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Field Evaluation of Flock Production Performance of In Ovo Injection of Infectious Bursal Disease Virus Immune Complex Vaccine in Commercial Broiler Farms

Posted on: Sunday, 3 July 2005, 03:01 CDT

Primary Audience: Veterinarians, Flock Supervisors, Plant Managers, Researchers

SUMMARY

Infectious bursal disease (IBD) is a highly contagious immunosuppressive disease caused by a birnavirus destroying primarily the immature B lymphocytes in the bursa of Fabricius of young chickens. The conventional method of controlling IBD is to hyperimmunize hens, followed by vaccinating progeny after maternal antibody levels decrease. In recent years, in ovo technology has become an alternative choice of vaccination of broiler chicks against diseases. This field investigation compared the selected flock-raising performances between in ovo injection of infectious bursal disease virus immune complex (IBDV-ICX) vaccine chicks and conventional IBD vaccination (non in ovo injection) chicks. The results showed that in ovo injection of IBDV-ICX vaccine could benefit livability (94.62%) and feed conversion ratio (1.73) significantly (P < 0.01) in commercial broilers better than non in ovo injection chicks whose livability and feed conversion ratio were 92.85% and 1.79, respectively. In addition, although not statistically different, the production efficiency factor of in ovo injection chicks (275.65) was higher than non in ovo injection chicks (263.62). Use of in ovo IBDV-ICX injection in commercial broilers increased weekly mortality during the first 2 wk (P > 0.05) but benefited production efficiency factor (P < 0.01) during the period of midwinter to spring. Due to the potential for selection biases of study flocks, the data, which were provided voluntarily, increasing the study population is necessary for a better understanding of the applications.

Key words: in ovo injection, infectious bursal disease vaccine, broiler production performance

2005 J. Appl. Poult. Res. 14:338-344

DESCRIPTION OF PROBLEM

In ovo injection has become a popular method of administering vaccines in the past 2 decades. Unlike conventional vaccination methods administered via aerosol spray, drinking water, eye drops, or subcutaneous injections to chicks after hatching, in ovo injections are administered to chick embryos on d 18 of incubation, which is normally when incubating eggs are transferred to the hatching cabinet. This method offers the advantages of reducing chick handling, improving hatchery manageability through automation, reducing the costs of live production and stimulating an early immune response [1]. Today, over 80% of commercial broiler flocks in the US have Marek's disease vaccine delivered by the in ovo route, and studies have proceeded to investigate the efficacy and safety of in ovo vaccination against Marek's disease [2], Newcastle disease [3], infectious bronchitis [4], infectious bursal disease (IBD) [5], and bacterial and parasitic diseases [6, 7]. In 1995, Sarma et al. [8| reported that in ovo vaccination of a bivalent Marek's disease vaccine in broilers in the field could significantly reduce the number of culled chicks and mortality and also improve feed efficiency.

The IBD virus (IBDV) is a double-stranded RNA virus belonging to the Birnaviridae family. By destroying progenitors of B cells in the bursa of Fabricius and decreasing the peripheral B lymphocytes in blood, IBDV causes immunosuppression of chicks under 2 wk old, rendering chicks susceptible to attack by opportunistic microorganisms and incapable of producing immune response to other vaccines [9, 10], thus, increasing mortality and causing economic loss. Many studies were designed to investigate the level of antibody liters of chicks after in ovo IBDV vaccination on a small scale under laboratory conditions [11, 12]. There is little work demonstrating the field practice of vaccinating infectious bursal disease virus immune complex (IBDV-ICX) by the in ovo route. Therefore, the objective of this study was to apply a field database to evaluate the production performance of IBDV-ICX vaccine administered in eggs on d 18 of incubation in commercial broilers in Taiwan.

MATERIALS AND METHODS

Data Collection

From 2000, the Taiwan Poultry Association started to investigate the rearing status in commercial broiler farms in Taiwan. By the end of 2003, there were 1,326 growers and up to a total of ~85% of broiler chicks produced in Taiwan were involved in this investigation. Broiler farms registered with the Taiwan Poultry Association were asked to file basic information (including farm location, types of ventilation, water supply, worker experience, raising capacity, density, immunization and plant disinfection program, and nearby agricultural activities) for an annual broiler survey. Broiler-chick data from broiler farms included date of arrival of each incoming flock, name of hatchery, breed and number of chicks, disease records, and culls and deaths of the first and second weeks of the flock, which were collected every week. Data of feeding records and total number and weight of flock at slaughter were also collected.

In this study, a broiler flock was treated as 1 observational unit. A broiler flock was defined as chicks delivered from the same hatchery and housed in the same production unit on the same day. Because of the low acceptance of the in ovo IBDV-ICX vaccine injection in the beginning application stage in Taiwan, only 3 hatcheries selected this technology for hatching a portion of their chicks. This in ovo injection study lasted from October 2002 to October 2003 and targeted 59 in ovo injection broiler flocks and their corresponding 83 conventional IBD vaccination (non in ovo injection) flocks from 17 broiler farms, which received broiler chicks from the above-mentioned 3 hatcheries. Detailed culls and deaths from the first week to the fifth week of these in ovo injection flocks were included. Arbor Acres dominated the breed of these broilers of the 3 hatcheries (hatchery A and B all selected Arbor Acres, and hatchery C reported several different breeds in the record). The conventional IBD vaccination is to hyperimmunize hens 10 wk before laying, followed by vaccinating progeny when they are 1 to 2 wk old, but a few growers may have provided 1 more dose of vaccine 1 to 2 wk later.

Data Calculation and Statistical Analyses

One broiler flock was the statistical unit. Flocks that were housed in combination ventilation systems, came from more than 1 hatchery, suffered from malpractice (improper feeding, watering, cannibalism, and temperature and ventilation control), and lacked any investigation item were treated as invalid and excluded from further calculation and analyses. Weekly mortality [13], livability [14], feed conversion ratio (FCR) [15], and production efficiency factor (PEF) [16] were calculated and used for further statistical comparison by using Microsoft Excel 2000 [17] and SAS software [18]. Calculation of PEF includes the average weight, livability, feeding days (age), and FCR at the time of slaughtering for each flock. For data analysis strategy, the first step was to separate the data into in ovo IBDV-ICX injection broiler-chicks and non in ovo injection chicks from the same 3 hatcheries in these 17 broiler farms. Then, the effects of in ovo IBDV-ICX injection, including seasonal differences, were analyzed. Lastly, the representation of the above non in ovo injection flocks in the 17 broiler farms were further compared with data of flocks from other broiler farms in Taiwan. Analyses were compared using student's t-test, χ^sup 2^ test, and Duncan's multiple range tests. Statistics were considered significant at P < 0.05.

RESULTS AND DISCUSSION

The conventional method of controlling of IBD in broiler-chicks in Taiwan is to vaccinate the chicks before maternal antibodies decrease below a protective level [19]. However, the timing for repeating vaccination is questionable because the tilers of maternal antibodies between individuals are not uniform [20]. The immune complex vaccine, by mixing intermediate plus live IBDV with a bursa- disease-neutralizing antibody, was reported to be insensitive to maternal antibodies [21] and could delay infection of the bursa, allowing the bursa to develop normally [22].

After excluding 17 (6 in ovo and 11 non in ovo flocks) malpractice flocks in our database, the current average in ovo injection performance from the 3 hatcheries (53 flocks, 2,019,586 chicks) for the mortality of the first, second, third, fourth, and fifth weeks were 1.33, 0.92, 0.83, 0.85, and 0.95% (Table 1), respectively. The average feeding days were 38.43 d; livability was 94.62%; FCR was 1.73, and PEF was 275.65. These data were compared further with the group treated non in ovo (72 flocks, 2,571,465 chicks) of the same broiler farms for chicks acquired from the same hatcheries (Table 1 ). Non in ovo injection chicks can be considered a control group due to the similar inheritance of chicks (the same hatcheries and parent stock) and the fact that they have grown up under the same environment and management (the same broiler farms). Results indicated that the overall livability and FCR were better in the in ovo injection chicks than the chicks treated non in ovo (P < 0.01) (Table 1), and there was no significant difference in the performance of in ovo injection groups among these 3 hatcheries (P > 0.05).

Flocks of the in ovo injection and non in ovo injection were divided ever\y 4 mo according to similar weather conditions of the year to test the differences of seasonal influences (Table 2). In the seasonal influences test, there was no difference in the sample distribution between the in ovo and non in ovo injection investigation flocks (χ^sup 2^ = 0.937, P = 0.626); however, statistical differences existed in the livability, FCR, and PEF of both groups when chicks were raised during January to April. Brooding chicks were susceptible to attack by pathogens during midwinter to spring due to unstable weather conditions as well as cool temperatures, and this might be the reason why flock production performance was worse under the period of midwinter to spring than other periods in non in ovo injection group. The data implied that in ovo injection provided better protection before the immune system was well developed. The PEF of both groups during May to August had relatively lower performance than other periods, most likely due to high environmental temperature.

In our database, the ratio of non in ovo injection flocks to in ovo injection flock of hatchery B during January to April was significantly higher than that of hatchery A and C. As for seasonal influences, in ovo injection showed better performance during the period of midwinter to spring, thus the major difference of overall livability and FCR between in ovo and non in ovo injection groups was contributed by hatchery B after detailed comparison of both groups in each hatchery (Table 1). In this study, it was difficult to draw an average distribution of the sample size among these 3 hatcheries as flock information was provided voluntarily. Thus, increasing the sample size is 1 way to decrease biases in future studies.

Although the mortality of the first week showed no significant difference between the in ovo and the non in ovo injection groups, a relatively higher mortality was found in in ovo injection chicks. The mortality of the second wk, in general, also showed the same performance in that chicks treated in ovo had relatively higher mortality. One procedure of in ovo injection is to punch a hole with a needle in the blunt end of the egg and leave the small hole unsealed alter injection. Airborne pathogens may be introduced into the egg during the hatching period and may lead to disease transmission. Aspergillus fumigatus, known to be the most common cause of respiratory mycosis in young chicks, can grow on the shell membrane surface if the membrane is in contact with yolk, which supplies the nutrition for A. fumigatus proliferation |23|. Data from monitoring the hygiene of chick hatcheries in Taiwan during 1999 to 2001 reported that 33 to 73% of the samples were contaminated with fungi in different quarters [24]. A relatively higher mortality in the first week may relied the hygienic practice in these hatcheries. Thus, poor environmental hygiene and management may sacrifice the survival of chicks in their early life.

TABLE 1. Comparison of the performance between in ovo injection group and non in ovo injection group of the 17 investigated broiler farms in 3 different hatcheries (A, B, and C) during October 2002 to October 2003

TABLE 2. Comparison of the performance between the in ovo injection group and non in ovo injection group of the 17 investigated broiler farms in different months from October 2002 to October 2003

Although in ovo injection increased early culls, a better method of protection was found later and benefited the livability of all of our investigation groups. Chicks in poor condition (sick or disabled) are normally eliminated in their early life to save feed thereafter. If IBDV attacks young chicks' bursa before B lymphocytes mature and produce antibody repertoire [10], viral respiratory infections of chicks may prevail and result in elevated mortality [9]. McIlroy et al. 1251 documented a 14% depression in financial return from flocks with subclinical IBD compared with unaffected flocks surveyed in Ireland. Hence, chicks that have undergone in ovo ABDV-ICX injection might have better protection than those that have not.

Different rearing planning in different broiler farms may lead to diverse production performance. Table 3 showed that statistical differences were found in mortality of the second week, feeding days, livability, and weights, but no difference was found in FCK and PEF between those chicks without in ovo injection from our study of 17 broiler farms (179) flocks, 6,600,261 chicks) and those of other broiler farms in Taiwan (4,784 flocks, 128,327,850 chicks) during the same investigation period. The increased weight gains were associated with feeding days. In Taiwan, sonic broiler farms may raise heavier-weight chicks (2.2 to 2.5 kg) for specific market needs, thus, contributing to the differences. Other investigation factors showed little or no difference; the current investigation of in ovo injection in these 17 broiler farms might be comparable to other broiler farms in Taiwan. However, due to the reliability of other grower's self-reported data, the application of the results to other broiler farms needs further verification.

TABLE 3. Comparison of the performance between non in ovo injection group of the 17 investigated broiler farms and non in ovo injection chicks of other broiler farms in Taiwan during October 2002 to October 2003

In this survey, all the information provided by broiler proprietors themselves was voluntary, and not all of the eggs in these 3 hatcheries were treated by in ovo IBDV-ICX injection. The study acknowledged the potential for selection bias to occur. For example, proprietors of hatcheries could have selected better quality eggs for in ovo injection or broiler proprietors could have just presented better results or both, thus, contributing to distinguished performance. Therefore, a strategy of rewarding broiler proprietors was executed in our study to encourage them to return all flock data to decrease the influence of selection bias. In the future, increasing the investigation population of the broiler farms and hatcheries using in ovo IBDV-ICX injection in the field is necessary for a better understanding of the applications.

CONCLUSIONS AND APPLICATIONS

1. In ovo IBDV-ICX injection increased chicks' livability and lowered FCR significantly, and PEF was not significantly higher than non in ovo injection chicks in commercial broilers field applications.

2. Chicks with in ovo IBDV-ICX injection showed a relatively higher first and second weekly mortality than those in the non in ovo injection group, but there is no statistical significance.

3. In ovo IBDV-ICX injection provided better protection during the midwinter to spring raising period in Taiwan.

4. Field evaluation of in ovo IBDV-ICX injection needs to be continued, and investigation population size needs to be increased for better understanding.

REFERENCES AND NOTES

I. Johnslon, P. A., H. Liu, T. O'Connell, P. Phelps, M. Bland. J. Tyczkowski. A. Kemper, T. Harding. A. Avakian. E. Haddad, C. Whitfill, R. Gildersleeve, and C. A. Ricks. 1997. Applications in in ovo technology. Poult. Sci. 76:165-178.

2. Sharma, J. M., and B. R. Burmester. 1982. Resistance to Marck's discase at hatching in chickens vaccinated as embryos with turkey herpesvirus. Avian Dis. 26:134-149.

3. Ahmad, J., and J. M. Sliarma. 1992. Evaluation of a modified live virus vaccine administered in ovo to protect chickens against Newcastle disease. Am. J. Vet. Res. 53:1999-2004.

4. Wakenell, P. S., and J. M. Sharma. 1986. Chicken embryonal vaccination with avian infectious bronchitis virus. Am. J. Vet. Res. 47:933-938.

5. Giambrone, J. J., T. Dormitorio, and T. Brown. 2001. Safety and efficacy of in ovo administration of infectious bursal disease viral vaccines. Avian Dis. 45:144-148.

6. McGruder, E. D., G. A. Ramirez. M. H. Kogut, R. W. Moore, D. E. Corrier, J. R. Dcloach. and B. M. Hargis. 1995. In ovo administration of Salmonella enteritidis-immune lymphokines confers protection to neonatal chicks against Salmonella enteritidis organ infectivity. Poult. Sci. 74:18-25.

7. Weber, F. H., and N. A. Evans. 2003. Immunization of broiler chicks by in ovo injection of Eimeria letiella sporozoites, sporocysts, oroocysts. Poult. Sci. 82:1701-1707.

8. Sarma, G.. W. Greer, R. P. Gildersleeve. D. L. Murray, and A. M. Miles. 1995. Field safety and efficacy of in ovo administration of HVT + SB-1 bivalent Marek's disease vaccine in commercial broilers. Avian Dis. 39:211-217.

9. Lasher. H. N.. and S. M. Shane. 1994. Infectious bursal disease. Worlds Poult. Sci. J. 50:133-159.

10. Davison, T. F. 2003. The immunologists' debt to the chicken. Br. Poult. Sci. 44:6-21.

11. Coletti, M., E. Del Rossi, M. P. Franciosini, F. Passamonti. G. Taeconi, and C. Marini. 2001. Efficacy and safety of an infectious bursal disease virus intermediate vaccine in ovo. Avian Dis. 45:1036-1043.

12. Corley, M. M., J. J. Giambrone, and T. V. Dormitorio. 2002. Evaluation of the immune response and detection of infectious bursal disease viruses by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay after in ovo vaccination of commercial broilers. Avian Dis. 46:803-809.

13. Weekly mortality - (the total number of culled and dead chicks during the week / number of housed chicks at the beginning) 100%.

14. Livability = (final chick number / starling chick number) 100.

15. Feed conversion ratio = total weight of consuming feed / (total final weight of chicks - total starting weight of chicks).

16. Production efficiency factor = (the average weight livability) / (feeding days feed conversion ratio)] 100.

17. Excel for Windows. 2000. Microsoft Corp. Redmond, WA.

18. SAS Institute. 1999. SAS User's Guide. Version 8.1. SAS Institute Inc., Cary, NC. Comparison between the data was assessed using analysis of variance (PROC ANOVA) and the Duncan's multiple range test. Statistical significance is consideredP < 0.05.

19. Sharma.J. M.,and J. M. Rosenberger. 1987. Infectious bursal disease and reovirus infection of chickens: immune responses and vaccine control. Page 143-157 in Avian Immunology: Basis and Practice. Vol. 2. A. Toivanen and P. Toivanen, ed. CRC Press, Boca Raton. FL.

20. Weisman, J.. and S. B. Hilchncr. 1978. Virus-neutralization versus agar-gel precipitin tests for detecting serological response to infectious bursal disease virus. Avian Dis. 22:598-603.

21. Haddad, E. E., C. E. Whitfill, A. P. Avakian, C. A. Ricks, P. D. Andrews, J. A. Thoma, and P. S. Wakenell. 1997. Efficacy of a novel infectious bursal disease virus immune complex vaccine in broiler chickens. Avian Dis. 41:882-889.

22. Whitfill, C. E., E. E. Haddad, C. A. Ricks, J. K. Skeeles, L. A. Newberry, J. N. Beasley, P. D. Andrews, J. A. Thoma, and P. S. Wakenell. 1995. Determination of optimum formulation of a novel infectious bursal disease virus (IBDV) vaccine constructed by mixing bursal disease antibody with IBDV. Avian Dis. 39:687-699.

23. Williams, C. J., D. L. Murray, and J. Brake. 2000. Development of a model to study Aspergillus fumigatus proliferation on the air cell membrane of in ovo injected broiler eggs. Poult. Sci. 79:1536-1542.

24. Chen, S. J., T. E. Lee, E. M. Wang. T. J. Cho. and C. H. Wang. 2002. Monitoring the hygiene of chicken hatcheries in Taiwan during 1999-2001. J. Microbiol. Immunol. Infect. 35:236-242.

25. McIlroy, S. G., E. A. Goodall, and A. M. McCracken. 1989. Economic effects of subclinical infectious bursal disease on broiler production. Avian Pathol. 18:465-480.

Acknowledgments

The authors thank the Taiwan Poultry Association and the Council of Agriculture for their assistance.

C. S. Li, L. Y. Wang, and C. C. Chou1

Department of Veterinary Medicine, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan

1 To whom correspondence should he addressed: chouchin@ccms.ntu.edu.tw.

Copyright Poultry Science Association Summer 2005

Source: Journal of Applied Poultry Research

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