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ISSN : 1598-5504(Print)
ISSN : 2383-8272(Online)
Journal of Agriculture & Life Science Vol.52 No.5 pp.63-69
DOI : https://doi.org/10.14397/jals.2018.52.5.63

Energy Utilization of Hatchery Waste Products by Pigs Can Be Estimated Using In vitro Data

Jung Yeol Sung1,Sang Yun Ji2,Beob Gyun Kim1*
1Department of Animal Science and Technology, Konkuk University, Seoul, 05029, Korea
2Animal Nutritional Physiology Team, National Institute of Animal Science, Rural Development Administration, Wanju, 55363, Korea
*Corresponding author: Beob Gyun Kim
Tel: +82-2-2049-6255
Fax: +82-2-455-1044
July 26, 2018 August 8, 2018 August 10, 2018

Abstract


The objectives of this study were to determine in vitro dry matter and energy utilization of hatchery waste products and to confirm whether in vivo energy digestibility of hatchery waste products could be estimated using in vitro data. Two in vitro assays were conducted for infertile eggs, unhatched eggs, culled chicks, and a mixture(20% dried infertile eggs, 20% dried unhatched eggs, and 60% dried culled chicks). In Exp.1, in vitro dry matter disappearance (IVDMD) of hatchery waste products was determined. In Exp.2, in vitro energy disappearance (IVED) was determined using undigested residues from Exp.1. The IVDMD of infertile eggs, unhatched eggs, culled chicks, and the mixture were 81.7, 88.7, 83.9, and 85.4%, respectively. The IVED of the test ingredients were 74.4, 85.1, 77.6, and 79.8%, respectively. Both IVDMD and IVED were greater in unhatched eggs compared with infertile eggs and culled chicks (p<0.05). In vivo energy digestibility was estimated well using prediction equations for hatchery waste products developed in the present study: In vivo energy digestibility(%) = 2.52 × IVDMD (%) – 133.95 with r2 = 0.70 and in vivo energy digestibility(%) = 1.63 × IVED(%) – 50.03 with r2 = 0.67. In conclusion, energy utilization of unhatched eggs was the greatest among test ingredients and energy utilization of hatchery waste products can be estimated using data from in vitro procedures.



초록


    Introduction

    Hatchery waste products are disposed from hatchery facilities and 6,335 tons were discarded in 2015 in Republic of Korea(Lee et al., 2018). Hatchery waste products listed in AAFCO(2016) are defined as “a mixture of egg shells, infertile eggs, unhatched eggs, and culled chicks which have been cooked, dried, and ground, with or without removal of part of the fat.” Traditionally, these products are disposed in landfill resulting in environment pollution and disposal costs. Hatchery waste products can potentially be used as high-quality ingredients rich in protein, mineral, and vitamin(Glatz et al., 2011).

    To use a feed ingredient in swine diets, nutritional evaluation of feed ingredient is necessary for precise feed formulation. Energy digestibility values of some hatchery waste products fed to nursery pigs have been reported(Sung et al., 2018). However, in vivo energy digestibility in hatchery waste products may vary depending on processing and hatchery facilities. As animal experiments are laborious and expensive, in vitro procedures have been widely used to simulate digestion in the gastrointestinal tract using digestive enzymes(Boisen & Fernández, 1997). Based on in vitro assays, prediction equations for energy digestibility of feed ingredients such as barley, copra meal, and wheat were developed(Regmi et al., 2008; 2009; Park et al., 2012). If in vitro data accurately estimate energy digestibility of hatchery waste products, prediction equations can be used for estimating in vivo energy digestibility of hatchery waste products with varying compositions based on in vitro disappearance. To our knowledge, however, in vitro digestibility data for hatchery waste products are not available. Therefore, the objectives of this study were to determine in vitro disappearance of hatchery waste products and to confirm whether in vivo energy digestibility of hatchery waste products could be estimated using in vitrobased independent variables.

    Materials and Methods

    The in vitro dry matter disappearance(IVDMD) and in vitro energy disappearance(IVED) of hatchery waste products were determined using in vitro digestibility techniques. Before analyses, the IVDMD and IVED for each sample were measured in 3 batches with 1 replicate per each batch.

    1 Preparation of hatchery waste products

    Infertile eggs, unhatched eggs, and culled chicks were obtained from a layer hatchery facility(Join Inc., Pyeongtaek, Republic of Korea). Each ingredient was ground and then dried at 130℃ for 20 h in a dryer(DN 2300, Dongnam Tech Inc., Hwaseong, Republic of Korea; Fig. 1). Then, a mixture of 3 ingredients was also prepared(20% dried infertile eggs, 20% dried unhatched eggs, and 60% dried culled chicks). The ratio of the mixture was determined based on the moisture contents and natural occurrence rate of the ingredients from the hatchery facility.

    2 in vitro dry matter disappearance

    The IVDMD method consists of three-steps which stimulate digestion of stomach, small intestine, and large intestine based on Boisen & Fernández(1997). Each ingredient was finely ground to pass a 1-mm screen(Cyclotech 1093; Foss Tecator AB, Höganäs, Sweden) before the in vitro digestion procedures.

    In the first step, 0.5 g of sample was weighed into a 125 mL conical flask, and 25 mL of phosphate buffer solution(0.1 M and pH 6.0) and 10 mL of 0.2 M HCl were added to the flask. The pH of the solution was adjusted to 2.0 using 1 M HCl and NaOH solution and 1mL of freshly prepared pepsin(10 mg/mL; ≥ 250 U/mg solid, P7000, Pepsin from porcine gastric mucosa, Sigma-Aldrich, St. Louis, MO, USA) was added. Thereafter, 0.5 mL of chloramphenicol(C0378, Chloramphenicol, Sigma-Aldrich, St. Louis, MO, USA; 0.5 g/100 mL of ethanol) was added to prevent bacterial fermentation. The flasks were incubated in a shaking incubator for 2 h at 39℃.

    In the second step, the flasks were added with 10 mL of phosphate buffer(0.2 M and pH 6.8) and 5 mL of NaOH solution. Then the pH was adjusted to 2.0 using 1M HCl and NaOH solution and 1mL of freshly prepared pancreatin solution(50 mg/mL; 4 × USP, P1750, pancreatin from porcine pancreas, Sigma- Aldrich, St. Louis, MO, USA) was added. The flasks were incubated in a shaking incubator for 4 h at 39℃.

    After the second incubation, 10 mL of 0.2 M EDTA solution was added and the pH was adjusted to 4.8 using 30% of acetic acid and 1M NaOH solution. The flasks were added with 0.5 mL of Viscozyme (V2010, Viscozyme® L, Sigma-Aldrich, St. Louis, MO, USA) and incubated for 18 h at 39℃.

    After the incubation, undigested residues were filtered through pre-dried and weighed glass filter crucibles containing 0.4 g of Celite using the Fibertec System(Fibertec System 1021 Cold Extractor, Tecator, Hӧganӓs, Sweden). The test flasks were rinsed twice by distilled water followed by rinsing twice with 10 mL of 95% ethanol and 99.5% acetone. Then, glass filter crucibles with undigested residues were dried at 130℃ for 6h. Glass filter crucibles were weighed after cooling for 1 h.

    3 in vitro energy disappearance

    The IVED method was based on the procedure slightly modified from Regmi et al.(2008) After conducting three-step IVDMD method, undigested residues on filter crucibles were collected to determine its gross energy.

    4 Chemical analysis

    Test ingredients were analyzed for dry matter (method 930.15; AOAC, 2005), crude protein(method 990.03; AOAC, 2005), ether extract(method 920.39; AOAC, 2005), ash(method 942.05; AOAC, 2005), calcium(method 978.02; AOAC, 2005), and phosphorus (method 946.6; AOAC, 2005). Gross energy was analyzed for each ingredient using a bomb calorimeter (Parr 1261 bomb calorimeter; Parr Instruments Co., Moline, IL, USA).

    5 Calculations and statistical analyses

    The IVDMD(%) and IVED(%) were calculated with following equations:

    IVDMD(%) = [(DMTI- DM UR )/DM TI ] × 100 

    Where DMTI and DMUR are the weight of dry matter content in the test ingredient and undigested residues, respectively.

    IVED(%) = [(DM TI × GE TI DM UR × GE UR ) / ( DM TI × GE TI ) ] × 100

    Where GETI and GEUR are the gross energy in the test ingredient and undigested residues, respectively. Each flask was considered as an experimental unit. The GLM procedure of SAS(SAS Inst. Inc., Cary, NC, USA) was used and least squares means for IVDMD and IVED were calculated for each ingredient. Differences among least squares means were tested using the PDIFF option with Tukey’s adjustment. The REG procedure was used to establish prediction equations for in vivo energy digestibility using in vitro disappearance as an independent variable(Park et al., 2012).

    Results and Discussion

    Crude protein contents in hatchery waste products ranged from 32.2 to 67.5%(Table 1). Infertile eggs (30.2%) and unhatched eggs(34.0%) had greater ash content compared with culled chicks(7.3%) due to the presence of egg shells in the infertile eggs and unhatched eggs. Culled chicks had less IVDMD and IVED compared with unhatched eggs(p<0.05; Table 2). The IVDMD and IVED of infertile eggs were less than those of unhatched eggs(p<0.05)

    Least squares mean of IVDMD and IVED for each ingredient in the current study was based on 3 replications(one replication per batch). Reliable results from the in vitro procedures(Boisen & Fernández, 1997) were obtained from 3 observations in the previous studies(Noblet & Jaguelin-Peyraud, 2007; Park et al., 2016) as this assay is highly reproducible and repeatable (Jaworski, 2012).

    The less IVDMD and IVED of culled chicks compared with unhatched eggs are likely due to the indigestible parts including feathers, beaks, and claws that are mainly composed of keratins(Grazziotin et al., 2006). The reason for the lower digestibility of infertile eggs compared with unhatched eggs is unclear. On day 8 post fertilization, eggs identified as infertile by inspection were separated from an incubator. Based on the microbiological analysis, there was also no evidence that the infertile eggs were spoiled(Lee et al., 2018). In contrast to the present pig digestibility experiment, infertile eggs were reported to have a greater true metabolizable energy concentration and energy metabolizability than unhatched eggs when fed to 50-d-old chickens(Choi et al., 2018). Further research is warranted to identify the reason for the low energy digestibility of infertile eggs fed to pigs.

    Considering the inclusion rate of infertile eggs, unhatched eggs, and culled chicks in the mixture, the IVDMD and IVED of the mixture were very close to the expected values(84.4% and 78.5%, respectively) given that the values are additive. As IVDMD and IVED showed similar results, both in vitro techniques were very highly correlated(r2=1.00). In the literature, strong correlations between IVDMD and IVED were reported in 7 barely samples(Regmi et al., 2008; r2=1.00) and 20 wheat samples(Regmi et al., 2009; r2=0.94). This strong correlation between IVDMD and IVED indicates that the digestibility of inorganic compounds has little contribution to dry matter digestibility or is very similar with the digestibility of organic compounds.

    Because in vivo and in vitro data showed high positive correlations(r=0.83 and r=0.82), prediction equations for in vivo energy digestibility of hatchery waste products were developed based on in vitro assays (Fig. 2). Both IVDMD and IVED fairly accurately predicted in vivo energy digestibility(r2=0.70 and 0.67, respectively).

    In agreement, reasonably accurate energy digestibility prediction equations are available for barley, cassava root, copra meal, palm kernel meal, and wheat using IVDMD or IVED as an independent variable(Regmi et al., 2008; 2009; Park et al., 2012). In general, in vivo energy digestibility is known to less than IVED (Regmi et al., 2008). This difference is likely from endogenous losses of energy. In vivo energy digestibility represents apparent values that do not reflect endogenous excretion of organic nutrients from the gastrointestinal tract. Thus, in vivo energy digestibility underestimates true value of energy digestibility. in vitro energy disappearance is very similar to true digestibility in that there is no endogenous excretion of nutrients(Boisen & Fernández, 1997). The small particle size of feed sample for in vitro analysis is also a potential reason for the greater IVED compared with in vivo energy digestibility. Feed samples are finely ground to pass through 1mm-sieve before in vitro assays that may allow greater digestion. Unexpectedly, however, in vivo energy digestibility of test ingredients except infertile eggs was numerically greater than the IVED in the present study.

    The equations predicting in vivo energy digestibility suggested by Boisen & Fernández(1997) were based on mostly plant-derived feedstuffs. Interestingly, Boisen & Fernández(1997) excluded meat and bone meal from the data for developing prediction models suggesting that animal protein sources may have different characteristics for in vitro assays compared with plant-derived feed ingredients.

    Animal body weight also influences nutrient digestibility. Generally, younger pigs have a bit less digestion capacity compared with older pigs(Kim et al., 2007). In the present work, in vivo data employed for developing energy digestibility prediction equations were from an experiment using 9.4 to 19.9-kg nursery pigs. In contrast, Boisen & Fernández(1997) developed the in vitro technique based on in vivo data from 40 to 60 kg-pigs. Considering that body weight of the pigs used by Boisen & Fernández(1997) was more than 20 kg greater compared with Sung et al.(2018), the equation developed in the present work would be more applicable to nursery pigs.

    Taken together, energy utilization of unhatched eggs was the greatest among test ingredients including infertile eggs, unhatched eggs, culled chicks, and the mixture, and in vitro assays are useful in estimating energy digestibility of hatchery waste products based on the high correlation between in vivo and in vitro data.

    Acknowledgement

    The authors are grateful for the support by Rural Development Administration(Republic of Korea; PJ01 2528).

    Figure

    JALS-52-63_F1.gif

    The drying process of hatchery waste products.

    JALS-52-63_F2.gif

    Relationship between in vivo energy digestibility and (a) in vitro dry matter disappearance or (b) in vitro energy disappearance in hatchery waste products

    Table

    Energy and nutrient composition of hatchery waste products, as-is basis

    in vitro disappearance and in vivo energy digestibility of hatchery waste products fed to nursery pigs1

    Reference

    1. Association of Official Analytical Chemists(AOAC). 2005. Official Methods of Analysis, 18th edn.AOAC, Arlington, VA, USA.
    2. Association of American Feed Control Officials(AAF CO). 2016. 2016 Official publication. AAFCO, Atlanta, GA, USA. pp.376.
    3. BoisenS and FernándezJA . 1997. Prediction of the total tract digestibility of energy in feedstuffs and pig diets by in vitro analyses . Anim. Feed Sci. Technol.68: 277-286.
    4. ChoiHS , ParkGH , PitargueFM , JiSY and KilDY . 2018. True metabolizable energy values for various hatchery by-products fed to broiler chickens. Proceedings of 2018 Annual Congress of KSAST. June 28-29. Korean Society of Animal Science and Technology, Korea. pp.175.
    5. GlatzP , MiaoZ and RoddaB . 2011. Handling and treatment of poultry hatchery waste: A review . Sustainability.3: 216-237.
    6. GrazziotinA , PimentelFA , De JongEV and BrandelliA . 2006. Nutritional improvement of feather protein by treatment with microbial keratinase . Anim. Feed Sci. Technol.126: 135-144.
    7. JaworskiNW . 2012. Carbohydrate composition, in vitro digestion, and effects of xylanase and phytase on nutrient and energy digestibility by pigs in grains and grain coproducts. MS Thesis, University of Illinois at Urbana-Champaign.
    8. KimBG , LindemannMD , CromwellGL , BalfagonA and AgudeloJH . 2007. The correlation between passage rate of digesta and dry matter digestibility in various stages of swine . Livest. Sci.109: 81-84.
    9. LeeS , LeeJ and YoonY . 2018. Prevalence of bacteria in hatchery by-products. Proceedings of 2018 Annual Congress of KSAST. June, 28-29. Korean Society of Animal Science and Technology. Korea. pp.164.
    10. NobletJ and Jaguelin-PeyraudY . 2007. Prediction of digestibility of organic matter and energy in the growing pig from an in vitro method . Anim. Feed Sci. Technol.134: 211-222.
    11. ParkCS , SonAR and KimBG . 2012. Prediction of gross energy and digestible energy in copra meal, palm kernel meal, and cassava root fed to pigs . J. Anim. Sci.90: 221-223.
    12. ParkKR , ParkCS and KimBG . 2016. An enzyme complex increases in vitro dry matter digestibility of corn and wheat in pigs . Springerplus.5: 598-604.
    13. RegmiPR , SauerWC and ZijlstraRT . 2008. Prediction of in vivo apparent total tract energy digestibility of barley in grower pigs using an in vitro digestibility technique . J. Anim. Sci.86: 2619-2626.
    14. RegmiPR , FergusonNS and ZijlstraRT . 2009. In vitro digestibility techniques to predict apparent total tract energy digestibility of wheat in grower pigs . J. Anim. Sci.87: 3620-3629.
    15. SungJY , SonAR and KimBG . 2018. Energy concentrations and phosphorus digestibility in hatchery byproducts fed to nursery pigs. J. Anim. Sci. 96(E-Suppl. 4) :(Abstr. in press).
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