albumen weight (RAW) (P < 0.05). The interaction of dietary Ca and NPP levels affected eggshell color (ESC) (P < 0.05), YC (P < 0.001), and relative eggshell weight (RESW) (P < 0.001), also had the trend to affect eggshell strength (ESS) (P = 0.073), albumen height (AH) (P = 0.077) and HU (P = 0.055). 4) 0.43 % NPP had a trend to affect malondialdehyde (MDA) (P = 0.064). In summary, dietary Ca and NPP levels alone and the interaction did not affect egg production of BYC, and FER in the group with 3.6 % Ca and 0.43 % NPP seemed to be the lowest during 35∼41 wks. Dietary NPP may be related to pre-graded follicular development. The recommended dietary Ca level is 3.6 % and NPP level is 0.43 % for BYC during the peak laying period. The Ca/NPP ratio in the range of 8.39∼9.67 may be beneficial to laying performance and egg quality of laying hens.

Production, purification and characterization of phytase from Pichia kudriavevii FSMP-Y17and its application in layers feed

INTRODUCTION

Phytase, recognized for its ability to enhance the nutritional value of phytate-rich foods, has has gained significant prominence. The production of this enzyme has been significantly boosted while preserving economic efficiency by utilizing natural substrates and optimizing essential factors. This study focuses on optimizing phytase production through solid-state fermentation and evaluating its effectiveness in enhancing nutrient utilization in chicken diets.

OBJECTIVE

The objective is to optimize phytase production via solid-state fermentation, characterize purified phytase properties, and assess its impact on nutrient utilization in chicken diets. Through these objectives, we aim to deepen understanding of phytase's role in poultry nutrition and contribute to more efficient feed formulations for improved agricultural outcomes.

METHODOLOGY

We utilized solid-state fermentation with Pichia kudriavzevii FSMP-Y17 yeast on orange peel substrate, optimizing variables like temperature, pH, incubation time, and supplementing with glucose and ammonium sulfate. Following fermentation, we purified the phytase enzyme using standard techniques, characterizing its properties, including molecular weight, optimal temperature and pH, substrate affinity, and kinetic parameters.

RESULTS

The optimized conditions yielded a remarkable phytase yield of 7.0 U/gds. Following purification, the enzyme exhibited a molecular weight of 64 kDa and displayed optimal activity at 55 °C and pH 5.5, with kinetic parameters (Km = 3.39 × 10-3 M and a Vmax of 7.092 mM/min) indicating efficient substrate affinity.

CONCLUSION

The addition of purified phytase to chicken diets resulted in significant improvements in nutrient utilization and overall performance, including increased feed intake, improved feed conversion ratio, enhanced bird growth, better phosphorus retention, and improved egg production and quality. By addressing challenges associated with phytate-rich diets, such as reduced nutrient availability and environmental pollution, phytase utilization promotes animal welfare and sustainability in poultry production.

Supplemental phosphorus can be completely replaced with microbial phytase in White Leghorn layer diets

1. A study was conducted to assess the possibility of totally replacing supplemental phosphorus sources in White Leghorn (WL) layer diets (aged 28 to 45 weeks of age) with microbial phytase supplementation. One thousand commercial layers (HyLine White) of 28 weeks of age were housed in California cages fitted in open-sided poultry shed at the rate of 20 layers in each replicate. Ten replicates were randomly allotted to each treatment, and the respective diet was fed from 28 to 45 weeks of age.2. A control diet (CD) containing the recommended levels of non-phytate phosphorus (3.6 g/kg NPP) and four other test diets (2-5) having sub-optimal levels of NPP (2.4, 2.0, 1.6 and 1.2 g/kg), but with supplemental microbial phytase (600 FTU/kg) were prepared and fed for the trial duration.3. The layers fed with lower levels of NPP with phytase had the same laying performance as the group fed the CD. Egg production, feed efficiency, egg mass, shell defects, egg density, shell weight, shell thickness, ash content and breaking strength of the tibia and sternum were not affected by feeding the lowest concentration of NPP (1.2 g/kg) plus microbial phytase.4. Phytase supplementation in diets with sub-optimal levels of NPP (2.4, 2 and 1.6 g/kg) significantly improved the Haugh unit score compared to those fed the CD.5. It was concluded that supplemental phosphorus can be completely replaced with microbial phytase (600 FTU/kg) in a diet without affecting egg production, shell quality or bone mineral variables in WL layers (28 to 45 weeks).

Nutritional and physiological responses to dietary phosphorus levels and phytase in pullets and laying hens

The objective of this study was to determine the effects of dietary available phosphorus (P) levels and dietary phytase added into the very low-P diet on the performance, mineral balance, odor emission, and stress responses in growing pullets and laying hens during 13 to 32 wk of age. One hundred sixty-eight pullets (Hy-Line Brown) were randomly assigned into 1 of 4 dietary treatments with 7 replicates of 6 birds each. Experimental diets were formulated to contain 3 graded P levels at 0.25, 0.35, and 0.45% during 13 to 15 wk (phase 1), 0.25, 0.35, and 0.45% during 16 to 18 wk (phase 2), and 0.20, 0.30, and 0.40% during 19 to 32 wk (phase 3). In addition, dietary phytase (500 FTU/kg matrix values) was added into the very low-P diets (0.20% during 13-15 wk, 0.25% during 16-18 wk, and 0.20% during 19-32 wk) to meet the nutritional adequacy with standard P diets. In all phases, decreasing dietary P levels did not affect (P > 0.05) growth, laying performance, and egg qualities. Decreasing dietary P levels linearly increased the relative duodenal and oviduct weights (P < 0.05), and quadratically increased the relative ovary weight in pullets (P = 0.016). Dietary phytase lowered (P = 0.021) the relative duodenal weight compared with the very low-P diet. Tibia breaking strength and tibia Mg contents in pullets were linearly lowered (P < 0.05) as dietary P levels decreased. Dietary phytase tended to increase (P = 0.091) tibia breaking strength and significantly increased (P = 0.025) tibia Mg content compared with the very low-P diet. Dietary P levels and dietary phytase affected (P < 0.05) ileal crypt depth and ileal villus height: crypt depth ratio in pullets. Decreasing dietary P levels linearly decreased (P < 0.01) crude fat digestibility and P excretion in both pullets and laying hens. Dietary phytase reversed (P < 0.05) the very low-P diet-mediated decrease of crude fat digestibility in pullets and laying hens. Dietary P levels and dietary phytase affected (P < 0.05) odor emission including ammonia in pullets and total volatile fatty acids in laying hens. Finally, lowering dietary P levels increased (P < 0.01) yolk corticosterone concentrations and the increased corticosterone concentration by the very low-P diet was reversed by dietary phytase. Collectively, our study shows that decreasing dietary P levels induced nutritional and physiological responses in pullets and laying hens and these P-mediated negative effects were mitigated by dietary phytase.

Dietary exogenous phytase improve egg quality, reproductive hormones, and prolongs the lifetime of the aging Hy-Line brown laying hens fed nonphytate phosphorus

The study examined how adding phytase to nonphytate phosphorus (NPP) diets affected performance, egg quality, reproductive hormones, and plasma biochemical indices in 73- to 80-wk-old laying hens. Six treatments with 5 replicates of 18 Hy-Line brown laying hens each were randomly assigned. Three isonitrogenous, isocaloric diets containing consistent calcium levels (3.8%) were formulated to contain 0.20, 0.25, and 0.30% NPP, treated with or without phytase supplementation (1,000 FYT per kg feed, Ronozyme HiPhos-L, Aspergillus oryzae 6-phytase). The results showed that the addition of phytase to the diet containing 0.20, 0.25, and 0.30% NPP increased egg production by 1.50, 1.64, and 0.97%, respectively, and improved eggshell thickness. Also, use of phytase in the diet contain 0.25, and 0.30% NPP increased the plasma concentration of albumin (ALB), high-density lipoprotein (HDL), phosphorus (P), and plasma follicle-stimulating hormone (FSH), plasma calcium (Ca), estradiol-17β (E2β), and luteinizing hormone (LH). In contrast, the egg weight, feed intake, egg mass, feed conversion ratio, albumen height, Haugh unit, yolk, and shell color were unaffected. It can be advisable to use phytase supplementation in an elderly laying hen's diet contain 0.25, and 0.30% NPP to improve shell quality and positively impact reproductive hormones leading to the persistence of egg production.

Effect of replacing dicalcium phosphate with mono-dicalcium phosphate to supplement phosphorus on laying performance, phosphorus-calcium metabolism and bone metabolism of aged laying hens

The objective of this study was to evaluate the effect of replacing dicalcium phosphate (DCP) with mono-dicalcium phosphate (MDCP) to formulate low-phosphorus (P) diets on laying performance, egg quality, phosphorus-calcium metabolism, and bone metabolism of 69-78-week-old aged laying hens. Hy-Line Brown laying hens (n = 1,350, 69 weeks old) were randomly assigned to six treatments, each with five replicates of 45 hens. A corn-soybean meal-based diet was formulated to contain 0.12% non-phytate phosphorus (NPP), 3.81% calcium (Ca), and 1,470 FTU/kg phytase. The control group (CON) was supplemented with DCP inorganic phosphorus (Pi) at the NPP level of 0.20% (dietary NPP levels of 0.32%). Test groups (T1-T5) were supplemented with MDCP Pi at NPP levels of 0.07%, 0.11%, 0.15%, 0.18, and 0.20% (dietary NPP levels of 0.19, 0.23, 0.27, 0.30, and 0.32%, respectively). Calcium carbonate levels were adjusted to ensure all experimental diets contained the same Ca levels (3.81%). The feeding trial lasted 10 weeks, with hens increasing in age from 69 to 78 weeks. When supplemented with 1,470 FTU/kg phytase, extra DCP Pi or MDCP Pi did not affect (p > 0.05) laying performance (day laying rate, average egg weight, feed intake, feed-to-egg mass ratio, broken egg rate), egg quality (eggshell strength, albumen height, haugh units), or serum P, Ca, copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn) levels. However, when laying hens were fed MDCP Pi (NPP levels of 0.07 to 0.20%), yolk color improved (p = 0.0148). The tibia breaking strength was significantly higher (p < 0.05) in the 0.18 and 0.20% NPP MDCP Pi groups than in the 0.20% NPP DCP Pi group. The breaking strength, Ca content, and P content of tibia in 0.11% and 0.15% NPP MDCP Pi hens were not significantly (p > 0.05) different from those in 0.20% NPP DCP Pi hens. Hens fed 0.07% NPP MDCP Pi had higher (p < 0.01) serum levels of osteoprotegerin (OPG), type-I collagen c-telopeptide (CTX-I), and tartrate-resistant acid phosphatase 5b (TRACP-5b) than those in all other groups. Serum levels of TRACP-5b and CTX-I in the 0.11% and 0.15% NPP MDCP Pi group were significantly lower than those in 0.18 and 0.20% NPP MDCP Pi groups and the 0.20% NPP DCP Pi group (p < 0.0001). Hens fed 0.07% and 0.11% NPP MDCP Pi had higher (p < 0.05) serum levels of parathyroid hormone (PTH) than those in all other groups. No differences were detected in serum calcitonin (CT), 1,25-dihydroxy-vitamin D3 (1,25-(OH)2D3), bone alkaline phosphatase (BAP), osteocalcin(OCN), and osteopontin (OPN) among all groups (p > 0.05). The expression of P transporters type IIa Na/Pi cotransporter (NaPi-IIa) in 0.11% and 0.15% NPP MDCP Pi hens were higher than those in 0.20% NPP MDCP Pi group and 0.20% NPP DCP Pi group (p < 0.05). The results indicated that both renal P reabsorption and bone resorption were involved in adapting to a low-P diet. In summary, when MDCP was used instead of DCP to supplement P, NPP levels could be reduced to 0.11% (dietary NPP level of 0.23%) without negative effects on laying performance and skeletal health of aged hens. In addition, MDCP was more beneficial than DCP for tibia quality. The results of the current study would provide references for the application of MDCP in low-P diets of aged laying hens.