Effect of Cage and Floor Rearing System on the Reproductive Performance and Immunocystochemistry of Pituitary Cells of Broiler Breeders

Waqas Alam1, Sar Zamin Khan1 and Rifat Ullah Khan2*

1Department of Poultry Science, Faculty of Animal Husbandry and Veterinary Sciences, The University of Agriculture, Peshawar, Pakistan

2College of Veterinary Sciences, Faculty of Animal Husbandry and Veterinary Sciences, The University of Agriculture, Peshawar, Pakistan

ABSTRACT

A total of 200 broiler breeders (22 weeks old) having uniform body weight were selected and randomly distributed into cage (60.96 × 60.96 × 53.34 cm) and floor housing systems having 90 females and 10 males. Each group was subdivided into three replicates (30/replicate female). Hubbard management guideline was followed for feeding, watering, and vaccination. Egg quality parameters were evaluated at pre-peak (22-30 weeks), peak (31-40 weeks) and post-peak (41-59 weeks) production stages. Compare to floor housing system, age of hen at first lay and mortality were lower (P ≤ 0.05) in cage housed birds. Egg production percentage and feed efficiency were significantly (P<0.05) higher in cage birds compared to the floor. Fertility and hatchability percentage were lower (P<0.05) in pre-peak stage and then increased during peak and post-peak stages. There was no significant effect of the housing system on the immunocytochemistry of the cells of follicle stimulating hormone (FSH), leutenizing hormone (LH) and growth hormone (GH). The results of the present study indicated that birds kept under cage had enhanced egg production, fertility, hatchability and lower mortality than the birds managed on floor.

Article Information

Received 01 July 2022

Revised 15 June 2022

Accepted 20 July 2022

Available online 15 September 2022

(early access)

Published 01 October 2023

Authors’ Contribution

SAK and WA presented the concept of the study, performed the experiments and wrote the manuscript. SAK and RUK supervised the study and edited the manuscript. WA performed the data analyses. RUK helped in editing the manuscript. WA helped in the analysis with constructive discussions. WA did the formal data analysis and raw materials supply.

Key words

Cage housing system, Floor housing system, Egg quality and quantity, Fertility and hatchability

DOI: https://dx.doi.org/10.17582/journal.pjz/20220701050728

* Corresponding author: rukhan@aup.edu.pk

030-9923/2023/0006-2625 $ 9.00/0

Copyright 2023 by the authors. Licensee Zoological Society of Pakistan.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

INTRODUCTION

An external factor that affects productive features and egg quality is the laying hen raising system, which has been the subject of extensive scientific research (Dong et al. 2017). According to some researchers (Rossi, 2007; Hidalgo et al., 2008; Dong et al., 2017), cage-raised hens produced more eggs and had better egg quality attributes than hens raised in other settings. The hormonal health of the hen controls how many eggs are produced (Pirsaraei et al., 2008). Changes in reproductive hormones such luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P4), and prolactin (PRL) may result in various performance qualities in layers (Onagbesan et al., 2006; Li et al., 2011).

Housing birds in cages or on floors can have both positive and bad effects on their well-being, growth, and reproduction. Birds have traditionally been raised in floor-rearing methods ever since they were domesticated. As egg production technology advanced, traditional cages increasingly took over as the primary housing option. Battery cages are criticised due to concerns about animal welfare because they reduce bird output by stressing them out and limiting their ability to exhibit their natural behaviour. However, maintaining a clean environment lowers the risk of sickness (Al-Bahouh et al., 2012). The poultry business suffers from substantial welfare problems due to the deprivation of natural activities in cages (Shields and Duncan, 2009). A cage housing system eliminates the need for a nest because it has self-nesting room and saves farmers money. In the current study, it was expected that the various housing arrangements (cage vs. floor) may have a significant impact on the productivity of broiler breeders.

In the conventional way of rearing, birds are raised on the ground and brooded before being relocated to cages when egg production starts. Most broiler breeders are kept on the deep floor rearing system in developing nations, including Pakistan, where fertile hatching eggs are produced. Notably, the floor raising system is a popular and affordable method of rearing (Aviagen, 2013). However, birds kept indoors are more likely to contract infections (Yaniz et al., 2010). Currently, millions of birds are raised in cages under an ecologically controlled system instead of the traditional housing system (Habibullah et al., 2016). Therefore, the most effective housing system for producing profitable poultry was determined by comparing its reproductive and productive characteristics. The aim of the present study was to investigate the cage and floor housing system on the productive and reproductive outcome of broilers from 22 to 50 weeks of age.

MATERIALS AND METHODS

Ethical considerations and study site

This research study was pre-approved by the Departmental Board of Studies meetings on ethics, methodology and welfare of birds, KP Agriculture University Peshawar, Pakistan.

Experimental design and bird’s selection

A total of 200 days old female and 50 days old male broiler breeders were placed in the poultry shed using the practices recommended by poultry companies. In floor housing system, 90 female broiler breeders were raised on standard space (3 × 3 feet). Males were added in the ratio of 1: 10 to both housing systems. In cage system, 90 females were reared in each individual cage (60.96 × 60.96 × 53.34 cm).

For the first 20 weeks of life, the males were housed in two identical pans and the females in six similar pens. The chicks received unlimited access to water during the whole experiment. Throughout the rearing and production phases, nibble drinkers were employed. Feed restriction was introduced following the second week. Every day, feed was delivered. 10 chicks from each pen were randomly selected at 2 weeks of age. They were reared utilizing the skip-a-day strategy of feed limitation from 12 to 19 weeks. Males and females birds were equally divided into four floor pens or four two-tier cages two weeks before the start of egg production (20 weeks of age). The broiler breeder management manual’s instructions for restricted feeding. The stocking density of floor pen and two cages unit occupied the same space.

Initially chicks were reared at a temperature of 90°F, which was gradually decreased at the rate of 5°F per week until a temperature of 70°F was reached. For the first three days, artificial light was provided for twenty-four h every day. From day 4 through day 21, the birds received 12 h of light every day, they were 20 weeks old. In all age groups, water was freely available via nipple drinkers.

Egg collection

Eggs were gathered 3 times each day during pre-peak (22-30 wks), peak (31-40 wks) and post peak (41-50 wks). Fertility test was held each week on ten eggs per replicate.

Reproductive performance

The reproductive traits such as age and weight of hen at first lay, weight of first lay egg and peak egg production was recorded. Mortality of the birds was recorded on daily basis when occurred.

Egg production and feed efficiency

Daily egg production was recorded. Feed efficiency was calculated on the basis of feed required for dozen of egg production or feed required for 1 kg egg production.

Egg fertility and hatchability

Eggs were incubated for 10 days after which they were broken out to test the fertility of the eggs. Egg samples were delivered to the lab after being kept for 24 h at 55°F and 65% humidity. Egg fertility and hatchability were determined as follow:

Egg fertility = fertile eggs ÷ number of eggs set × 100

Egg hatchability= hatched eggs/ total fertile eggs set × 100

Removal of pituitary gland and slides preparation

At the end of peak production, five birds per replicate were slaughtered. Skin and feathers were removed around the head. The pituitary gland was removed from below the brain mass. Pituitary gland was immediately immersed in Bouin’s Holland solution for 24 h following treatment of 4% formaldehyde and then embedded in paraffin wax. The samples were cut into slices of 4µm thin sections with the help of microtome (Microm GmbH, Walldorf, Germany). The samples were placed on slides precoated with 0.1% poly-L-lysine.

Immunohistochemistry of FSH, LH and GH cells

The following steps were used to localize antigens of FSH, LH and GH in pituitary gland samples by using specific antibodies (Khan et al., 2013). Tissue sample were deparaffinized and rehydrated. Antigen retrieval/unmasking of the antigen were done in Tris HCl solution (0.1 M: pH 6.6) at 121oC for 10 min. The H2O2 was applied for washing the specimen, and deactivating the peroxidase activities, incubate for 10 min at room temperature. Washing four times with PBS was repeated and add BSA (bovine serum albumin)/ protein block were applied to the sections for 5 min to block the non-specific sites. Before drying, prediluted primary antibody of FSH and LH were added to the section and keep the slide in a humidified chamber for 2 h at room temperature. Slide was washed four times with PBS, then applied secondary antibody on the tissue sections and incubate for 10 min. These washing and incubation process were repeated after applying streptavidin peroxidase, chromogenic and DAB substrate for 30 min for color development. Normal goat serum (10%) was used on negative control slides.

Morphometric analysis of immunoreactive cells

A compound microscope was used to conduct morphometric analysis. For this analysis, cells with excellent cross sections and clean non-reactive nuclei were chosen. Total six samples per group were considered. Two slides for each sample were prepared and total microscopic fields slides were counted with the help of Image J Software (Image J 1.44P Wayne Rasband, National Institutes of Health, and Bethesda, MD, USA).

Statistical analysis of data

General linear model (GLM) procedure and completely randomized design (CRD) was used to analyze the experimental data. Birds on floor and cage were compared under t-test. Least significant difference (LSD) test was applied for difference in significance at probability level P≤0.05 (SAS, 1996).

RESULTS

Table I shows the effects of different production systems (cage vs. floor) on broiler breeder performance. Broiler breeders raised in cages begin egg production two weeks earlier (P≤0.05) than broiler breeders raised on the floor. The weight of the hen and the weight of the egg at the first lay was not significantly (P≥0.05) different under either housing system. However, in the cage housed system, the peak egg production age was lower (P<0.05) compare to the floor birds. Broiler breeders reared in cages had a higher (P≤0.05) peak egg production percentage and lower mortality than those kept on the floor.

Data on egg production, and feed conversion ratio (FCR) of broiler breeders reared under floor versus cage housing systems are presented in Table II. Overall, egg production at pre-peak, peak and post peak was considerably higher (P≤0.05) in cage housing system compared to floor housing system. Similarly, significantly improved feed efficiency (P≤0.05) was recorded in cages at pre-peak, peak, and post peak production stage than floor housing.

Table III shows the fertility and hatchability of broiler breeders raised on the floor compared in cages. Floor housed broiler breeders had a significantly greater (P≤0.05) pre-peak fertility percentage than cage housed broiler breeders, whereas caged birds had a higher (P≤0.05) hatchability than floor at pre-peak production stage. Cage housing system had greater fertility and hatchability throughout peak and post-peak production stages than floor.

 

Table I. Experimental diet of broiler breeders.

Ingredients%	Pre peak	Peak	Post peak
Maize corn	61.79	64	62.92
Wheat bran	8.19	5.0	6.36
Soybean meal	18.7	19.2	18.92
Corn gluten meal	2.00	2.00	2.00
Dicalcium phosphate	1.3	1.2	1.2
Limestone	6.2	6.2	6.2
Salt	0.41	0.41	0.41
Lysine-HCL	0.06	0.05	0.05
DL- Methionine	0.03	0.07	0.07
Choline -Cl and Coban90	1.22	1.22	1.22
Vitamin premix1	0.1	0.1	0.1
Mineral premix mintrex2	0.05	0.05	0.05
Coccdiostat	0.05	0.5	0.5
Total	100	100	100
Calculated analysis (%)
Crude protein (CP)	15.3	16.04	15.90
ME per kg	2750	2920	2800
Met and cysteine	0.50	0.64	0.58
Lysine	0.62	0.83	0.66
Ca	1.50	3.30	3.39
P	0.41	0.41	0.38
Chemical analysis %
Crude protein	15.45	16.14	16.02

 

1 A, 82,000 IU; D3, 12500 IU; B2, 45 mg; B1, 4 mg; B6, 8 mg; B12, 40 µg; E, 20 mg; niacin, 60 mg

2 Contained: Ca, 32%; Mn, 0.44%; P, 6%; I, 150 ppm; Zn, 0.33%; Cu, 250 ppm; Fe, 2000 ppm; calcium pantothenate, 12.5 mg

 

Table II. Reproductive performances of broiler breeders under cage versus floor system.

Parameters	Housing system		P value
	Cage	Floor
Age of hen at first lay (week)	22b±0.28	24a±0.30	0.00
Weight of hen at first lay (g)	2400.2± 115.47	2341.6± 110.23	0.71
Egg weight at first lay (g)	51.23±0.54	50.51±0.39	0.39
Peak production age (weeks)	30.32b±0.46	32.50a±0.31	0.05
Mortality (%)	3.25b±0.59	7.12a±0.67	0.00

 

ab means with different letters within the rows differs at P < 0.05.

 

Table III. Egg production and feed efficiency of broiler breeders under floor vs cage rearing system.

Stages of production	Egg production (%)		P value	Feed efficiency (%)		P value
	Cage	Floor		Cage	Floor
Pre peak (22-30 wks)	49.40±1.30 a	44.31±1.10 b	0.00	3.19±0.29 b	4.00±0.49 a	0.01
Peak (31-40 wks)	86.28±0.50 a	84.88±1.12 b	0.04	2.18±0.45 b	2.47±0.89 a	0.04
Post peak (41-50wks)	83.49±0.67 a	82.28±1.13 b	0.05	2.19±0.03 b	2.45±0.79 a	0.04

 

ab means with different letters within the rows differs at P < 0.05. wks for weeks.

 

Table IV. Fertility and hatchability of broiler breeders under floor vs cage rearing system.

Stages of production	Fertility (%)		P- Value	Hatchability (%)		P- Value
	Cage	Floor		Cage	Floor
Pre peak (22-30 wks)	63.99±0.98 b	70.78±0.29 a	0.001	78.60±0.48 a	74.42±0.18 b	0.01
Peak (31-40 wks)	93.58±0.22 a	90.89±0.19 b	0.03	84.55±0.46 a	79.63±0.41 b	0.001
Post peak (41-50 wks)	93.00±0.09 a	90.61±0.05 b	0.05	83.99±0.31 a	79.16±0.98 b	0.001

 

ab means with different letters within the column differs significantly at P < 0.05 Wks for weeks.

 

Table IV shows the number and size of FSH, LH and GH cell, respectively in microscopic field area of chicken pituitary gland reared under floor and cage housing system. The result showed that the number and size of FSL, LH and GH under both housing system were not disturbed (P≥0.05).

 

 

Table V. Number and mean size (µm) of FSH, LH and GH cells in microscopic field area of pituitary gland of broiler breeders under floor versus cage housing system.

Group	FSH	LH	GH
Number of cells/ microscopic field
Cage	40.67±5.03	39.33±1.15	43±3.606
Floor	42.67±9.07	38±1.00	44±7.55
P-Value	0.760	0.20	0.85
Size of cells (µm)
Cage	9.01±0.16	6.67±0.02	7.12±0.04
Floor	9.23±0.03	7.12±0.07	6.98±0.02
P-Value	0.573	0.090	0.375

 

FSH, follicular stimulating hormone; LH, luteinizing hormone, GH, growth hormone.

 

DISCUSSION

In the current study, the cage housing arrangement resulted in considerably increased egg production and decreased mortality. These findings are similar with those made by Voslarova et al. (2006) and Dong et al. (2017). It is commonly accepted that eggs with weak shells, fractured shells, or no shells are more susceptible to breaking when hens peck at them in floored flocks. The cracked egg will be swiftly consumed by hens, going unnoticed (Khan and Khan, 2018). The hostility and injury of the birds in the competition for food and their innate dominant tendency may be to blame for the greater death rate in the floor housing arrangement. The increased death rate on the floor may be related to exposure to microbial contamination of food, water, and litter. The primary indicator of inadequate welfare is mortality (Blokhuis et al., 2007). Due to automation in feeding and drinking, the cage housing used in this study has the lowest likelihood of such contamination and is best suited for the production of high-quality eggs (Stanley et al., 2013; Philippe et al., 2020).

In the current investigation, the cage system had a much higher feed efficiency than the floor. Dong et al. (2017) discovered that Xianju chickens raised in cages had a significantly lower FCR than those raised on the floor. They also believed that because floor-raised birds had more room to peck, walk, run, and engage in natural behaviours, they consumed more energy and experience growth restrictions. These findings are similar to those of Starcevic et al. (2021).

In the current study, fertility and hatchability were significantly different in cages than on the floor, supporting the findings of Khabisi et al. (2012) and Habibullah et al. (2016). According to Penfold et al. (2000) and Brillard (2003), there is a trend towards the hatch during the pre-peak production period of egg laying, while Sayyazadeh and Shahsavarani (2005) found that there is an increase in fertility and hatchability during the post-peak production phase. Hatchability increased from the pre-peak to the peak and subsequently decreased with the production phase. Similar trends have been seen by Brillard (2003), Penfold et al. (2000), Mahmoud et al. (1996), and McDaniel et al. (1996) in relation to the low percentile of hatch during the pre-peak period of lay. After reaching a peak, flock fertility naturally declines as hen ages, which is a physiological fact. Male broiler breeders experience physical issues as they mature. As a result, broiler breeders using a floor system had poorer fertility due to both large body weight and advancing age (Bramwell et al., 2004). Furthermore, since more birds must eat from a single floor feeder, the rivalry for food is more significant than in a cage. Floored birds’ uneven feed consumption reduces flock homogeneity, which causes them to lay eggs of varying sizes and lowers the percentile hatch rate (Dong et al., 2017; Khan and Khan, 2018). The eggs generated in deep litter are more susceptible to faecal contamination, where the likelihood of bacterial contamination is greater; this infectious organism may have penetrated the egg and resulted in the decreased fertility and hatchability in floor housing systems.

Hubbard broiler breeders housed in cages lay more eggs there than on the ground. These results are consistent with Hulzeboschs (2006) and Yakabu et al. (2007) findings. The same flock was placed on the floor two weeks after the broiler breeders in cages started producing eggs at the Hubbard Company-recommended age. By providing the cages, the productivity of the birds increases (Huneau-Salaun et al., 2011). Currently, egg production in cages grew more during pre-peak by 5.09 %, peak by 1.4 %, and post-peak by 1.21 % than in the floor housing system. Due to the comfortable environment in the cages, greater percentage of egg were produced. Tumova and Ebeid (2005) and Pistekova et al. (2006) found larger numbers of high-quality eggs in floor housing systems, contradicting the findings of the current study (Ericsson et al., 2016).

The number and dimension of immunostained cells in anterior pituitary gland was non-significantly different under both housing system. There is a dearth of information on the immunostained cells of FSH, LH and GH in poultry pituitary gland. The present study provides a baseline of profitable and healthy poultry production in cage rearing system. Li et al. (2017) found higher level of FSH, LH hormones in breeders raised in cages.

CONCLUSION

Hubbard broiler breeders reared in cages showed better performance in term of improved fertility, hatchability, egg production and feed conversion ratio compared to floor housing.

Acknowledgement

This study was financially supported by Higher Education Commission of Pakistan (HEC) under national research program for universities (NRPU) under project number (20-3783/NRPU/R&D/HEC/2014 /690).

Statement of conflict of interest

The authors have declared no conflict of interest.

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