Antibiotic use to the production performance of ISA brown layer

The present study was designed with a view to study the effects of enrofloxacin antibiotic on ISA brown layer performance. A total of 1,80,000 laying hens (ISA brown) received and supplied enrofloxacin antibiotic in the dose of 0 mg, 10mg and 20 mg/kg BW with normal diet. Each layer was fed 120 g feed/day from 42 to 48 weeks of age. Antibiotic made significant differences in egg production (p<0.05) and especially on mortality (p<0.01). The different doses of enrocin (0 mg, 10mg and 20mg/kg BW) had no significant effect on feed conversion efficiency and egg weight. Therefore, it can be suggested that a lower dose (10mg/kg BW) of antibiotic may be benefited in commercial layer diet.


Introduction
In Bangladesh, Livestock contributes 2.73% in GDP (GEP, 2008-09).In Fiscal year 2008-09 the estimated growth rate in this subsector was 3.46% and poultry has now become a major contributor.At present, poultry farming is one of the most profitable businesses.Commercial layer production started in Bangladesh during 1980, but faster growth took from 1999 and is increasing day by day.Antibiotic is a chemical substance produced by a microorganism that inhibits the growth or kills other microorganisms.Antibiotics as growth promoters have long been supplemented to poultry feed to stabilize the intestinal microbial flora and improve the general performance and prevent some specific intestinal pathogens (Miles et el., 2006;Waldroup et al., 1995).The biological basis of using antibiotic as growth promoter in poultry production is that, it stimulates appetite, increase feed intake, reduce microbial load in gastro-intestinal tract, inhibit sub-clinical infection, increase nutrient utilization and ultimately improve the performance.Without scientific knowledge most farmers administer antibiotics.Enrofloxacin, a fluoroquinolone developed exclusively for veterinary use is advocated in poultry in large-scale for treatment of chronic respiratory disease, colibacillosis, salmonellosis and fowl cholera.The effect of enrofloxacin on the immune response is not well documented.Enrofloxacin and chloramphenicol decreased the level of specific IgY in laying hens immunized with living cells of Salmonella enterica subsp.Enteric serovar enteritidis and lipopolysaccharide.After administration, enrofloxacin is metabolized in the liver via de-ethylation into pharmacologically active metabolite ciprofloxacin.Porchezhian reported that ciprofloxacin significantly reduced the antibody titre against Lasota and Sheep Red Blood Cells (SRBC) antigens in broiler chicks.This depends on the production level of the flock.No research has been conducted to identify, quantify and assess the effect of enrofloxacin on production performances of ISA brown layer in large scale.Therefore, the present study was undertaken in order to assess the effect of Enrocin (Enrofloxacin) antibiotic on the production performance of ISA brown layer.

Statement of experiment
The experiment was conducted from 1 April to 12 May, 2013 with 1,80,000 ISA brown layer aged 42 weeks for a period of 42 days to investigate the effect of enrofloxacin antibiotic on ISA brown layer.

Venue of the experiment
The experiment was conducted at a commercial layer farm of CP Bangladesh Co. Ltd located at Ghatail upazila under Tangail district.

Experimental layer
A total of 1,80,000 of pullets transfer from Pullet project of CP Bangladesh Co. Ltd located at Seed store bazaar Valuka, Mymensingh.All pullets transfer at 16 weeks of age from pullet's project to the layer project.

Collection of enrofloxacin antibiotic
Enrofloxacin antibiotic was collected from Animal Health Division of CP Bangladesh Co. Ltd.

Layout of the experiment
In this experiment, three treatment and four replication in each treatment (Table 1).There were 15000 layers in each replication.

The technique used in providing antibiotics
In the experimental farm one house contained four towers.Medicator used to provide antibiotic, vaccine & medicine.House 1 kept control, two given 10 mg enrofloxacin antibiotic in per kg body weight and house number 3 given 20 mg enrofloxacin antibiotic in per kg body weight of the layer.Enrofloxacin antibiotic was mixed with 2700 ml water.

Ration
In this experiment feed from C.P. Rajshahi feed mill was used.The ingredients and nutrient composition of this feed is given below in Table 2.The nutrients requirement of layers was followed by ISA brown management guide.

House management
The experiment was conducted in a tunnel ventilated environmental controlled house.Proper management procedures according to ISA brown management guide were followed during experimental period.

Feeding method
The layers were supplied diets in a day on a fixed amount (120g/layer/day) of mash diet.Fresh clean drinking water was made available at all times.Normally three times in a day chain feeding process was running in the house and supplying the diet for the layers.

Lighting management
In this experimental period 15 hours continuous light was given in layer house and 9 hours dark.

Vaccination and medication
 The water was treated with chlorine before starting house. Multivitamin was used at three times per week at 1 gm/4 ltr water.
 ND+IB vaccine was used at every six weeks following the vaccination schedule (Table 3).

Bio-security measures
As a commercial layer farm biosecurity always maintained in farm to prevent diseases.To maintain strict biosecurity in farm following steps always followed:

Litter management
Litter was managed in the farm automatically by running litter belt.Then litter is out into CHUBU machine (USA) & process.Finally we get bio-fertilizer from this machine.

Data collection and record keeping
The following records were kept during the experiment:

Body weight
The body weight of layers (about 3 %) was taken at the beginning of the experiment.Thereafter, body weights were taken at weekly intervals until the termination of the experiment.The layers were weekly weighed after collection of egg.

Egg production
Egg production performance after used the enrocin (enrofloxacin) antibiotic was recorded in experimental period.So, daily egg production (%) of layers was recorded after use enrofloxacin antibiotic.

Mortality
Mortality and survivability data was recorded every day before egg collection and took out the dead layer from the cages.
2.9.9.Egg weight Egg weight data was recorded after finishing egg collection every day from each replication.

Feed conversion ratio (FCR)
The FCR was calculated as the total feed consumption divided by egg mass of each replication, as an indicator of feed conversion.FCR= Feed intake of the hen (g/b/d) / Egg mass (g/b/d)

Statistical analysis
All recorded and calculated data were statistically analyzed using SAS statistical computer package program in accordance with the principles of Completely Randomized Design (CRD).Least Significant differences (LSD) were calculated to compare variations among diets

Egg production (%)
Generally egg production was increased with the increasing dose of antibiotic (Table 4).In control group (0mg/kg BW) the mean of egg production was 91.05% whether in the dose of enrofloxacin antibiotic (10mg/kg BW) the mean of egg production was 92.74%.In terms of enrofloxacin antibiotic level 20mg/kg BW the mean of egg production was 93.76%.In this study, egg production was increased with increasing dose of enrofloxacin antibiotic followed by 10mg/kg BW and 0 mg/kg BW.It indicates that egg production (%) significantly (p<0.05)higher when the dose of enrofloxacin antibiotic was 20mg/kg BW.It was also observed that there was little variation in egg production in the dose of enrofloxacin antibiotic at the level of 0 & 10 mg/kg BW.

Egg weight (gm)
There was no significant difference among the dose of enrocfloxacin antibiotic 0, 10 and 20 mg/kg BW (Table 4).In control group mean of egg weight was 61.78g whether in the dose of 10mg/kg BW 60.95g and in the dose of 20 mg/kg BW mean of egg weight was 61.00g (Table 4).

Mortality (%)
Mortality was highly significant in the experiment.Mortality percentage decreased with increasing the dose of enrofloxacin antibiotic.In control group mean of mortality percentage was 0.164 whereas 0.130 & 0.108 for 10mg/kg BW and 20mg/kg BW.Mortality was significantly higher (p<0.01) in 0mg/kg BW than 10mg/kg BW & 20mg/kg BW.

Initial weight (gm)
There was no significant difference observed of initial weight that was collected before starting the experiment.

Final weight (gm)
No significant difference was found in case of final weight at different doses of enrofloxacin.Weight gainwas more or less similar among the different doses of enrofloxacin.

Feed conversion ratio (FCR)
Feed conversion was more or less similar on different doses of enrofloxacin antibiotic.There was no significant variation in FCR for adding enrofloxacin antibiotic from control dose (0mg/kg BW) to higher dose (20mg/kg BW).

Discussion
4.1.Egg production (%) Lucky (2010) found providing 15and 20mg/kg body weight in the diet increased egg production by 2% to 5%, respectively.Mahanta JD et al. (2009) found egg production and egg mass of hens (ISA brown layer aged 26 weeks) were improved by biocilin supplementation.Auguspurger et al. (2007) stated supplementation of Interflox increased egg production during the first 4 weeks of experimental period.Liu et al. (2005) showed increased egg production and egg mass of hens due to supplementation of antibiotic with water at the level of 20, 25, 30mg/kg BW.In this experiment egg production was increased 1.7% to 2.7% which is similar to Lucky (2010) and other authors.

Egg weight (gm)
Rahman ( 2007) indicated different levels of antibiotic 15% and 30% had (P<0.05)influence on egg weig ht, whereas control had no improved egg mass production.Jalal and Scheideler (2001) noted that supplementation of antibiotics diets at the low (0.10%) improved egg weight.Miao et al. (2000) investigated that the effect of antibiotics on egg weight enhanced by addition of antibiotics into diet.Um et al. (1999) andSilverside et al. (2006) found supplementation of antibiotics enhanced egg production of chicken coupled with increased egg weight.In this study egg weight of ISA brown layers with different doses (0, 10 and 20mg/kg BW) did not affect significantly.

Mortality (%)
Different doses (0, 10 and 20mg/kg BW) of antibiotic (enrofloxacin) had significant effect on mortality percentage of layer.With the increasing level of doses (20 mg/kg BW) decreased the mortality percentage (0.108%) than the dose of 10 mg/kg BW and control (0mg/kg BW).

Final body weight (gm)
In layer body weight has not greater importance.This experiment showed that at 10 mg/kg BW of enrocin antibiotic level average body weight of layers was 1978.75gmfollowed by higher dose (20 mg/kg BW) 1967.50gm and control (0mg/kg BW) 1965.00gm.Therefore a further research can be done among different doses of antibiotic with lower differences.

Feed conversion (FC)
In conducted experiment at different doses of antibiotic (0, 10 and 20 mg/kg BW) FCR had no significant effect.Though the efficiency of feed conversion was increased at the advancement of dose of enrocin antibiotic according to 2.135, 2.127 and 2.095.

Conclusions
After geting the findings it can be suggested that a lower dose (10ml/kg BW) of antibiotic may be supplied with normal diet to layer for increasing the production performances.