*Dr. William A. Dudley-Cash is a poultry and fish nutritionist and has his own consulting firm in Kamuela, Hawaii.

THE 105th annual meeting of the Poultry Science Assn. was held in New Orleans, La. At the meeting, 314 technical papers were presented orally in 37 sessions, and 214 technical papers were poster presentations.

Sessions were presented on at least 11 subjects, including: immunology, health and disease; management and production; metabolism and nutrition; microbiology and food safety; processing and products; physiology and reproduction; well-being and behavior; molecular and cellular biology; genetics and genomics; animal well-being and behavior; extension, and instruction.

There were 10 symposia, including the national extension workshop, the informal nutrition symposium and the World's Poultry Science Assn. lecture.

An interesting and timely symposium topic was "Challenges with Antibiotic-Free Poultry Production." This included presentations by four company representatives about their experiences and perspectives on the production of antibiotic-free broilers. (For more information about these four presentations, please refer to my column in the Sept. 5, 2016, issue of Feedstuffs.)

The Monday morning and Tuesday morning technical sessions were devoted to approximately 134 student competition oral presentations on a variety of topics. These competition sessions are an opportunity for students to showcase their research and presentation ability. The presentations are judged and awards are presented at the annual banquet.

The abstracts from the annual meeting may be found at www.poultryscience.org/abstracts.asp.

Oregano oil as antioxidant

The essential oil from oregano has generated interest as a possible feed additive for poultry. The results of several papers were presented at the meeting. The research reviewed here was conducted with Orego-Stem (OS), an oregano essential oil product produced by Anpario PLC in the U.K.

In abstract 240, A. Konstanti et al. presented the results of an experiment conducted to determine the effect of OS on the intestinal cell proliferation, antioxidant capability and performance of broilers.

In the study, 480 Ross 308 broilers were divided into two groups, with eight replicates per group and 30 birds per replicate. Group 1 served as the control, and group 2 (OS) was supplemented with 300 g of the OS product per ton of feed. Both groups were fed the experimental diets until 42 days of age, in three phases: days 1-14, days 15-28 and days 29-42.

On day 42, intestinal cell proliferation was determined by measuring proliferating cell nuclear antigen in the duodenum, jejunum and ileum by immunohistochemistry. The antioxidant status was assessed using two markers: malondialdehyde and the stable 2,2-diphenyl-1-pierylhydrazyl radical scavenging test. Both antioxidant tests were conducted on breast and thigh samples obtained at the end of the trial.

OS improved the feed conversion ratio (FCR) in all three growth phases and overall (1.73 for control versus 1.44 for OS). The OS birds consumed significantly less feed and had numerically greater bodyweight gain. Intestinal cell proliferation was higher for the OS treatment in all three intestinal sections. A better antioxidant status was also observed with the OS treatment.

The researchers concluded that OS can help mitigate intestinal damage through greater erythrocyte production, reduce oxidative stress and improve performance of broilers.

Oregano oil for coccidiosis

In abstract 241, D. Harrington et al. reviewed the results of an experiment conducted to evaluate the ability of OS to improve performance in coccidiosis-vaccinated broilers. A total of 1,125 Cobb 500 broilers were divided into five treatments, with nine replicates of 25 birds per replicate for each treatment.

The experimental design was: (1) vaccinated; (2) non-vaccinated + 450 g per ton OS (OS450); (3) vaccinated + 150 g per ton OS (VOS150); (4) vaccinated + 300 g per ton OS (VOS300), and (5) vaccinated + 450 g per ton OS (VOS450). All birds were reared in floor pens on reused litter from zero to 42 days of age. OS was included in the feed from day 0. The birds that were vaccinated were spray vaccinated in the hatchery with Coccivac-B52 at one day of age.

The performance results are shown in Table 1. The vaccinated control birds had a significantly higher FCR than all other treatments, and there was no significant difference in the FCR among any of the other treatments. The vaccinated control treatment had significantly lower bodyweight gain compared with all other treatments. The OS450 treatment had a significantly greater bodyweight gain than all of the other treatments except VOS450.

Not all of the mortality data were reported. However, the researchers stated that the vaccinated control treatment had significantly higher mortality than any of the other treatments, with the exception of OS450. Treatment VOS300 had the lowest mortality of all of the treatments.

The vaccinated control treatment had a significantly lower European Production Efficiency Factor (EPEF) compared with all of the other treatments.

The researchers concluded that the use of the oregano essential oil in the diet of birds vaccinated against coccidiosis ameliorated the apparent negative effect of vaccination on performance and mortality. In addition, inclusion of the oregano essential oil in non-vaccinated birds also improved performance compared with the coccidial vaccination alone.

Oregano oil for immunity

In abstract 242, K. Constanti et al. reviewed the results of an experiment conducted to investigate the effect of OS on the development of coccidial immunity following vaccination with a coccidiosis vaccine that was administered by hatchery spray at one day of age.

This research appears to be a continuation of the experiment described in abstract 241, with the same experimental design and the same treatments.

On day 21 of the experiment, five birds per pen were moved to cages and challenged orally with a mixture of Eimeria acervulina, Eimeria maxima and Eimeria tenella. In addition, 45 non-vaccinated coccidial-free birds (control) were also challenged. On day 27, the birds were killed, and coccidial lesion scores (LS) were taken for the upper, mid and cecal regions of the gut. Oocysts per gram (OPG) of feces in each pen were measured on days 7, 14, 21, 28 and 35. The results are shown in Table 2.

The LS for the control treatment demonstrated that the Eimeria challenge was successful. The mean LS was significantly higher for the control treatment than for all other treatments. The LS in the upper and mid regions of the gut did not differ significantly among treatments, with the exception that the LS for the control treatment was higher. Treatment OS450 had significantly higher LS in the cecal region of the gut than all other treatments.

There was a peak in OPG in the feces on day 14 and day 35 for all vaccinated groups. The size of the day 14 OPG peak decreased with increasing OS inclusion. The OPG level for treatment OS450 was low throughout the study, but a small peak was observed on day 21, followed by a larger peak on day 35.

The Bottom Line

This research shows that a specific oregano essential oil formulation was effective for improving growth performance both in the presence and in the absence of a coccidiosis vaccination challenge.

Volume:88 Issue:10