ammonia emission and performance of laying hens as ... · or triterpenoid structure, with one or...

DESCRIPTION OF PROBLEM

Yucca schidigera is a species of the yucca plant that is native to the southwestern United States and Mexico. the yucca plant is rich in the natural steroid saponin, which adds commercial

value to the plant. Saponins are naturally occur-ring chemical compounds found in a wide va-riety of food, forage plants, and a few marine animals [1]. they have detergent or surfactant properties because they contain both water-sol-uble and fat-soluble components. they consist

© 2012 poultry Science association, Inc.

Ammonia emission and performance of laying hens as affected by different dosages

of Yucca schidigera in the diet

H. J. Chepete ,*1 H. Xin ,†2 L. B. Mendes ,† H. Li ,‡ and T. B. Bailey §

* Department of Agricultural Engineering and Land Planning, Botswana College of Agriculture, Gaborone, Botswana; † Department of Agricultural

and Biosystems Engineering, Iowa State University, Ames 50011; ‡ Department of Animal and Food Sciences, University of Delaware, Newark 19716;

and § Department of Statistics, Iowa State University, Ames 50011

Primary Audience: poultry Nutritionists, Veterinarians, Researchers

SUMMARY

a laboratory-scale study was conducted to determine the effect of feeding laying hens a standard commercial diet supplemented with different dosages of Yucca schidigera powder on Nh3 emission rate and production performance. a total of 72 W36 laying hens at 25 wk of age were used during the 12-wk study. the birds were equally divided into 4 groups and randomly allocated among 4 diets containing, respectively, 0, 50, 100, and 200 ppm (by weight) yucca powder. the hens were reared in an environment of 24 ± 1°C and a concomitant Rh of 45 to 65%. Measurement of Nh3 emission rate was done with a Gaseous emission Vessels System. the Y. schidigera powder in the laying-hen diet at a dosage of 50, 100, or 200 ppm did not af-fect the production performance of laying hens when compared with the 0-ppm dosage. the 100-ppm dosage significantly (P < 0.05) reduced Nh3 emission by 44 and 28%, respectively, for the first and second day of manure storage when compared with the other dosages. On the third day, Nh3 reduction was 14% but was not significantly different from the other treatments. adding 50 or 200 ppm of yucca in the diet did not reduce Nh3 emission. hence, adding 100 ppm of yucca in the laying-hen diet coupled with frequent manure removal (once every 1 to 2 d) would be conducive to reducing Nh3 generation and emission in laying-hen barns.

Key words: ammonia mitigation , laying hen , Yucca schidigera

2012 J. appl. poult. Res. 21 :522–530 http://dx.doi.org/ 10.3382/japr.2011-00420

1 Visiting professor at Iowa State University. 2 Corresponding author: [email protected]

523Chepete et al.: aMMONIa VS. YUCCA SCHIDIGERA

of a fat-soluble nucleus, having either a steroid or triterpenoid structure, with one or more side chains of water-soluble carbohydrates [2]. Un-like the triterpenoid saponins, steroid saponins of Y. schidigera (yucca) powder have proven beneficial to livestock and poultry producers [3, 4].

Most commercial production of Y. schidigera currently takes place in Mexico. the trunk of the plant is mechanically macerated and either dried and ground to produce 100% yucca powder, or the macerated material is subjected to mechani-cal squeezing in a press to produce yucca juice or extract. Yucca is currently used as a dietary additive for livestock primarily for Nh3 [2, 4, 5] and odor [6, 7] control. although the mode of action is not certain, the effects of yucca on reducing aerial Nh3 levels in livestock buildings are probably not due to the saponin components [8]. these authors could not conclusively iden-tify the active Nh3-reducing constituent. there are propositions that carbohydrates [8] and stil-benes (trans-tetrahydroxy-methoxystilbene) [9] may be involved, and the yucca bark is rich in stilbenes [10].

Yucca has been reported to reduce Nh3 con-centration in poultry barns [11, 12] and to im-prove egg production [11]. however, others have reported no effect on production param-eters of laying hens [13], laying quail [14], or on turkey poults [15]. poultry feed has been supplemented with different levels of yucca powder in different studies to examine their ef-fect on various parameters. although most of the studies were focused on the effect of yucca on aerial Nh3 concentration, which is subject to the influence of air exchange or ventilation rate (VR), this study was focused on the effect on Nh3 emission rate (ER), which combines the effects of both concentration and VR. Sectors of the US egg industry have adopted 100 ppm of yucca powder as the recommended level of dietary supplementation to reduce Nh3 levels in pullet or laying-hen barns. hence, the objec-tives of this study were to determine the effect of the recommended yucca dosage (100 ppm) vs. higher or lower dosages (0, 50, and 200 ppm of yucca) in the laying-hen diet on 1) production performance of the hens and 2) Nh3 eR from the laying-hen manure. Yucca powder with a >9% saponin content was used.

MATERIALS AND METHODS

the use and handling of the laying hens in this experiment were approved by the Iowa State University Institutional animal Care and Use Committee before the experiment commenced.

Experimental Facility

livestock environment and animal physiol-ogy laboratory I of Iowa State University was used in the study. a 2.21 × 2.26 × 2.41 m (width, length, height) environmentally controlled room was used to rear the laying hens. the birds were kept in 24 metabolic cages, each measuring 0.34 × 0.51 × 0.35 m (width, length, height). One water trough and one feed trough were provided for each cage. the feeders were placed such that cross-feeding between neighboring cages was not possible. Similarly, the cages were par-titioned with a solid sheet-metal plate to avoid cross-deposition of manure. Manure trays were provided underneath each cage and were lined with plastic film for easy manure removal. air temperature, Rh, and VR of the room were con-trolled to maintain an indoor environment of 24 ± 1°C and 45 to 65% Rh [16].

Dietary Regimens

the dietary regimens involved a standard laying-hen diet supplemented with different dosages of yucca powder, namely, 0, 50, 100 (positive control), and 200 ppm. the 100-ppm level was considered the positive control be-cause it was the industry-recommended level. a single batch of basal diet was prepared and divided among the regimens, which ensured that the feed was consistently the same throughout the experiment. the basal diet was formulated and mixed at the Iowa State University poultry Research Farm feed mill plant.

Laying Hens

a total of 72 hy-line W36 laying hens [17] at 25 wk of age were procured from a commer-cial laying-hen farm in Iowa. Upon arrival at the laboratory, the hens were randomly divided into 4 groups of 18 hens each. each group was randomly assigned a dietary regimen. each

524 JapR: Research Report

group was further divided into subgroups of 3 hens, resulting in 6 subgroups or replicates per treatment. the subgroups were then randomly placed in the cages at a stocking density of 581 cm2 (90 in2) per hen.

the experiment lasted 12 wk, with the first week being the acclimation period, when all the birds were fed the 0-ppm diet. at the beginning of the second week, the respective diets were fed to the hens as earlier assigned until the end of the experiment. Water and feed were provided ad libitum, and the lighting program was 16l:8D for the entire experiment. Manure was removed once a week until the 10th week, after which it was handled differently for Nh3 emission mea-surements, as described below. the welfare of the hens was monitored throughout.

On a daily basis, the eggs were collected, counted and weighed. the feed supplied to the birds was also weighed daily. Once a week, 9 hens per treatment were weighed. these data were used to determine production performance of the hens, including feed intake (FI), egg pro-duction (hen-day egg production and mass out-put), and Fe. the FI was determined as the dif-ference in mass between the feed given to the hens and that left over after a particular period. Feed efficiency was calculated as the ratio of the mass of feed consumed to the mass of eggs pro-duced over the same time period.

Manure Handling for NH3 ER Measurement

the manure produced during wk 11 and 12 was used in comparative Nh3 emission mea-surements. During this period, the hens had been well conditioned to the dietary regimens. at the beginning of wk 11, all the manure was removed. Manure was then allowed to accumu-late for 3 d. at end of the third day, 2 manure pans per regimen were randomly selected and their manure was separately collected into Zip-loc bags [18] and transported to another labo-ratory (approximately 5 km away on campus), where Nh3 emissions from the manure samples were measured continuously for 3 d using a Gaseous emission Vessels System [19, 20], as illustrated in Figure 1. Further manure handling is described in the following section. at the same time the samples were taken the first time,

another pair of manure pans per regimen were randomly selected and manure was removed in preparation for manure accumulation to be used in the second Nh3 emission measurement ses-sion. the remaining pair of manure pans in the regimen were similarly scheduled for the third session. thus, for each of the 3 measurement sessions, there were 8 manure samples (i.e., 2 manure samples or replicates per regimen × 4 regimens).

Placement of Manure Samples in the Emission Vessels

Upon arrival at the emissions measurement laboratory, the manure samples were placed in individual plastic containers and thoroughly mixed with an electric handheld mechanical mixer. a sample of 500 g from each container was placed in small plastic buckets (16.5 cm in diameter and 19.0 cm in height) and leveled by hand to obtain a uniform surface area in all the buckets. the small buckets were then randomly placed in each of the 8 vessels and their lids were tightly closed. the vessels were then placed into the measurement system, followed by the emis-sions monitoring. a thorough check for leaks on the vessels and air lines was performed. another manure sample from each mixing container was separately placed in Ziploc bags [18] and stored in the freezer for analysis of physical and chemi-cal properties. Measurements of Nh3 concentra-tion and emissions were made continuously for 3 d, after which a new session was begun fol-lowing the same procedures described above.

after completion of the 3 measurement sessions, all the stored manure samples were thawed at room temperature overnight. Manure samples belonging to the same dietary regimen were thoroughly mixed together and a compos-ite sample was taken. the manure samples were then sent to a certified commercial manure test-ing laboratory for analyses of total N [21], am-monium N [21], organic N [21], moisture con-tent (MC) [22], and ph [23].

Calculation of NH3 ER

the Nh3 eR (eRNh3, g/h per kilogram of ma-nure) was calculated as follows:


ER

QM

WV

TT

PP

e i

m

m

std

a

a

std

NH 3 33NH NH= [ ] −[ ]{ }×

× × × ×

−10 6

, (1)

where [Nh3]e and [Nh3]i are the Nh3 concentra-tion in the vessel exhaust and fresh air (ppm), re-spectively, Q is the airflow rate through the ves-sel (m3/h per vessel) at the ambient temperature and pressure, M is the initial mass of manure in the vessel (kg), Wm is the molar weight of Nh3 (17.031 g/mol), Vm is the molar volume of Nh3 (0.022414 m3/mol) at the standard temperature (0°C) and pressure (101.325 kpa), Tstd is the standard temperature (273.15 K), Ta is the ab-solute room ambient temperature (°C + 273.15

K), Pa is the atmospheric barometric pressure (98 kpa, based on site elevation), and Pstd is the standard barometric pressure (101.325 kpa).

Experimental Design and Statistical Analysis

For measurement of production perfor-mance, the experiment was a completely ran-domized design. analysis of variance was con-ducted on the data using the GlM procedure of SaS software [24] to determine treatment effects on the various production performance variables. the production performance data were summarized into daily averages per hen before being analyzed. For Nh3 eR, the experi-ment may be described in 2 parts: 1) a com-

Figure 1. Schematic representation of the Gaseous Emission Vessels (EV) System. DAQ = data acquisition. The CR10, SDM switch, and AM16/32 mulitplexer constitute a measurement and control module (Campbell Scientific, Logan, UT).


pletely randomized block design, in which the 3 measurement sessions were the blocks and the cages within each session (that were ran-domly assigned the dietary regimens) were the experimental units, and 2) repeated measures undertaken on manure from each cage over a 3-d period. the same SaS procedure was used to determine treatment effects on Nh3 eR. the Nh3 eR data were summarized into daily totals before being analyzed.

RESULTS AND DISCUSSION

Production Performance

the data collected during the first week were excluded from the analysis because the hens were still acclimatizing to their new environ-ment. No mortality was recorded in the entire experiment. the results of the production per-formance of the hens are shown in table 1. No significant differences (P = 0.3463 to 0.9146) were observed among the regimens in all the production performance variables. Kutlu et al. [13] reported that yucca powder with a 10.76% saponin content at dosages of 0, 30, 60, and 120 ppm did not affect FI, egg production, Fe, BW gain, or egg quality parameters of White hy-line laying hens reared over an 8-wk period (28 to 36 wk of age). Similar results had been reported in laying quails fed dosages of 0, 100, and 200 ppm of yucca powder [14] and in tur-key poults [15]. the addition of 31 to 155 ppm of yucca extract containing 40% steroid sapo-nins increased egg production and 465 ppm of extract decreased egg production in laying hens [11]. Further, the 31- to 155-ppm dosage had little effect on Fe and mortality. positive effects on growth rate and Fe had been reported when

yucca was included at a dosage of 60 or 120 ppm in the broiler diet [25].

Only the regimen × bird age interaction for the FI variable was significant (P = 0.05435). the aDFI per hen was approximately 100 g, which agrees with the literature value of 100 g/hen per day [26]. however, it was lower at 35 and 36 wk of age, ranging from 92.2 to 97.5 g/hen per day across all treatments. During this period, slightly warmer temperatures were ex-perienced, which may have caused the decline in FI when compared with the other time periods. the P-values for the regimen × bird age interac-tions for other production variables ranged from 0.3739 to 0.7916.

NH3 ER

Figure 2 shows typical dynamic Nh3 emis-sion profiles of the laying-hen manure over a 3-d measurement period for each of the 4 regi-mens. It was observed that the Nh3 eR gener-ally increased with storage time, especially in the first 2 d. this may be due to a higher micro-bial degradation rate because the nutrients were abundant during this period when manure was relatively fresh [27]. the trend was expected to diminish with time because of exhaustion of the nutrients by the microbes. Variations existed in Nh3 eR between replications, and these may have been caused by the differences in manure MC as manure moisture evaporated to varying degrees during the 3-d accumulation or collec-tion period. Furthermore, some Nh3 may have volatilized during the manure collection period.

No significant differences (P = 0.4863) were observed among the 3 measurement sessions conducted. as such, the data from all the ses-sions were pooled for each regimen. Compared

Table 1. Effect of Yucca schidigera powder on production performance of laying hens1

Dietary regimen (yucca dosage)

production performance variable

FI hD Megg Fe BW

0 ppm 98 ± 1.7 94 ± 0.9 53 ± 1.1 1.85 ± 0.02 1.47 ± 0.0150 ppm 99 ± 1.7 94 ± 0.9 54 ± 1.1 1.82 ± 0.02 1.44 ± 0.01100 ppm 100 ± 1.7 93 ± 0.9 53 ± 1.1 1.88 ± 0.02 1.45 ± 0.01200 ppm 98 ± 1.7 92 ± 0.9 54 ± 1.1 1.86 ± 0.02 1.43 ± 0.01average 99 ± 0.8 93 ± 0.5 54 ± 0.6 1.85 ± 0.01 1.45 ± 0.011FI = feed intake (g/hen per day); hD = hen-day egg production (%); Megg = mass of eggs produced (g of egg/hen per day); Fe (g of feed consumed/g of egg produced); BW (kg/hen). Values are means ± SeM.


among themselves, the 0-, 50-, and 200-ppm regimen means (nonrecommended dosages) were not significantly different (P = 0.3973). Subsequently, the means for these regimens were averaged by day for comparison with the 100-ppm regimen. these data are presented in table 2.

When the regimen means were compared on a daily basis, the mean Nh3 eR for the 100-ppm dosage was significantly lower (P < 0.05) than that of the other dosages on the first and second days of manure storage (280 vs. 500 and 390 vs. 544 mg/d per kilogram of manure, respec-

tively). the means were not significantly dif-ferent on the third day (P = 0.7609) of manure storage. therefore, yucca powder (100-ppm dosage) was effective in suppressing Nh3 emis-sion during the first and second days of manure storage. thus, to make use of the Nh3-emission mitigation effect by the yucca powder (100-ppm dosage) in laying-hen barns (e.g., manure-belt houses), frequent manure removal (every 1 to 2 d) is desirable. For manure-belt laying-hen houses in the United States, manure is com-monly removed once every 1 to 3 d to reduce Nh3 levels in the laying-hen barns and protect

Figure 2. Typical dynamic NH3 emission rate profile of the laying-hen manure from diets with different yucca inclu-sion dosages over a 3-d measurement period. The pooled SEM were 0.7, 0.5, 0.9, and 0.8 for the 0-, 50-, 100-, and 200-ppm dosages, respectively.

Table 2. The average ammonia emission rates (mg/d per kilogram of manure ± SEM) of the 4 treatments1

Dietary regimen (yucca dosage)

Manure storage time, d

Mean1 2 3

100 ppm (rec. rate) 280 ± 92a 390 ± 92a 439 ± 92a 370 ± 53a

Mean of 0, 50, and 200 ppm (nonrec. rate) 500 ± 53b 544 ± 53b 511 ± 53a 518 ± 31b

Mean difference2 −220 ± 46 −154 ± 46 −72 ± 46 −148 ± 26a,bMeans within a column with the same superscript letters are not significantly different (α = 0.05).1Rec. rate = recommended yucca inclusion rate; nonrec. rate = nonrecommended yucca inclusion rate.2Mean difference = recommended rate mean − nonrecommended rate mean (mean ± Se of the difference).


the manure belt from damage by the excessive weight of accumulated manure. During the first, second, and third days, the 100-ppm treatment had 220 mg/d per kilogram of manure (44%), 154 mg/d per kilogram of manure (28%), and 72 mg/d per kilogram of manure (14%) lower Nh3 eR, respectively, with a cumulative 3-d re-duction of 30%, when compared with the aver-age Nh3 eR for the 0-, 50-, and 200-ppm regi-mens. a regression analysis was conducted on the data in table 2, and the results are shown in Figure 3. although yucca at a dosage of 100 ppm significantly reduced Nh3 emission in the first and second days of manure storage, the ma-nure thereafter tended to release Nh3 at a much faster rate, as shown by the greater slope of the 100-ppm regimen when compared with that of the averaged 0-, 50-, and 200-ppm regimens (80 vs. 6.7, respectively). thus, the question of how the feed additive would affect Nh3 emissions during long-term manure storage (e.g., 6 mo) typical of commercial operation remains to be addressed. Data from the current study are not adequate to answer such a question.

Manure properties for the different diet regi-mens are shown in table 3. Compared with the 0-, 50-, and 200-ppm regimens, the manure of the 100-ppm regimen had most of its N exist-ing in the organic form (10.2 ± 0.9 g/kg), which was conducive to lower Nh3 emission. Under anaerobic conditions, organic nitrogenous ma-terials would ferment and release Nh3, Ch4, CO2, h2S, and volatile fatty acids [28]. the am-monium N (Nh4-N) is the dominant inorganic or mineral form of N in poultry manure over nitrate N (NO3-N) and nitrite N (NO2-N) [29]. the Nh4-N would release Nh3 gas through the aerobic and anaerobic microbial transformation processes [30].

Manure of the 100-ppm regimen had lower MC (65.8 ± 4.7%) than that of the other treat-ments. the MC affects microbial activity, and thus Nh3 volatilization [31], and Nh3 genera-tion from stored manure decreases when MC falls below 30% [32]. Moisture is required for both dissolution of solid urea forms and sub-sequent urea hydrolysis, and these processes must occur before Nh3 volatilization [30]. the

Figure 3. Ammonia emission vs. storage time of laying-hen manure for diets containing 0, 50, 100, or 200 ppm of yucca.


ph of manure in all the regimens was above 7.0 (neutral ph), which was favorable for aerobic N decomposition and Nh3 release. ammonium (Nh4

+) is the predominant form of N under acid-ic and neutral conditions, whereas Nh3 gas is the predominant form at higher ph levels [33]. the higher MC in the 0-, 50-, and 200-ppm treat-ments coupled with above-neutral ph may have contributed to higher Nh3 eR in these regimens when compared with the 100-ppm regimen.

CONCLUSIONS AND APPLICATIONS

1. Yucca schidigera powder in the laying-hen diet at a dosage of 50, 100, or 200 ppm did not affect the production per-formance of laying hens when compared with the 0-ppm dosage.

2. Measured with an Nh3 emission vessels system, hen manure from the 100-ppm yucca dosage treatment emitted signifi-cantly (P < 0.05) lower Nh3 in the first day (44% lower) and second day (28% lower) of manure storage when com-pared with the other yucca inclusion lev-els. On the third day, Nh3 emission was 14% lower but was not significantly dif-ferent from the other treatments. adding 50 or 200 ppm of yucca in the diet did not reduce Nh3 emission.

3. Field verification studies are warranted, considering the promising results with the 100-ppm dosage and the observation that after 3 d of manure storage, Nh3 emission increased at a faster rate for the 100-ppm dosage than for the other dos-ages. the field studies need to quantify the impact of the 100-ppm inclusion rate on cumulative Nh3 emissions over an

extended (e.g., 3 to 6 mo) manure stor-age period.

REFERENCES AND NOTES

1. Milgate, J., and D. C. K. Roberts. 1995. the nutri-tional and biological significance of saponins. Nutr. Res. 15:1223–1249.

2. Cheeke, p. R. 2000. actual and potential applica-tions of Yucca schidigera and Quillaja sapanaria sapo-nins in human and animal nutrition. pages 1–10 in 1999 proc. am. Soc. anim. Sci. am. Soc. anim. Sci., Cham-paign, Il. accessed Feb. 20, 2012. http://www.asas.org/symposia/9899proc/0909.pdf.

3. al-Bar, a., a. Ismail, p. R. Cheeke, and N. S. Nakaue. 1993. effect of dietary Yucca schidigera powder (Deodor-ase) on environmental ammonia and growth performance of chickens and rabbits. proc. West. Sect. am. Soc. anim. Sci. 44:106–108.

4. hussain, I., and p. R. Cheeke. 1995. effect of dietary Yucca schidigera extract on rumen and blood profiles of steers fed concentrate-based diets. anim. Feed Sci. technol. 51:231–242.

5. Wallace, R. J., l. arthaud, and C. J. Newbold. 1994. Influence of Yucca schidigera extract on ruminal ammonia concentrations and ruminal microorganisms. appl. environ. Microbiol. 60:1762–1767.

6. lowe, J. a., and S. J. Kershaw. 1997. the ameliorat-ing effect of Yucca schidigera extract on canine and feline faecal aroma. Res. Vet. Sci. 63:61–66.

7. lowe, J. a., S. J. Kershaw, a. J. taylor, and R. S. t. linforth. 1997. the effect of Yucca schidigera extract on ca-nine and feline faecal volatiles occurring concurrently with faecal aroma amelioration. Res. Vet. Sci. 63:67–71.

8. Killeen, G. F., C. R. Connolly, G. a. Walsh, C. F. Duffy, D. R. headon, and R. F. power. 1998. the effects of dietary supplementation with Yucca schidigera extract or fractions thereof on nitrogen metabolism and gastrointesti-nal fermentation processes in the rat. J. Sci. Food agric. 76:91–99.

9. Kong, Z. 1998. Separation and characterization of biologically important substances. phD Diss. University of Illinois, Urbana-Champaign.

10. Oleszek, W., M. Sitek, a. Stochmal, S. Burda, and p. Cheeke. 1999. Saponin and phenolic constituents from Yuc-ca schidigera bark. page 31 in Saponins in Food, Feedstuffs and Medicinal plants. Inst. Soil Sci. plant Cultiv., pulawy, poland. (abstr.)

Table 3. Compositions (as-is basis) of the laying-hen manure for the different dietary regimens at the beginning of NH3 emissions measurement

Manure property

Dosage of Yucca schidigera powder in hen diet

0 ppm 50 ppm 100 ppm 200 ppm

total N, g/kg 10.6 ± 1.2 11.4 ± 0.4 12.7 ± 0.7 11.0 ± 0.2Organic N, g/kg 7.8 ± 1.3 8.8 ± 0.4 10.2 ± 0.9 8.0 ± 0.2Nh4-N, g/kg 2.8 ± 0.2 2.6 ± 0.1 2.5 ± 0.2 3.0 ± 0.3Moisture, % 73.5 ± 4.3 72.8 ± 0.6 65.8 ± 4.7 72.2 ± 1.0ph 7.7 ± 0.2 7.4 ± 0.3 7.6 ± 0.3 7.7 ± 0.1

Nh4-N = ammonium N.


11. Rowland, l. O., J. e. pleyler, and J. W. Bradley. 1976. Yucca schidigera extract effect on egg production and house ammonia levels. poult. Sci. 55:2086–2093.

12. Johnson, N. l., C. l. Quarles, D. J. Fegerberg, and D. D. Caveny. 1981. evaluation of yucca saponin on broiler performance and ammonia suppression. poult. Sci. 60:2289–2292.

13. Kutlu, h. R., M. Gorgulu, and I. Unsal. 2001. effects of dietary Yucca schidigera powder on performance and egg cholesterol content of laying hens. J. appl. anim. Res. 20:49–56.

14. Kaya, S., Z. erdogan, and S. erdogan. 2003. effect of different dietary levels of Yucca schidigera powder on performance, blood parameters and egg yolk cholesterol of laying quails. J. Vet. Med. a physiol. pathol. Clin. Med. 50:14–17.

15. Dziuk, h. e., G. e. Duke, R. J. Buck, and K. a. Janni. 1985. Digestive parameters in young turkeys fed yucca sa-ponin. poult. Sci. 64:1143–1147.

16. a variable-speed exhaust fan provided the required VR, with the inlet baffle situated on the ceiling of the cham-ber. a thermostat-controlled 1,500-W heater/fan (Model 3VU37a, Dayton electric Mfg. Co., Niles, Il) was used to maintain the desired temperature. a portable humidifier (Model V745a, Kaz Inc., hudson, NY) was used to provide the desired Rh.

17. hy-line W36 laying hens, West Des Moines, Ia.18. S. C. Johnson & Son, Racine, WI.19. the Gaseous emission Vessels System is composed

of 8 emission vessels. the vessels were placed in an envi-ronmentally controlled room with a constant temperature of 21°C at livestock environment and animal physiology laboratory II of Iowa State University. the vessels were made of 19-l (5-gal) plastic containers. to prevent potential interference of the vessel material with Nh3 emission mea-surement, each vessel was lined with teflon Fep 100 film (200a, Dupont teflon Films, Wilmington, De). the air inlet and outlet were located in the airtight lid. teflon tubing (1/4 in. diameter) and manifold, along with polyvinyl chloride compression fittings, were used in constructing the emission vessel system. the vessels were operated under positive pressure. a diaphragm pump (Model DOa-p104-aa, Gast Manufacturing Inc., Benton harbor, MI) was used to supply fresh air to the emission vessels. Flow rate of the fresh sup-ply air was controlled and measured with an air mass flow controller [0 to 30 l/min (lpM), stainless steel wetted part, aalborg Instruments and Control Inc., Orangeburg, NY]. the supply air was connected to a distribution manifold in which air was further divided via 8 identical flow meters (0.2 to 4 lpM, stainless steel valve, VFB-65-SSV, Dwyer Instruments Inc., Michigan City, IN). a flow rate of 3 lpM was introduced into each vessel, resulting in an air exchange of 11 air changes/h. each vessel was equipped with a small stirring fan (12VDC, Radio Shack, Fort Worth, tX) located 6 cm below the lid for uniform mixing of the headspace. exhaust air of the vessels was connected to a common 5-cm polyvinyl chloride pipe that was routed to the building vent outlet. Samples of the exhaust air from each of the 8 vessels, the supply air, and the room air were sequentially taken at 6-min intervals, with the first 4 min used for stabilization and the last 2 min for measurement. this yielded a measure-ment cycle of 1 h for each vessel. the sequential sampling was achieved by controlled operation of 8 solenoid valves

(type 6014, 24 V, stainless steel valve body, Burket Contro-matic USa, Irvine, Ca). a teflon filter was placed in front of each solenoid valve. an advanced photoacoustic multi-gas analyzer (Model 1314, Innova, Ballerup, Denmark) was used to measure the Nh3 concentrations. the digital signal from the Innova analyzer was converted into an analog sig-nal by the Nh3 analog module (Model J1210hW type 4X, California analytical Instruments Inc., Orange, Ca), which was in turn connected to the measurement and control mod-ule (Model CR10, Campbell Scientific Inc., logan, Ut) that logged the data.

20. li, h., h. Xin, Y. liang, and R. t. Burns. 2008. Re-duction of ammonia emissions from stored laying hen ma-nure through topical application of zeolite, al+Clear, Ferix-3, or poultry litter treatment. J. appl. poult. Res. 17:421–431.

21. aOaC International. 1990. Method 2001-11: Kjel-dahl method. In Official Methods of analysis of aOaC In-ternational. aOaC Int., Gaithersburg, MD.

22. aOaC International. 1990. Method 930.15: Standard moisture loss-on-drying. In Official Methods of analysis of aOaC International. aOaC Int., Gaithersburg, MD.

23. aSa-CSSa-SSSa. 2004. aSa #9: Methods of Soil analysis, part 2. Chemical and Microbiological properties. 2nd ed. agronomy, No. 9. am. Soc. of agron.-Crop Sci. Soc. of am.-Soil Sci. Soc. of am., Madison, WI.

24. SaS Institute. 2008. SaS User’s Guide: Statistics. Version 9.2 ed. SaS Inst. Inc., Cary, NC.

25. lundeen, t. 2000. Yucca extract improves feed effi-ciency, decreases abdominal fat in broilers. Feedstuffs Repr. 72:1.

26. hy-line. 2009–2011. hy-line W-36 Commercial Management Guide. hy-line Int., Dallas Center, Ia.

27. Kirchman, h., and e. Witter. 1989. ammonia volatil-ization during aerobic and anaerobic manure decomposition. plant Soil 115:35–41.

28. Groot Koerkamp, p. W. G., N. Verdoes, G. J. Mon-teny, and t. De haan. 1990. towards housing System with low ammonia emission: Sources and processes. Stuur-groep emissiearme huisvestingssystemen, DlO, Wagenin-gen, the Netherlands.

29. Bitzer, C. C., and J. t. Sims. 1988. estimating the availability of nitrogen in poultry manure through labora-tory and field studies. J. environ. Qual. 17:47–54.

30. Nahm, K. h. 2003. evaluation of the nitrogen content in poultry manure. World’s poult. Sci. J. 59:77–88.

31. pratt, e. V., S. p. Rose, and a. a. Keeling. 2002. ef-fect of ambient temperature on losses of volatile nitrogen compounds from stored laying hen manure. Bioresour. technol. 84:203–205.

32. Carr, l. e., F. W. Wheaton, and l. W. Douglass. 1990. empirical models to determine ammonia concentrations from broiler chicken litter. trans. aSae 25:413–424.

33. Gay, S. W., e. F. Wheeler, J. l. Zajaczkowski, and p. a. topper. 2006. ammonia emissions from U.S. tom turkey growout and brooder houses under cold weather minimum ventilation. appl. eng. agric. 22:127–134.

AcknowledgmentsFunding for the study was provided in part by the Iowa

egg Council (Urbandale, Ia) and is acknowledged with gratitude.

ammonia emission and performance of laying hens as ... · or triterpenoid structure, with one or...

Documents