Skip to main content
NCBI home page
Poultry Science logoLink to Poultry Science
. 2023 Jun 28;102(9):102895. doi: 10.1016/j.psj.2023.102895

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

Hatem M Eltahan ⁎,‡, Sungbo Cho †, Md Masud Rana ‡,§, Ahmed A Saleh , Alaa E Elkomy ǁ,#, Mohammad AM Wadaan ⁎⁎, Mahmoud Alagawany ††, In Ho Kim †,1, Hossam M Eltahan ⁎,†
PMCID: PMC10362347  PMID: 37441904

Abstract

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.

Key words: phytase, laying hens, reproductive performance, egg quality, hormones

INTRODUCTION

Phosphorus (P) is a crucial and vital nutrient in many metabolic activities, and one of the essential mineral components poultry requires. Calcium and P are critical to the formation and maintenance of skeletal function and eggshells (Bello et al., 2020; Zhang et al., 2023). Phytic acid comprises approximately two-thirds of the total P in feed items of plant origin (cereal grains, beans, and oilseed meals). It is salt in phytate form (Viveros et al., 2000). The P from phytate is poorly utilized by monogastric animals, including poultry, because of the poor phytase activity in the digestive tract (Singh, 2008). Phytate is an antinutrient factor that can bind to proteins and essential minerals such as calcium, zinc, P, and iron in the digestive tract and create insoluble complexes making them unavailable for absorption and excreted into the environment via manure as a source of environmental pollution (Guo et al., 2009). This can lead to mineral deficiencies in the hens, decreased eggshell quality and decreased egg production. Therefore, reducing the phytate content in the diets of laying hens is important to ensure optimal health and performance. Phytase enzymes have been widespread in poultry diets over the past few decades to reduce P excretion (Yu et al., 2004) and make P available to birds by hydrolysis of phytate complexes (Khan et al., 2013; Rodehutscord et al., 2023).

The phytase in poultry diets releases not only the phytate-bound minerals but also the subsequent improvement of other essential nutrient availability, such as protein, and amino acids which leads to the higher nutritional value of the diet (Selle and Ravindran, 2007). There are different factors involved with the efficacy of phytase in the diet of poultry that depends upon the composition of the diet, dietary mineral content, the source of phytase, genotype, and age of birds (Abd-Hack et al., 2018). Nevertheless, several studies have shown that adding phytase to diets has improved the productive performance and eggshell quality of laying hens from 23 to 28 wk of age (Liu et al., 2007), from 29 to 40 wk of age (Attia et al., 2010; Englmaierova et al., 2015), from 40 to 60 wk (Jalal and Scheideler, 2001; Salah et al., 2021), 60 to 73 wk (Englmaierová et al., 2017; Ren et al., 2020), and 68 to 78 wk (Bello et al., 2020; Ren et al., 2023).

The commercial laying hens usually start laying at 17 to 19 wk of age and continue being reared for up to 72 wk for satisfactory economic production. Beyond 72 wk, hens’ egg production steadily drops, but there is a trend to keep the hens even longer than 80 wk of age to gain more under the dire economic issue. However, studies on aged laying hens are scarce. It has been reported that aging chickens may produce insufficient levels of FSH, resulting in a decrease in follicular growth rate and a consequent decline in egg production (Palmer and Bahr, 1992). Additionally, microbial phytase can liberate minerals, including Zn, Mn, Fe, Cu, and Mg, by dephosphorylating insoluble phytate salts (Liu et al., 1998). These minerals, after phytase supplementation, may have a role in controlling how the oviduct and ovary develop in layers hens mainly, Mn involved in the synthesis of cholesterol which is a precursor for the steroid hormones (Saleh et al., 2020).

Furthermore, Xie et al. (2014) found that long-term Mn supplementation can control the GnRH-I and FSH genes, thereby increasing egg production and improving eggshell quality. Phytase can increase egg production, as established by numerous researches upon administering phytase to 42-wk-old hens; no effect was observed on the ovary index, relative weight, or oviduct length (Saleh et al., 2021). Therefore, the current study examined the effect of phytase on production performance, egg quality, reproductive hormones, and plasma biochemical indices of laying hens fed with different concentrations of inorganic P diets at 73 to 80 wk of age.

MATERIALS AND METHODS

Bird's Management

A total of 540 Hy-Line brown laying hens at the age of 72 wk belonged to Jeonbuk National University experimental farm were housed in cages (2 hens per cage) measuring 1,200 cm2 (600 cm2 cage space per hen) and equipped with nipple drinkers and plastic feeding troughs. Hens were allocated randomly into 6 treatments of 5 replicates, with 18 hens each. Before starting the experiment, the egg production of laying hens was recorded, and the replicates had initially been made based on a similar laying performance rate. Three adjacent upper, middle, and bottom cages were included as one replicate to reduce the cage level effect. A continuous plastic feeding trough was partitioned each repeat to prevent hens from consuming feed from adjacent replicates. Throughout the trial period, the house's ambient temperature was kept between 18°C and 23°C, and 16 h of light per day were provided. This study followed the instruction for the animal committee at the Faculty of Agriculture of Jeonbuk National University under the ethical approval number 2021-0168 JBNU.

Experimental Diets

Hens were fed 1 of the 6 experimental diets, similar at metabolizable energy of 2,650 Kcal/kg, crude protein 15%, and Ca level of 3.80%. The diets consisted of 0.20, 0.25 and 0.30% NPP with or without the addition of phytase enzyme at 1,000 FYT phytase per kg of feed (Ronozyme HiPhos-L, 6-phytase produced by the strain of Aspergillus oryzae. The experimental diets of 0.12, 0.2, 0.25, and 0.3% NPP were obtained from added 0, 0.08, 0.13, and 0.18% of di-calcium phosphate (CaPO42H2O) to the basal diet, respectively (Table 1). All the hens were provided free access to mash feed and water until 80 wk of age.

Table 1.

The ingredient and nutrient composition of experimental diets.

Ingredient %
Corn 60.53
Soybean meal, 46% 15.09
Corn germ meal, 23% 4.00
Corn gluten meal, 60% 3.00
DDGS, 27.5%* 4.00
Soybean oil 0.47
Sodium chloride 0.20
Choline chloride, 50% 0.08
Di-calcium phosphate, 2H2O -
Calcium carbonate 9.60
L-lysine-H2SO4, 65% 0.26
DL-methionine, 99% 0.16
L-tryptophan, 99% 0.08
Premix1 0.53
Zeolite powder 2.00
Total 100
Nutrient contents
 Metabolic energy (Mcal/kg) 2,650
 Crude protein 15.80
 Calcium 3.80
 Total phosphorus (analyzed) 0.34
 NPP* 0.12
 Lysine 0.80
 Methionine + cysteine 0.69
Open in a new tab
1

Supplement provided per kilogram of diet: vitamin A, 10,000 IU; vitamin D3, 2,500 IU; vitamin E, 20 IU; vitamin B1, 1.5 mg; vitamin B2, 5.0 mg; vitamin B6, 0.15 mg; vitamin B12, 15.0 mg; choline, 300 mg; pantothenate, 12 mg; nicotinic acid, 50 mg; biotin, 0.15 mg; folic acid, 1.5 mg; Fe, 60 mg; Cu, 10 mg; Zn, 80 mg; Mn, 110 mg; iodine, 0.48 mg; Se, 0.40 mg.

⁎

DDGS, distillers dried grains with soluble; NPP, nonphytate phosphorus.

Performance and Egg Quality

Laying hens’ performance was assessed every 4 wk by tracking their eggs (production, weight, and mass), feed intake, and conversion ratio. Daily egg production was recorded and expressed as the output rate per hen per day. Eggs were weighed twice a week according to the replicate basis, and egg mass was calculated by multiplying average egg weight by egg production rate. Replicates were utilized to quantify feed intake by subtracting the residual feed from the initial amount of feed. The feed conversion ratio was determined by dividing the quantity of feed consumed in grams by the egg mass in grams. At 76 and 80 wk of age, 30 eggs from each treatment were collected arbitrarily to determine egg quality traits. After removing the shell membranes, the eggshell thickness was measured in 3 different locations at the air cell, equator, and sharp end using a micrometer caliper with 0.01 mm precision (Digimatic micrometer, series 293-330) and took the average of the 3 data. The eggs were weighed cautiously using a QCBi digital balance and broken on the parallel glass plate; the color of the eggshell, albumen height, Haugh unit, and yolk color was semiautomatically measured using the egg multitester device (QCM+ System, TSS, Telford, UK).

Blood Biochemical Analysis

Ten laying hens from each group were randomly chosen at the end of the experiment, and blood samples were collected from the wing vein in K2-EDTA heparinized tubes (K2-EDTA, BD Vacutainer, Plymouth, Devon, UK). The blood samples were centrifuged at 3,000 rpm for 15 min at 4°C to separate the plasma into Eppendorf tubes and kept at −20°C until further analysis. The concentrations of ALB, HDL, Ca, P, total protein (TP), glucose (GLU), triglycerides (TG), total cholesterol (TC), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were determined by an automatic blood biochemistry analyzer (Konelab 20 analyzer, Thermo Fisher Scientific, Vantaa, Finland), using commercial diagnostic kits and following the manufacturer's guidelines. Besides, plasma FSH, LH, and E2β were determined using a homologous radioimmunoassay (Krishnan et al., 1993).

Statistical Analysis

Data were analyzed using a 1-way analysis of variance (ANOVA) with the general linear model procedure in the SAS software (SAS, 2009). Duncan's multiple range test determined the mean comparison of treatments with significant differences in variance analysis. Significant differences represented the statistical difference level at P < 0.05, while it was considered a tendency at P < 0.1. Results are presented in the tables as the mean and standard error of the mean (SEM).

RESULTS

Productive Performance

According to the present study, dietary phytase treatments significantly enhanced egg production for the entire trial period of 73 to 80 wk; it increased linearly between 73 to 76 and 77 to 80 wk of age (Table 2). Phytase supplementation for the NPP diets 0.20, 0.25, and 0.30% significantly (P < 0.05) increased egg production by 1.50, 1.64, and 0.97%, respectively, in the entire period while showing the tendency increment in egg production at 73 to 76 and 77 to 80 wk of age compared to the diets without phytase groups. Egg production (%) was significantly increased in 0.25% NPP with phytase-treated hens (P < 0.05). Hens fed a diet of 0.25% NPP with phytase had more outstanding egg production. Phytase added for NPP treatment groups showed no significant effects on the egg mass, egg weight, feed intake and feed conversion ratio in elder laying hens fed the NPP diets with or without phytase (Table 2).

Table 2.

Effects of phytase supplementation on performance of laying hens during 73–80 wk of age.

Parameters % of NPP without phytase
 % of NPP with phytase
 SEM P value
0.20 0.25 0.30 0.20 0.25 0.30
Egg production (%)
 73–76 wk 72.25 72.89 73.14 73.32 74.11 73.51 0.21 0.17
 77–80 wk 70.12 70.59 70.52 71.18 71.74 71.56 0.20 0.12
 73–80 wk 71.18c 71.74bc 71.83abc 72.25abc 72.92a 72.53ab 0.17 0.04
Egg weight (g)
 73–76 wk 64.31 64.13 63.94 64.26 63.88 64.13 0.11 0.86
 77–80 wk 64.38 64.17 63.83 64.11 64.04 64.23 0.10 0.78
 73–80 wk 64.35 64.15 63.88 64.19 63.96 64.18 0.07 0.56
Egg mass (g/h/d)
 73–76 wk 46.46 46.74 46.76 47.12 47.34 47.14 0.13 0.41
 77–80 wk 45.14 45.29 45.01 45.63 45.94 45.96 0.13 0.15
 73–80 wk 45.81 46.02 45.88 46.37 46.64 46.55 0.12 0.16
Feed intake (g/h/d)
 73–76 wk 115.29 115.25 115.58 115.90 116.06 115.18 0.15 0.49
 77–80 wk 116.37 116.42 115.96 115.52 115.30 116.26 0.21 0.59
 73–80 wk 115.83 115.84 115.77 115.71 115.68 115.72 0.06 0.96
Feed conversion ratio (g of feed consumed/g of egg mass)
 73–76 wk 2.48 2.46 2.47 2.46 2.45 2.44 0.01 0.80
 77–80 wk 2.57 2.57 2.58 2.53 2.51 2.53 0.01 0.15
 73–80 wk 2.52 2.57 2.58 2.53 2.51 2.51 0.01 0.15
Open in a new tab
a–c

Values with different superscripts in the same row are significantly different (P < 0.05). SEM, standard error of the mean; Ronozyme HiPhos-L, 6-phytase produced by the strain of Aspergillus oryzae was used to supply 1,000 FTY per kg of feed.

Egg Quality

The effects of dietary nonphytate phosphorus levels and phytase addition on egg quality are presented in Table 3. The levels of NPP in diet or phytase had not significantly affected shell color, albumen height, Haugh unit, and yolk color on wk 76 and 80. Compared to the without phytase-added groups, the eggshell thickness almost tended (P = 0.16) to be linearly higher in phytase groups at 76 wk of age. A significant influence effect (P = 0.04) was observed in eggshell thickness in the dietary phytase-added groups at 80 wk of age. Since, eggshell thickness (mm) was significantly increased in 0.25% NPP with phytase-treated hens (P < 0.05).

Table 3.

Effects of phytase supplementation on egg quality traits of laying hens at 76 and 80 wk of age.

Parameters % of NPP without phytase
 % of NPP with phytase
 SEM P value
0.20 0.25 0.30 0.20 0.25 0.30
Shell color score
 76 wk 25.38 25.06 25.56 25.69 26.81 25.13 0.34 0.71
 80 wk 24.19 24.69 26.06 27.13 25.75 25.63 0.43 0.44
Albumen height (mm)
 76 wk 5.81 5.78 5.79 6.013 6.40 5.86 0.10 0.46
 80 wk 6.33 5.79 5.96 5.44 5.91 5.61 0.14 0.56
Haugh unit score
 76 wk 73.14 73.25 72.53 74.18 76.46 72.88 0.78 0.74
 80 wk 75.12 72.36 73.46 69.02 71.28 70.74 1.08 0.67
Yolk color score
 76 wk 4.38 4.50 4.75 4.44 4.88 4.88 0.08 0.29
 80 wk 6.19 5.81 6.25 6.13 6.31 6.13 0.07 0.46
Eggshell thickness (mm)
 76 wk 0.372 0.373 0.383 0.387 0.392 0.394 0.003 0.160
 80 wk 0.371b 0.371b 0.376ab 0.389ab 0.395a 0.396a 0.003 0.042
Open in a new tab
a,b

Values with different superscripts in the same row are significantly different (P < 0.05). SEM, standard error of the mean; Ronozyme HiPhos-L, 6-phytase produced by the strain of Aspergillus oryzae was used to supply 1,000 FTY per kg of feed.

Plasma Chemistry

The effects concerning the dietary NPP levels and phytase supplementation on the blood biochemical parameters at the end of the experiment are summarized in Tables 4 and 5. The concentration of ALB, HDL, FSH, and level of P in plasma showed a significant increment in phytase-treated groups rather than without phytase groups and specific at 0.25 and 0.3% of NPP treatment. While the concentration levels of Ca, LH, and estradiol‐17β (E2β) tended to increase regarding the phytase with 0.25 and 0.3% of NPP treatments. Besides, no significant differences in dietary treatments were observed in the plasma CHOL, GLU, TP, ALT, AST, and TG concentrations (Table 4).

Table 4.

Effects of phytase supplementation on blood biochemical characteristics of laying hens at 80 wk of age.

Parameters % of NPP without phytase
 % of NPP with phytase
 SEM P value
0.20 0.25 0.30 0.20 0.25 0.30
ALB (g/dL) 2.30ab 2.20b 2.32ab 2.33ab 2.43a 2.37a 0.02 0.02
TP (IU/L) 7.61 6.51 7.29 6.91 7.63 7.36 0.14 0.12
CHOL (mg/dL) 164.77 171.29 201.08 193.91 168.28 191.10 5.34 0.22
HDL (mg/dL) 6.54b 8.713ab 11.33a 11.52 11.37 11.61 0.59 0.05
GLU (mg/dL) 281.42 297.65 275.07 291.49 288.76 301.88 3.57 0.26
ALT (g/dL) 0.76 0.71 0.86 0.78 0.73 0.95 0.11 0.98
AST (mg/dL) 187.01 195.77 193.81 191.97 197.32 199.36 3.37 0.93
TG (IU/µL) 2082 2194 2452 2494 2292 2128 75.58 0.53
Ca (mg/dL) 15.68 16.56 16.97 17.24 17.45 17.62 0.21 0.08
P (mg/dL) 5.58b 5.93b 6.43ab 6.63ab 7.24a 7.06a 0.17 0.02
Open in a new tab
a,b

Values with different superscripts in the same row are significantly different (P < 0.05). SEM, standard error of the mean; ALB, albumin; TP, total protein; CHOL, cholesterol; HDL, high-density lipoprotein; GLU, glucose; ALT, alanine aminotransferase; AST, aspartate aminotransferase; TG, triglyceride; Ca, calcium; P, phosphorus. Ronozyme HiPhos-L, 6-phytase produced by the strain of Aspergillus oryzae was used to supply 1,000 FTY per kg of feed.

Table 5.

Effects of phytase supplementation on reproductive hormones of laying hens at 80 wk of age.

Parameters % of NPP without phytase
 % of NPP with phytase
 SEM P value
0.20 0.25 0.30 0.20 0.25 0.30
LH (ng/mL) 2.65 2.96 3.58 3.75 4.27 4.16 0.19 0.080
FSH (ng/mL) 3.03c 3.38bc 4.27abc 4.78ab 5.23a 5.18a 0.24 0.013
E2β (pg/mL) 288.73 310.01 304.30 317.08 326.09 322.79 4.23 0.090
Open in a new tab
a–c

Values with different superscripts in the same row are significantly different (P < 0.05). SEM, standard error of the mean; LH, luteinizing hormone; FSH, follicle-stimulating hormone; and E2β, estradiol-17β. Ronozyme HiPhos-L, 6-phytase produced by the strain of Aspergillus oryzae was used to supply 1,000 FTY per kg of feed.

DISCUSSION

Productive Performance

Higher egg production in the phytase-treated group was in line with the findings of Fernandez et al. (2019), who illustrated that adding phytase to laying hens’ diets could increase egg output. Similar to this, Kim et al. (2017) showed that feeding laying hens a diet containing 2.6 g/kg NPP with 1,000, 2,000, or 3,000 FTU phytase per kg of feed significantly enhanced the egg production compared to hens fed a diet containing 2.6 and 3.8 g/kg NPP without phytase. In contrast, Wang et al. (2013) found that adding phytase to diets containing 0.26, 0.21, and 0.16% NPP compared to the control diet containing 0.36% NPP had no impact on egg production. Ahmed et al. (2017), Saleh et al. (2021), and Ren et al. (2023) also showed a nonsignificant difference in egg production rate between the treatments when hens fed diets containing 0.32 or 0.26% NPP with supplemented phytase and the diet containing 0.38% NPP in the absence of phytase. The current study showed increased egg production, which could be explained by the fact that adding phytase releases the minerals and enhances the diet's nutritional value from phytate complexes, which could favorably affect the productive performance of laying hens (Dersjant-Li et al., 2018).

In line with Panda et al. (2005), who noticed that feeding laying hens NPP at various concentrations ranging from 0.15 to 0.45% did not affect their productivity, the current study found that variations in the NPP content or the addition of phytase to the diets had no effect on egg weight and feed intake (Table 2). Similar outcomes were achieved by Kim et al. (2017) and Dersjant-Li et al. (2018), who could not find a statistical difference in the average egg weight of laying hens fed NPP diets or with added phytase. Besides, dietary levels of 2.6, 2.1, or 1.6 g/kg NPP with supplemental phytase did not affect egg weight compared with the control diet containing 3.6 g/kg NPP (Wang et al., 2013). Furthermore, Pelicia et al. (2009) reported no significant differences in egg weight by dietary treatments of available phosphorus (AP) ranging from 0.25 to 0.40% in aged laying hens over 90 wk. Egg production was not affected by phytase supplemented in available P-reduced and Ca-reduced diets (Bello et al., 2020). Thus, the present study's egg weight data indicated that different NPP levels from 2.0 to 3.0 g/kg diet without supplemented phytase in laying hens were insufficient to support the average egg weight.

Phytase supplementation in a 2.5 g/kg NPP diet did not influence egg mass during the late laying period at 62 to 72 wk of age (Habibollahi et al., 2019). Moreover, Meyer and Parsons (2011) and Kim et al. (2017) found no significant difference among the dietary treatments on egg mass. While, Englmaierova et al. (2014) reported that feeding a diet containing 0.21% NPP-reduced egg mass, supplementation with phytase totally reversed the negative effect and showed statistically comparable results with 0.30% NPP in the presence or absence of phytase enzyme. In the current study, we found that phytase coadded with NPP diets tendency increased the egg mass in elder laying hens which might be due to the calculation response for egg production increments.

Previously, Um et al. (1999) and Jalal and Scheideler (2001) reported that phytase supplementation to various NPP-containing diets had significantly increased feed consumption and improved feed efficiency. On the other hand, Wang et al. (2013), Englmaierova et al. (2014), Kim et al. (2017), and Saleh et al. (2021) elucidated that phytase supplementation to the NPP diets or only phytase did not affect feed consumption and feed efficiency in layer hens. In the current finding, feed intake did not show a significant effect. In contrast, the feed conversion ratio has shown a tendency to increase (Table 2) in laying hens fed due to variation of NPP diets with the addition of phytase may be because of the calculation response for egg production increments.

Egg Quality

In the current study, the levels of NPP in diet or phytase had not significantly affected shell color, albumen height, Haugh unit, and yolk color at 76 and 80 wk (Table 3). The eggshell thickness was significantly increased in the dietary phytase-added groups at 80 wk of age compared to the without phytase-added groups. According to the present study results, Habibollahi et al. (2019) obtained that adding phytase to the 2.5 g/kg NPP diet significantly improved eggshell thickness compared to the control group, while albumen height and Haugh unit could not be affected. Kim et al. (2017) also demonstrated that super-dosing phytase (10,000–30,000 FTU/kg) did not affect the eggshell thickness and strength of hens aged 47 wk. Englmaierova et al. (2015) treated 38- to 52-wk-old hens with 350 FTU/kg of phytase and 2.1 g/kg of nonphytate P and recorded high eggshell thickness values but no impact on shell-breaking strength. Rama Rao et al. (1999) reported that eggshell thickness increased due to incorporating the phytase enzyme in layers diet. Moreover, numerous studies have shown that adding phytase to the diet has a positive impact on eggshell quality (Liu et al., 2007; Sharifi et al., 2012; Saleh et al., 2021), while some other studies did not find any effect on egg quality parameters (Wang et al., 2013; Rojas et al., 2017; Ren et al., 2020, 2023). The improvement in eggshell quality could probably be connected with the increased absorption and availability of minerals that may be attributed due to the beneficial effect of phytase supplementation in the diet.

Blood Parameters

Our findings demonstrated that ALB and HDL plasma concentrations were significantly increased in phytase-treated groups when compared to control group and specific at 0.25 and 0.3% of NPP treatment (Table 4). A similar observation was reported by Jalali and Babaei (2012), who stated that the addition of phytase increased albumin plasma concentration. Moreover, Yossef et al. (2001) found that albumin concentration in plasma was increased due to the inclusion level of supplementing phytase at 600 and 1,000 FTU/kg to laying hens diets containing either 0.25 or 0.40% AP. The increase of albumin may be related to the positive effects of phytase on protein digestibility by hydrolysis of phytate complexes and the release of phytate-bound proteins or amino acids (Liebert et al., 2005; Selle et al., 2006). Regarding the plasma concentration, P was significantly higher in hens fed levels of 0.25 and 0.3% NPP with supplemented phytase groups. Similar results were observed in a study conducted by Yan et al. (2009), who reported that the serum P concentration increased in response to phytase supplementation, which might be due to the hydrolysis of phytate-bound P by the phytase. However, the plasma Ca level showed a tendency (P = 0.08) increment response for adding phytase to NPP diets, but we believed that phytase has a pronounced influence on digestive enzymes and the solubility of phytate-bound minerals; therefore, the eggshell quality enhanced.

Blood biochemical parameters of CHOL, GLU, TP, ALT, AST, and TG are not significantly affected by dietary treatments (Table 4). These unaffected parameters are in agreement with the reported findings of many researchers who stated that phytase enzyme addition to the diets did not affect the plasma biochemical constituents in layers (Gao et al., 2014; Ahmed et al., 2017) and broilers (Cowieson et al., 2013; Islam et al., 2014).

However, we found that adding phytase to the NPP diets tendency increased the plasma level of FSH while there was no significant effect on LH or E2β which it did not consistent with Palmer and Bahr's (1992) who found that the injection of FSH increased the serum level of E2β concentration in the old laying chicken and increased egg production. We found that adding phytase to the NPP diets significantly increased the plasma level of FSH and showed a tendency to raise the plasma level of LH and E2β (Table 5). This is the first study concerning phytase's effect on the reproductive hormones beyond 72 wk of age. In contrast, Saleh et al. (2021) demonstrated that phytase does not influence the oviduct's productive performance, ovary index, or relative weight or length. We speculate their finding might be due to the age of laying hens still under the high egg production peak at 43 wk. It has been reported that phytase liberates minerals, including Zn, Mn, Fe, Cu, and Mg, by dephosphorylating insoluble phytate salts in the diets (Abd EI-Hack et al., 2018). Moreover, Saleh et al. (2020) reported that Mn is a cofactor in cholesterol synthesis which is precursor for the steroid hormone's production. Furthermore, Bahry et al. (2023) found that plasma E2 have a positive correlation with bone mineral content and density. Therefore, we speculate that phytase might be prolong the lifetime of egg production through increasing the reproductive hormones and afforded sufficient minerals. Future studies are needed to indicate the effect of minerals on the reproductive hormones in laying hens under phytase administration. Numerous factors, such as the time of sampling, feedback mechanism, minerals, stress, and the environment, may affect the level of the hormones in our results.

CONCLUSIONS

The current study showed that adding phytase (1,000 FYT phytase per kg of feed) to elder laying hen diets containing inorganic P (0.25, and 0.30% NPP) increased egg production. While, the egg weight, feed intake, egg mass, feed conversion ratio, albumen height, Haugh unit, yolk, and shell color were unaffected. Moreover, supplementation of exogenous phytase to the diet containing 0.25, and 0.30% of NPP raise the level of albumin, HDL, P concentration, and FSH hormone in plasma to allow for the dietary reductions without negative consequences on productivity. These effects contributed to improving eggshell quality and persistence of the laying rate. Additionally, it may be concluded that phytase supplements possibly prolong the optimal laying phase period by increasing reproductive hormones in the elder layer.

ACKNOWLEDGMENTS

The authors express their sincere appreciation to the Researchers Supporting Project number (RSP2023R466), King Saud University, Riyadh, Saudi Arabia.

DISCLOSURES

The authors declare no conflicts of interest either financially or in the article's content.

REFERENCES

  1. Abd EI-Hack M.E., Alagawany M., Arif M., Emam M., Saeed M., Arain M.A., Siyal F.A., Patra A., Elneser S.S., Khan R.U. The uses of microbial phytase as a feed additive in poultry nutrition – a review. Ann. Anim. Sci. 2018;18:639–658. [Google Scholar]
  2. Ahmed H.A., Abdel-Latif M.A., Ghoraba A.A., Ganna S.A. Comparative effect of microbial phytase supplementation on layer chickens fed diets with required or low phosphorus level. Int. J. Res. 2017;5:437–449. [Google Scholar]
  3. Attia Y.A., Qota E.M., Bovera F., Tag El-Din A.E., Mansour S.A. Effect of amount and source of manganese and/or phytase supplementation on productive and reproductive performance and some physiological traits of dual-purpose cross-bred hens in the tropics. Br. Poult. Sci. 2010;51:235–245. doi: 10.1080/00071661003786111. [DOI] [PubMed] [Google Scholar]
  4. Bahry M.A., Charlene H., Ziezold J., Schaus S., Bédécarrats G.Y. Impact of growth trajectory on sexual maturation in layer chickens. Front. Physiol. 2023;14 doi: 10.3389/fphys.2023.1174238. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bello A., Dersjant-Li Y., Korver D.R. Effects of dietary calcium and available phosphorus levels and phytase supplementation on performance, bone mineral density, and serum biochemical bone markers in aged white egg-laying hens. Poult. Sci. 2020;99:5792–5801. doi: 10.1016/j.psj.2020.06.082. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Cowieson A.J., Ptak A., Mackowiak P., Sassek M., Pruszynska-Oszmalek E., Zyla K., Swiatkiewicz S., Kaczmarek S., Jozefiak D. The effect of microbial phytase and Myo-inositol on performance and blood biochemistry of broiler chickens fed wheat/corn-based diets. Poult. Sci. 2013;92:2124–2134. doi: 10.3382/ps.2013-03140. [DOI] [PubMed] [Google Scholar]
  7. Dersjant-Li Y., Millan C., Casabuena O., Quiles A., Romero L.F., Gracia M.I. Supplementation of Buttiauxella sp. 6-phytase to commercial laying hen diets with reduced nutrient density on productive performance and egg quality. J. Appl. Anim. Nutr. 2018;6:1–8. [Google Scholar]
  8. Englmaierova M., Skrivan M., Skrivanova E., Bubancova I., Cermak L., Vlckova J. Effects of a low-phosphorus diet and exogenous phytase on performance, egg quality, and bacterial colonization and digestibility of minerals in the digestive tract of laying hens. Czech. J. Anim. Sci. 2015;60:542–549. [Google Scholar]
  9. Englmaierová M., Skřivan M., Skřivanová E., Čermák L. Limestone particle size and Aspergillus niger phytase in the diet of older hens. Ital. J. Anim. Sci. 2017;16:608–615. [Google Scholar]
  10. Englmaierova M., Skrivanova V., Skrivan M. The effect of non-phytate phosphorus and phytase levels on performance, egg quality and tibia quality, and pH of the digestive tract in hens fed higher-calcium-content diets. Czech. J. Anim. Sci. 2014;59:107–115. [Google Scholar]
  11. Fernandez S.R., Charraga S., Avila-Gonzalez E. Evaluation of a new generation phytase on phytate phosphorus release for egg production and tibia strength in hens fed a corn-soybean meal diet. Poult. Sci. 2019;98:2087–2093. doi: 10.3382/ps/pey558. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Gao C., Ma Q., Zhao L., Zhang J., Ji C. Effect of dietary phytase transgenic corn on physiological characteristics and the fate of recombinant plant DNA in laying hens. Asian-Australas. J. Anim. Sci. 2014;27:77–82. doi: 10.5713/ajas.2013.13265. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Guo Y., Shi Y., Li F., Chen J., Zhen C., Hao Z. Effects of sodium gluconate and phytase on performance and bone characteristics in broiler chickens. Anim. Feed Sci. Technol. 2009;150:270–282. [Google Scholar]
  14. Habibollahi M., Abousadi M.A., Nakhaee P. The effect of phytase on production performance, egg quality, calcium, and phosphorus excretion, and fatty acids and cholesterol concentration in Hy-line layers fed diets containing rice bran. J. Appl. Poult. Res. 2019;28:688–698. [Google Scholar]
  15. Islam R., Ideris A., Kasim A., Omar A., Meor Hussin A., Yasmin F., Akter Y. Effects of locally produced bacterial phytase on humoral immunity, live body weight and blood characteristics in broilers vaccinated against Newcastle disease. J. Vet. Malays. Res. 2014;26:8–16. [Google Scholar]
  16. Jalal M.A., Scheideler S.E. Effect of supplementation of two different sources of phytase on egg production parameters in laying hens and nutrient digestibility. Poult. Sci. 2001;80:1463–1471. doi: 10.1093/ps/80.10.1463. [DOI] [PubMed] [Google Scholar]
  17. Jalali M.A., Babaei M. Effects of supplemental dietary phytase on performance and blood biochemical parameters of broiler chicks. Int. J. Biosci. Biochem. Bioinform. 2012;2:60–63. [Google Scholar]
  18. Khan S.A., Chaudhry H.R., Butt Y.S., Jameel T., Ahmad F. The effect of phytase enzyme on the performance of broiler flock (a review) Poult. Sci. 2013;1:117–125. [Google Scholar]
  19. Kim J.H., Pitargue F.M., Jung H., Han G.P., Choi H.S., Ki D.Y. Effect of super dosing phytase on productive performance and egg quality in laying hens. Asian-Australas. J. Anim. Sci. 2017;30:994–998. doi: 10.5713/ajas.17.0149. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Krishnan K.A., Proudman J.A., Bolt D.J. Development of a homologous radioimmunoassay for chicken follicle-stimulating hormone and measurement of plasma FSH during the ovulatory cycle. Comp. Biochem. Physiol. Part A. 1993;105:729–734. doi: 10.1016/0300-9629(93)90275-9. [DOI] [PubMed] [Google Scholar]
  21. Liebert F., Htoo J.K., Sunder A. Performance and nutrient utilization of laying hens fed low-phosphorus corn-soybean and wheat-soybean diets supplemented with microbial phytase. Poult. Sci. 2005;84:1576–1583. doi: 10.1093/ps/84.10.1576. [DOI] [PubMed] [Google Scholar]
  22. Liu N., Liu G.H., Li F.D., Sands J.S., Zhang S., Zheng A.J., Rus Y.J. Efficacy of phytases on egg production and nutrient digestibility in layers fed reduced phosphorus diets. Poult. Sci. 2007;86:2337–2342. doi: 10.3382/ps.2007-00079. [DOI] [PubMed] [Google Scholar]
  23. Liu B.-L., Rafiq A., Tzeng Y.-M., Rob A. The induction and characterization of phytase and beyond. Enzym. Microb. Technol. 1998;22:415–424. [Google Scholar]
  24. Meyer E., Parsons C. The efficacy of a phytase enzyme fed to Hy-Line W-36 laying hens from 32 to 62 weeks of age. J. Appl. Poult. Res. 2011;20:136–142. [Google Scholar]
  25. Palmer S.S., Bahr J.M. Follicle-stimulating hormone increases serum oestradiol-17 beta concentrations, a number of growing follicles and yolk deposition in aging hens (Gallus gallus domesticus) with decreased egg production. Br. Poult. Sci. 1992;33:403–414. doi: 10.1080/00071669208417478. [DOI] [PubMed] [Google Scholar]
  26. Panda A.K., Rama Rao S.V., Raju M.V.L.N., Bhanja S.K. Effects of dietary non-phytate phosphorus levels on egg production, shell quality and nutrition retention in white leghorns layers. Asian-Australas. J. Anim. Sci. 2005;18:1171–1175. [Google Scholar]
  27. Pelicia K., Garcia E.A., Faitarone A.B.G., Silva A.P., Berto D.A., Molino A.B., Vercese F. Calcium and available phosphorus levels for laying hens in the second production cycle. Braz. J. Poult. Sci. 2009;11:39–49. [Google Scholar]
  28. Rama Rao S.V., Ravindra R.V., Ramasubba R.V. Enhancement of phytate phosphorus availability in the diets of commercial broilers and layers. Anim. Feed Sci. Technol. 1999;79:211–222. [Google Scholar]
  29. Ren Y., Liu Y., Jiang K., Li L., Jiao N., Zhu Z., Zhang K., Jiang S., Yang W., Li Y. 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. Animals. 2023;13:1042. doi: 10.3390/ani13061042. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Ren Z., Sun W., Cheng X., Liu Y., Han D., Yan J., Pan C., Duan Y., Yang X. The adaptability of Hy-Line brown laying hens to low-phosphorus diets supplemented with phytase. Poult. Sci. 2020;99:3525–3531. doi: 10.1016/j.psj.2020.03.033. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Rodehutscord M., Sommerfeld V., Angel C.R., Korver D.R. Minimum phosphorus requirements for laying hen feed formulations. Poult. Sci. 2023;102 doi: 10.1016/j.psj.2022.102344. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Rojasa I.Y.M., Gonzaleza E.A., Mencalc J.A., Santosb T.T.D., Arguellob J.R., Coello C.L. Assessment of a phytase included with lactic acid on productive parameters and on the deposition of phosphorus, calcium, and zinc in laying hens fed with sorghum-soybean-meal-based diets. J. Appl. Poult. Res. 2017;46:314–321. [Google Scholar]
  33. Saleh A.A., Elsawee M., Soliman M.M., Elkon R.Y.N., Alzawqari M.H., Shukry M., Abdel-Moneim A.-M.E., Eltahan H. Effect of bacterial or fungal phytase supplementation on the performance, egg quality, plasma biochemical parameters, and reproductive morphology of laying hens. Animals. 2021;11:540. doi: 10.3390/ani11020540. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Saleh A.A., Eltantawy M.S., Gawish E.M., Younis H.H., Amber K.A., Abd El-Moneim A.E.-M.E., Ebeid T.A. Impact of dietary organic mineral supplementation on reproductive performance, egg quality characteristics, lipid oxidation, ovarian follicular development, and immune response in laying hens under high ambient temperature. Biol. Trace Elem. Res. 2020;195:506–514. doi: 10.1007/s12011-019-01861-w. [DOI] [PubMed] [Google Scholar]
  35. SAS. (2009). Statistical Analysis Software, Users’ Guide Statistics, SAS Institute, Inc., Cary Version 9.1.
  36. Selle P.H., Ravindran V. Microbial phytase in poultry nutrition. Anim. Feed Sci. Technol. 2007;135:1–41. [Google Scholar]
  37. Selle P.H., Ravindran V., Bryden W.L., Scott T. Influence of dietary phytate and exogenous phytase on amino acid digestibility in poultry, a review. Poult. Sci. 2006;43:89–103. [Google Scholar]
  38. Sharifi M.R., Shargh M.S., Hassani S., Senobar H., Jenabi S. The effects of dietary phytate phosphorus levels and phytase on laying performance and egg quality parameters of Japanese quails (Coturnix coturnix japonica) Eur. Poult. Sci. 2012;76:13–19. [Google Scholar]
  39. Singh P.K. Significance of phytic acid and supplemental phytase in chicken nutrition: a review. World's Poult. Sci. 2008;64:553–577. [Google Scholar]
  40. Um J.S., Paik I.K., Chang M.B., Lee B.H. Effects of microbial phytase supplementation to diets with low non-phytate phosphorus levels on the performance and bioavailability of nutrients in laying hens. Asian-Australas. J. Anim. Sci. 1999;12:203–208. [Google Scholar]
  41. Viveros A., Centeno C., Brenes A., Canales R., Lozano A. Phytase and acid phosphatase activities in plant feedstuffs. J. Agric. Food Chem. 2000;48:4009–4013. doi: 10.1021/jf991126m. [DOI] [PubMed] [Google Scholar]
  42. Wang S., Tang C.H., Zhang J.M., Wang X.Q. The effect of dietary supplementation with phytase transgenic maize and different concentrations of non-phytate phosphorus on the performance of laying hens. Br. Poult. Sci. 2013;54:466–470. doi: 10.1080/00071668.2013.796339. [DOI] [PubMed] [Google Scholar]
  43. Xie J., Tian C., Zhu Y., Zhang L., Lu L., Luo X. Effects of inorganic and organic manganese supplementation on gonadotropin releasing hormone-I and follicle-stimulating hormone expression and reproductive performance of broiler breeder hens. Poult. Sci. 2014;93:959–969. doi: 10.3382/ps.2013-03598. [DOI] [PubMed] [Google Scholar]
  44. Yan L., Zhou T.X., Jang H.D., Hyun Y., Kim H.S., Kim I.H. Comparative effects of phytase derived from Escherichia coli and Aspergillus niger in sixty-eight-week-old laying hens fed corn-soy diet. Asian-Australas. J. Anim. Sci. 2009;22:1391˗1399. [Google Scholar]
  45. Yossef M.S.E., Abaza M.A., Yakout H.M., Abdalla A.A., EI-Sebai A. Influence of microbial phytase supplementation on performance parameters and blood constituents of Gimmizah hens fed different dietary phosphorus levels. Egypt. Poult. Sci. 2001;21:997–1020. [Google Scholar]
  46. Yu B., Jan Y.C., Chung T.K., Lee T.T., Chiou P.W.S. Exogenous phytase activity in the gastrointestinal tract of broiler chickens. Anim. Feed Sci. Technol. 2004;117:295–303. [Google Scholar]
  47. Zhang Q.Q., Chang C., Chu Q., Wang H.H., Zhang J., Yan Z.X., Song Z.G., Geng A.L. Dietary calcium and non-phytate phosphorus levels affect the performance, serum biochemical indices, and lipid metabolism in growing pullets. Poult. Sci. 2023;102 doi: 10.1016/j.psj.2022.102354. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Poultry Science are provided here courtesy of Elsevier

RESOURCES